Support tree view drag and drop.

packages/core/src/browser/frontend-application.ts

@@ -224,10 +224,18 @@ export class FrontendApplication {
             document.body.addEventListener('wheel', preventNavigation, { passive: false });
         }
         // Prevent the default browser behavior when dragging and dropping files into the window.
-        window.addEventListener('dragover', event => {
+        document.addEventListener('dragenter', event => {
+            if (event.dataTransfer) {
+                event.dataTransfer.dropEffect = 'none';
+            }
             event.preventDefault();
         }, false);
-        window.addEventListener('drop', event => {
+        document.addEventListener('dragover', event => {
+            if (event.dataTransfer) {
+                event.dataTransfer.dropEffect = 'none';
+            } event.preventDefault();
+        }, false);
+        document.addEventListener('drop', event => {
             event.preventDefault();
         }, false);
 

packages/core/src/browser/shell/application-shell.ts

@@ -41,6 +41,8 @@ import { Deferred } from '../../common/promise-util';
 import { SaveResourceService } from '../save-resource-service';
 import { nls } from '../../common/nls';
 import { SecondaryWindowHandler } from '../secondary-window-handler';
+import URI from '../../common/uri';
+import { OpenerService } from '../opener-service';
 
 /** The class name added to ApplicationShell instances. */
 const APPLICATION_SHELL_CLASS = 'theia-ApplicationShell';
@@ -190,10 +192,14 @@ export class ApplicationShell extends Widget {
 
     private readonly tracker = new FocusTracker<Widget>();
     private dragState?: WidgetDragState;
+    additionalDraggedUris: URI[] | undefined;
 
     @inject(ContextKeyService)
     protected readonly contextKeyService: ContextKeyService;
 
+    @inject(OpenerService)
+    protected readonly openerService: OpenerService;
+
     protected readonly onDidAddWidgetEmitter = new Emitter<Widget>();
     readonly onDidAddWidget = this.onDidAddWidgetEmitter.event;
     protected fireDidAddWidget(widget: Widget): void {
@@ -498,9 +504,68 @@ export class ApplicationShell extends Widget {
         dockPanel.id = MAIN_AREA_ID;
         dockPanel.widgetAdded.connect((_, widget) => this.fireDidAddWidget(widget));
         dockPanel.widgetRemoved.connect((_, widget) => this.fireDidRemoveWidget(widget));
+
+        const openUri = async (fileUri: URI) => {
+            try {
+                const opener = await this.openerService.getOpener(fileUri);
+                opener.open(fileUri);
+            } catch (e) {
+                console.info(`no opener found for '${fileUri}'`);
+            }
+        };
+
+        dockPanel.node.addEventListener('drop', event => {
+            if (event.dataTransfer) {
+                const uris = this.additionalDraggedUris || ApplicationShell.getDraggedEditorUris(event.dataTransfer);
+                if (uris.length > 0) {
+                    uris.forEach(openUri);
+                } else if (event.dataTransfer.files?.length > 0) {
+                    // the files were dragged from the outside the workspace
+                    Array.from(event.dataTransfer.files).forEach(async file => {
+                        if (file.path) {
+                            const fileUri = URI.fromComponents({
+                                scheme: 'file',
+                                path: file.path,
+                                authority: '',
+                                query: '',
+                                fragment: ''
+                            });
+                            openUri(fileUri);
+                        }
+                    });
+                }
+            }
+        });
+        const handler = (e: DragEvent) => {
+            if (e.dataTransfer) {
+                e.dataTransfer.dropEffect = 'link';
+                e.preventDefault();
+                e.stopPropagation();
+            }
+        };
+        dockPanel.node.addEventListener('dragover', handler);
+        dockPanel.node.addEventListener('dragenter', handler);
+
         return dockPanel;
     }
 
+    addAdditionalDraggedEditorUris(uris: URI[]): void {
+        this.additionalDraggedUris = uris;
+    }
+
+    clearAdditionalDraggedEditorUris(): void {
+        this.additionalDraggedUris = undefined;
+    }
+
+    static getDraggedEditorUris(dataTransfer: DataTransfer): URI[] {
+        const data = dataTransfer.getData('theia-editor-dnd');
+        return data ? data.split('\n').map(entry => new URI(entry)) : [];
+    }
+
+    static setDraggedEditorUris(dataTransfer: DataTransfer, uris: URI[]): void {
+        dataTransfer.setData('theia-editor-dnd', uris.map(uri => uri.toString()).join('\r\n'));
+    }
+
     /**
      * Create the dock panel in the bottom shell area.
      */

packages/filesystem/src/browser/file-tree/file-tree-widget.tsx

@@ -25,6 +25,7 @@ import { FileUploadService } from '../file-upload-service';
 import { DirNode, FileStatNode, FileStatNodeData } from './file-tree';
 import { FileTreeModel } from './file-tree-model';
 import { IconThemeService } from '@theia/core/lib/browser/icon-theme-service';
+import { ApplicationShell } from '@theia/core/lib/browser/shell';
 import { FileStat, FileType } from '../../common/files';
 import { isOSX } from '@theia/core';
 
@@ -119,14 +120,18 @@ export class FileTreeWidget extends CompressedTreeWidget {
 
     protected handleDragStartEvent(node: TreeNode, event: React.DragEvent): void {
         event.stopPropagation();
-        let selectedNodes;
-        if (this.model.selectedNodes.find(selected => TreeNode.equals(selected, node))) {
-            selectedNodes = [...this.model.selectedNodes];
-        } else {
-            selectedNodes = [node];
-        }
-        this.setSelectedTreeNodesAsData(event.dataTransfer, node, selectedNodes);
         if (event.dataTransfer) {
+            let selectedNodes;
+            if (this.model.selectedNodes.find(selected => TreeNode.equals(selected, node))) {
+                selectedNodes = [...this.model.selectedNodes];
+            } else {
+                selectedNodes = [node];
+            }
+            this.setSelectedTreeNodesAsData(event.dataTransfer, node, selectedNodes);
+            const uris = selectedNodes.filter(n => FileStatNode.is(n)).map(n => (n as FileStatNode).fileStat.resource);
+            if (uris.length > 0) {
+                ApplicationShell.setDraggedEditorUris(event.dataTransfer, uris);
+            }
             let label: string;
             if (selectedNodes.length === 1) {
                 label = this.toNodeName(node);

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

@@ -18,16 +18,14 @@ import { injectable, inject, postConstruct } from '@theia/core/shared/inversify'
 import { Message } from '@theia/core/shared/@phosphor/messaging';
 import URI from '@theia/core/lib/common/uri';
 import { CommandService } from '@theia/core/lib/common';
-import { Key, TreeModel, SelectableTreeNode, OpenerService, ContextMenuRenderer, ExpandableTreeNode, TreeProps, TreeNode } from '@theia/core/lib/browser';
-import { FileNode, DirNode } from '@theia/filesystem/lib/browser';
+import { Key, TreeModel, ContextMenuRenderer, ExpandableTreeNode, TreeProps, TreeNode } from '@theia/core/lib/browser';
+import { DirNode } from '@theia/filesystem/lib/browser';
 import { WorkspaceService, WorkspaceCommands } from '@theia/workspace/lib/browser';
-import { ApplicationShell } from '@theia/core/lib/browser/shell/application-shell';
 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 { FileNavigatorCommands } from './file-navigator-commands';
 import { nls } from '@theia/core/lib/common/nls';
 import { AbstractNavigatorTreeWidget } from './abstract-navigator-tree-widget';
 
@@ -38,10 +36,8 @@ export const CLASS = 'theia-Files';
 @injectable()
 export class FileNavigatorWidget extends AbstractNavigatorTreeWidget {
 
-    @inject(ApplicationShell) protected readonly shell: ApplicationShell;
     @inject(CommandService) protected readonly commandService: CommandService;
     @inject(NavigatorContextKeyService) protected readonly contextKeyService: NavigatorContextKeyService;
-    @inject(OpenerService) protected readonly openerService: OpenerService;
     @inject(WorkspaceService) protected readonly workspaceService: WorkspaceService;
 
     constructor(
@@ -97,36 +93,6 @@ export class FileNavigatorWidget extends AbstractNavigatorTreeWidget {
         }
     }
 
-    protected enableDndOnMainPanel(): void {
-        const mainPanelNode = this.shell.mainPanel.node;
-        this.addEventListener(mainPanelNode, 'drop', async ({ dataTransfer }) => {
-            const treeNodes = dataTransfer && this.getSelectedTreeNodesFromData(dataTransfer) || [];
-            if (treeNodes.length > 0) {
-                treeNodes.filter(FileNode.is).forEach(treeNode => {
-                    if (!SelectableTreeNode.isSelected(treeNode)) {
-                        this.model.toggleNode(treeNode);
-                    }
-                });
-                this.commandService.executeCommand(FileNavigatorCommands.OPEN.id);
-            } else if (dataTransfer && dataTransfer.files?.length > 0) {
-                // the files were dragged from the outside the workspace
-                Array.from(dataTransfer.files).forEach(async file => {
-                    const fileUri = new URI(file.path);
-                    const opener = await this.openerService.getOpener(fileUri);
-                    opener.open(fileUri);
-                });
-            }
-        });
-        const handler = (e: DragEvent) => {
-            if (e.dataTransfer) {
-                e.dataTransfer.dropEffect = 'link';
-                e.preventDefault();
-            }
-        };
-        this.addEventListener(mainPanelNode, 'dragover', handler);
-        this.addEventListener(mainPanelNode, 'dragenter', handler);
-    }
-
     override getContainerTreeNode(): TreeNode | undefined {
         const root = this.model.root;
         if (this.workspaceService.isMultiRootWorkspaceOpened) {
@@ -153,7 +119,6 @@ export class FileNavigatorWidget extends AbstractNavigatorTreeWidget {
         super.onAfterAttach(msg);
         this.addClipboardListener(this.node, 'copy', e => this.handleCopy(e));
         this.addClipboardListener(this.node, 'paste', e => this.handlePaste(e));
-        this.enableDndOnMainPanel();
     }
 
     protected handleCopy(event: ClipboardEvent): void {

packages/plugin-ext/src/common/plugin-api-rpc.ts

@@ -726,16 +726,26 @@ export interface TreeViewRevealOptions {
 }
 
 export interface TreeViewsMain {
-    $registerTreeDataProvider(treeViewId: string): void;
+    $registerTreeDataProvider(treeViewId: string, dragMimetypes: string[] | undefined, dropMimetypes: string[] | undefined): void;
+    $readDroppedFile(contentId: string): Promise<BinaryBuffer>;
     $unregisterTreeDataProvider(treeViewId: string): void;
     $refresh(treeViewId: string): Promise<void>;
     $reveal(treeViewId: string, elementParentChain: string[], options: TreeViewRevealOptions): Promise<any>;
     $setMessage(treeViewId: string, message: string): void;
     $setTitle(treeViewId: string, title: string): void;
     $setDescription(treeViewId: string, description: string): void;
 }
+export class DataTransferFileDTO {
+    constructor(readonly name: string, readonly contentId: string, readonly uri?: UriComponents) { }
+
+    static is(value: string | DataTransferFileDTO): value is DataTransferFileDTO {
+        return !(typeof value === 'string');
+    }
+}
 
 export interface TreeViewsExt {
+    $dragStarted(treeViewId: string, treeItemIds: string[], token: CancellationToken): Promise<UriComponents[] | undefined>;
+    $drop(treeViewId: string, treeItemId: string | undefined, dataTransferItems: [string, string | DataTransferFileDTO][], token: CancellationToken): Promise<void>;
     $getChildren(treeViewId: string, treeItemId: string | undefined): Promise<TreeViewItem[] | undefined>;
     $hasResolveTreeItem(treeViewId: string): Promise<boolean>;
     $resolveTreeItem(treeViewId: string, treeItemId: string, token: CancellationToken): Promise<TreeViewItem | undefined>;

packages/plugin-ext/src/main/browser/plugin-ext-frontend-module.ts

@@ -50,7 +50,7 @@ import { SelectionProviderCommandContribution } from './selection-provider-comma
 import { ViewColumnService } from './view-column-service';
 import { ViewContextKeyService } from './view/view-context-key-service';
 import { PluginViewWidget, PluginViewWidgetIdentifier } from './view/plugin-view-widget';
-import { TreeViewWidgetIdentifier, VIEW_ITEM_CONTEXT_MENU, PluginTree, TreeViewWidget, PluginTreeModel } from './view/tree-view-widget';
+import { TreeViewWidgetOptions, VIEW_ITEM_CONTEXT_MENU, PluginTree, TreeViewWidget, PluginTreeModel } from './view/tree-view-widget';
 import { RPCProtocol } from '../../common/rpc-protocol';
 import { LanguagesMainFactory, OutputChannelRegistryFactory } from '../../common';
 import { LanguagesMainImpl } from './languages-main';
@@ -80,6 +80,7 @@ import { bindTreeViewDecoratorUtilities, TreeViewDecoratorService } from './view
 import { CodeEditorWidgetUtil } from './menus/vscode-theia-menu-mappings';
 import { PluginMenuCommandAdapter } from './menus/plugin-menu-command-adapter';
 import './theme-icon-override';
+import { DnDFileContentStore } from './view/dnd-file-content-store';
 
 export default new ContainerModule((bind, unbind, isBound, rebind) => {
 
@@ -143,9 +144,10 @@ export default new ContainerModule((bind, unbind, isBound, rebind) => {
     bindTreeViewDecoratorUtilities(bind);
     bind(PluginTreeViewNodeLabelProvider).toSelf().inSingletonScope();
     bind(LabelProviderContribution).toService(PluginTreeViewNodeLabelProvider);
+    bind(DnDFileContentStore).toSelf().inSingletonScope();
     bind(WidgetFactory).toDynamicValue(({ container }) => ({
         id: PLUGIN_VIEW_DATA_FACTORY_ID,
-        createWidget: (identifier: TreeViewWidgetIdentifier) => {
+        createWidget: (identifier: TreeViewWidgetOptions) => {
             const props = {
                 contextMenuPath: VIEW_ITEM_CONTEXT_MENU,
                 expandOnlyOnExpansionToggleClick: true,
@@ -161,7 +163,7 @@ export default new ContainerModule((bind, unbind, isBound, rebind) => {
                 widget: TreeViewWidget,
                 decoratorService: TreeViewDecoratorService
             });
-            child.bind(TreeViewWidgetIdentifier).toConstantValue(identifier);
+            child.bind(TreeViewWidgetOptions).toConstantValue(identifier);
             return child.get(TreeWidget);
         }
     })).inSingletonScope();

packages/plugin-ext/src/main/browser/view/dnd-file-content-store.ts

@@ -0,0 +1,41 @@
+// *****************************************************************************
+// Copyright (C) 2022 ST Microelectronics 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 WITH Classpath-exception-2.0
+// *****************************************************************************
+
+import { injectable } from '@theia/core/shared/inversify';
+
+@injectable()
+export class DnDFileContentStore {
+    static id: number = 0;
+    private files: Map<string, File> = new Map();
+    addFile(f: File): string {
+        const id = (DnDFileContentStore.id++).toString();
+        this.files.set(id, f);
+        return id;
+    }
+
+    removeFile(id: string): boolean {
+        return this.files.delete(id);
+    }
+
+    getFile(id: string): File {
+        const file = this.files.get(id);
+        if (file) {
+            return file;
+        }
+
+        throw new Error(`File with id ${id} not found in dnd operation`);
+    }
+}