Implement basic SCM DnD (microsoft#181463)

Author: joyceerhl

src/vs/workbench/contrib/scm/browser/scmViewPane.ts

@@ -27,7 +27,7 @@ import { isSCMResource, isSCMResourceGroup, connectPrimaryMenuToInlineActionBar,
 import { WorkbenchCompressibleObjectTree, IOpenEvent } from 'vs/platform/list/browser/listService';
 import { IConfigurationService, ConfigurationTarget, IConfigurationChangeEvent } from 'vs/platform/configuration/common/configuration';
 import { disposableTimeout, ThrottledDelayer } from 'vs/base/common/async';
-import { ITreeNode, ITreeFilter, ITreeSorter, ITreeContextMenuEvent } from 'vs/base/browser/ui/tree/tree';
+import { ITreeNode, ITreeFilter, ITreeSorter, ITreeContextMenuEvent, ITreeDragAndDrop, ITreeDragOverReaction } from 'vs/base/browser/ui/tree/tree';
 import { ResourceTree, IResourceNode } from 'vs/base/common/resourceTree';
 import { ISplice } from 'vs/base/common/sequence';
 import { ICompressibleTreeRenderer, ICompressibleKeyboardNavigationLabelProvider } from 'vs/base/browser/ui/tree/objectTree';
@@ -92,6 +92,10 @@ import { InlineCompletionsController } from 'vs/editor/contrib/inlineCompletions
 import { CodeActionController } from 'vs/editor/contrib/codeAction/browser/codeActionController';
 import { IResolvedTextEditorModel, ITextModelContentProvider, ITextModelService } from 'vs/editor/common/services/resolverService';
 import { Schemas } from 'vs/base/common/network';
+import { IDragAndDropData } from 'vs/base/browser/dnd';
+import { fillEditorsDragData } from 'vs/workbench/browser/dnd';
+import { ElementsDragAndDropData } from 'vs/base/browser/ui/list/listView';
+import { CodeDataTransfers } from 'vs/platform/dnd/browser/dnd';
 
 type TreeElement = ISCMRepository | ISCMInput | ISCMActionButton | ISCMResourceGroup | IResourceNode<ISCMResource, ISCMResourceGroup> | ISCMResource;
 
@@ -166,6 +170,58 @@ class ActionButtonRenderer implements ICompressibleTreeRenderer<ISCMActionButton
 	}
 }
 
+
+class SCMTreeDragAndDrop implements ITreeDragAndDrop<TreeElement> {
+	constructor(private readonly instantiationService: IInstantiationService) { }
+
+	getDragURI(element: TreeElement): string | null {
+		if (isSCMResource(element)) {
+			return element.sourceUri.toString();
+		}
+
+		return null;
+	}
+
+	onDragStart(data: IDragAndDropData, originalEvent: DragEvent): void {
+		const items = SCMTreeDragAndDrop.getResourcesFromDragAndDropData(data as ElementsDragAndDropData<TreeElement, TreeElement[]>);
+		if (originalEvent.dataTransfer && items?.length) {
+			this.instantiationService.invokeFunction(accessor => fillEditorsDragData(accessor, items, originalEvent));
+
+			const fileResources = items.filter(s => s.scheme === Schemas.file).map(r => r.fsPath);
+			if (fileResources.length) {
+				originalEvent.dataTransfer.setData(CodeDataTransfers.FILES, JSON.stringify(fileResources));
+			}
+		}
+	}
+
+	getDragLabel(elements: TreeElement[], originalEvent: DragEvent): string | undefined {
+		if (elements.length === 1) {
+			const element = elements[0];
+			if (isSCMResource(element)) {
+				return basename(element.sourceUri);
+			}
+		}
+
+		return String(elements.length);
+	}
+
+	onDragOver(data: IDragAndDropData, targetElement: TreeElement | undefined, targetIndex: number | undefined, originalEvent: DragEvent): boolean | ITreeDragOverReaction {
+		return true;
+	}
+
+	drop(data: IDragAndDropData, targetElement: TreeElement | undefined, targetIndex: number | undefined, originalEvent: DragEvent): void { }
+
+	private static getResourcesFromDragAndDropData(data: ElementsDragAndDropData<TreeElement, TreeElement[]>): URI[] {
+		const uris: URI[] = [];
+		for (const element of [...data.context ?? [], ...data.elements]) {
+			if (isSCMResource(element)) {
+				uris.push(element.sourceUri);
+			}
+		}
+		return uris;
+	}
+}
+
 interface InputTemplate {
 	readonly inputWidget: SCMInputWidget;
 	readonly elementDisposables: DisposableStore;
@@ -2307,6 +2363,7 @@ export class SCMViewPane extends ViewPane {
 		const sorter = new SCMTreeSorter(() => this._viewModel);
 		const keyboardNavigationLabelProvider = this.instantiationService.createInstance(SCMTreeKeyboardNavigationLabelProvider, () => this._viewModel);
 		const identityProvider = new SCMResourceIdentityProvider();
+		const dnd = new SCMTreeDragAndDrop(this.instantiationService);
 
 		this.tree = this.instantiationService.createInstance(
 			WorkbenchCompressibleObjectTree,
@@ -2317,6 +2374,7 @@ export class SCMViewPane extends ViewPane {
 			{
 				transformOptimization: false,
 				identityProvider,
+				dnd,
 				horizontalScrolling: false,
 				setRowLineHeight: false,
 				filter,