Enable file dnd in tree views

Part of #32592

src/vs/workbench/api/browser/mainThreadTreeViews.ts

@@ -32,13 +32,13 @@ export class MainThreadTreeViews extends Disposable implements MainThreadTreeVie
 		this._proxy = extHostContext.getProxy(ExtHostContext.ExtHostTreeViews);
 	}
 
-	async $registerTreeViewDataProvider(treeViewId: string, options: { showCollapseAll: boolean, canSelectMany: boolean, dragAndDropMimeTypes: string[] }): Promise<void> {
+	async $registerTreeViewDataProvider(treeViewId: string, options: { showCollapseAll: boolean, canSelectMany: boolean, dragAndDropMimeTypes: string[] | undefined }): Promise<void> {
 		this.logService.trace('MainThreadTreeViews#$registerTreeViewDataProvider', treeViewId, options);
 
 		this.extensionService.whenInstalledExtensionsRegistered().then(() => {
 			const dataProvider = new TreeViewDataProvider(treeViewId, this._proxy, this.notificationService);
 			this._dataProviders.set(treeViewId, dataProvider);
-			const dndController = (options.dragAndDropMimeTypes.length > 0)
+			const dndController = options.dragAndDropMimeTypes
 				? new TreeViewDragAndDropController(treeViewId, options.dragAndDropMimeTypes, this._proxy) : undefined;
 			const viewer = this.getTreeView(treeViewId);
 			if (viewer) {

src/vs/workbench/api/common/extHost.protocol.ts

@@ -295,7 +295,7 @@ export interface MainThreadTextEditorsShape extends IDisposable {
 }
 
 export interface MainThreadTreeViewsShape extends IDisposable {
-	$registerTreeViewDataProvider(treeViewId: string, options: { showCollapseAll: boolean, canSelectMany: boolean, dragAndDropMimeTypes: string[] }): Promise<void>;
+	$registerTreeViewDataProvider(treeViewId: string, options: { showCollapseAll: boolean, canSelectMany: boolean, dragAndDropMimeTypes: string[] | undefined}): Promise<void>;
 	$refresh(treeViewId: string, itemsToRefresh?: { [treeItemHandle: string]: ITreeItem; }): Promise<void>;
 	$reveal(treeViewId: string, itemInfo: { item: ITreeItem, parentChain: ITreeItem[] } | undefined, options: IRevealOptions): Promise<void>;
 	$setMessage(treeViewId: string, message: string): void;

src/vs/workbench/api/common/extHostTreeViews.ts

@@ -85,7 +85,7 @@ export class ExtHostTreeViews implements ExtHostTreeViewsShape {
 		if (!options || !options.treeDataProvider) {
 			throw new Error('Options with treeDataProvider is mandatory');
 		}
-		const dragAndDropMimeTypes = (options.dragAndDropController === undefined) ? [] : options.dragAndDropController.supportedMimeTypes;
+		const dragAndDropMimeTypes = options.dragAndDropController?.supportedMimeTypes;
 		const registerPromise = this._proxy.$registerTreeViewDataProvider(viewId, { showCollapseAll: !!options.showCollapseAll, canSelectMany: !!options.canSelectMany, dragAndDropMimeTypes });
 		const treeView = this.createExtHostTreeView(viewId, options, extension);
 		return {

src/vs/workbench/browser/parts/views/treeView.ts

@@ -57,6 +57,8 @@ import { CancellationToken, CancellationTokenSource } from 'vs/base/common/cance
 import { Command } from 'vs/editor/common/modes';
 import { isPromiseCanceledError } from 'vs/base/common/errors';
 import { ElementsDragAndDropData } from 'vs/base/browser/ui/list/listView';
+import { CodeDataTransfers, fillEditorsDragData } from 'vs/workbench/browser/dnd';
+import { Schemas } from 'vs/base/common/network';
 
 export class TreeViewPane extends ViewPane {
 
@@ -1224,7 +1226,8 @@ export class CustomTreeViewDragAndDrop implements ITreeDragAndDrop<ITreeItem> {
 	private readonly treeMimeType: string;
 	constructor(
 		private readonly treeId: string,
-		@ILabelService private readonly labelService: ILabelService) {
+		@ILabelService private readonly labelService: ILabelService,
+		@IInstantiationService private readonly instantiationService: IInstantiationService) {
 		this.treeMimeType = `tree/${treeId.toLowerCase()}`;
 	}
 
@@ -1233,21 +1236,43 @@ export class CustomTreeViewDragAndDrop implements ITreeDragAndDrop<ITreeItem> {
 		this.dndController = controller;
 	}
 
+	private addResourceInfoToTransfer(originalEvent: DragEvent, resources: URI[]) {
+		if (resources.length && originalEvent.dataTransfer) {
+			// Apply some datatransfer types to allow for dragging the element outside of the application
+			this.instantiationService.invokeFunction(accessor => fillEditorsDragData(accessor, resources, originalEvent));
+
+			// The only custom data transfer we set from the explorer is a file transfer
+			// to be able to DND between multiple code file explorers across windows
+			const fileResources = resources.filter(s => s.scheme === Schemas.file).map(r => r.fsPath);
+			if (fileResources.length) {
+				originalEvent.dataTransfer.setData(CodeDataTransfers.FILES, JSON.stringify(fileResources));
+			}
+		}
+	}
+
 	onDragStart(data: IDragAndDropData, originalEvent: DragEvent): void {
 		if (originalEvent.dataTransfer) {
 			const treeItemsData = (data as ElementsDragAndDropData<ITreeItem, ITreeItem[]>).getData();
+			const resources: URI[] = [];
 			const sourceInfo: TreeDragSourceInfo = {
 				id: this.treeId,
-				itemHandles: treeItemsData.map(item => item.handle)
+				itemHandles: []
 			};
+			treeItemsData.forEach(item => {
+				sourceInfo.itemHandles.push(item.handle);
+				if (item.resourceUri) {
+					resources.push(URI.revive(item.resourceUri));
+				}
+			});
+			this.addResourceInfoToTransfer(originalEvent, resources);
 			originalEvent.dataTransfer.setData(this.treeMimeType,
 				JSON.stringify(sourceInfo));
 		}
 	}
 
 	onDragOver(data: IDragAndDropData, targetElement: ITreeItem, targetIndex: number, originalEvent: DragEvent): boolean | ITreeDragOverReaction {
 		const dndController = this.dndController;
-		if (!dndController || !originalEvent.dataTransfer) {
+		if (!dndController || !originalEvent.dataTransfer || (dndController.supportedMimeTypes.length === 0)) {
 			return false;
 		}
 		const dragContainersSupportedType = originalEvent.dataTransfer.types.some((value, index) => {

src/vscode-dts/vscode.proposed.treeViewDragAndDrop.d.ts

@@ -96,7 +96,7 @@ declare module 'vscode' {
 		 *
 		 * @param source The source items for the drag and drop operation.
 		 */
-		onWillDrop(source: T[]): Thenable<TreeDataTransfer>;
+		onWillDrop?(source: T[]): Thenable<TreeDataTransfer>;
 
 		/**
 		 * Called when a drag and drop action results in a drop on the tree that this `DragAndDropController` belongs too.