Fixes #45131: Render a floating click widget when the diff editor has...

Fixes #45131: Render a floating click widget when the diff editor has whitespace only changes and whitespace is ignored

src/vs/editor/browser/editorBrowser.ts

@@ -18,6 +18,7 @@ import { IModelContentChangedEvent, IModelDecorationsChangedEvent, IModelLanguag
 import { OverviewRulerZone } from 'vs/editor/common/view/overviewZoneManager';
 import { IEditorWhitespace } from 'vs/editor/common/viewLayout/whitespaceComputer';
 import { ServicesAccessor } from 'vs/platform/instantiation/common/instantiation';
+import { IDiffComputationResult } from 'vs/editor/common/services/editorWorkerService';
 
 /**
  * A view zone is a full horizontal rectangle that 'pushes' text down.
@@ -906,6 +907,12 @@ export interface IDiffEditor extends editorCommon.IEditor {
 	 */
 	getLineChanges(): editorCommon.ILineChange[] | null;
 
+	/**
+	 * Get the computed diff information.
+	 * @internal
+	 */
+	getDiffComputationResult(): IDiffComputationResult | null;
+
 	/**
 	 * Get information based on computed diff about a line number from the original model.
 	 * If the diff computation is not finished or the model is missing, will return null.

src/vs/editor/browser/widget/diffEditorWidget.ts

@@ -578,6 +578,10 @@ export class DiffEditorWidget extends Disposable implements editorBrowser.IDiffE
 		return this._diffComputationResult.changes;
 	}
 
+	public getDiffComputationResult(): IDiffComputationResult | null {
+		return this._diffComputationResult;
+	}
+
 	public getOriginalEditor(): editorBrowser.ICodeEditor {
 		return this.originalEditor;
 	}

src/vs/workbench/contrib/codeEditor/browser/codeEditor.contribution.ts

@@ -5,6 +5,7 @@
 
 import './menuPreventer';
 import './accessibility/accessibility';
+import './diffEditorHelper';
 import './inspectKeybindings';
 import './largeFileOptimizations';
 import './selectionClipboard';

src/vs/workbench/contrib/codeEditor/browser/diffEditorHelper.ts

+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import * as nls from 'vs/nls';
+import { IDiffEditor } from 'vs/editor/browser/editorBrowser';
+import { registerDiffEditorContribution } from 'vs/editor/browser/editorExtensions';
+import { IEditorContribution } from 'vs/editor/common/editorCommon';
+import { Disposable, IDisposable } from 'vs/base/common/lifecycle';
+import { FloatingClickWidget } from 'vs/workbench/browser/parts/editor/editorWidgets';
+import { IDiffComputationResult } from 'vs/editor/common/services/editorWorkerService';
+import { IInstantiationService } from 'vs/platform/instantiation/common/instantiation';
+import { IConfigurationService, ConfigurationTarget } from 'vs/platform/configuration/common/configuration';
+
+const enum WidgetState {
+	Hidden,
+	HintWhitespace
+}
+
+class DiffEditorHelperContribution extends Disposable implements IEditorContribution {
+
+	private _helperWidget: FloatingClickWidget | null;
+	private _helperWidgetListener: IDisposable | null;
+	private _state: WidgetState;
+
+	constructor(
+		private readonly _diffEditor: IDiffEditor,
+		@IInstantiationService private readonly _instantiationService: IInstantiationService,
+		@IConfigurationService private readonly _configurationService: IConfigurationService,
+	) {
+		super();
+		this._helperWidget = null;
+		this._helperWidgetListener = null;
+		this._state = WidgetState.Hidden;
+
+
+		this._register(this._diffEditor.onDidUpdateDiff(() => {
+			this._setState(this._deduceState(this._diffEditor.getDiffComputationResult()));
+		}));
+	}
+
+	private _deduceState(diffComputationResult: IDiffComputationResult | null): WidgetState {
+		if (!diffComputationResult) {
+			return WidgetState.Hidden;
+		}
+		if (this._diffEditor.ignoreTrimWhitespace && diffComputationResult.changes.length === 0 && !diffComputationResult.identical) {
+			return WidgetState.HintWhitespace;
+		}
+		return WidgetState.Hidden;
+	}
+
+	private _setState(newState: WidgetState) {
+		if (this._state === newState) {
+			return;
+		}
+
+		this._state = newState;
+
+		if (this._helperWidgetListener) {
+			this._helperWidgetListener.dispose();
+			this._helperWidgetListener = null;
+		}
+		if (this._helperWidget) {
+			this._helperWidget.dispose();
+			this._helperWidget = null;
+		}
+
+		if (this._state === WidgetState.HintWhitespace) {
+			this._helperWidget = this._instantiationService.createInstance(FloatingClickWidget, this._diffEditor.getModifiedEditor(), nls.localize('hintWhitespace', "Show Whitespace Differences"), null);
+			this._helperWidgetListener = this._helperWidget.onClick(() => this._onDidClickHelperWidget());
+			this._helperWidget.render();
+		}
+	}
+
+	private _onDidClickHelperWidget(): void {
+		if (this._state === WidgetState.HintWhitespace) {
+			this._configurationService.updateValue('diffEditor.ignoreTrimWhitespace', false, ConfigurationTarget.USER);
+		}
+	}
+
+	dispose(): void {
+		super.dispose();
+	}
+
+	getId(): string {
+		return 'editor.contrib.diffEditorHelper';
+	}
+}
+
+registerDiffEditorContribution(DiffEditorHelperContribution);