deploy: current vibn theia state

Made-with: Cursor

packages/navigator/.eslintrc.js

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+/** @type {import('eslint').Linter.Config} */
+module.exports = {
+    extends: [
+        '../../configs/build.eslintrc.json'
+    ],
+    parserOptions: {
+        tsconfigRootDir: __dirname,
+        project: 'tsconfig.json'
+    }
+};

packages/navigator/README.md

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+<div align='center'>
+
+<br />
+
+<img src='https://raw.githubusercontent.com/eclipse-theia/theia/master/logo/theia.svg?sanitize=true' alt='theia-ext-logo' width='100px' />
+
+<h2>ECLIPSE THEIA - NAVIGATOR EXTENSION</h2>
+
+<hr />
+
+</div>
+
+## Description
+
+The `@theia/navigator` extension contributes the `file explorer` widget.\
+The `file explorer` can be used to easily view, open, and manage the files that correspond to a given workspace.
+
+## Additional Information
+
+- [API documentation for `@theia/navigator`](https://eclipse-theia.github.io/theia/docs/next/modules/_theia_navigator.html)
+- [Theia - GitHub](https://github.com/eclipse-theia/theia)
+- [Theia - Website](https://theia-ide.org/)
+
+## License
+
+- [Eclipse Public License 2.0](http://www.eclipse.org/legal/epl-2.0/)
+- [一 (Secondary) GNU General Public License, version 2 with the GNU Classpath Exception](https://projects.eclipse.org/license/secondary-gpl-2.0-cp)
+
+## Trademark
+
+"Theia" is a trademark of the Eclipse Foundation
+<https://www.eclipse.org/theia>

packages/navigator/package.json

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+{
+  "name": "@theia/navigator",
+  "version": "1.68.0",
+  "description": "Theia - Navigator Extension",
+  "dependencies": {
+    "@theia/core": "1.68.0",
+    "@theia/filesystem": "1.68.0",
+    "@theia/workspace": "1.68.0",
+    "minimatch": "^10.0.3",
+    "tslib": "^2.6.2"
+  },
+  "publishConfig": {
+    "access": "public"
+  },
+  "theiaExtensions": [
+    {
+      "frontend": "lib/browser/navigator-frontend-module",
+      "backend": "lib/node/navigator-backend-module"
+    },
+    {
+      "frontendElectron": "lib/electron-browser/electron-navigator-module"
+    }
+  ],
+  "keywords": [
+    "theia-extension"
+  ],
+  "license": "EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/eclipse-theia/theia.git"
+  },
+  "bugs": {
+    "url": "https://github.com/eclipse-theia/theia/issues"
+  },
+  "homepage": "https://github.com/eclipse-theia/theia",
+  "files": [
+    "lib",
+    "src"
+  ],
+  "scripts": {
+    "build": "theiaext build",
+    "clean": "theiaext clean",
+    "compile": "theiaext compile",
+    "lint": "theiaext lint",
+    "test": "theiaext test",
+    "watch": "theiaext watch"
+  },
+  "devDependencies": {
+    "@theia/ext-scripts": "1.68.0"
+  },
+  "nyc": {
+    "extends": "../../configs/nyc.json"
+  },
+  "gitHead": "21358137e41342742707f660b8e222f940a27652"
+}

packages/navigator/src/browser/abstract-navigator-tree-widget.ts

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+// *****************************************************************************
+// Copyright (C) 2022 Ericsson and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+// *****************************************************************************
+
+import { injectable, inject, postConstruct } from '@theia/core/shared/inversify';
+import { FileNavigatorPreferences } from '../common/navigator-preferences';
+import { FileTreeWidget } from '@theia/filesystem/lib/browser';
+import { Attributes, HTMLAttributes } from '@theia/core/shared/react';
+import { TreeNode } from '@theia/core/lib/browser';
+
+@injectable()
+export class AbstractNavigatorTreeWidget extends FileTreeWidget {
+
+    @inject(FileNavigatorPreferences)
+    protected readonly navigatorPreferences: FileNavigatorPreferences;
+
+    @postConstruct()
+    protected override init(): void {
+        super.init();
+        this.toDispose.push(
+            this.preferenceService.onPreferenceChanged(preference => {
+                if (preference.preferenceName === 'explorer.decorations.colors') {
+                    this.update();
+                }
+            })
+        );
+    }
+
+    protected override decorateCaption(node: TreeNode, attrs: HTMLAttributes<HTMLElement>): Attributes & HTMLAttributes<HTMLElement> {
+        const attributes = super.decorateCaption(node, attrs);
+        if (this.navigatorPreferences.get('explorer.decorations.colors')) {
+            return attributes;
+        } else {
+            return {
+                ...attributes,
+                style: {
+                    ...attributes.style,
+                    color: undefined,
+                }
+            };
+        }
+    }
+}

packages/navigator/src/browser/file-navigator-commands.ts

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+// *****************************************************************************
+// Copyright (C) 2022 Ericsson and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+// *****************************************************************************
+
+import { codicon, CommonCommands } from '@theia/core/lib/browser';
+import { Command } from '@theia/core/lib/common';
+import { WorkspaceCommands } from '@theia/workspace/lib/browser';
+
+export namespace FileNavigatorCommands {
+    export const REVEAL_IN_NAVIGATOR = Command.toLocalizedCommand({
+        id: 'navigator.reveal',
+        label: 'Reveal in Explorer'
+    }, 'theia/navigator/reveal');
+    export const TOGGLE_HIDDEN_FILES = Command.toLocalizedCommand({
+        id: 'navigator.toggle.hidden.files',
+        label: 'Toggle Hidden Files'
+    }, 'theia/navigator/toggleHiddenFiles');
+    export const TOGGLE_AUTO_REVEAL = Command.toLocalizedCommand({
+        id: 'navigator.toggle.autoReveal',
+        category: CommonCommands.FILE_CATEGORY,
+        label: 'Auto Reveal'
+    }, 'theia/navigator/autoReveal', CommonCommands.FILE_CATEGORY_KEY);
+    export const REFRESH_NAVIGATOR = Command.toLocalizedCommand({
+        id: 'navigator.refresh',
+        category: CommonCommands.FILE_CATEGORY,
+        label: 'Refresh in Explorer',
+        iconClass: codicon('refresh')
+    }, 'theia/navigator/refresh', CommonCommands.FILE_CATEGORY_KEY);
+    export const COLLAPSE_ALL = Command.toDefaultLocalizedCommand({
+        id: 'navigator.collapse.all',
+        category: CommonCommands.FILE_CATEGORY,
+        label: 'Collapse Folders in Explorer',
+        iconClass: codicon('collapse-all')
+    });
+    export const ADD_ROOT_FOLDER: Command = {
+        id: 'navigator.addRootFolder'
+    };
+    export const FOCUS = Command.toDefaultLocalizedCommand({
+        id: 'workbench.files.action.focusFilesExplorer',
+        category: CommonCommands.FILE_CATEGORY,
+        label: 'Focus on Files Explorer'
+    });
+    export const OPEN: Command = {
+        id: 'navigator.open',
+    };
+    export const OPEN_WITH: Command = {
+        id: 'navigator.openWith',
+    };
+    export const NEW_FILE_TOOLBAR: Command = {
+        id: `${WorkspaceCommands.NEW_FILE.id}.toolbar`,
+        iconClass: codicon('new-file')
+    };
+    export const NEW_FOLDER_TOOLBAR: Command = {
+        id: `${WorkspaceCommands.NEW_FOLDER.id}.toolbar`,
+        iconClass: codicon('new-folder')
+    };
+
+    /**
+     * @deprecated since 1.21.0. Use WorkspaceCommands.COPY_RELATIVE_FILE_COMMAND instead.
+     */
+    export const COPY_RELATIVE_FILE_PATH = WorkspaceCommands.COPY_RELATIVE_FILE_PATH;
+}

packages/navigator/src/browser/index.ts

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+// *****************************************************************************
+// Copyright (C) 2018 TypeFox and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+// *****************************************************************************
+
+export * from './navigator-model';
+export * from './navigator-widget';
+export * from './navigator-widget-factory';
+export * from './navigator-decorator-service';

packages/navigator/src/browser/navigator-container.ts

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+// *****************************************************************************
+// Copyright (C) 2017 TypeFox and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+// *****************************************************************************
+
+import { Container, interfaces } from '@theia/core/shared/inversify';
+import { TreeProps, defaultTreeProps } from '@theia/core/lib/browser';
+import { createFileTreeContainer } from '@theia/filesystem/lib/browser';
+import { FileNavigatorTree } from './navigator-tree';
+import { FileNavigatorModel } from './navigator-model';
+import { FileNavigatorWidget } from './navigator-widget';
+import { NAVIGATOR_CONTEXT_MENU } from './navigator-contribution';
+import { NavigatorDecoratorService } from './navigator-decorator-service';
+
+export const FILE_NAVIGATOR_PROPS = <TreeProps>{
+    ...defaultTreeProps,
+    contextMenuPath: NAVIGATOR_CONTEXT_MENU,
+    multiSelect: true,
+    search: true,
+    globalSelection: true
+};
+
+export function createFileNavigatorContainer(parent: interfaces.Container): Container {
+    const child = createFileTreeContainer(parent, {
+        tree: FileNavigatorTree,
+        model: FileNavigatorModel,
+        widget: FileNavigatorWidget,
+        decoratorService: NavigatorDecoratorService,
+        props: FILE_NAVIGATOR_PROPS,
+    });
+
+    return child;
+}
+
+export function createFileNavigatorWidget(parent: interfaces.Container): FileNavigatorWidget {
+    return createFileNavigatorContainer(parent).get(FileNavigatorWidget);
+}

packages/navigator/src/browser/navigator-context-key-service.ts

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+// *****************************************************************************
+// Copyright (C) 2019 TypeFox and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+// *****************************************************************************
+
+import { injectable, inject, postConstruct } from '@theia/core/shared/inversify';
+import { ContextKeyService, ContextKey } from '@theia/core/lib/browser/context-key-service';
+
+@injectable()
+export class NavigatorContextKeyService {
+
+    @inject(ContextKeyService)
+    protected readonly contextKeyService: ContextKeyService;
+
+    protected _explorerViewletVisible: ContextKey<boolean>;
+    get explorerViewletVisible(): ContextKey<boolean> {
+        return this._explorerViewletVisible;
+    }
+
+    protected _explorerViewletFocus: ContextKey<boolean>;
+    /** True if Explorer view has keyboard focus. */
+    get explorerViewletFocus(): ContextKey<boolean> {
+        return this._explorerViewletFocus;
+    }
+
+    protected _filesExplorerFocus: ContextKey<boolean>;
+    /** True if File Explorer section has keyboard focus. */
+    get filesExplorerFocus(): ContextKey<boolean> {
+        return this._filesExplorerFocus;
+    }
+
+    protected _explorerResourceIsFolder: ContextKey<boolean>;
+    get explorerResourceIsFolder(): ContextKey<boolean> {
+        return this._explorerResourceIsFolder;
+    }
+
+    protected _isFileSystemResource: ContextKey<boolean>;
+
+    /**
+     * True when the Explorer or editor file is a file system resource that can be handled from a file system provider.
+     */
+    get isFileSystemResource(): ContextKey<boolean> {
+        return this._isFileSystemResource;
+    }
+
+    @postConstruct()
+    protected init(): void {
+        this._explorerViewletVisible = this.contextKeyService.createKey<boolean>('explorerViewletVisible', false);
+        this._explorerViewletFocus = this.contextKeyService.createKey<boolean>('explorerViewletFocus', false);
+        this._filesExplorerFocus = this.contextKeyService.createKey<boolean>('filesExplorerFocus', false);
+        this._explorerResourceIsFolder = this.contextKeyService.createKey<boolean>('explorerResourceIsFolder', false);
+        this._isFileSystemResource = this.contextKeyService.createKey<boolean>('isFileSystemResource', false);
+    }
+
+}

packages/navigator/src/browser/navigator-contribution.ts

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+// *****************************************************************************
+// Copyright (C) 2017-2018 TypeFox and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+// *****************************************************************************
+
+import { inject, injectable, optional, postConstruct } from '@theia/core/shared/inversify';
+import { AbstractViewContribution } from '@theia/core/lib/browser/shell/view-contribution';
+import {
+    CommonCommands,
+    CompositeTreeNode,
+    FrontendApplication,
+    FrontendApplicationContribution,
+    KeybindingRegistry,
+    OpenerService,
+    SelectableTreeNode,
+    Widget,
+    NavigatableWidget,
+    ApplicationShell,
+    TabBar,
+    Title,
+    SHELL_TABBAR_CONTEXT_MENU,
+    OpenWithService
+} from '@theia/core/lib/browser';
+import { FileDownloadCommands } from '@theia/filesystem/lib/browser/download/file-download-command-contribution';
+import {
+    CommandRegistry,
+    isOSX,
+    MenuModelRegistry,
+    MenuPath,
+    Mutable,
+    PreferenceScope,
+    PreferenceService,
+    QuickInputService,
+} from '@theia/core/lib/common';
+import {
+    DidCreateNewResourceEvent,
+    WorkspaceCommandContribution,
+    WorkspaceCommands,
+    WorkspaceService
+} from '@theia/workspace/lib/browser';
+import { EXPLORER_VIEW_CONTAINER_ID, EXPLORER_VIEW_CONTAINER_TITLE_OPTIONS } from './navigator-widget-factory';
+import { FILE_NAVIGATOR_ID, FileNavigatorWidget } from './navigator-widget';
+import { FileNavigatorPreferences } from '../common/navigator-preferences';
+import { FileNavigatorFilter } from './navigator-filter';
+import { WorkspaceNode } from './navigator-tree';
+import { NavigatorContextKeyService } from './navigator-context-key-service';
+import {
+    RenderedToolbarAction,
+    TabBarToolbarContribution,
+    TabBarToolbarRegistry
+} from '@theia/core/lib/browser/shell/tab-bar-toolbar';
+import { FileSystemCommands } from '@theia/filesystem/lib/browser/filesystem-frontend-contribution';
+import { NavigatorDiff, NavigatorDiffCommands } from './navigator-diff';
+import { DirNode, FileNode } from '@theia/filesystem/lib/browser';
+import { FileNavigatorModel } from './navigator-model';
+import { ClipboardService } from '@theia/core/lib/browser/clipboard-service';
+import { SelectionService } from '@theia/core/lib/common/selection-service';
+import { OpenEditorsWidget } from './open-editors-widget/navigator-open-editors-widget';
+import { OpenEditorsContextMenu } from './open-editors-widget/navigator-open-editors-menus';
+import { OpenEditorsCommands } from './open-editors-widget/navigator-open-editors-commands';
+import { nls } from '@theia/core/lib/common/nls';
+import URI from '@theia/core/lib/common/uri';
+import { UriAwareCommandHandler } from '@theia/core/lib/common/uri-command-handler';
+import { FileNavigatorCommands } from './file-navigator-commands';
+import { WorkspacePreferences } from '@theia/workspace/lib/common';
+export { FileNavigatorCommands };
+
+/**
+ * Navigator `More Actions...` toolbar item groups.
+ * Used in order to group items present in the toolbar.
+ */
+export namespace NavigatorMoreToolbarGroups {
+    export const NEW_OPEN = '1_navigator_new_open';
+    export const TOOLS = '2_navigator_tools';
+    export const WORKSPACE = '3_navigator_workspace';
+}
+
+export const NAVIGATOR_CONTEXT_MENU: MenuPath = ['navigator-context-menu'];
+export const SHELL_TABBAR_CONTEXT_REVEAL: MenuPath = [...SHELL_TABBAR_CONTEXT_MENU, '2_reveal'];
+
+/**
+ * Navigator context menu default groups should be aligned
+ * with VS Code default groups: https://code.visualstudio.com/api/references/contribution-points#contributes.menus
+ */
+export namespace NavigatorContextMenu {
+    export const NAVIGATION = [...NAVIGATOR_CONTEXT_MENU, 'navigation'];
+    /** @deprecated use NAVIGATION */
+    export const OPEN = NAVIGATION;
+    /** @deprecated use NAVIGATION */
+    export const NEW = NAVIGATION;
+
+    export const WORKSPACE = [...NAVIGATOR_CONTEXT_MENU, '2_workspace'];
+
+    export const COMPARE = [...NAVIGATOR_CONTEXT_MENU, '3_compare'];
+    /** @deprecated use COMPARE */
+    export const DIFF = COMPARE;
+
+    export const SEARCH = [...NAVIGATOR_CONTEXT_MENU, '4_search'];
+    export const CLIPBOARD = [...NAVIGATOR_CONTEXT_MENU, '5_cutcopypaste'];
+
+    export const MODIFICATION = [...NAVIGATOR_CONTEXT_MENU, '7_modification'];
+    /** @deprecated use MODIFICATION */
+    export const MOVE = MODIFICATION;
+    /** @deprecated use MODIFICATION */
+    export const ACTIONS = MODIFICATION;
+
+    /** @deprecated use the `FileNavigatorCommands.OPEN_WITH` command */
+    export const OPEN_WITH = [...NAVIGATION, 'open_with'];
+}
+
+export const FILE_NAVIGATOR_TOGGLE_COMMAND_ID = 'fileNavigator:toggle';
+
+@injectable()
+export class FileNavigatorContribution extends AbstractViewContribution<FileNavigatorWidget> implements FrontendApplicationContribution, TabBarToolbarContribution {
+
+    @inject(ClipboardService)
+    protected readonly clipboardService: ClipboardService;
+
+    @inject(CommandRegistry)
+    protected readonly commandRegistry: CommandRegistry;
+
+    @inject(TabBarToolbarRegistry)
+    protected readonly tabbarToolbarRegistry: TabBarToolbarRegistry;
+
+    @inject(NavigatorContextKeyService)
+    protected readonly contextKeyService: NavigatorContextKeyService;
+
+    @inject(MenuModelRegistry)
+    protected readonly menuRegistry: MenuModelRegistry;
+
+    @inject(NavigatorDiff)
+    protected readonly navigatorDiff: NavigatorDiff;
+
+    @inject(PreferenceService)
+    protected readonly preferenceService: PreferenceService;
+
+    @inject(SelectionService)
+    protected readonly selectionService: SelectionService;
+
+    @inject(WorkspaceCommandContribution)
+    protected readonly workspaceCommandContribution: WorkspaceCommandContribution;
+
+    @inject(OpenWithService)
+    protected readonly openWithService: OpenWithService;
+
+    @inject(QuickInputService) @optional()
+    protected readonly quickInputService: QuickInputService;
+
+    constructor(
+        @inject(FileNavigatorPreferences) protected readonly fileNavigatorPreferences: FileNavigatorPreferences,
+        @inject(OpenerService) protected readonly openerService: OpenerService,
+        @inject(FileNavigatorFilter) protected readonly fileNavigatorFilter: FileNavigatorFilter,
+        @inject(WorkspaceService) protected readonly workspaceService: WorkspaceService,
+        @inject(WorkspacePreferences) protected readonly workspacePreferences: WorkspacePreferences
+    ) {
+        super({
+            viewContainerId: EXPLORER_VIEW_CONTAINER_ID,
+            widgetId: FILE_NAVIGATOR_ID,
+            widgetName: EXPLORER_VIEW_CONTAINER_TITLE_OPTIONS.label,
+            defaultWidgetOptions: {
+                area: 'left',
+                rank: 100
+            },
+            toggleCommandId: FILE_NAVIGATOR_TOGGLE_COMMAND_ID,
+            toggleKeybinding: 'ctrlcmd+shift+e'
+        });
+    }
+
+    @postConstruct()
+    protected init(): void {
+        this.doInit();
+    }
+
+    protected async doInit(): Promise<void> {
+        await this.fileNavigatorPreferences.ready;
+        this.shell.onDidChangeCurrentWidget(() => this.onCurrentWidgetChangedHandler());
+
+        const updateFocusContextKeys = () => {
+            const hasFocus = this.shell.activeWidget instanceof FileNavigatorWidget;
+            this.contextKeyService.explorerViewletFocus.set(hasFocus);
+            this.contextKeyService.filesExplorerFocus.set(hasFocus);
+        };
+        updateFocusContextKeys();
+        this.shell.onDidChangeActiveWidget(updateFocusContextKeys);
+        this.workspaceCommandContribution.onDidCreateNewFile(async event => this.onDidCreateNewResource(event));
+        this.workspaceCommandContribution.onDidCreateNewFolder(async event => this.onDidCreateNewResource(event));
+    }
+
+    private async onDidCreateNewResource(event: DidCreateNewResourceEvent): Promise<void> {
+        const navigator = this.tryGetWidget();
+        if (!navigator || !navigator.isVisible) {
+            return;
+        }
+        const model: FileNavigatorModel = navigator.model;
+        const parent = await model.revealFile(event.parent);
+        if (DirNode.is(parent)) {
+            await model.refresh(parent);
+        }
+        const node = await model.revealFile(event.uri);
+        if (SelectableTreeNode.is(node)) {
+            model.selectNode(node);
+            if (DirNode.is(node)) {
+                this.openView({ activate: true });
+            }
+        }
+    }
+
+    async initializeLayout(app: FrontendApplication): Promise<void> {
+        await this.openView();
+    }
+
+    override registerCommands(registry: CommandRegistry): void {
+        super.registerCommands(registry);
+        registry.registerCommand(FileNavigatorCommands.FOCUS, {
+            execute: () => this.openView({ activate: true })
+        });
+        registry.registerCommand(FileNavigatorCommands.REVEAL_IN_NAVIGATOR, UriAwareCommandHandler.MonoSelect(this.selectionService, {
+            execute: async uri => {
+                if (await this.selectFileNode(uri)) {
+                    this.openView({ activate: false, reveal: true });
+                }
+            },
+            isEnabled: uri => !!this.workspaceService.getWorkspaceRootUri(uri),
+            isVisible: uri => !!this.workspaceService.getWorkspaceRootUri(uri),
+        }));
+        registry.registerCommand(FileNavigatorCommands.TOGGLE_HIDDEN_FILES, {
+            execute: () => {
+                this.fileNavigatorFilter.toggleHiddenFiles();
+            },
+            isEnabled: () => true,
+            isVisible: () => true
+        });
+        registry.registerCommand(FileNavigatorCommands.TOGGLE_AUTO_REVEAL, {
+            isEnabled: widget => this.withWidget(widget, () => this.workspaceService.opened),
+            isVisible: widget => this.withWidget(widget, () => this.workspaceService.opened),
+            execute: () => {
+                const autoReveal = !this.fileNavigatorPreferences['explorer.autoReveal'];
+                this.preferenceService.set('explorer.autoReveal', autoReveal, PreferenceScope.User);
+                if (autoReveal) {
+                    this.selectWidgetFileNode(this.shell.currentWidget);
+                }
+            },
+            isToggled: () => this.fileNavigatorPreferences['explorer.autoReveal']
+        });
+        registry.registerCommand(FileNavigatorCommands.COLLAPSE_ALL, {
+            execute: widget => this.withWidget(widget, () => this.collapseFileNavigatorTree()),
+            isEnabled: widget => this.withWidget(widget, () => this.workspaceService.opened),
+            isVisible: widget => this.withWidget(widget, () => this.workspaceService.opened)
+        });
+        registry.registerCommand(FileNavigatorCommands.REFRESH_NAVIGATOR, {
+            execute: widget => this.withWidget(widget, () => this.refreshWorkspace()),
+            isEnabled: widget => this.withWidget(widget, () => this.workspaceService.opened),
+            isVisible: widget => this.withWidget(widget, () => this.workspaceService.opened)
+        });
+        registry.registerCommand(FileNavigatorCommands.ADD_ROOT_FOLDER, {
+            execute: (...args) => registry.executeCommand(WorkspaceCommands.ADD_FOLDER.id, ...args),
+            isEnabled: (...args) => registry.isEnabled(WorkspaceCommands.ADD_FOLDER.id, ...args),
+            isVisible: (...args) => {
+                if (!registry.isVisible(WorkspaceCommands.ADD_FOLDER.id, ...args)) {
+                    return false;
+                }
+                const navigator = this.tryGetWidget();
+                const selection = navigator?.model.getFocusedNode();
+                // The node that is selected when the user clicks in empty space.
+                const root = navigator?.getContainerTreeNode();
+                return selection === root;
+            }
+        });
+
+        registry.registerCommand(NavigatorDiffCommands.COMPARE_FIRST, {
+            execute: () => {
+                this.navigatorDiff.addFirstComparisonFile();
+            },
+            isEnabled: () => true,
+            isVisible: () => true
+        });
+        registry.registerCommand(NavigatorDiffCommands.COMPARE_SECOND, {
+            execute: () => {
+                this.navigatorDiff.compareFiles();
+            },
+            isEnabled: () => this.navigatorDiff.isFirstFileSelected,
+            isVisible: () => this.navigatorDiff.isFirstFileSelected
+        });
+        registry.registerCommand(FileNavigatorCommands.OPEN, {
+            isEnabled: () => this.getSelectedFileNodes().length > 0,
+            isVisible: () => this.getSelectedFileNodes().length > 0,
+            execute: () => {
+                this.getSelectedFileNodes().forEach(async node => {
+                    const opener = await this.openerService.getOpener(node.uri);
+                    opener.open(node.uri);
+                });
+            }
+        });
+        registry.registerCommand(FileNavigatorCommands.OPEN_WITH, UriAwareCommandHandler.MonoSelect(this.selectionService, {
+            isEnabled: uri => this.openWithService.getHandlers(uri).length > 0,
+            isVisible: uri => this.openWithService.getHandlers(uri).length > 0,
+            execute: uri => this.openWithService.openWith(uri)
+        }));
+        registry.registerCommand(OpenEditorsCommands.CLOSE_ALL_TABS_FROM_TOOLBAR, {
+            execute: widget => this.withOpenEditorsWidget(widget, () => this.shell.closeMany(this.editorWidgets)),
+            isEnabled: widget => this.withOpenEditorsWidget(widget, () => true),
+            isVisible: widget => this.withOpenEditorsWidget(widget, () => true)
+        });
+        registry.registerCommand(OpenEditorsCommands.SAVE_ALL_TABS_FROM_TOOLBAR, {
+            execute: widget => this.withOpenEditorsWidget(widget, () => registry.executeCommand(CommonCommands.SAVE_ALL.id)),
+            isEnabled: widget => this.withOpenEditorsWidget(widget, () => true),
+            isVisible: widget => this.withOpenEditorsWidget(widget, () => true)
+        });
+
+        const filterEditorWidgets = (title: Title<Widget>) => {
+            const { owner } = title;
+            return NavigatableWidget.is(owner);
+        };
+        registry.registerCommand(OpenEditorsCommands.CLOSE_ALL_EDITORS_IN_GROUP_FROM_ICON, {
+            execute: (tabBarOrArea: ApplicationShell.Area | TabBar<Widget>): void => {
+                this.shell.closeTabs(tabBarOrArea, filterEditorWidgets);
+            },
+            isVisible: () => false
+        });
+        registry.registerCommand(OpenEditorsCommands.SAVE_ALL_IN_GROUP_FROM_ICON, {
+            execute: (tabBarOrArea: ApplicationShell.Area | TabBar<Widget>) => {
+                this.shell.saveTabs(tabBarOrArea, filterEditorWidgets);
+            },
+            isVisible: () => false
+        });
+
+        registry.registerCommand(FileNavigatorCommands.NEW_FILE_TOOLBAR, {
+            execute: (...args) => registry.executeCommand(WorkspaceCommands.NEW_FILE.id, ...args),
+            isEnabled: widget => this.withWidget(widget, () => this.workspaceService.opened),
+            isVisible: widget => this.withWidget(widget, () => this.workspaceService.opened)
+        });
+        registry.registerCommand(FileNavigatorCommands.NEW_FOLDER_TOOLBAR, {
+            execute: (...args) => registry.executeCommand(WorkspaceCommands.NEW_FOLDER.id, ...args),
+            isEnabled: widget => this.withWidget(widget, () => this.workspaceService.opened),
+            isVisible: widget => this.withWidget(widget, () => this.workspaceService.opened)
+        });
+    }
+
+    protected get editorWidgets(): NavigatableWidget[] {
+        const openEditorsWidget = this.widgetManager.tryGetWidget<OpenEditorsWidget>(OpenEditorsWidget.ID);
+        return openEditorsWidget?.editorWidgets ?? [];
+    }
+
+    protected getSelectedFileNodes(): FileNode[] {
+        return this.tryGetWidget()?.model.selectedNodes.filter(FileNode.is) || [];
+    }
+
+    protected withWidget<T>(widget: Widget | undefined = this.tryGetWidget(), cb: (navigator: FileNavigatorWidget) => T): T | false {
+        if (widget instanceof FileNavigatorWidget && widget.id === FILE_NAVIGATOR_ID) {
+            return cb(widget);
+        }
+        return false;
+    }
+
+    protected withOpenEditorsWidget<T>(widget: Widget, cb: (navigator: OpenEditorsWidget) => T): T | false {
+        if (widget instanceof OpenEditorsWidget && widget.id === OpenEditorsWidget.ID) {
+            return cb(widget);
+        }
+        return false;
+    }
+
+    override registerMenus(registry: MenuModelRegistry): void {
+        super.registerMenus(registry);
+        registry.registerMenuAction(SHELL_TABBAR_CONTEXT_REVEAL, {
+            commandId: FileNavigatorCommands.REVEAL_IN_NAVIGATOR.id,
+            label: FileNavigatorCommands.REVEAL_IN_NAVIGATOR.label,
+            order: '5'
+        });
+
+        registry.registerMenuAction(NavigatorContextMenu.NAVIGATION, {
+            commandId: FileNavigatorCommands.OPEN.id,
+            label: nls.localizeByDefault('Open')
+        });
+        registry.registerMenuAction(NavigatorContextMenu.NAVIGATION, {
+            commandId: FileNavigatorCommands.OPEN_WITH.id,
+            when: '!explorerResourceIsFolder',
+            label: nls.localizeByDefault('Open With...')
+        });
+
+        registry.registerMenuAction(NavigatorContextMenu.CLIPBOARD, {
+            commandId: CommonCommands.COPY.id,
+            order: 'a'
+        });
+        registry.registerMenuAction(NavigatorContextMenu.CLIPBOARD, {
+            commandId: CommonCommands.PASTE.id,
+            order: 'b'
+        });
+        registry.registerMenuAction(NavigatorContextMenu.CLIPBOARD, {
+            commandId: CommonCommands.COPY_PATH.id,
+            order: 'c'
+        });
+        registry.registerMenuAction(NavigatorContextMenu.CLIPBOARD, {
+            commandId: WorkspaceCommands.COPY_RELATIVE_FILE_PATH.id,
+            label: WorkspaceCommands.COPY_RELATIVE_FILE_PATH.label,
+            order: 'd'
+        });
+        registry.registerMenuAction(NavigatorContextMenu.CLIPBOARD, {
+            commandId: FileDownloadCommands.COPY_DOWNLOAD_LINK.id,
+            order: 'z'
+        });
+
+        registry.registerMenuAction(NavigatorContextMenu.MODIFICATION, {
+            commandId: WorkspaceCommands.FILE_RENAME.id
+        });
+        registry.registerMenuAction(NavigatorContextMenu.MODIFICATION, {
+            commandId: WorkspaceCommands.FILE_DELETE.id
+        });
+        registry.registerMenuAction(NavigatorContextMenu.MODIFICATION, {
+            commandId: WorkspaceCommands.FILE_DUPLICATE.id
+        });
+
+        const downloadUploadMenu = [...NAVIGATOR_CONTEXT_MENU, '6_downloadupload'];
+        registry.registerMenuAction(downloadUploadMenu, {
+            commandId: FileSystemCommands.UPLOAD.id,
+            order: 'a'
+        });
+        registry.registerMenuAction(downloadUploadMenu, {
+            commandId: FileDownloadCommands.DOWNLOAD.id,
+            order: 'b'
+        });
+
+        registry.registerMenuAction(NavigatorContextMenu.NAVIGATION, {
+            commandId: WorkspaceCommands.NEW_FILE.id,
+            when: 'explorerResourceIsFolder'
+        });
+        registry.registerMenuAction(NavigatorContextMenu.NAVIGATION, {
+            commandId: WorkspaceCommands.NEW_FOLDER.id,
+            when: 'explorerResourceIsFolder'
+        });
+        registry.registerMenuAction(NavigatorContextMenu.COMPARE, {
+            commandId: WorkspaceCommands.FILE_COMPARE.id
+        });
+        registry.registerMenuAction(NavigatorContextMenu.MODIFICATION, {
+            commandId: FileNavigatorCommands.COLLAPSE_ALL.id,
+            label: nls.localizeByDefault('Collapse All'),
+            order: 'z2'
+        });
+
+        registry.registerMenuAction(NavigatorContextMenu.COMPARE, {
+            commandId: NavigatorDiffCommands.COMPARE_FIRST.id,
+            order: 'za'
+        });
+        registry.registerMenuAction(NavigatorContextMenu.COMPARE, {
+            commandId: NavigatorDiffCommands.COMPARE_SECOND.id,
+            order: 'zb'
+        });
+
+        // Open Editors Widget Menu Items
+        registry.registerMenuAction(OpenEditorsContextMenu.CLIPBOARD, {
+            commandId: CommonCommands.COPY_PATH.id,
+            order: 'a'
+        });
+        registry.registerMenuAction(OpenEditorsContextMenu.CLIPBOARD, {
+            commandId: WorkspaceCommands.COPY_RELATIVE_FILE_PATH.id,
+            order: 'b'
+        });
+        registry.registerMenuAction(OpenEditorsContextMenu.SAVE, {
+            commandId: CommonCommands.SAVE.id,
+            order: 'a'
+        });
+
+        registry.registerMenuAction(OpenEditorsContextMenu.COMPARE, {
+            commandId: NavigatorDiffCommands.COMPARE_FIRST.id,
+            order: 'a'
+        });
+        registry.registerMenuAction(OpenEditorsContextMenu.COMPARE, {
+            commandId: NavigatorDiffCommands.COMPARE_SECOND.id,
+            order: 'b'
+        });
+
+        registry.registerMenuAction(OpenEditorsContextMenu.MODIFICATION, {
+            commandId: CommonCommands.CLOSE_TAB.id,
+            label: nls.localizeByDefault('Close'),
+            order: 'a'
+        });
+        registry.registerMenuAction(OpenEditorsContextMenu.MODIFICATION, {
+            commandId: CommonCommands.CLOSE_OTHER_TABS.id,
+            label: nls.localizeByDefault('Close Others'),
+            order: 'b'
+        });
+        registry.registerMenuAction(OpenEditorsContextMenu.MODIFICATION, {
+            commandId: CommonCommands.CLOSE_ALL_MAIN_TABS.id,
+            label: nls.localizeByDefault('Close All'),
+            order: 'c'
+        });
+
+        registry.registerMenuAction(NavigatorContextMenu.WORKSPACE, {
+            commandId: FileNavigatorCommands.ADD_ROOT_FOLDER.id,
+            label: WorkspaceCommands.ADD_FOLDER.label
+        });
+        registry.registerMenuAction(NavigatorContextMenu.WORKSPACE, {
+            commandId: WorkspaceCommands.REMOVE_FOLDER.id
+        });
+    }
+
+    override registerKeybindings(registry: KeybindingRegistry): void {
+        super.registerKeybindings(registry);
+        registry.registerKeybinding({
+            command: FileNavigatorCommands.REVEAL_IN_NAVIGATOR.id,
+            keybinding: 'alt+r'
+        });
+
+        registry.registerKeybinding({
+            command: WorkspaceCommands.FILE_DELETE.id,
+            keybinding: isOSX ? 'cmd+backspace' : 'del',
+            when: 'filesExplorerFocus'
+        });
+
+        registry.registerKeybinding({
+            command: WorkspaceCommands.FILE_RENAME.id,
+            keybinding: 'f2',
+            when: 'filesExplorerFocus'
+        });
+
+        registry.registerKeybinding({
+            command: FileNavigatorCommands.TOGGLE_HIDDEN_FILES.id,
+            keybinding: 'ctrlcmd+i',
+            when: 'filesExplorerFocus'
+        });
+    }
+
+    async registerToolbarItems(toolbarRegistry: TabBarToolbarRegistry): Promise<void> {
+        toolbarRegistry.registerItem({
+            id: FileNavigatorCommands.NEW_FILE_TOOLBAR.id,
+            command: FileNavigatorCommands.NEW_FILE_TOOLBAR.id,
+            tooltip: nls.localizeByDefault('New File...'),
+            priority: 0,
+        });
+        toolbarRegistry.registerItem({
+            id: FileNavigatorCommands.NEW_FOLDER_TOOLBAR.id,
+            command: FileNavigatorCommands.NEW_FOLDER_TOOLBAR.id,
+            tooltip: nls.localizeByDefault('New Folder...'),
+            priority: 1,
+        });
+        toolbarRegistry.registerItem({
+            id: FileNavigatorCommands.REFRESH_NAVIGATOR.id,
+            command: FileNavigatorCommands.REFRESH_NAVIGATOR.id,
+            tooltip: nls.localizeByDefault('Refresh Explorer'),
+            priority: 2,
+        });
+        toolbarRegistry.registerItem({
+            id: FileNavigatorCommands.COLLAPSE_ALL.id,
+            command: FileNavigatorCommands.COLLAPSE_ALL.id,
+            tooltip: nls.localizeByDefault('Collapse All'),
+            priority: 3,
+        });
+
+        // More (...) toolbar items.
+        this.registerMoreToolbarItem({
+            id: FileNavigatorCommands.TOGGLE_AUTO_REVEAL.id,
+            command: FileNavigatorCommands.TOGGLE_AUTO_REVEAL.id,
+            tooltip: FileNavigatorCommands.TOGGLE_AUTO_REVEAL.label,
+            group: NavigatorMoreToolbarGroups.TOOLS,
+        });
+        this.registerMoreToolbarItem({
+            id: WorkspaceCommands.ADD_FOLDER.id,
+            command: WorkspaceCommands.ADD_FOLDER.id,
+            tooltip: WorkspaceCommands.ADD_FOLDER.label,
+            group: NavigatorMoreToolbarGroups.WORKSPACE,
+        });
+
+        // Open Editors toolbar items.
+        toolbarRegistry.registerItem({
+            id: OpenEditorsCommands.SAVE_ALL_TABS_FROM_TOOLBAR.id,
+            command: OpenEditorsCommands.SAVE_ALL_TABS_FROM_TOOLBAR.id,
+            tooltip: OpenEditorsCommands.SAVE_ALL_TABS_FROM_TOOLBAR.label,
+            priority: 0,
+        });
+        toolbarRegistry.registerItem({
+            id: OpenEditorsCommands.CLOSE_ALL_TABS_FROM_TOOLBAR.id,
+            command: OpenEditorsCommands.CLOSE_ALL_TABS_FROM_TOOLBAR.id,
+            tooltip: OpenEditorsCommands.CLOSE_ALL_TABS_FROM_TOOLBAR.label,
+            priority: 1,
+        });
+    }
+
+    /**
+     * Register commands to the `More Actions...` navigator toolbar item.
+     */
+    public registerMoreToolbarItem = (item: Mutable<RenderedToolbarAction> & { command: string }) => {
+        const commandId = item.command;
+        const id = 'navigator.tabbar.toolbar.' + commandId;
+        const command = this.commandRegistry.getCommand(commandId);
+        this.commandRegistry.registerCommand({ id, iconClass: command && command.iconClass }, {
+            execute: (w, ...args) => w instanceof FileNavigatorWidget
+                && this.commandRegistry.executeCommand(commandId, ...args),
+            isEnabled: (w, ...args) => w instanceof FileNavigatorWidget
+                && this.commandRegistry.isEnabled(commandId, ...args),
+            isVisible: (w, ...args) => w instanceof FileNavigatorWidget
+                && this.commandRegistry.isVisible(commandId, ...args),
+            isToggled: (w, ...args) => w instanceof FileNavigatorWidget
+                && this.commandRegistry.isToggled(commandId, ...args),
+        });
+        item.command = id;
+        this.tabbarToolbarRegistry.registerItem(item);
+    };
+
+    /**
+     * Reveals and selects node in the file navigator to which given widget is related.
+     * Does nothing if given widget undefined or doesn't have related resource.
+     *
+     * @param widget widget file resource of which should be revealed and selected
+     */
+    async selectWidgetFileNode(widget: Widget | undefined): Promise<boolean> {
+        return this.selectFileNode(NavigatableWidget.getUri(widget));
+    }
+
+    async selectFileNode(uri?: URI): Promise<boolean> {
+        if (uri) {
+            const { model } = await this.widget;
+            const node = await model.revealFile(uri);
+            if (SelectableTreeNode.is(node)) {
+                model.selectNode(node);
+                return true;
+            }
+        }
+        return false;
+    }
+
+    protected onCurrentWidgetChangedHandler(): void {
+        if (this.fileNavigatorPreferences['explorer.autoReveal']) {
+            this.selectWidgetFileNode(this.shell.currentWidget);
+        }
+    }
+
+    /**
+     * Collapse file navigator nodes and set focus on first visible node
+     * - single root workspace: collapse all nodes except root
+     * - multiple root workspace: collapse all nodes, even roots
+     */
+    async collapseFileNavigatorTree(): Promise<void> {
+        const { model } = await this.widget;
+
+        // collapse all child nodes which are not the root (single root workspace)
+        // collapse all root nodes (multiple root workspace)
+        let root = model.root as CompositeTreeNode;
+        if (WorkspaceNode.is(root) && root.children.length === 1) {
+            root = root.children[0];
+        }
+        root.children.forEach(child => CompositeTreeNode.is(child) && model.collapseAll(child));
+
+        // select first visible node
+        const firstChild = WorkspaceNode.is(root) ? root.children[0] : root;
+        if (SelectableTreeNode.is(firstChild)) {
+            model.selectNode(firstChild);
+        }
+    }
+
+    /**
+     * force refresh workspace in navigator
+     */
+    async refreshWorkspace(): Promise<void> {
+        const { model } = await this.widget;
+        await model.refresh();
+    }
+
+}

packages/navigator/src/browser/navigator-decorator-service.ts

@@ -0,0 +1,36 @@
+// *****************************************************************************
+// Copyright (C) 2018 TypeFox and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+// *****************************************************************************
+
+import { inject, injectable, named } from '@theia/core/shared/inversify';
+import { ContributionProvider } from '@theia/core/lib/common/contribution-provider';
+import { TreeDecorator, AbstractTreeDecoratorService } from '@theia/core/lib/browser/tree/tree-decorator';
+
+/**
+ * Symbol for all decorators that would like to contribute into the navigator.
+ */
+export const NavigatorTreeDecorator = Symbol('NavigatorTreeDecorator');
+
+/**
+ * Decorator service for the navigator.
+ */
+@injectable()
+export class NavigatorDecoratorService extends AbstractTreeDecoratorService {
+
+    constructor(@inject(ContributionProvider) @named(NavigatorTreeDecorator) protected readonly contributions: ContributionProvider<TreeDecorator>) {
+        super(contributions.getContributions());
+    }
+
+}

packages/navigator/src/browser/navigator-diff.spec.ts

@@ -0,0 +1,113 @@
+// *****************************************************************************
+// Copyright (C) 2019 David Saunders and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+// *****************************************************************************
+
+import { enableJSDOM } from '@theia/core/lib/browser/test/jsdom';
+const disableJSDOM = enableJSDOM();
+
+import { FrontendApplicationConfigProvider } from '@theia/core/lib/browser/frontend-application-config-provider';
+FrontendApplicationConfigProvider.set({});
+
+import { expect } from 'chai';
+import { NavigatorDiff } from './navigator-diff';
+import * as path from 'path';
+import { Container, ContainerModule } from '@theia/core/shared/inversify';
+import { SelectionService, ILogger } from '@theia/core/lib/common';
+import { MockLogger } from '@theia/core/lib/common/test/mock-logger';
+import URI from '@theia/core/lib/common/uri';
+import { OpenerService } from '@theia/core/lib/browser';
+import { MockOpenerService } from '@theia/core/lib/browser/test/mock-opener-service';
+import { MessageService } from '@theia/core/lib/common/message-service';
+import { MessageClient } from '@theia/core/lib/common/message-service-protocol';
+import { FileUri } from '@theia/core/lib/common/file-uri';
+import { FileService } from '@theia/filesystem/lib/browser/file-service';
+import { DiskFileSystemProvider } from '@theia/filesystem/lib/node/disk-file-system-provider';
+
+disableJSDOM();
+
+let testContainer: Container;
+beforeEach(() => {
+    testContainer = new Container();
+
+    const module = new ContainerModule((bind, unbind, isBound, rebind) => {
+        bind(ILogger).to(MockLogger).inSingletonScope();
+        bind(SelectionService).toSelf().inSingletonScope();
+        bind(NavigatorDiff).toSelf().inSingletonScope();
+        bind(OpenerService).to(MockOpenerService);
+        const fileService = new FileService();
+        fileService['resourceForError'] = (resource: URI) => resource.toString();
+        fileService.registerProvider('file', new DiskFileSystemProvider());
+        bind(FileService).toConstantValue(fileService);
+        bind(MessageService).toSelf().inSingletonScope();
+        bind(MessageClient).toSelf().inSingletonScope();
+    });
+
+    testContainer.load(module);
+});
+
+describe('NavigatorDiff', () => {
+    it('should allow a valid first file to be added', async () => {
+        const diff = testContainer.get(NavigatorDiff);
+        testContainer.get(SelectionService).selection = [{
+            uri: new URI(FileUri.create(path.resolve(__dirname, '../../test-resources/testFileA.json')).toString())
+        }];
+
+        const result = await diff.addFirstComparisonFile();
+        expect(result).to.be.true;
+    });
+
+    it('should reject invalid file when added', async () => {
+        const diff = testContainer.get(NavigatorDiff);
+        testContainer.get(SelectionService).selection = [{
+            uri: new URI(FileUri.create(path.resolve(__dirname, '../../test-resources/nonExistentFile.json')).toString())
+        }];
+
+        const result = await diff.addFirstComparisonFile();
+        expect(result).to.be.false;
+    });
+
+    it('should run comparison when second file is added', done => {
+        const diff = testContainer.get(NavigatorDiff);
+        testContainer.get(SelectionService).selection = [{
+            uri: new URI(FileUri.create(path.resolve(__dirname, '../../test-resources/testFileA.json')).toString())
+        }];
+
+        diff.addFirstComparisonFile()
+            .then(result => {
+                testContainer.get(SelectionService).selection = [{
+                    uri: new URI(FileUri.create(path.resolve(__dirname, '../../test-resources/testFileB.json')).toString())
+                }];
+
+                diff.compareFiles()
+                    .then(compareResult => {
+                        expect(compareResult).to.be.true;
+                        done();
+                    });
+            });
+    });
+
+    it('should fail to run comparison if first file not added', done => {
+        const diff = testContainer.get(NavigatorDiff);
+        testContainer.get(SelectionService).selection = [{
+            uri: new URI(FileUri.create(path.resolve(__dirname, '../../test-resources/testFileA.json')).toString())
+        }];
+
+        diff.compareFiles()
+            .then(compareResult => {
+                expect(compareResult).to.be.false;
+                done();
+            });
+    });
+});

packages/navigator/src/browser/navigator-diff.ts

@@ -0,0 +1,136 @@
+// *****************************************************************************
+// Copyright (C) 2019 David Saunders and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+// *****************************************************************************
+
+import { inject, injectable } from '@theia/core/shared/inversify';
+import URI from '@theia/core/lib/common/uri';
+import { SelectionService, UriSelection } from '@theia/core/lib/common';
+import { OpenerService, open } from '@theia/core/lib/browser/opener-service';
+import { MessageService } from '@theia/core/lib/common/message-service';
+import { Command } from '@theia/core/lib/common/command';
+import { DiffUris } from '@theia/core/lib/browser/diff-uris';
+import { FileService } from '@theia/filesystem/lib/browser/file-service';
+import { FileOperationError, FileOperationResult } from '@theia/filesystem/lib/common/files';
+
+export namespace NavigatorDiffCommands {
+    const COMPARE_CATEGORY = 'Compare';
+    export const COMPARE_FIRST = Command.toDefaultLocalizedCommand({
+        id: 'compare:first',
+        category: COMPARE_CATEGORY,
+        label: 'Select for Compare'
+    });
+    export const COMPARE_SECOND = Command.toDefaultLocalizedCommand({
+        id: 'compare:second',
+        category: COMPARE_CATEGORY,
+        label: 'Compare with Selected'
+    });
+}
+
+@injectable()
+export class NavigatorDiff {
+    @inject(FileService)
+    protected readonly fileService: FileService;
+
+    @inject(OpenerService)
+    protected openerService: OpenerService;
+
+    @inject(MessageService)
+    protected readonly notifications: MessageService;
+
+    @inject(SelectionService)
+    protected readonly selectionService: SelectionService;
+
+    constructor(
+    ) {
+    }
+
+    protected _firstCompareFile: URI | undefined = undefined;
+    protected get firstCompareFile(): URI | undefined {
+        return this._firstCompareFile;
+    }
+    protected set firstCompareFile(uri: URI | undefined) {
+        this._firstCompareFile = uri;
+        this._isFirstFileSelected = true;
+    }
+
+    protected _isFirstFileSelected: boolean;
+    get isFirstFileSelected(): boolean {
+        return this._isFirstFileSelected;
+    }
+
+    protected async isDirectory(uri: URI): Promise<boolean> {
+        try {
+            const stat = await this.fileService.resolve(uri);
+            return stat.isDirectory;
+        } catch (e) {
+            if (e instanceof FileOperationError && e.fileOperationResult === FileOperationResult.FILE_NOT_FOUND) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    protected async getURISelection(): Promise<URI | undefined> {
+        const uri = UriSelection.getUri(this.selectionService.selection);
+        if (!uri) {
+            return undefined;
+        }
+
+        if (await this.isDirectory(uri)) {
+            return undefined;
+        }
+
+        return uri;
+    }
+
+    /**
+     * Adds the initial file for comparison
+     * @see SelectionService
+     * @see compareFiles
+     * @returns Promise<boolean> indicating whether the uri is valid
+     */
+    async addFirstComparisonFile(): Promise<boolean> {
+        const uriSelected = await this.getURISelection();
+
+        if (uriSelected === undefined) {
+            return false;
+        }
+
+        this.firstCompareFile = uriSelected;
+
+        return true;
+    }
+
+    /**
+     * Compare selected files.  First file is selected through addFirstComparisonFile
+     * @see SelectionService
+     * @see addFirstComparisonFile
+     * @returns Promise<boolean> indicating whether the comparison was completed successfully
+     */
+    async compareFiles(): Promise<boolean> {
+        const uriSelected = await this.getURISelection();
+
+        if (this.firstCompareFile === undefined || uriSelected === undefined) {
+            return false;
+        }
+        const diffUri = DiffUris.encode(this.firstCompareFile, uriSelected);
+
+        open(this.openerService, diffUri).catch(e => {
+            this.notifications.error(e.message);
+        });
+        return true;
+    }
+}

packages/navigator/src/browser/navigator-filter.spec.ts

@@ -0,0 +1,148 @@
+// *****************************************************************************
+// Copyright (C) 2018 TypeFox and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+// *****************************************************************************
+
+import { enableJSDOM } from '@theia/core/lib/browser/test/jsdom';
+const disableJSDOM = enableJSDOM();
+
+import { expect } from 'chai';
+import { FileNavigatorFilterPredicate } from './navigator-filter';
+
+disableJSDOM();
+
+interface Input {
+    readonly patterns: { [key: string]: boolean };
+    readonly includes: string[];
+    readonly excludes: string[];
+}
+
+describe('navigator-filter-glob', () => {
+
+    const pathPrefix = 'file:///some/path/to';
+    const toItem = (id: string) => ({ id: `${pathPrefix}${id}` });
+    const itemsToFilter = [
+        '/.git/',
+        '/.git/a',
+        '/.git/b',
+
+        '/src/foo/',
+        '/src/foo/a.js',
+        '/src/foo/b.js',
+        '/src/foo/a.ts',
+        '/src/foo/b.ts',
+
+        '/src/foo/test/bar/a.js',
+        '/src/foo/test/bar/b.js',
+
+        '/test/baz/bar/a.js',
+        '/test/baz/bar/b.js'
+    ].map(toItem);
+
+    ([
+        {
+            patterns: {
+                '**/.git/**': true
+            },
+            includes: [
+                '/src/foo/'
+            ],
+            excludes: [
+                '/.git/',
+                '/.git/a',
+                '/.git/b'
+            ]
+        },
+        {
+            patterns: {
+                '*.js': true
+            },
+            includes: [
+                '/src/foo/a.ts',
+                '/.git/'
+            ],
+            excludes: [
+                '/src/foo/a.js',
+                '/test/baz/bar/a.js'
+            ]
+        },
+        {
+            patterns: {
+                '**/test/bar/**': true
+            },
+            includes: [
+                '/test/baz/bar/a.js',
+                '/test/baz/bar/b.js',
+                '/.git/'
+            ],
+            excludes: [
+                '/src/foo/test/bar/a.js',
+                '/src/foo/test/bar/b.js'
+            ]
+        },
+        {
+            patterns: {
+                '*.js': true,
+                '**/.git/**': true
+            },
+            includes: [
+                '/src/foo/a.ts'
+            ],
+            excludes: [
+                '/.git/',
+                '/src/foo/a.js',
+                '/test/baz/bar/a.js'
+            ]
+        },
+        {
+            patterns: {
+                '*.js': false,
+                '**/.git/**': false
+            },
+            includes: [
+                '/.git/',
+                '/.git/a',
+                '/.git/b',
+                '/src/foo/',
+                '/src/foo/a.js',
+                '/src/foo/b.js',
+                '/src/foo/a.ts',
+                '/src/foo/b.ts',
+                '/src/foo/test/bar/a.js',
+                '/src/foo/test/bar/b.js',
+                '/test/baz/bar/a.js',
+                '/test/baz/bar/b.js'
+            ],
+            excludes: [
+
+            ]
+        }
+    ] as Input[]).forEach((test, index) => {
+        it(`${index < 10 ? `0${index + 1}` : `${index + 1}`} glob-filter: (${Object.keys(test.patterns).map(key => `${key} [${test.patterns[key]}]`).join(', ')}) `, () => {
+            const filter = new FileNavigatorFilterPredicate(test.patterns);
+            const result = itemsToFilter.filter(filter.filter.bind(filter));
+            test.includes.map(toItem).forEach(item => includes(result, item));
+            test.excludes.map(toItem).forEach(item => excludes(result, item));
+        });
+    });
+
+});
+
+function includes<T>(array: T[], item: T, message: string = `Expected ${JSON.stringify(array)} to include ${JSON.stringify(item)}.`): void {
+    expect(array).to.deep.include(item, message);
+}
+
+function excludes<T>(array: T[], item: T, message: string = `Expected ${JSON.stringify(array)} to not include ${JSON.stringify(item)}.`): void {
+    expect(array).to.not.deep.include(item, message);
+}

packages/navigator/src/browser/navigator-filter.ts

@@ -0,0 +1,165 @@
+// *****************************************************************************
+// Copyright (C) 2018 TypeFox and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+// *****************************************************************************
+
+import { inject, injectable, postConstruct } from '@theia/core/shared/inversify';
+import { Minimatch } from 'minimatch';
+import { MaybePromise } from '@theia/core/lib/common/types';
+import { Event, Emitter } from '@theia/core/lib/common/event';
+import { FileSystemPreferences, FileSystemConfiguration } from '@theia/filesystem/lib/common/filesystem-preferences';
+import { FileNavigatorPreferences, FileNavigatorConfiguration } from '../common/navigator-preferences';
+import { PreferenceChangeEvent } from '@theia/core';
+
+/**
+ * Filter for omitting elements from the navigator. For more details on the exclusion patterns,
+ * one should check either the manual with `man 5 gitignore` or just [here](https://git-scm.com/docs/gitignore).
+ */
+@injectable()
+export class FileNavigatorFilter {
+    protected readonly emitter: Emitter<void> = new Emitter<void>();
+
+    protected filterPredicate: FileNavigatorFilter.Predicate;
+    protected showHiddenFiles: boolean;
+
+    @inject(FileSystemPreferences)
+    protected readonly filesPreferences: FileSystemPreferences;
+
+    constructor(
+        @inject(FileNavigatorPreferences) protected readonly preferences: FileNavigatorPreferences
+    ) { }
+
+    @postConstruct()
+    protected init(): void {
+        this.doInit();
+    }
+
+    protected async doInit(): Promise<void> {
+        this.filterPredicate = this.createFilterPredicate(this.filesPreferences['files.exclude']);
+        this.filesPreferences.onPreferenceChanged(event => this.onFilesPreferenceChanged(event));
+        this.preferences.onPreferenceChanged(event => this.onPreferenceChanged(event));
+    }
+
+    async filter<T extends { id: string }>(items: MaybePromise<T[]>): Promise<T[]> {
+        return (await items).filter(item => this.filterItem(item));
+    }
+
+    get onFilterChanged(): Event<void> {
+        return this.emitter.event;
+    }
+
+    protected filterItem(item: { id: string }): boolean {
+        return this.filterPredicate.filter(item);
+    }
+
+    protected fireFilterChanged(): void {
+        this.emitter.fire(undefined);
+    }
+
+    protected onFilesPreferenceChanged(event: PreferenceChangeEvent<FileSystemConfiguration>): void {
+        const { preferenceName } = event;
+        if (preferenceName === 'files.exclude') {
+            const filesExcludes = this.filesPreferences['files.exclude'];
+            this.filterPredicate = this.createFilterPredicate(filesExcludes);
+            this.fireFilterChanged();
+        }
+    }
+
+    protected onPreferenceChanged(event: PreferenceChangeEvent<FileNavigatorConfiguration>): void {
+    }
+
+    protected createFilterPredicate(exclusions: FileNavigatorFilter.Exclusions): FileNavigatorFilter.Predicate {
+        return new FileNavigatorFilterPredicate(this.interceptExclusions(exclusions));
+    }
+
+    toggleHiddenFiles(): void {
+        this.showHiddenFiles = !this.showHiddenFiles;
+        const filesExcludes = this.filesPreferences['files.exclude'];
+
+        this.filterPredicate = this.createFilterPredicate(filesExcludes || {});
+        this.fireFilterChanged();
+    }
+
+    protected interceptExclusions(exclusions: FileNavigatorFilter.Exclusions): FileNavigatorFilter.Exclusions {
+        return {
+            ...exclusions,
+            '**/.*': this.showHiddenFiles
+        };
+    }
+
+}
+
+export namespace FileNavigatorFilter {
+
+    /**
+     * File navigator filter predicate.
+     */
+    export interface Predicate {
+
+        /**
+         * Returns `true` if the item should filtered our from the navigator. Otherwise, `true`.
+         *
+         * @param item the identifier of a tree node.
+         */
+        filter(item: { id: string }): boolean;
+
+    }
+
+    export namespace Predicate {
+
+        /**
+         * Wraps a bunch of predicates and returns with a new one that evaluates to `true` if
+         * each of the wrapped predicates evaluates to `true`. Otherwise, `false`.
+         */
+        export function and(...predicates: Predicate[]): Predicate {
+            return {
+                filter: id => predicates.every(predicate => predicate.filter(id))
+            };
+        }
+
+    }
+
+    /**
+     * Type for the exclusion patterns. The property keys are the patterns, values are whether the exclusion is enabled or not.
+     */
+    export interface Exclusions {
+        [key: string]: boolean;
+    }
+
+}
+
+/**
+ * Concrete filter navigator filter predicate that is decoupled from the preferences.
+ */
+export class FileNavigatorFilterPredicate implements FileNavigatorFilter.Predicate {
+
+    private readonly delegate: FileNavigatorFilter.Predicate;
+
+    constructor(exclusions: FileNavigatorFilter.Exclusions) {
+        const patterns = Object.keys(exclusions).map(pattern => ({ pattern, enabled: exclusions[pattern] })).filter(object => object.enabled).map(object => object.pattern);
+        this.delegate = FileNavigatorFilter.Predicate.and(...patterns.map(pattern => this.createDelegate(pattern)));
+    }
+
+    filter(item: { id: string }): boolean {
+        return this.delegate.filter(item);
+    }
+
+    protected createDelegate(pattern: string): FileNavigatorFilter.Predicate {
+        const delegate = new Minimatch(pattern, { matchBase: true });
+        return {
+            filter: item => !delegate.match(item.id)
+        };
+    }
+
+}

packages/navigator/src/browser/navigator-frontend-module.ts

@@ -0,0 +1,89 @@
+// *****************************************************************************
+// Copyright (C) 2017 TypeFox and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+// *****************************************************************************
+
+import '../../src/browser/style/index.css';
+import '../../src/browser/open-editors-widget/open-editors.css';
+
+import { ContainerModule } from '@theia/core/shared/inversify';
+import {
+    bindViewContribution,
+    FrontendApplicationContribution,
+    ApplicationShellLayoutMigration
+} from '@theia/core/lib/browser';
+import { FileNavigatorWidget, FILE_NAVIGATOR_ID } from './navigator-widget';
+import { FileNavigatorContribution } from './navigator-contribution';
+import { createFileNavigatorWidget } from './navigator-container';
+import { WidgetFactory } from '@theia/core/lib/browser/widget-manager';
+import { bindFileNavigatorPreferences } from '../common/navigator-preferences';
+import { FileNavigatorFilter } from './navigator-filter';
+import { NavigatorContextKeyService } from './navigator-context-key-service';
+import { TabBarToolbarContribution } from '@theia/core/lib/browser/shell/tab-bar-toolbar';
+import { NavigatorDiff } from './navigator-diff';
+import { NavigatorLayoutVersion3Migration, NavigatorLayoutVersion5Migration } from './navigator-layout-migrations';
+import { NavigatorTabBarDecorator } from './navigator-tab-bar-decorator';
+import { TabBarDecorator } from '@theia/core/lib/browser/shell/tab-bar-decorator';
+import { NavigatorWidgetFactory } from './navigator-widget-factory';
+import { bindContributionProvider } from '@theia/core/lib/common';
+import { OpenEditorsTreeDecorator } from './open-editors-widget/navigator-open-editors-decorator-service';
+import { OpenEditorsWidget } from './open-editors-widget/navigator-open-editors-widget';
+import { NavigatorTreeDecorator } from './navigator-decorator-service';
+import { NavigatorDeletedEditorDecorator } from './open-editors-widget/navigator-deleted-editor-decorator';
+import { NavigatorSymlinkDecorator } from './navigator-symlink-decorator';
+import { FileTreeDecoratorAdapter } from '@theia/filesystem/lib/browser';
+
+export default new ContainerModule(bind => {
+    bindFileNavigatorPreferences(bind);
+    bind(FileNavigatorFilter).toSelf().inSingletonScope();
+
+    bind(NavigatorContextKeyService).toSelf().inSingletonScope();
+
+    bindViewContribution(bind, FileNavigatorContribution);
+    bind(FrontendApplicationContribution).toService(FileNavigatorContribution);
+    bind(TabBarToolbarContribution).toService(FileNavigatorContribution);
+
+    bind(FileNavigatorWidget).toDynamicValue(ctx =>
+        createFileNavigatorWidget(ctx.container)
+    );
+    bind(WidgetFactory).toDynamicValue(({ container }) => ({
+        id: FILE_NAVIGATOR_ID,
+        createWidget: () => container.get(FileNavigatorWidget)
+    })).inSingletonScope();
+    bindContributionProvider(bind, NavigatorTreeDecorator);
+    bindContributionProvider(bind, OpenEditorsTreeDecorator);
+    bind(NavigatorTreeDecorator).toService(FileTreeDecoratorAdapter);
+    bind(OpenEditorsTreeDecorator).toService(FileTreeDecoratorAdapter);
+    bind(NavigatorDeletedEditorDecorator).toSelf().inSingletonScope();
+    bind(OpenEditorsTreeDecorator).toService(NavigatorDeletedEditorDecorator);
+
+    bind(WidgetFactory).toDynamicValue(({ container }) => ({
+        id: OpenEditorsWidget.ID,
+        createWidget: () => OpenEditorsWidget.createWidget(container)
+    })).inSingletonScope();
+
+    bind(NavigatorWidgetFactory).toSelf().inSingletonScope();
+    bind(WidgetFactory).toService(NavigatorWidgetFactory);
+    bind(ApplicationShellLayoutMigration).to(NavigatorLayoutVersion3Migration).inSingletonScope();
+    bind(ApplicationShellLayoutMigration).to(NavigatorLayoutVersion5Migration).inSingletonScope();
+
+    bind(NavigatorDiff).toSelf().inSingletonScope();
+    bind(NavigatorTabBarDecorator).toSelf().inSingletonScope();
+    bind(FrontendApplicationContribution).toService(NavigatorTabBarDecorator);
+    bind(TabBarDecorator).toService(NavigatorTabBarDecorator);
+
+    bind(NavigatorSymlinkDecorator).toSelf().inSingletonScope();
+    bind(NavigatorTreeDecorator).toService(NavigatorSymlinkDecorator);
+    bind(OpenEditorsTreeDecorator).toService(NavigatorSymlinkDecorator);
+});

packages/navigator/src/browser/navigator-layout-migrations.ts

@@ -0,0 +1,65 @@
+// *****************************************************************************
+// Copyright (C) 2019 TypeFox and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+// *****************************************************************************
+
+import { injectable } from '@theia/core/shared/inversify';
+import { ApplicationShellLayoutMigration, WidgetDescription, ApplicationShellLayoutMigrationContext } from '@theia/core/lib/browser/shell/shell-layout-restorer';
+import { EXPLORER_VIEW_CONTAINER_ID, EXPLORER_VIEW_CONTAINER_TITLE_OPTIONS } from './navigator-widget-factory';
+import { FILE_NAVIGATOR_ID } from './navigator-widget';
+
+@injectable()
+export class NavigatorLayoutVersion3Migration implements ApplicationShellLayoutMigration {
+    readonly layoutVersion = 3.0;
+    onWillInflateWidget(desc: WidgetDescription, { parent }: ApplicationShellLayoutMigrationContext): WidgetDescription | undefined {
+        if (desc.constructionOptions.factoryId === FILE_NAVIGATOR_ID && !parent) {
+            return {
+                constructionOptions: {
+                    factoryId: EXPLORER_VIEW_CONTAINER_ID
+                },
+                innerWidgetState: {
+                    parts: [
+                        {
+                            widget: {
+                                constructionOptions: {
+                                    factoryId: FILE_NAVIGATOR_ID
+                                },
+                                innerWidgetState: desc.innerWidgetState
+                            },
+                            partId: {
+                                factoryId: FILE_NAVIGATOR_ID
+                            },
+                            collapsed: false,
+                            hidden: false
+                        }
+                    ],
+                    title: EXPLORER_VIEW_CONTAINER_TITLE_OPTIONS
+                }
+            };
+        }
+        return undefined;
+    }
+}
+
+@injectable()
+export class NavigatorLayoutVersion5Migration implements ApplicationShellLayoutMigration {
+    readonly layoutVersion = 5.0;
+    onWillInflateWidget(desc: WidgetDescription): WidgetDescription | undefined {
+        if (desc.constructionOptions.factoryId === EXPLORER_VIEW_CONTAINER_ID && typeof desc.innerWidgetState === 'string') {
+            desc.innerWidgetState = desc.innerWidgetState.replace(/navigator-tab-icon/g, EXPLORER_VIEW_CONTAINER_TITLE_OPTIONS.iconClass!);
+            return desc;
+        }
+        return undefined;
+    }
+}

packages/navigator/src/browser/navigator-model.ts

@@ -0,0 +1,221 @@
+// *****************************************************************************
+// Copyright (C) 2017 TypeFox and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+// *****************************************************************************
+
+import { injectable, inject, postConstruct } from '@theia/core/shared/inversify';
+import URI from '@theia/core/lib/common/uri';
+import { FileNode, FileTreeModel } from '@theia/filesystem/lib/browser';
+import { OpenerService, open, TreeNode, ExpandableTreeNode, CompositeTreeNode, SelectableTreeNode } from '@theia/core/lib/browser';
+import { FileNavigatorTree, WorkspaceRootNode, WorkspaceNode } from './navigator-tree';
+import { WorkspaceService } from '@theia/workspace/lib/browser';
+import { FrontendApplicationStateService } from '@theia/core/lib/browser/frontend-application-state';
+import { ProgressService } from '@theia/core/lib/common/progress-service';
+import { Deferred } from '@theia/core/lib/common/promise-util';
+import { Disposable } from '@theia/core/lib/common/disposable';
+
+@injectable()
+export class FileNavigatorModel extends FileTreeModel {
+
+    @inject(OpenerService) protected readonly openerService: OpenerService;
+    @inject(FileNavigatorTree) protected override readonly tree: FileNavigatorTree;
+    @inject(WorkspaceService) protected readonly workspaceService: WorkspaceService;
+    @inject(FrontendApplicationStateService) protected readonly applicationState: FrontendApplicationStateService;
+
+    @inject(ProgressService)
+    protected readonly progressService: ProgressService;
+
+    @postConstruct()
+    protected override init(): void {
+        super.init();
+        this.reportBusyProgress();
+        this.initializeRoot();
+    }
+
+    protected readonly pendingBusyProgress = new Map<string, Deferred<void>>();
+    protected reportBusyProgress(): void {
+        this.toDispose.push(this.onDidChangeBusy(node => {
+            const pending = this.pendingBusyProgress.get(node.id);
+            if (pending) {
+                if (!node.busy) {
+                    pending.resolve();
+                    this.pendingBusyProgress.delete(node.id);
+                }
+                return;
+            }
+            if (node.busy) {
+                const progress = new Deferred<void>();
+                this.pendingBusyProgress.set(node.id, progress);
+                this.progressService.withProgress('', 'explorer', () => progress.promise);
+            }
+        }));
+        this.toDispose.push(Disposable.create(() => {
+            for (const pending of this.pendingBusyProgress.values()) {
+                pending.resolve();
+            }
+            this.pendingBusyProgress.clear();
+        }));
+    }
+
+    protected async initializeRoot(): Promise<void> {
+        await Promise.all([
+            this.applicationState.reachedState('initialized_layout'),
+            this.workspaceService.roots
+        ]);
+        await this.updateRoot();
+        if (this.toDispose.disposed) {
+            return;
+        }
+        this.toDispose.push(this.workspaceService.onWorkspaceChanged(() => this.updateRoot()));
+        this.toDispose.push(this.workspaceService.onWorkspaceLocationChanged(() => this.updateRoot()));
+        if (this.selectedNodes.length) {
+            return;
+        }
+        const root = this.root;
+        if (CompositeTreeNode.is(root) && root.children.length === 1) {
+            const child = root.children[0];
+            if (SelectableTreeNode.is(child) && !child.selected && ExpandableTreeNode.is(child)) {
+                this.selectNode(child);
+                this.expandNode(child);
+            }
+        }
+    }
+
+    previewNode(node: TreeNode): void {
+        if (FileNode.is(node)) {
+            open(this.openerService, node.uri, { mode: 'reveal', preview: true });
+        }
+    }
+
+    protected override doOpenNode(node: TreeNode): void {
+        if (node.visible === false) {
+            return;
+        } else if (FileNode.is(node)) {
+            open(this.openerService, node.uri);
+        }
+    }
+
+    override *getNodesByUri(uri: URI): IterableIterator<TreeNode> {
+        const workspace = this.root;
+        if (WorkspaceNode.is(workspace)) {
+            for (const root of workspace.children) {
+                const id = this.tree.createId(root, uri);
+                const node = this.getNode(id);
+                if (node) {
+                    yield node;
+                }
+            }
+        }
+    }
+
+    protected async updateRoot(): Promise<void> {
+        this.root = await this.createRoot();
+    }
+
+    protected async createRoot(): Promise<TreeNode | undefined> {
+        if (this.workspaceService.opened) {
+            const stat = this.workspaceService.workspace;
+            const isMulti = (stat) ? !stat.isDirectory : false;
+            const workspaceNode = isMulti
+                ? this.createMultipleRootNode()
+                : WorkspaceNode.createRoot();
+            const roots = await this.workspaceService.roots;
+            for (const root of roots) {
+                workspaceNode.children.push(
+                    await this.tree.createWorkspaceRoot(root, workspaceNode)
+                );
+            }
+            return workspaceNode;
+        }
+    }
+
+    /**
+     * Create multiple root node used to display
+     * the multiple root workspace name.
+     *
+     * @returns `WorkspaceNode`
+     */
+    protected createMultipleRootNode(): WorkspaceNode {
+        const workspace = this.workspaceService.workspace;
+        let name = workspace
+            ? workspace.resource.path.name
+            : 'untitled';
+        name += ' (Workspace)';
+        return WorkspaceNode.createRoot(name);
+    }
+
+    /**
+     * Move the given source file or directory to the given target directory.
+     */
+    override async move(source: TreeNode, target: TreeNode): Promise<URI | undefined> {
+        if (source.parent && WorkspaceRootNode.is(source)) {
+            // do not support moving a root folder
+            return undefined;
+        }
+        return super.move(source, target);
+    }
+
+    /**
+     * Reveals node in the navigator by given file uri.
+     *
+     * @param uri uri to file which should be revealed in the navigator
+     * @returns file tree node if the file with given uri was revealed, undefined otherwise
+     */
+    async revealFile(uri: URI): Promise<TreeNode | undefined> {
+        if (!uri.path.isAbsolute) {
+            return undefined;
+        }
+        let node = this.getNodeClosestToRootByUri(uri);
+
+        // success stop condition
+        // we have to reach workspace root because expanded node could be inside collapsed one
+        if (WorkspaceRootNode.is(node)) {
+            if (ExpandableTreeNode.is(node)) {
+                if (!node.expanded) {
+                    node = await this.expandNode(node);
+                }
+                return node;
+            }
+            // shouldn't happen, root node is always directory, i.e. expandable
+            return undefined;
+        }
+
+        // fail stop condition
+        if (uri.path.isRoot) {
+            // file system root is reached but workspace root wasn't found, it means that
+            // given uri is not in workspace root folder or points to not existing file.
+            return undefined;
+        }
+
+        if (await this.revealFile(uri.parent)) {
+            if (node === undefined) {
+                // get node if it wasn't mounted into navigator tree before expansion
+                node = this.getNodeClosestToRootByUri(uri);
+            }
+            if (ExpandableTreeNode.is(node) && !node.expanded) {
+                node = await this.expandNode(node);
+            }
+            return node;
+        }
+        return undefined;
+    }
+
+    protected getNodeClosestToRootByUri(uri: URI): TreeNode | undefined {
+        const nodes = [...this.getNodesByUri(uri)];
+        return nodes.length > 0
+            ? nodes.reduce((node1, node2) => // return the node closest to the workspace root
+                node1.id.length >= node2.id.length ? node1 : node2
+            ) : undefined;
+    }
+}

packages/navigator/src/browser/navigator-symlink-decorator.ts

@@ -0,0 +1,68 @@
+// *****************************************************************************
+// Copyright (C) 2021 Ericsson and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+// *****************************************************************************
+
+import { inject, injectable, postConstruct } from '@theia/core/shared/inversify';
+import { Emitter, Event, nls } from '@theia/core';
+import { TreeDecorator, Tree, TreeDecoration, DepthFirstTreeIterator } from '@theia/core/lib/browser';
+import { FileStatNode } from '@theia/filesystem/lib/browser';
+import { DecorationsService } from '@theia/core/lib/browser/decorations-service';
+
+@injectable()
+export class NavigatorSymlinkDecorator implements TreeDecorator {
+
+    readonly id = 'theia-navigator-symlink-decorator';
+
+    @inject(DecorationsService)
+    protected readonly decorationsService: DecorationsService;
+
+    @postConstruct()
+    protected init(): void {
+        this.decorationsService.onDidChangeDecorations(() => {
+            this.fireDidChangeDecorations((tree: Tree) => this.collectDecorator(tree));
+        });
+    }
+
+    async decorations(tree: Tree): Promise<Map<string, TreeDecoration.Data>> {
+        return this.collectDecorator(tree);
+    }
+
+    protected collectDecorator(tree: Tree): Map<string, TreeDecoration.Data> {
+        const result = new Map<string, TreeDecoration.Data>();
+        if (tree.root === undefined) {
+            return result;
+        }
+        for (const node of new DepthFirstTreeIterator(tree.root)) {
+            if (FileStatNode.is(node) && node.fileStat.isSymbolicLink) {
+                const decorations: TreeDecoration.Data = {
+                    tailDecorations: [{ data: '⤷', tooltip: nls.localizeByDefault('Symbolic Link') }]
+                };
+                result.set(node.id, decorations);
+            }
+        }
+        return result;
+    }
+
+    protected readonly onDidChangeDecorationsEmitter = new Emitter<(tree: Tree) => Map<string, TreeDecoration.Data>>();
+
+    get onDidChangeDecorations(): Event<(tree: Tree) => Map<string, TreeDecoration.Data>> {
+        return this.onDidChangeDecorationsEmitter.event;
+    }
+
+    fireDidChangeDecorations(event: (tree: Tree) => Map<string, TreeDecoration.Data>): void {
+        this.onDidChangeDecorationsEmitter.fire(event);
+    }
+
+}

packages/navigator/src/browser/navigator-tab-bar-decorator.ts

@@ -0,0 +1,71 @@
+// *****************************************************************************
+// Copyright (C) 2020 Ericsson and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+// *****************************************************************************
+
+import { injectable } from '@theia/core/shared/inversify';
+import { Emitter, Event } from '@theia/core/lib/common/event';
+import { TabBarDecorator } from '@theia/core/lib/browser/shell/tab-bar-decorator';
+import { ApplicationShell, FrontendApplication, FrontendApplicationContribution, Saveable, Title, ViewContainer, Widget } from '@theia/core/lib/browser';
+import { WidgetDecoration } from '@theia/core/lib/browser/widget-decoration';
+import { Disposable, DisposableCollection } from '@theia/core/lib/common/disposable';
+import { OpenEditorsWidget } from './open-editors-widget/navigator-open-editors-widget';
+
+@injectable()
+export class NavigatorTabBarDecorator implements TabBarDecorator, FrontendApplicationContribution {
+    readonly id = 'theia-navigator-tabbar-decorator';
+    protected applicationShell: ApplicationShell;
+
+    protected readonly emitter = new Emitter<void>();
+    private readonly toDispose = new DisposableCollection();
+    private readonly toDisposeOnDirtyChanged = new Map<string, Disposable>();
+
+    onStart(app: FrontendApplication): void {
+        this.applicationShell = app.shell;
+        if (!!this.getDirtyEditorsCount()) {
+            this.fireDidChangeDecorations();
+        }
+        this.toDispose.pushAll([
+            this.applicationShell.onDidAddWidget(widget => {
+                const saveable = Saveable.get(widget);
+                if (saveable) {
+                    this.toDisposeOnDirtyChanged.set(widget.id, saveable.onDirtyChanged(() => this.fireDidChangeDecorations()));
+                }
+            }),
+            this.applicationShell.onDidRemoveWidget(widget => this.toDisposeOnDirtyChanged.get(widget.id)?.dispose())
+        ]);
+    }
+
+    decorate(title: Title<Widget>): WidgetDecoration.Data[] {
+        const { owner } = title;
+        if (owner instanceof ViewContainer && owner.getParts().find(part => part.wrapped instanceof OpenEditorsWidget)) {
+            const changes = this.getDirtyEditorsCount();
+            return changes > 0 ? [{ badge: changes }] : [];
+        } else {
+            return [];
+        }
+    }
+
+    protected getDirtyEditorsCount(): number {
+        return this.applicationShell.widgets.filter(widget => Saveable.isDirty(widget)).length;
+    }
+
+    get onDidChangeDecorations(): Event<void> {
+        return this.emitter.event;
+    }
+
+    protected fireDidChangeDecorations(): void {
+        this.emitter.fire(undefined);
+    }
+}

packages/navigator/src/browser/navigator-tree.ts

@@ -0,0 +1,128 @@
+// *****************************************************************************
+// Copyright (C) 2017 TypeFox and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+// *****************************************************************************
+
+import { injectable, inject, postConstruct } from '@theia/core/shared/inversify';
+import { FileTree, DirNode } from '@theia/filesystem/lib/browser';
+import { FileStat } from '@theia/filesystem/lib/common/files';
+import URI from '@theia/core/lib/common/uri';
+import { TreeNode, CompositeTreeNode, SelectableTreeNode, CompressionToggle } from '@theia/core/lib/browser';
+import { FileNavigatorFilter } from './navigator-filter';
+import { EXPLORER_COMPACT_FOLDERS, FileNavigatorPreferences } from '../common/navigator-preferences';
+
+@injectable()
+export class FileNavigatorTree extends FileTree {
+
+    @inject(FileNavigatorFilter) protected readonly filter: FileNavigatorFilter;
+
+    @inject(FileNavigatorPreferences) protected readonly navigatorPreferences: FileNavigatorPreferences;
+
+    @inject(CompressionToggle) protected readonly compressionToggle: CompressionToggle;
+
+    @postConstruct()
+    protected init(): void {
+        this.toDispose.push(this.filter.onFilterChanged(() => this.refresh()));
+        this.navigatorPreferences.ready.then(() => this.toggleCompression());
+        this.toDispose.push(this.navigatorPreferences.onPreferenceChanged(({ preferenceName }) => {
+            if (preferenceName === EXPLORER_COMPACT_FOLDERS) {
+                this.toggleCompression();
+            }
+        }));
+    }
+
+    protected toggleCompression(): void {
+        this.compressionToggle.compress = this.navigatorPreferences.get(EXPLORER_COMPACT_FOLDERS, true);
+        this.refresh();
+    }
+
+    override async resolveChildren(parent: CompositeTreeNode): Promise<TreeNode[]> {
+        if (WorkspaceNode.is(parent)) {
+            return parent.children;
+        }
+        return this.filter.filter(super.resolveChildren(parent));
+    }
+
+    protected override toNodeId(uri: URI, parent: CompositeTreeNode): string {
+        const workspaceRootNode = WorkspaceRootNode.find(parent);
+        if (workspaceRootNode) {
+            return this.createId(workspaceRootNode, uri);
+        }
+        return super.toNodeId(uri, parent);
+    }
+    createId(root: WorkspaceRootNode, uri: URI): string {
+        const id = super.toNodeId(uri, root);
+        return id === root.id ? id : `${root.id}:${id}`;
+    }
+
+    async createWorkspaceRoot(rootFolder: FileStat, workspaceNode: WorkspaceNode): Promise<WorkspaceRootNode> {
+        const node = this.toNode(rootFolder, workspaceNode) as WorkspaceRootNode;
+        Object.assign(node, {
+            visible: workspaceNode.name !== WorkspaceNode.name,
+        });
+        return node;
+    }
+}
+
+/**
+ * File tree root node for multi-root workspaces.
+ */
+export interface WorkspaceNode extends CompositeTreeNode, SelectableTreeNode {
+    children: WorkspaceRootNode[];
+}
+export namespace WorkspaceNode {
+
+    export const id = 'WorkspaceNodeId';
+    export const name = 'WorkspaceNode';
+
+    export function is(node: TreeNode | undefined): node is WorkspaceNode {
+        return CompositeTreeNode.is(node) && node.id === WorkspaceNode.id;
+    }
+
+    /**
+     * Create a `WorkspaceNode` that can be used as a `Tree` root.
+     */
+    export function createRoot(multiRootName?: string): WorkspaceNode {
+        return {
+            id: WorkspaceNode.id,
+            name: multiRootName || WorkspaceNode.name,
+            parent: undefined,
+            children: [],
+            visible: false,
+            selected: false
+        };
+    }
+}
+
+/**
+ * A node representing a folder from a multi-root workspace.
+ */
+export interface WorkspaceRootNode extends DirNode {
+    parent: WorkspaceNode;
+}
+export namespace WorkspaceRootNode {
+
+    export function is(node: unknown): node is WorkspaceRootNode {
+        return DirNode.is(node) && WorkspaceNode.is(node.parent);
+    }
+
+    export function find(node: TreeNode | undefined): WorkspaceRootNode | undefined {
+        if (node) {
+            if (is(node)) {
+                return node;
+            }
+            return find(node.parent);
+        }
+    }
+}

packages/navigator/src/browser/navigator-widget-factory.ts

@@ -0,0 +1,75 @@
+// *****************************************************************************
+// Copyright (C) 2021 SAP SE or an SAP affiliate company and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+// *****************************************************************************
+
+import { inject, injectable } from '@theia/core/shared/inversify';
+import {
+    codicon,
+    ViewContainer,
+    ViewContainerTitleOptions,
+    WidgetFactory,
+    WidgetManager
+} from '@theia/core/lib/browser';
+import { FILE_NAVIGATOR_ID } from './navigator-widget';
+import { OpenEditorsWidget } from './open-editors-widget/navigator-open-editors-widget';
+import { nls } from '@theia/core/lib/common/nls';
+
+export const EXPLORER_VIEW_CONTAINER_ID = 'explorer-view-container';
+export const EXPLORER_VIEW_CONTAINER_TITLE_OPTIONS: ViewContainerTitleOptions = {
+    label: nls.localizeByDefault('Explorer'),
+    iconClass: codicon('files'),
+    closeable: true
+};
+
+@injectable()
+export class NavigatorWidgetFactory implements WidgetFactory {
+
+    static ID = EXPLORER_VIEW_CONTAINER_ID;
+
+    readonly id = NavigatorWidgetFactory.ID;
+
+    protected openEditorsWidgetOptions: ViewContainer.Factory.WidgetOptions = {
+        order: 0,
+        canHide: true,
+        initiallyCollapsed: true,
+        // this property currently has no effect (https://github.com/eclipse-theia/theia/issues/7755)
+        weight: 20
+    };
+
+    protected fileNavigatorWidgetOptions: ViewContainer.Factory.WidgetOptions = {
+        order: 1,
+        canHide: false,
+        initiallyCollapsed: false,
+        weight: 80,
+        disableDraggingToOtherContainers: true
+    };
+
+    @inject(ViewContainer.Factory)
+    protected readonly viewContainerFactory: ViewContainer.Factory;
+    @inject(WidgetManager) protected readonly widgetManager: WidgetManager;
+
+    async createWidget(): Promise<ViewContainer> {
+        const viewContainer = this.viewContainerFactory({
+            id: EXPLORER_VIEW_CONTAINER_ID,
+            progressLocationId: 'explorer'
+        });
+        viewContainer.setTitleOptions(EXPLORER_VIEW_CONTAINER_TITLE_OPTIONS);
+        const openEditorsWidget = await this.widgetManager.getOrCreateWidget(OpenEditorsWidget.ID);
+        const navigatorWidget = await this.widgetManager.getOrCreateWidget(FILE_NAVIGATOR_ID);
+        viewContainer.addWidget(navigatorWidget, this.fileNavigatorWidgetOptions);
+        viewContainer.addWidget(openEditorsWidget, this.openEditorsWidgetOptions);
+        return viewContainer;
+    }
+}

packages/navigator/src/browser/navigator-widget.tsx

@@ -0,0 +1,219 @@
+// *****************************************************************************
+// Copyright (C) 2017 TypeFox and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+// *****************************************************************************
+
+import { injectable, inject, postConstruct } from '@theia/core/shared/inversify';
+import { Message } from '@theia/core/shared/@lumino/messaging';
+import URI from '@theia/core/lib/common/uri';
+import { CommandService } from '@theia/core/lib/common';
+import { Key, TreeModel, ContextMenuRenderer, ExpandableTreeNode, TreeProps, TreeNode } from '@theia/core/lib/browser';
+import { DirNode, FileStatNodeData } from '@theia/filesystem/lib/browser';
+import { WorkspaceService, WorkspaceCommands } from '@theia/workspace/lib/browser';
+import { WorkspaceNode, WorkspaceRootNode } from './navigator-tree';
+import { FileNavigatorModel } from './navigator-model';
+import { isOSX, environment } from '@theia/core';
+import * as React from '@theia/core/shared/react';
+import { NavigatorContextKeyService } from './navigator-context-key-service';
+import { nls } from '@theia/core/lib/common/nls';
+import { AbstractNavigatorTreeWidget } from './abstract-navigator-tree-widget';
+
+export const FILE_NAVIGATOR_ID = 'files';
+export const LABEL = nls.localizeByDefault('No Folder Opened');
+export const CLASS = 'theia-Files';
+
+@injectable()
+export class FileNavigatorWidget extends AbstractNavigatorTreeWidget {
+
+    @inject(CommandService) protected readonly commandService: CommandService;
+    @inject(NavigatorContextKeyService) protected readonly contextKeyService: NavigatorContextKeyService;
+    @inject(WorkspaceService) protected readonly workspaceService: WorkspaceService;
+
+    constructor(
+        @inject(TreeProps) props: TreeProps,
+        @inject(FileNavigatorModel) override readonly model: FileNavigatorModel,
+        @inject(ContextMenuRenderer) contextMenuRenderer: ContextMenuRenderer,
+    ) {
+        super(props, model, contextMenuRenderer);
+        this.id = FILE_NAVIGATOR_ID;
+        this.addClass(CLASS);
+    }
+
+    @postConstruct()
+    protected override init(): void {
+        super.init();
+        // This ensures that the context menu command to hide this widget receives the label 'Folders'
+        // regardless of the name of workspace. See ViewContainer.updateToolbarItems.
+        const dataset = { ...this.title.dataset, visibilityCommandLabel: nls.localizeByDefault('Folders') };
+        this.title.dataset = dataset;
+        this.updateSelectionContextKeys();
+        this.toDispose.pushAll([
+            this.model.onSelectionChanged(() =>
+                this.updateSelectionContextKeys()
+            ),
+            this.model.onExpansionChanged(node => {
+                if (node.expanded && node.children.length === 1) {
+                    const child = node.children[0];
+                    if (ExpandableTreeNode.is(child) && !child.expanded) {
+                        this.model.expandNode(child);
+                    }
+                }
+
+            })
+        ]);
+    }
+
+    protected override doUpdateRows(): void {
+        super.doUpdateRows();
+        this.title.label = LABEL;
+        if (WorkspaceNode.is(this.model.root)) {
+            if (this.model.root.name === WorkspaceNode.name) {
+                const rootNode = this.model.root.children[0];
+                if (WorkspaceRootNode.is(rootNode)) {
+                    this.title.label = this.toNodeName(rootNode);
+                    this.title.caption = this.labelProvider.getLongName(rootNode.uri);
+                }
+            } else {
+                this.title.label = this.toNodeName(this.model.root);
+                this.title.caption = this.title.label;
+            }
+        } else {
+            this.title.caption = this.title.label;
+        }
+    }
+
+    override getContainerTreeNode(): TreeNode | undefined {
+        const root = this.model.root;
+        if (this.workspaceService.isMultiRootWorkspaceOpened) {
+            return root;
+        }
+        if (WorkspaceNode.is(root)) {
+            return root.children[0];
+        }
+        return undefined;
+    }
+
+    protected override renderTree(model: TreeModel): React.ReactNode {
+        if (this.model.root && this.isEmptyMultiRootWorkspace(model)) {
+            return this.renderEmptyMultiRootWorkspace();
+        }
+        return super.renderTree(model);
+    }
+
+    protected override shouldShowWelcomeView(): boolean {
+        return this.model.root === undefined;
+    }
+
+    protected override onAfterAttach(msg: Message): void {
+        super.onAfterAttach(msg);
+        this.addClipboardListener(this.node, 'copy', e => this.handleCopy(e));
+        this.addClipboardListener(this.node, 'paste', e => this.handlePaste(e));
+    }
+
+    protected handleCopy(event: ClipboardEvent): void {
+        const uris = this.model.selectedFileStatNodes.map(node => node.uri.toString());
+        if (uris.length > 0 && event.clipboardData) {
+            event.clipboardData.setData('text/plain', uris.join('\n'));
+            event.preventDefault();
+        }
+    }
+
+    protected handlePaste(event: ClipboardEvent): void {
+        if (event.clipboardData) {
+            const raw = event.clipboardData.getData('text/plain');
+            if (!raw) {
+                return;
+            }
+            const target = this.model.selectedFileStatNodes[0];
+            if (!target) {
+                return;
+            }
+            for (const file of raw.split('\n')) {
+                event.preventDefault();
+                const source = new URI(file);
+                this.model.copy(source, target);
+            }
+        }
+    }
+
+    protected canOpenWorkspaceFileAndFolder: boolean = isOSX || !environment.electron.is();
+
+    protected readonly openWorkspace = () => this.doOpenWorkspace();
+    protected doOpenWorkspace(): void {
+        this.commandService.executeCommand(WorkspaceCommands.OPEN_WORKSPACE.id);
+    }
+
+    protected readonly openFolder = () => this.doOpenFolder();
+    protected doOpenFolder(): void {
+        this.commandService.executeCommand(WorkspaceCommands.OPEN_FOLDER.id);
+    }
+
+    protected readonly addFolder = () => this.doAddFolder();
+    protected doAddFolder(): void {
+        this.commandService.executeCommand(WorkspaceCommands.ADD_FOLDER.id);
+    }
+
+    protected readonly keyUpHandler = (e: React.KeyboardEvent) => {
+        if (Key.ENTER.keyCode === e.keyCode) {
+            (e.target as HTMLElement).click();
+        }
+    };
+
+    /**
+     * When a multi-root workspace is opened, a user can remove all the folders from it.
+     * Instead of displaying an empty navigator tree, this will show a button to add more folders.
+     */
+    protected renderEmptyMultiRootWorkspace(): React.ReactNode {
+        return <div className='theia-navigator-container'>
+            <div className='center'>{nls.localizeByDefault('You have not yet added a folder to the workspace.\n{0}', '')}</div>
+            <div className='open-workspace-button-container'>
+                <button className='theia-button open-workspace-button' title={nls.localizeByDefault('Add Folder to Workspace')}
+                    onClick={this.addFolder}
+                    onKeyUp={this.keyUpHandler}>
+                    {nls.localizeByDefault('Open Folder')}
+                </button>
+            </div>
+        </div>;
+    }
+
+    protected isEmptyMultiRootWorkspace(model: TreeModel): boolean {
+        return WorkspaceNode.is(model.root) && model.root.children.length === 0;
+    }
+
+    protected override tapNode(node?: TreeNode): void {
+        if (node && this.corePreferences['workbench.list.openMode'] === 'singleClick') {
+            this.model.previewNode(node);
+        }
+        super.tapNode(node);
+    }
+
+    protected override onAfterShow(msg: Message): void {
+        super.onAfterShow(msg);
+        this.contextKeyService.explorerViewletVisible.set(true);
+    }
+
+    protected override onAfterHide(msg: Message): void {
+        super.onAfterHide(msg);
+        this.contextKeyService.explorerViewletVisible.set(false);
+    }
+
+    protected updateSelectionContextKeys(): void {
+        this.contextKeyService.explorerResourceIsFolder.set(DirNode.is(this.model.selectedNodes[0]));
+        // As `FileStatNode` only created if `FileService.resolve` was successful, we can safely assume that
+        // a valid `FileSystemProvider` is available for the selected node. So we skip an additional check
+        // for provider availability here and check the node type.
+        this.contextKeyService.isFileSystemResource.set(FileStatNodeData.is(this.model.selectedNodes[0]));
+    }
+
+}

packages/navigator/src/browser/open-editors-widget/navigator-deleted-editor-decorator.ts

@@ -0,0 +1,92 @@
+// *****************************************************************************
+// Copyright (C) 2021 Ericsson and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+// *****************************************************************************
+
+import { injectable, inject, postConstruct } from '@theia/core/shared/inversify';
+import { ApplicationShell, DepthFirstTreeIterator, NavigatableWidget, Tree, TreeDecoration, TreeDecorator } from '@theia/core/lib/browser';
+import { FileSystemFrontendContribution } from '@theia/filesystem/lib/browser/filesystem-frontend-contribution';
+import { Emitter } from '@theia/core';
+import { FileStatNode } from '@theia/filesystem/lib/browser';
+import { FileChangeType } from '@theia/filesystem/lib/common/files';
+
+@injectable()
+export class NavigatorDeletedEditorDecorator implements TreeDecorator {
+
+    @inject(FileSystemFrontendContribution)
+    protected readonly fileSystemContribution: FileSystemFrontendContribution;
+    @inject(ApplicationShell)
+    protected readonly shell: ApplicationShell;
+
+    readonly id = 'theia-deleted-editor-decorator';
+    protected readonly onDidChangeDecorationsEmitter = new Emitter();
+    readonly onDidChangeDecorations = this.onDidChangeDecorationsEmitter.event;
+    protected deletedURIs = new Set<string>();
+
+    @postConstruct()
+    init(): void {
+        this.fileSystemContribution.onDidChangeEditorFile(({ editor, type }) => {
+            const uri = editor.getResourceUri()?.toString();
+            if (uri) {
+                if (type === FileChangeType.DELETED) {
+                    this.deletedURIs.add(uri);
+                } else if (type === FileChangeType.ADDED) {
+                    this.deletedURIs.delete(uri);
+                }
+                this.fireDidChangeDecorations((tree: Tree) => this.collectDecorators(tree));
+            }
+        });
+        this.shell.onDidAddWidget(() => {
+            const newDeletedURIs = new Set<string>();
+            this.shell.widgets.forEach(widget => {
+                if (NavigatableWidget.is(widget)) {
+                    const uri = widget.getResourceUri()?.toString();
+                    if (uri && this.deletedURIs.has(uri)) {
+                        newDeletedURIs.add(uri);
+                    }
+                }
+            });
+            this.deletedURIs = newDeletedURIs;
+        });
+    }
+
+    decorations(tree: Tree): Map<string, TreeDecoration.Data> {
+        return this.collectDecorators(tree);
+    }
+
+    protected collectDecorators(tree: Tree): Map<string, TreeDecoration.Data> {
+        const result = new Map<string, TreeDecoration.Data>();
+        if (tree.root === undefined) {
+            return result;
+        }
+        for (const node of new DepthFirstTreeIterator(tree.root)) {
+            if (FileStatNode.is(node)) {
+                const uri = node.uri.toString();
+                if (this.deletedURIs.has(uri)) {
+                    const deletedDecoration: TreeDecoration.Data = {
+                        fontData: {
+                            style: 'line-through',
+                        }
+                    };
+                    result.set(node.id, deletedDecoration);
+                }
+            }
+        }
+        return result;
+    }
+
+    protected fireDidChangeDecorations(event: (tree: Tree) => Map<string, TreeDecoration.Data>): void {
+        this.onDidChangeDecorationsEmitter.fire(event);
+    }
+}

packages/navigator/src/browser/open-editors-widget/navigator-open-editors-commands.ts

@@ -0,0 +1,48 @@
+// *****************************************************************************
+// Copyright (C) 2021 Ericsson and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+// *****************************************************************************
+
+import { CommonCommands } from '@theia/core/lib/browser';
+import { Command } from '@theia/core/lib/common';
+
+export namespace OpenEditorsCommands {
+    export const CLOSE_ALL_TABS_FROM_TOOLBAR = Command.toDefaultLocalizedCommand({
+        id: 'navigator.close.all.editors.toolbar',
+        category: CommonCommands.FILE_CATEGORY,
+        label: 'Close All Editors',
+        iconClass: 'codicon codicon-close-all'
+    });
+
+    export const SAVE_ALL_TABS_FROM_TOOLBAR = Command.toDefaultLocalizedCommand({
+        id: 'navigator.save.all.editors.toolbar',
+        category: CommonCommands.FILE_CATEGORY,
+        label: 'Save All',
+        iconClass: 'codicon codicon-save-all'
+    });
+
+    export const CLOSE_ALL_EDITORS_IN_GROUP_FROM_ICON = Command.toDefaultLocalizedCommand({
+        id: 'navigator.close.all.in.area.icon',
+        category: CommonCommands.VIEW_CATEGORY,
+        label: 'Close Group',
+        iconClass: 'codicon codicon-close-all'
+    });
+
+    export const SAVE_ALL_IN_GROUP_FROM_ICON = Command.toDefaultLocalizedCommand({
+        id: 'navigator.save.all.in.area.icon',
+        category: CommonCommands.FILE_CATEGORY,
+        label: 'Save All in Group',
+        iconClass: 'codicon codicon-save-all'
+    });
+}

packages/navigator/src/browser/open-editors-widget/navigator-open-editors-decorator-service.ts

@@ -0,0 +1,28 @@
+// *****************************************************************************
+// Copyright (C) 2021 Ericsson and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+// *****************************************************************************
+
+import { inject, injectable, named } from '@theia/core/shared/inversify';
+import { TreeDecorator, AbstractTreeDecoratorService } from '@theia/core/lib/browser/tree/tree-decorator';
+import { ContributionProvider } from '@theia/core/lib/common';
+
+export const OpenEditorsTreeDecorator = Symbol('OpenEditorsTreeDecorator');
+
+@injectable()
+export class OpenEditorsTreeDecoratorService extends AbstractTreeDecoratorService {
+    constructor(@inject(ContributionProvider) @named(OpenEditorsTreeDecorator) protected readonly contributions: ContributionProvider<TreeDecorator>) {
+        super(contributions.getContributions());
+    }
+}

packages/navigator/src/browser/open-editors-widget/navigator-open-editors-menus.ts

@@ -0,0 +1,26 @@
+// *****************************************************************************
+// Copyright (C) 2021 Ericsson and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+// *****************************************************************************
+
+import { MenuPath } from '@theia/core/lib/common';
+
+export const OPEN_EDITORS_CONTEXT_MENU: MenuPath = ['open-editors-context-menu'];
+export namespace OpenEditorsContextMenu {
+    export const NAVIGATION = [...OPEN_EDITORS_CONTEXT_MENU, '1_navigation'];
+    export const CLIPBOARD = [...OPEN_EDITORS_CONTEXT_MENU, '2_clipboard'];
+    export const SAVE = [...OPEN_EDITORS_CONTEXT_MENU, '3_save'];
+    export const COMPARE = [...OPEN_EDITORS_CONTEXT_MENU, '4_compare'];
+    export const MODIFICATION = [...OPEN_EDITORS_CONTEXT_MENU, '5_modification'];
+}

packages/navigator/src/browser/open-editors-widget/navigator-open-editors-tree-model.ts

@@ -0,0 +1,254 @@
+// *****************************************************************************
+// Copyright (C) 2021 Ericsson and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+// *****************************************************************************
+
+import { injectable, inject, postConstruct } from '@theia/core/shared/inversify';
+import { FileNode, FileStatNode, FileTreeModel } from '@theia/filesystem/lib/browser';
+import {
+    ApplicationShell,
+    CompositeTreeNode,
+    open,
+    NavigatableWidget,
+    OpenerService,
+    SelectableTreeNode,
+    TreeNode,
+    Widget,
+    ExpandableTreeNode,
+    TabBar
+} from '@theia/core/lib/browser';
+import { WorkspaceService } from '@theia/workspace/lib/browser';
+import debounce = require('@theia/core/shared/lodash.debounce');
+import { nls } from '@theia/core/lib/common';
+import { FileStat } from '@theia/filesystem/lib/common/files';
+
+export interface OpenEditorNode extends FileStatNode {
+    widget: Widget;
+};
+
+export namespace OpenEditorNode {
+    export function is(node: unknown): node is OpenEditorNode {
+        return FileStatNode.is(node) && 'widget' in node;
+    }
+}
+
+@injectable()
+export class OpenEditorsModel extends FileTreeModel {
+    static GROUP_NODE_ID_PREFIX = 'group-node';
+    static AREA_NODE_ID_PREFIX = 'area-node';
+
+    @inject(ApplicationShell) protected readonly applicationShell: ApplicationShell;
+    @inject(WorkspaceService) protected readonly workspaceService: WorkspaceService;
+    @inject(OpenerService) protected readonly openerService: OpenerService;
+
+    // Returns the collection of editors belonging to a tabbar group in the main area
+    protected _editorWidgetsByGroup = new Map<number, { widgets: NavigatableWidget[], tabbar: TabBar<Widget> }>();
+
+    // Returns the collection of editors belonging to an area grouping (main, left, right bottom)
+    protected _editorWidgetsByArea = new Map<ApplicationShell.Area, NavigatableWidget[]>();
+
+    // Last collection of editors before a layout modification, used to detect changes in widget ordering
+    protected _lastEditorWidgetsByArea = new Map<ApplicationShell.Area, NavigatableWidget[]>();
+
+    protected cachedFileStats = new Map<string, FileStat>();
+
+    get editorWidgets(): NavigatableWidget[] {
+        const editorWidgets: NavigatableWidget[] = [];
+        this._editorWidgetsByArea.forEach(widgets => editorWidgets.push(...widgets));
+        return editorWidgets;
+    }
+
+    getTabBarForGroup(id: number): TabBar<Widget> | undefined {
+        return this._editorWidgetsByGroup.get(id)?.tabbar;
+    }
+
+    @postConstruct()
+    protected override init(): void {
+        super.init();
+        this.setupHandlers();
+        this.initializeRoot();
+    }
+
+    protected setupHandlers(): void {
+        this.toDispose.push(this.applicationShell.onDidChangeCurrentWidget(({ newValue }) => {
+            const nodeToSelect = this.tree.getNode(newValue?.id);
+            if (nodeToSelect && SelectableTreeNode.is(nodeToSelect)) {
+                this.selectNode(nodeToSelect);
+            }
+        }));
+        this.toDispose.push(this.applicationShell.onDidAddWidget(async () => {
+            await this.updateOpenWidgets();
+            const existingWidgetIds = new Set(this.editorWidgets.map(widget => widget.id));
+            this.cachedFileStats.forEach((_fileStat, id) => {
+                if (!existingWidgetIds.has(id)) {
+                    this.cachedFileStats.delete(id);
+                }
+            });
+        }));
+        this.toDispose.push(this.applicationShell.onDidRemoveWidget(() => this.updateOpenWidgets()));
+        // Check for tabs rearranged in main and bottom
+        this.applicationShell.mainPanel.layoutModified.connect(() => this.doUpdateOpenWidgets('main'));
+        this.applicationShell.bottomPanel.layoutModified.connect(() => this.doUpdateOpenWidgets('bottom'));
+    }
+
+    protected async initializeRoot(): Promise<void> {
+        await this.updateOpenWidgets();
+        this.fireChanged();
+    }
+
+    protected updateOpenWidgets = debounce(this.doUpdateOpenWidgets, 250);
+
+    protected async doUpdateOpenWidgets(layoutModifiedArea?: ApplicationShell.Area): Promise<void> {
+        this._lastEditorWidgetsByArea = this._editorWidgetsByArea;
+        this._editorWidgetsByArea = new Map<ApplicationShell.Area, NavigatableWidget[]>();
+        let doRebuild = true;
+        const areas: ApplicationShell.Area[] = ['main', 'bottom', 'left', 'right', 'top', 'secondaryWindow'];
+        areas.forEach(area => {
+            const editorWidgetsForArea = this.applicationShell.getWidgets(area).filter((widget): widget is NavigatableWidget => NavigatableWidget.is(widget));
+            if (editorWidgetsForArea.length) {
+                this._editorWidgetsByArea.set(area, editorWidgetsForArea);
+            }
+        });
+        if (this._lastEditorWidgetsByArea.size === 0) {
+            this._lastEditorWidgetsByArea = this._editorWidgetsByArea;
+        }
+        // `layoutModified` can be triggered when tabs are clicked, even if they are not rearranged.
+        // This will check for those instances and prevent a rebuild if it is unnecessary. Rebuilding
+        // the tree if there is no change can cause the tree's selection to flicker.
+        if (layoutModifiedArea) {
+            doRebuild = this.shouldRebuildTreeOnLayoutModified(layoutModifiedArea);
+        }
+        if (doRebuild) {
+            this.root = await this.buildRootFromOpenedWidgets(this._editorWidgetsByArea);
+        }
+    }
+
+    protected shouldRebuildTreeOnLayoutModified(area: ApplicationShell.Area): boolean {
+        const currentOrdering = this._editorWidgetsByArea.get(area);
+        const previousOrdering = this._lastEditorWidgetsByArea.get(area);
+        if (currentOrdering?.length === 1) {
+            return true;
+        }
+        if (currentOrdering?.length !== previousOrdering?.length) {
+            return true;
+        }
+        if (!!currentOrdering && !!previousOrdering) {
+            return !currentOrdering.every((widget, index) => widget === previousOrdering[index]);
+        }
+        return true;
+    }
+
+    protected tryCreateWidgetGroupMap(): Map<Widget, CompositeTreeNode> {
+        const mainTabBars = this.applicationShell.mainAreaTabBars;
+        this._editorWidgetsByGroup = new Map();
+        const widgetGroupMap = new Map<Widget, CompositeTreeNode>();
+        if (mainTabBars.length > 1) {
+            mainTabBars.forEach((tabbar, index) => {
+                const groupNumber = index + 1;
+                const newCaption = nls.localizeByDefault('Group {0}', groupNumber);
+                const groupNode = {
+                    parent: undefined,
+                    id: `${OpenEditorsModel.GROUP_NODE_ID_PREFIX}:${groupNumber}`,
+                    name: newCaption,
+                    children: []
+                };
+                const widgets: NavigatableWidget[] = [];
+                tabbar.titles.map(title => {
+                    const { owner } = title;
+                    widgetGroupMap.set(owner, groupNode);
+                    if (NavigatableWidget.is(owner)) {
+                        widgets.push(owner);
+                    }
+                });
+                this._editorWidgetsByGroup.set(groupNumber, { widgets, tabbar });
+            });
+        }
+        return widgetGroupMap;
+    }
+
+    protected async buildRootFromOpenedWidgets(widgetsByArea: Map<ApplicationShell.Area, NavigatableWidget[]>): Promise<CompositeTreeNode> {
+        const rootNode: CompositeTreeNode = {
+            id: 'open-editors:root',
+            parent: undefined,
+            visible: false,
+            children: [],
+        };
+
+        const mainAreaWidgetGroups = this.tryCreateWidgetGroupMap();
+
+        for (const [area, widgetsInArea] of widgetsByArea.entries()) {
+            const areaNode: CompositeTreeNode & ExpandableTreeNode = {
+                id: `${OpenEditorsModel.AREA_NODE_ID_PREFIX}:${area}`,
+                parent: rootNode,
+                name: ApplicationShell.areaLabels[area],
+                expanded: true,
+                children: []
+            };
+            for (const widget of widgetsInArea) {
+                const uri = widget.getResourceUri();
+                if (uri) {
+                    let fileStat: FileStat;
+                    try {
+                        fileStat = await this.fileService.resolve(uri);
+                        this.cachedFileStats.set(widget.id, fileStat);
+                    } catch {
+                        const cachedStat = this.cachedFileStats.get(widget.id);
+                        if (cachedStat) {
+                            fileStat = cachedStat;
+                        } else {
+                            continue;
+                        }
+                    }
+
+                    const openEditorNode: OpenEditorNode = {
+                        id: widget.id,
+                        fileStat,
+                        uri,
+                        selected: false,
+                        parent: undefined,
+                        name: widget.title.label,
+                        icon: widget.title.iconClass,
+                        widget
+                    };
+                    // only show groupings for main area widgets if more than one tabbar
+                    if ((area === 'main') && (mainAreaWidgetGroups.size > 1)) {
+                        const groupNode = mainAreaWidgetGroups.get(widget);
+                        if (groupNode) {
+                            CompositeTreeNode.addChild(groupNode, openEditorNode);
+                            CompositeTreeNode.addChild(areaNode, groupNode);
+                        }
+                    } else {
+                        CompositeTreeNode.addChild(areaNode, openEditorNode);
+                    }
+                }
+            }
+            // If widgets are only in the main area and in a single tabbar, then don't show area node
+            if (widgetsByArea.size === 1 && widgetsByArea.has('main') && area === 'main') {
+                areaNode.children.forEach(child => CompositeTreeNode.addChild(rootNode, child));
+            } else {
+                CompositeTreeNode.addChild(rootNode, areaNode);
+            }
+
+        }
+        return rootNode;
+    }
+
+    protected override doOpenNode(node: TreeNode): void {
+        if (node.visible === false) {
+            return;
+        } else if (FileNode.is(node)) {
+            open(this.openerService, node.uri);
+        }
+    }
+}

packages/navigator/src/browser/open-editors-widget/navigator-open-editors-widget.tsx

@@ -0,0 +1,274 @@
+// *****************************************************************************
+// Copyright (C) 2021 Ericsson and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+// *****************************************************************************
+
+import * as React from '@theia/core/shared/react';
+import { injectable, interfaces, Container, postConstruct, inject } from '@theia/core/shared/inversify';
+import {
+    ApplicationShell,
+    codicon,
+    ContextMenuRenderer,
+    defaultTreeProps,
+    NavigatableWidget,
+    NodeProps,
+    Saveable,
+    TabBar,
+    TreeDecoration,
+    TreeDecoratorService,
+    TreeModel,
+    TreeNode,
+    TreeProps,
+    TreeWidget,
+    TREE_NODE_CONTENT_CLASS,
+    Widget,
+} from '@theia/core/lib/browser';
+import { OpenEditorNode, OpenEditorsModel } from './navigator-open-editors-tree-model';
+import { createFileTreeContainer, FileTreeModel, FileTreeWidget } from '@theia/filesystem/lib/browser';
+import { OpenEditorsTreeDecoratorService } from './navigator-open-editors-decorator-service';
+import { OPEN_EDITORS_CONTEXT_MENU } from './navigator-open-editors-menus';
+import { CommandService } from '@theia/core/lib/common';
+import { OpenEditorsCommands } from './navigator-open-editors-commands';
+import { nls } from '@theia/core/lib/common/nls';
+import { WorkspaceService } from '@theia/workspace/lib/browser';
+import { AbstractNavigatorTreeWidget } from '../abstract-navigator-tree-widget';
+
+export const OPEN_EDITORS_PROPS: TreeProps = {
+    ...defaultTreeProps,
+    virtualized: false,
+    contextMenuPath: OPEN_EDITORS_CONTEXT_MENU,
+    leftPadding: 22
+};
+
+export interface OpenEditorsNodeRow extends TreeWidget.NodeRow {
+    node: OpenEditorNode;
+}
+@injectable()
+export class OpenEditorsWidget extends AbstractNavigatorTreeWidget {
+    static ID = 'theia-open-editors-widget';
+    static LABEL = nls.localizeByDefault('Open Editors');
+
+    @inject(ApplicationShell) protected readonly applicationShell: ApplicationShell;
+    @inject(CommandService) protected readonly commandService: CommandService;
+    @inject(WorkspaceService) protected readonly workspaceService: WorkspaceService;
+
+    static createContainer(parent: interfaces.Container): Container {
+        const child = createFileTreeContainer(parent);
+
+        child.unbind(FileTreeModel);
+        child.bind(OpenEditorsModel).toSelf();
+        child.rebind(TreeModel).toService(OpenEditorsModel);
+
+        child.unbind(FileTreeWidget);
+        child.bind(OpenEditorsWidget).toSelf();
+
+        child.rebind(TreeProps).toConstantValue(OPEN_EDITORS_PROPS);
+
+        child.bind(OpenEditorsTreeDecoratorService).toSelf().inSingletonScope();
+        child.rebind(TreeDecoratorService).toService(OpenEditorsTreeDecoratorService);
+        return child;
+    }
+
+    static createWidget(parent: interfaces.Container): OpenEditorsWidget {
+        return OpenEditorsWidget.createContainer(parent).get(OpenEditorsWidget);
+    }
+
+    constructor(
+        @inject(TreeProps) props: TreeProps,
+        @inject(OpenEditorsModel) override readonly model: OpenEditorsModel,
+        @inject(ContextMenuRenderer) contextMenuRenderer: ContextMenuRenderer
+    ) {
+        super(props, model, contextMenuRenderer);
+    }
+
+    @postConstruct()
+    override init(): void {
+        super.init();
+        this.id = OpenEditorsWidget.ID;
+        this.title.label = OpenEditorsWidget.LABEL;
+        this.addClass(OpenEditorsWidget.ID);
+        this.update();
+    }
+
+    get editorWidgets(): NavigatableWidget[] {
+        return this.model.editorWidgets;
+    }
+
+    // eslint-disable-next-line no-null/no-null
+    protected activeTreeNodePrefixElement: string | undefined | null;
+
+    protected override renderNode(node: OpenEditorNode, props: NodeProps): React.ReactNode {
+        if (!TreeNode.isVisible(node)) {
+            return undefined;
+        }
+        const attributes = this.createNodeAttributes(node, props);
+        const isEditorNode = !(node.id.startsWith(OpenEditorsModel.GROUP_NODE_ID_PREFIX) || node.id.startsWith(OpenEditorsModel.AREA_NODE_ID_PREFIX));
+        const content = <div className={`${TREE_NODE_CONTENT_CLASS}`}>
+            {this.renderExpansionToggle(node, props)}
+            {isEditorNode && this.renderPrefixIcon(node)}
+            {this.decorateIcon(node, this.renderIcon(node, props))}
+            <div className='noWrapInfo theia-TreeNodeSegmentGrow'>
+                {this.renderCaptionAffixes(node, props, 'captionPrefixes')}
+                {this.renderCaption(node, props)}
+                {this.renderCaptionAffixes(node, props, 'captionSuffixes')}
+            </div>
+            {this.renderTailDecorations(node, props)}
+            {(this.isGroupNode(node) || this.isAreaNode(node)) && this.renderInteractables(node, props)}
+        </div>;
+        return React.createElement('div', attributes, content);
+    }
+
+    protected override getDecorationData<K extends keyof TreeDecoration.Data>(node: TreeNode, key: K): Required<Pick<TreeDecoration.Data, K>>[K][] {
+        const contributed = super.getDecorationData(node, key);
+        if (key === 'captionSuffixes' && OpenEditorNode.is(node)) {
+            (contributed as Array<Array<TreeDecoration.CaptionAffix>>).push(this.getWorkspaceDecoration(node));
+        }
+        return contributed;
+    }
+
+    protected getWorkspaceDecoration(node: OpenEditorNode): TreeDecoration.CaptionAffix[] {
+        const color = this.getDecorationData(node, 'fontData').find(data => data.color)?.color;
+        return [{
+            fontData: { color },
+            data: this.labelProvider.getDetails(node.fileStat),
+        }];
+    }
+
+    protected isGroupNode(node: OpenEditorNode): boolean {
+        return node.id.startsWith(OpenEditorsModel.GROUP_NODE_ID_PREFIX);
+    }
+
+    protected isAreaNode(node: OpenEditorNode): boolean {
+        return node.id.startsWith(OpenEditorsModel.AREA_NODE_ID_PREFIX);
+    }
+
+    protected override doRenderNodeRow({ node, depth }: OpenEditorsNodeRow): React.ReactNode {
+        let groupClass = '';
+        if (this.isGroupNode(node)) {
+            groupClass = 'group-node';
+        } else if (this.isAreaNode(node)) {
+            groupClass = 'area-node';
+        }
+        return <div className={`open-editors-node-row ${this.getPrefixIconClass(node)}${groupClass}`}>
+            {this.renderNode(node, { depth })}
+        </div>;
+    }
+
+    protected renderInteractables(node: OpenEditorNode, props: NodeProps): React.ReactNode {
+        return (<div className='open-editors-inline-actions-container'>
+            <div className='open-editors-inline-action'>
+                <a className='codicon codicon-save-all'
+                    title={OpenEditorsCommands.SAVE_ALL_IN_GROUP_FROM_ICON.label}
+                    onClick={this.handleGroupActionIconClicked}
+                    data-id={node.id}
+                    id={OpenEditorsCommands.SAVE_ALL_IN_GROUP_FROM_ICON.id}
+                />
+            </div>
+            <div className='open-editors-inline-action' >
+                <a className='codicon codicon-close-all'
+                    title={OpenEditorsCommands.CLOSE_ALL_EDITORS_IN_GROUP_FROM_ICON.label}
+                    onClick={this.handleGroupActionIconClicked}
+                    data-id={node.id}
+                    id={OpenEditorsCommands.CLOSE_ALL_EDITORS_IN_GROUP_FROM_ICON.id}
+                />
+            </div>
+        </div>
+        );
+    }
+
+    protected handleGroupActionIconClicked = async (e: React.MouseEvent<HTMLAnchorElement>) => this.doHandleGroupActionIconClicked(e);
+    protected async doHandleGroupActionIconClicked(e: React.MouseEvent<HTMLAnchorElement>): Promise<void> {
+        e.stopPropagation();
+        const groupName = e.currentTarget.getAttribute('data-id');
+        const command = e.currentTarget.id;
+        if (groupName && command) {
+            const groupFromTarget: string | number | undefined = groupName.split(':').pop();
+            const areaOrTabBar = this.sanitizeInputFromClickHandler(groupFromTarget);
+            if (areaOrTabBar) {
+                return this.commandService.executeCommand(command, areaOrTabBar);
+            }
+        }
+    }
+
+    protected sanitizeInputFromClickHandler(groupFromTarget?: string): ApplicationShell.Area | TabBar<Widget> | undefined {
+        let areaOrTabBar: ApplicationShell.Area | TabBar<Widget> | undefined;
+        if (groupFromTarget) {
+            if (ApplicationShell.isValidArea(groupFromTarget)) {
+                areaOrTabBar = groupFromTarget;
+            } else {
+                const groupAsNum = parseInt(groupFromTarget);
+                if (!isNaN(groupAsNum)) {
+                    areaOrTabBar = this.model.getTabBarForGroup(groupAsNum);
+                }
+            }
+        }
+        return areaOrTabBar;
+    }
+
+    protected renderPrefixIcon(node: OpenEditorNode): React.ReactNode {
+        return (
+            <div className='open-editors-prefix-icon-container'>
+                <div data-id={node.id}
+                    className={`open-editors-prefix-icon dirty ${codicon('circle-filled', true)}`}
+                />
+                <div data-id={node.id}
+                    onClick={this.closeEditor}
+                    className={`open-editors-prefix-icon close ${codicon('close', true)}`}
+                />
+            </div>);
+    }
+
+    protected getPrefixIconClass(node: OpenEditorNode): string {
+        const saveable = Saveable.get(node.widget);
+        if (saveable) {
+            return saveable.dirty ? 'dirty' : '';
+        }
+        return '';
+    }
+
+    protected closeEditor = async (e: React.MouseEvent<HTMLDivElement>) => this.doCloseEditor(e);
+    protected async doCloseEditor(e: React.MouseEvent<HTMLDivElement>): Promise<void> {
+        const widgetId = e.currentTarget.getAttribute('data-id');
+        if (widgetId) {
+            await this.applicationShell.closeWidget(widgetId);
+        }
+    }
+
+    protected override tapNode(node?: TreeNode): void {
+        if (OpenEditorNode.is(node)) {
+            this.applicationShell.activateWidget(node.widget.id);
+        }
+        super.tapNode(node);
+    }
+
+    protected override handleContextMenuEvent(node: OpenEditorNode | undefined, event: React.MouseEvent<HTMLElement>): void {
+        super.handleContextMenuEvent(node, event);
+        if (node) {
+            // Since the CommonCommands used in the context menu act on the shell's activeWidget, this is necessary to ensure
+            // that the EditorWidget is activated, not the Navigator itself
+            this.applicationShell.activateWidget(node.widget.id);
+        }
+    }
+
+    protected override getPaddingLeft(node: TreeNode): number {
+        if (node.id.startsWith(OpenEditorsModel.AREA_NODE_ID_PREFIX)) {
+            return 0;
+        }
+        return this.props.leftPadding;
+    }
+
+    // The state of this widget is derived from external factors. No need to store or restore it.
+    override storeState(): object { return {}; }
+    override restoreState(): void { }
+}

packages/navigator/src/browser/open-editors-widget/open-editors.css

@@ -0,0 +1,104 @@
+/********************************************************************************
+ * Copyright (C) 2021 Ericsson and others.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * This Source Code may also be made available under the following Secondary
+ * Licenses when the conditions for such availability set forth in the Eclipse
+ * Public License v. 2.0 are satisfied: GNU General Public License, version 2
+ * with the GNU Classpath Exception which is available at
+ * https://www.gnu.org/software/classpath/license.html.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+ ********************************************************************************/
+
+:root {
+  --theia-open-editors-icon-width: 20px;
+}
+
+.theia-open-editors-widget .theia-caption-suffix {
+  margin-left: var(--theia-ui-padding);
+  font-size: var(--theia-ui-font-size0);
+}
+
+.theia-open-editors-widget
+  .open-editors-node-row
+  .open-editors-prefix-icon-container {
+  min-width: var(--theia-open-editors-icon-width);
+}
+
+.theia-open-editors-widget
+  .open-editors-node-row
+  .open-editors-prefix-icon.dirty,
+.theia-open-editors-widget
+  .open-editors-node-row.dirty:hover
+  .open-editors-prefix-icon.dirty {
+  display: none;
+}
+
+.theia-open-editors-widget
+  .open-editors-node-row.dirty
+  .open-editors-prefix-icon.dirty {
+  display: block;
+}
+
+.theia-open-editors-widget
+  .open-editors-node-row
+  .open-editors-prefix-icon.close {
+  display: none;
+}
+
+.theia-open-editors-widget
+  .open-editors-node-row:not(.dirty)
+  .theia-mod-selected
+  .open-editors-prefix-icon.close,
+.theia-open-editors-widget
+  .open-editors-node-row:hover
+  .open-editors-prefix-icon.close {
+  display: block;
+}
+
+.theia-open-editors-widget .open-editors-node-row.group-node,
+.theia-open-editors-widget .open-editors-node-row.area-node {
+  font-weight: 700;
+  text-transform: uppercase;
+  font-size: var(--theia-ui-font-size0);
+}
+
+.theia-open-editors-widget .open-editors-node-row.area-node {
+  font-style: italic;
+}
+
+.theia-open-editors-widget .open-editors-inline-actions-container {
+  display: flex;
+  justify-content: flex-end;
+  margin-left: 3px;
+  min-height: 16px;
+}
+
+.theia-open-editors-widget .open-editors-inline-action a {
+  color: var(--theia-icon-foreground);
+}
+
+.theia-open-editors-widget .open-editors-inline-action {
+  padding: 0px 3px;
+  font-size: var(--theia-ui-font-size1);
+  margin: 0 2px;
+  cursor: pointer;
+  display: flex;
+  align-items: center;
+}
+
+.theia-open-editors-widget
+  .open-editors-node-row
+  .open-editors-inline-actions-container {
+  visibility: hidden;
+}
+
+.theia-open-editors-widget
+  .open-editors-node-row:hover
+  .open-editors-inline-actions-container {
+  visibility: visible;
+}

packages/navigator/src/browser/style/files.svg

@@ -0,0 +1,4 @@
+<!--Copyright (c) Microsoft Corporation. All rights reserved.-->
+<!--Copyright (C) 2019 TypeFox and others.-->
+<!--Licensed under the MIT License. See License.txt in the project root for license information.-->
+<svg fill="#F6F6F6" height="28" viewBox="0 0 28 28" width="28" xmlns="http://www.w3.org/2000/svg"><path d="m14.965 7h-8.91642s-2.04858.078-2.04858 2v15s0 2 2.04858 2l11.26722-.004c2.0486.004 2.0486-1.996 2.0486-1.996v-11.491zm-1.7464 2v5h4.0972v10h-11.26722v-15zm5.6428-6h-8.6993s-2.06493.016-2.0803 2h8.2097v.454l4.0265 4.546h1.095v12c2.0485 0 2.0485-1.995 2.0485-1.995v-11.357z" fill="#F6F6F6"/></svg>

packages/navigator/src/browser/style/index.css

@@ -0,0 +1,43 @@
+/********************************************************************************
+ * Copyright (C) 2017 TypeFox and others.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * This Source Code may also be made available under the following Secondary
+ * Licenses when the conditions for such availability set forth in the Eclipse
+ * Public License v. 2.0 are satisfied: GNU General Public License, version 2
+ * with the GNU Classpath Exception which is available at
+ * https://www.gnu.org/software/classpath/license.html.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+ ********************************************************************************/
+
+.theia-Files {
+  height: 100%;
+}
+
+.theia-navigator-container {
+  font-size: var(--theia-ui-font-size1);
+  padding: 5px;
+  position: relative;
+}
+
+.theia-navigator-container .open-workspace-button-container {
+  margin: auto;
+  margin-top: 5px;
+  display: flex;
+  justify-content: center;
+  align-self: center;
+}
+
+.theia-navigator-container .center {
+  text-align: center;
+}
+
+.lm-Widget .open-workspace-button {
+  padding: 4px 12px;
+  width: calc(100% - var(--theia-ui-padding) * 4);
+  margin-left: 0;
+}

packages/navigator/src/common/navigator-preferences.ts

@@ -0,0 +1,66 @@
+// *****************************************************************************
+// Copyright (C) 2018 TypeFox and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+// *****************************************************************************
+
+import { interfaces } from '@theia/core/shared/inversify';
+import { createPreferenceProxy, PreferenceContribution, PreferenceProxy, PreferenceSchema, PreferenceService } from '@theia/core';
+import { nls } from '@theia/core/lib/common/nls';
+
+export const EXPLORER_COMPACT_FOLDERS = 'explorer.compactFolders';
+
+export const FileNavigatorConfigSchema: PreferenceSchema = {
+    properties: {
+        'explorer.autoReveal': {
+            type: 'boolean',
+            description: nls.localizeByDefault('Controls whether the Explorer should automatically reveal and select files when opening them.'),
+            default: true
+        },
+        'explorer.decorations.colors': {
+            type: 'boolean',
+            description: nls.localizeByDefault('Controls whether file decorations should use colors.'),
+            default: true
+        },
+        [EXPLORER_COMPACT_FOLDERS]: {
+            type: 'boolean',
+            // eslint-disable-next-line max-len
+            description: nls.localizeByDefault('Controls whether the Explorer should render folders in a compact form. In such a form, single child folders will be compressed in a combined tree element. Useful for Java package structures, for example.'),
+            default: true,
+        }
+    },
+};
+
+export interface FileNavigatorConfiguration {
+    'explorer.autoReveal': boolean;
+    'explorer.decorations.colors': boolean;
+    [EXPLORER_COMPACT_FOLDERS]: boolean;
+}
+
+export const FileNavigatorPreferenceContribution = Symbol('FileNavigatorPreferenceContribution');
+export const FileNavigatorPreferences = Symbol('NavigatorPreferences');
+export type FileNavigatorPreferences = PreferenceProxy<FileNavigatorConfiguration>;
+
+export function createNavigatorPreferences(preferences: PreferenceService, schema: PreferenceSchema = FileNavigatorConfigSchema): FileNavigatorPreferences {
+    return createPreferenceProxy(preferences, schema);
+}
+
+export function bindFileNavigatorPreferences(bind: interfaces.Bind): void {
+    bind(FileNavigatorPreferences).toDynamicValue(ctx => {
+        const preferences = ctx.container.get<PreferenceService>(PreferenceService);
+        const contribution = ctx.container.get<PreferenceContribution>(FileNavigatorPreferenceContribution);
+        return createNavigatorPreferences(preferences, contribution.schema);
+    }).inSingletonScope();
+    bind(FileNavigatorPreferenceContribution).toConstantValue({ schema: FileNavigatorConfigSchema });
+    bind(PreferenceContribution).toService(FileNavigatorPreferenceContribution);
+}

packages/navigator/src/electron-browser/electron-navigator-menu-contribution.ts

@@ -0,0 +1,119 @@
+// *****************************************************************************
+// Copyright (C) 2021 EclipseSource and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+// *****************************************************************************
+
+import { Command, CommandContribution, CommandRegistry, MenuContribution, MenuModelRegistry, SelectionService, URI } from '@theia/core';
+import { CommonCommands, KeybindingContribution, KeybindingRegistry, OpenWithService } from '@theia/core/lib/browser';
+import { WidgetManager } from '@theia/core/lib/browser/widget-manager';
+import { nls } from '@theia/core/lib/common';
+import { FileUri } from '@theia/core/lib/common/file-uri';
+import { isOSX, isWindows } from '@theia/core/lib/common/os';
+import { UriAwareCommandHandler } from '@theia/core/lib/common/uri-command-handler';
+import '@theia/core/lib/electron-common/electron-api';
+import { inject, injectable } from '@theia/core/shared/inversify';
+import { FileStatNode } from '@theia/filesystem/lib/browser';
+import { WorkspaceService } from '@theia/workspace/lib/browser';
+import { FILE_NAVIGATOR_ID, FileNavigatorWidget } from '../browser';
+import { NavigatorContextMenu, SHELL_TABBAR_CONTEXT_REVEAL } from '../browser/navigator-contribution';
+
+export const OPEN_CONTAINING_FOLDER = Command.toDefaultLocalizedCommand({
+    id: 'revealFileInOS',
+    category: CommonCommands.FILE_CATEGORY,
+    label: isWindows ? 'Reveal in File Explorer' :
+        isOSX ? 'Reveal in Finder' :
+        /* linux */ 'Open Containing Folder'
+});
+
+export const OPEN_WITH_SYSTEM_APP = Command.toLocalizedCommand({
+    id: 'openWithSystemApp',
+    category: CommonCommands.FILE_CATEGORY,
+    label: 'Open With System Editor'
+}, 'theia/navigator/openWithSystemEditor');
+
+@injectable()
+export class ElectronNavigatorMenuContribution implements MenuContribution, CommandContribution, KeybindingContribution {
+
+    @inject(SelectionService)
+    protected readonly selectionService: SelectionService;
+
+    @inject(WidgetManager)
+    protected readonly widgetManager: WidgetManager;
+
+    @inject(WorkspaceService)
+    protected readonly workspaceService: WorkspaceService;
+
+    @inject(OpenWithService)
+    protected readonly openWithService: OpenWithService;
+
+    registerCommands(commands: CommandRegistry): void {
+        commands.registerCommand(OPEN_CONTAINING_FOLDER, UriAwareCommandHandler.MonoSelect(this.selectionService, {
+            execute: async uri => {
+                window.electronTheiaCore.showItemInFolder(FileUri.fsPath(uri));
+            },
+            isEnabled: uri => !!this.workspaceService.getWorkspaceRootUri(uri),
+            isVisible: uri => !!this.workspaceService.getWorkspaceRootUri(uri),
+        }));
+        commands.registerCommand(OPEN_WITH_SYSTEM_APP, UriAwareCommandHandler.MonoSelect(this.selectionService, {
+            execute: async uri => {
+                this.openWithSystemApplication(uri);
+            }
+        }));
+        this.openWithService.registerHandler({
+            id: 'system-editor',
+            label: nls.localize('theia/navigator/systemEditor', 'System Editor'),
+            providerName: nls.localizeByDefault('Built-in'),
+            // Low priority to avoid conflicts with other open handlers.
+            canHandle: uri => (uri.scheme === 'file') ? 10 : 0,
+            open: uri => {
+                this.openWithSystemApplication(uri);
+                return {};
+            }
+        });
+    }
+
+    protected openWithSystemApplication(uri: URI): void {
+        window.electronTheiaCore.openWithSystemApp(FileUri.fsPath(uri));
+    }
+
+    registerMenus(menus: MenuModelRegistry): void {
+        menus.registerMenuAction(NavigatorContextMenu.NAVIGATION, {
+            commandId: OPEN_CONTAINING_FOLDER.id,
+            label: OPEN_CONTAINING_FOLDER.label
+        });
+        menus.registerMenuAction(SHELL_TABBAR_CONTEXT_REVEAL, {
+            commandId: OPEN_CONTAINING_FOLDER.id,
+            label: OPEN_CONTAINING_FOLDER.label,
+            order: '4'
+        });
+    }
+
+    registerKeybindings(keybindings: KeybindingRegistry): void {
+        keybindings.registerKeybinding({
+            command: OPEN_CONTAINING_FOLDER.id,
+            keybinding: 'ctrlcmd+alt+p',
+            when: 'filesExplorerFocus'
+        });
+    }
+
+    protected getSelectedFileStatNodes(): FileStatNode[] {
+        const navigator = this.tryGetNavigatorWidget();
+        return navigator ? navigator.model.selectedNodes.filter(FileStatNode.is) : [];
+    }
+
+    tryGetNavigatorWidget(): FileNavigatorWidget | undefined {
+        return this.widgetManager.tryGetWidget(FILE_NAVIGATOR_ID);
+    }
+
+}

packages/navigator/src/electron-browser/electron-navigator-module.ts

@@ -0,0 +1,26 @@
+// *****************************************************************************
+// Copyright (C) 2021 EclipseSource and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+// *****************************************************************************
+
+import { CommandContribution, MenuContribution } from '@theia/core';
+import { ContainerModule } from '@theia/core/shared/inversify';
+import { KeybindingContribution } from '@theia/core/lib/browser';
+import { ElectronNavigatorMenuContribution } from './electron-navigator-menu-contribution';
+
+export default new ContainerModule(bind => {
+    bind(MenuContribution).to(ElectronNavigatorMenuContribution).inSingletonScope();
+    bind(CommandContribution).to(ElectronNavigatorMenuContribution).inSingletonScope();
+    bind(KeybindingContribution).to(ElectronNavigatorMenuContribution).inSingletonScope();
+});

packages/navigator/src/node/navigator-backend-module.ts

@@ -0,0 +1,22 @@
+// *****************************************************************************
+// Copyright (C) 2025 STMicroelectronics and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+// *****************************************************************************
+
+import { ContainerModule } from '@theia/core/shared/inversify';
+import { bindFileNavigatorPreferences } from '../common/navigator-preferences';
+
+export default new ContainerModule(bind => {
+    bindFileNavigatorPreferences(bind);
+});

packages/navigator/src/package.spec.ts

@@ -0,0 +1,28 @@
+// *****************************************************************************
+// Copyright (C) 2017 Ericsson and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+// *****************************************************************************
+
+/* note: this bogus test file is required so that
+   we are able to run mocha unit tests on this
+   package, without having any actual unit tests in it.
+   This way a coverage report will be generated,
+   showing 0% coverage, instead of no report.
+   This file can be removed once we have real unit
+   tests in place. */
+
+describe('navigator package', () => {
+
+    it('support code coverage statistics', () => true);
+});

packages/navigator/test-resources/testFileA.json

@@ -0,0 +1,3 @@
+{
+  "1": "hello"
+}

packages/navigator/test-resources/testFileB.json

@@ -0,0 +1,3 @@
+{
+  "2": "hello"
+}

packages/navigator/tsconfig.json

@@ -0,0 +1,22 @@
+{
+  "extends": "../../configs/base.tsconfig",
+  "compilerOptions": {
+    "composite": true,
+    "rootDir": "src",
+    "outDir": "lib"
+  },
+  "include": [
+    "src"
+  ],
+  "references": [
+    {
+      "path": "../core"
+    },
+    {
+      "path": "../filesystem"
+    },
+    {
+      "path": "../workspace"
+    }
+  ]
+}