Refactors diff editor helper (microsoft#188205)

Author: hediet

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

@@ -9,10 +9,8 @@ import { registerDiffEditorContribution } from 'vs/editor/browser/editorExtensio
 import { ICodeEditorService } from 'vs/editor/browser/services/codeEditorService';
 import { DiffReviewNext, DiffReviewPrev } from 'vs/editor/browser/widget/diffEditor.contribution';
 import { DiffEditorWidget2 } from 'vs/editor/browser/widget/diffEditorWidget2/diffEditorWidget2';
-import { EmbeddedDiffEditorWidget } from 'vs/editor/browser/widget/embeddedCodeEditorWidget';
-import { IDiffComputationResult } from 'vs/editor/common/diff/smartLinesDiffComputer';
+import { EmbeddedDiffEditorWidget, EmbeddedDiffEditorWidget2 } from 'vs/editor/browser/widget/embeddedCodeEditorWidget';
 import { IDiffEditorContribution } from 'vs/editor/common/editorCommon';
-import * as nls from 'vs/nls';
 import { IConfigurationService } from 'vs/platform/configuration/common/configuration';
 import { ContextKeyEqualsExpr, ContextKeyExpr } from 'vs/platform/contextkey/common/contextkey';
 import { IInstantiationService } from 'vs/platform/instantiation/common/instantiation';
@@ -22,20 +20,13 @@ import { FloatingClickWidget } from 'vs/workbench/browser/codeeditor';
 import { AccessibilityHelpAction } from 'vs/workbench/contrib/accessibility/browser/accessibilityContribution';
 import { IEditorService } from 'vs/workbench/services/editor/common/editorService';
 import { AccessibleViewType, IAccessibleViewService } from 'vs/workbench/contrib/accessibility/browser/accessibleView';
-
-const enum WidgetState {
-	Hidden,
-	HintWhitespace
-}
+import { localize } from 'vs/nls';
+import { observableFromEvent } from 'vs/base/common/observable';
+import { autorunWithStore2 } from 'vs/base/common/observableImpl/autorun';
 
 class DiffEditorHelperContribution extends Disposable implements IDiffEditorContribution {
-
 	public static readonly ID = 'editor.contrib.diffEditorHelper';
 
-	private _helperWidget: FloatingClickWidget | null;
-	private _helperWidgetListener: IDisposable | null;
-	private _state: WidgetState;
-
 	constructor(
 		private readonly _diffEditor: IDiffEditor,
 		@IInstantiationService private readonly _instantiationService: IInstantiationService,
@@ -46,21 +37,36 @@ class DiffEditorHelperContribution extends Disposable implements IDiffEditorCont
 
 		this._register(createScreenReaderHelp());
 
-		this._helperWidget = null;
-		this._helperWidgetListener = null;
-		this._state = WidgetState.Hidden;
+		const isEmbeddedDiffEditor = (this._diffEditor instanceof EmbeddedDiffEditorWidget) || (this._diffEditor instanceof EmbeddedDiffEditorWidget2);
+
+		if (!isEmbeddedDiffEditor) {
+			const computationResult = observableFromEvent(e => this._diffEditor.onDidUpdateDiff(e), () => this._diffEditor.getDiffComputationResult());
+			const onlyWhiteSpaceChange = computationResult.map(r => r && !r.identical && r.changes2.length === 0);
+
+			this._register(autorunWithStore2('update state', (reader, store) => {
+				if (onlyWhiteSpaceChange.read(reader)) {
+					const helperWidget = store.add(this._instantiationService.createInstance(
+						FloatingClickWidget,
+						this._diffEditor.getModifiedEditor(),
+						localize('hintWhitespace', "Show Whitespace Differences"),
+						null
+					));
+					store.add(helperWidget.onClick(() => {
+						this._configurationService.updateValue('diffEditor.ignoreTrimWhitespace', false);
+					}));
+					helperWidget.render();
+				}
+			}));
 
-		if (!(this._diffEditor instanceof EmbeddedDiffEditorWidget)) {
 			this._register(this._diffEditor.onDidUpdateDiff(() => {
 				const diffComputationResult = this._diffEditor.getDiffComputationResult();
-				this._setState(this._deduceState(diffComputationResult));
 
 				if (diffComputationResult && diffComputationResult.quitEarly) {
 					this._notificationService.prompt(
 						Severity.Warning,
-						nls.localize('hintTimeout', "The diff algorithm was stopped early (after {0} ms.)", this._diffEditor.maxComputationTime),
+						localize('hintTimeout', "The diff algorithm was stopped early (after {0} ms.)", this._diffEditor.maxComputationTime),
 						[{
-							label: nls.localize('removeTimeout', "Remove Limit"),
+							label: localize('removeTimeout', "Remove Limit"),
 							run: () => {
 								this._configurationService.updateValue('diffEditor.maxComputationTime', 0);
 							}
@@ -71,49 +77,6 @@ class DiffEditorHelperContribution extends Disposable implements IDiffEditorCont
 			}));
 		}
 	}
-
-	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);
-		}
-	}
-
-	override dispose(): void {
-		super.dispose();
-	}
 }
 
 function createScreenReaderHelp(): IDisposable {
@@ -140,14 +103,14 @@ function createScreenReaderHelp(): IDisposable {
 		accessibleViewService.show({
 			verbositySettingKey: 'diffEditor',
 			provideContent: () => [
-				nls.localize('msg1', "You are in a diff editor."),
-				nls.localize('msg2', "Press {0} or {1} to view the next or previous diff in the diff review mode that is optimized for screen readers.", next, previous),
-				nls.localize('msg3', "To control which audio cues should be played, the following settings can be configured: {0}.", keys.join(', ')),
+				localize('msg1', "You are in a diff editor."),
+				localize('msg2', "Press {0} or {1} to view the next or previous diff in the diff review mode that is optimized for screen readers.", next, previous),
+				localize('msg3', "To control which audio cues should be played, the following settings can be configured: {0}.", keys.join(', ')),
 			].join('\n'),
 			onClose: () => {
 				codeEditor.focus();
 			},
-			options: { type: AccessibleViewType.HelpMenu, ariaLabel: nls.localize('chat-help-label', "Diff editor accessibility help") }
+			options: { type: AccessibleViewType.HelpMenu, ariaLabel: localize('chat-help-label', "Diff editor accessibility help") }
 		});
 	}, ContextKeyExpr.and(
 		ContextKeyEqualsExpr.create('diffEditorVersion', 2),