Git - implement branch protection provider (#179752)

* Branch protection using settings is working

* Revert extension api changes

* Refactor code

extensions/git/src/branchProtection.ts

@@ -0,0 +1,50 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import { Disposable, Event, EventEmitter, Uri, workspace } from 'vscode';
+import { BranchProtectionProvider } from './api/git';
+import { dispose, filterEvent } from './util';
+
+export interface IBranchProtectionProviderRegistry {
+	readonly onDidChangeBranchProtectionProviders: Event<Uri>;
+
+	getBranchProtectionProviders(root: Uri): BranchProtectionProvider[];
+	registerBranchProtectionProvider(root: Uri, provider: BranchProtectionProvider): Disposable;
+}
+
+export class GitBranchProtectionProvider implements BranchProtectionProvider {
+
+	private readonly _onDidChangeBranchProtection = new EventEmitter<Uri>();
+	onDidChangeBranchProtection = this._onDidChangeBranchProtection.event;
+
+	private branchProtection = new Map<'', string[]>();
+	private disposables: Disposable[] = [];
+
+	constructor(private readonly repositoryRoot: Uri) {
+		const onDidChangeBranchProtectionEvent = filterEvent(workspace.onDidChangeConfiguration, e => e.affectsConfiguration('git.branchProtection', repositoryRoot));
+		onDidChangeBranchProtectionEvent(this.updateBranchProtection, this, this.disposables);
+		this.updateBranchProtection();
+	}
+
+	provideBranchProtection(): Map<string, string[]> {
+		return this.branchProtection;
+	}
+
+	private updateBranchProtection(): void {
+		const scopedConfig = workspace.getConfiguration('git', this.repositoryRoot);
+		const branchProtectionConfig = scopedConfig.get<unknown>('branchProtection') ?? [];
+		const branchProtectionValues = Array.isArray(branchProtectionConfig) ? branchProtectionConfig : [branchProtectionConfig];
+
+		this.branchProtection.set('', branchProtectionValues
+			.map(bp => typeof bp === 'string' ? bp.trim() : '')
+			.filter(bp => bp !== ''));
+
+		this._onDidChangeBranchProtection.fire(this.repositoryRoot);
+	}
+
+	dispose(): void {
+		this.disposables = dispose(this.disposables);
+	}
+}