Fixes #209324

src/vs/base/common/controlFlow.ts

@@ -0,0 +1,69 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+import { BugIndicatingError } from 'vs/base/common/errors';
+
+/*
+ * This file contains helper classes to manage control flow.
+*/
+
+/**
+ * Prevents code from being re-entrant.
+*/
+export class ReentrancyBarrier {
+	private _isOccupied = false;
+
+	/**
+	 * Calls `runner` if the barrier is not occupied.
+	 * During the call, the barrier becomes occupied.
+	 */
+	public runExclusivelyOrSkip(runner: () => void): void {
+		if (this._isOccupied) {
+			return;
+		}
+		this._isOccupied = true;
+		try {
+			runner();
+		} finally {
+			this._isOccupied = false;
+		}
+	}
+
+	/**
+	 * Calls `runner`. If the barrier is occupied, throws an error.
+	 * During the call, the barrier becomes active.
+	 */
+	public runExclusivelyOrThrow(runner: () => void): void {
+		if (this._isOccupied) {
+			throw new BugIndicatingError(`ReentrancyBarrier: reentrant call detected!`);
+		}
+		this._isOccupied = true;
+		try {
+			runner();
+		} finally {
+			this._isOccupied = false;
+		}
+	}
+
+	/**
+	 * Indicates if some runner occupies this barrier.
+	*/
+	public get isOccupied() {
+		return this._isOccupied;
+	}
+
+	public makeExclusiveOrSkip<TFunction extends Function>(fn: TFunction): TFunction {
+		return ((...args: any[]) => {
+			if (this._isOccupied) {
+				return;
+			}
+			this._isOccupied = true;
+			try {
+				return fn(...args);
+			} finally {
+				this._isOccupied = false;
+			}
+		}) as any;
+	}
+}

src/vs/workbench/contrib/mergeEditor/browser/model/textModelDiffs.ts

@@ -10,7 +10,7 @@ import { ITextModel } from 'vs/editor/common/model';
 import { DetailedLineRangeMapping } from 'vs/workbench/contrib/mergeEditor/browser/model/mapping';
 import { LineRangeEdit } from 'vs/workbench/contrib/mergeEditor/browser/model/editing';
 import { LineRange } from 'vs/workbench/contrib/mergeEditor/browser/model/lineRange';
-import { ReentrancyBarrier } from 'vs/workbench/contrib/mergeEditor/browser/utils';
+import { ReentrancyBarrier } from '../../../../../base/common/controlFlow';
 import { IMergeDiffComputer } from './diffComputer';
 import { autorun, IObservable, IReader, ITransaction, observableSignal, observableValue, transaction } from 'vs/base/common/observable';
 import { UndoRedoGroup } from 'vs/platform/undoRedo/common/undoRedo';
@@ -24,7 +24,7 @@ export class TextModelDiffs extends Disposable {
 	private _isDisposed = false;
 
 	public get isApplyingChange() {
-		return this._barrier.isActive;
+		return this._barrier.isOccupied;
 	}
 
 	constructor(
@@ -44,14 +44,14 @@ export class TextModelDiffs extends Disposable {
 
 		this._register(
 			baseTextModel.onDidChangeContent(
-				this._barrier.makeExclusive(() => {
+				this._barrier.makeExclusiveOrSkip(() => {
 					recomputeSignal.trigger(undefined);
 				})
 			)
 		);
 		this._register(
 			textModel.onDidChangeContent(
-				this._barrier.makeExclusive(() => {
+				this._barrier.makeExclusiveOrSkip(() => {
 					recomputeSignal.trigger(undefined);
 				})
 			)

src/vs/workbench/contrib/mergeEditor/browser/utils.ts

@@ -4,60 +4,14 @@
  *--------------------------------------------------------------------------------------------*/
 
 import { ArrayQueue, CompareResult } from 'vs/base/common/arrays';
-import { BugIndicatingError, onUnexpectedError } from 'vs/base/common/errors';
+import { onUnexpectedError } from 'vs/base/common/errors';
 import { DisposableStore, IDisposable, toDisposable } from 'vs/base/common/lifecycle';
 import { IObservable, autorunOpts, observableFromEvent } from 'vs/base/common/observable';
 import { CodeEditorWidget } from 'vs/editor/browser/widget/codeEditor/codeEditorWidget';
 import { IModelDeltaDecoration } from 'vs/editor/common/model';
 import { IConfigurationService } from 'vs/platform/configuration/common/configuration';
 import { IStorageService, StorageScope, StorageTarget } from 'vs/platform/storage/common/storage';
 
-export class ReentrancyBarrier {
-	private _isActive = false;
-
-	public get isActive() {
-		return this._isActive;
-	}
-
-	public makeExclusive<TFunction extends Function>(fn: TFunction): TFunction {
-		return ((...args: any[]) => {
-			if (this._isActive) {
-				return;
-			}
-			this._isActive = true;
-			try {
-				return fn(...args);
-			} finally {
-				this._isActive = false;
-			}
-		}) as any;
-	}
-
-	public runExclusively(fn: () => void): void {
-		if (this._isActive) {
-			return;
-		}
-		this._isActive = true;
-		try {
-			fn();
-		} finally {
-			this._isActive = false;
-		}
-	}
-
-	public runExclusivelyOrThrow(fn: () => void): void {
-		if (this._isActive) {
-			throw new BugIndicatingError();
-		}
-		this._isActive = true;
-		try {
-			fn();
-		} finally {
-			this._isActive = false;
-		}
-	}
-}
-
 export function setStyle(
 	element: HTMLElement,
 	style: {

src/vs/workbench/contrib/mergeEditor/browser/view/scrollSynchronizer.ts

@@ -8,7 +8,7 @@ import { autorunWithStore, IObservable } from 'vs/base/common/observable';
 import { CodeEditorWidget } from 'vs/editor/browser/widget/codeEditor/codeEditorWidget';
 import { ScrollType } from 'vs/editor/common/editorCommon';
 import { DocumentLineRangeMap } from 'vs/workbench/contrib/mergeEditor/browser/model/mapping';
-import { ReentrancyBarrier } from 'vs/workbench/contrib/mergeEditor/browser/utils';
+import { ReentrancyBarrier } from '../../../../../base/common/controlFlow';
 import { BaseCodeEditorView } from 'vs/workbench/contrib/mergeEditor/browser/view/editors/baseCodeEditorView';
 import { IMergeEditorLayout } from 'vs/workbench/contrib/mergeEditor/browser/view/mergeEditor';
 import { MergeEditorViewModel } from 'vs/workbench/contrib/mergeEditor/browser/view/viewModel';
@@ -62,7 +62,7 @@ export class ScrollSynchronizer extends Disposable {
 
 		this._store.add(
 			this.input1View.editor.onDidScrollChange(
-				this.reentrancyBarrier.makeExclusive((c) => {
+				this.reentrancyBarrier.makeExclusiveOrSkip((c) => {
 					if (c.scrollTopChanged) {
 						handleInput1OnScroll();
 					}
@@ -77,7 +77,7 @@ export class ScrollSynchronizer extends Disposable {
 
 		this._store.add(
 			this.input2View.editor.onDidScrollChange(
-				this.reentrancyBarrier.makeExclusive((c) => {
+				this.reentrancyBarrier.makeExclusiveOrSkip((c) => {
 					if (!this.model) {
 						return;
 					}
@@ -112,7 +112,7 @@ export class ScrollSynchronizer extends Disposable {
 		);
 		this._store.add(
 			this.inputResultView.editor.onDidScrollChange(
-				this.reentrancyBarrier.makeExclusive((c) => {
+				this.reentrancyBarrier.makeExclusiveOrSkip((c) => {
 					if (c.scrollTopChanged) {
 						if (this.shouldAlignResult) {
 							this.input1View.editor.setScrollTop(c.scrollTop, ScrollType.Immediate);
@@ -146,7 +146,7 @@ export class ScrollSynchronizer extends Disposable {
 				const baseView = this.baseView.read(reader);
 				if (baseView) {
 					store.add(baseView.editor.onDidScrollChange(
-						this.reentrancyBarrier.makeExclusive((c) => {
+						this.reentrancyBarrier.makeExclusiveOrSkip((c) => {
 							if (c.scrollTopChanged) {
 								if (!this.model) {
 									return;

src/vs/workbench/contrib/scrollLocking/browser/scrollLocking.ts

@@ -12,7 +12,7 @@ import { IKeybindingService } from 'vs/platform/keybinding/common/keybinding';
 import { SideBySideEditor } from 'vs/workbench/browser/parts/editor/sideBySideEditor';
 import { IWorkbenchContribution } from 'vs/workbench/common/contributions';
 import { IEditorPane, IEditorPaneScrollPosition, isEditorPaneWithScrolling } from 'vs/workbench/common/editor';
-import { ReentrancyBarrier } from 'vs/workbench/contrib/mergeEditor/browser/utils';
+import { ReentrancyBarrier } from 'vs/base/common/controlFlow';
 import { IEditorService } from 'vs/workbench/services/editor/common/editorService';
 import { IStatusbarEntryAccessor, IStatusbarService, StatusbarAlignment } from 'vs/workbench/services/statusbar/browser/statusbar';
 
@@ -75,7 +75,7 @@ export class SyncScroll extends Disposable implements IWorkbenchContribution {
 
 			this.paneInitialScrollTop.set(pane, pane.getScrollPosition());
 			this.paneDisposables.add(pane.onDidChangeScroll(() =>
-				this._reentrancyBarrier.runExclusively(() => {
+				this._reentrancyBarrier.runExclusivelyOrSkip(() => {
 					this.onDidEditorPaneScroll(pane);
 				})
 			));