Connection Browse Tab (#12222)

* add browse tab and flat tree provider for azure

* fix tests

* add comment

* fix build errors

* fix test cases

Co-authored-by: Alan Ren <alanren@microsoft.com>

src/sql/workbench/services/connection/common/connectionTreeService.ts

@@ -0,0 +1,82 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the Source EULA. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import { IDisposable, toDisposable } from 'vs/base/common/lifecycle';
+import { registerSingleton } from 'vs/platform/instantiation/common/extensions';
+import { createDecorator } from 'vs/platform/instantiation/common/instantiation';
+import { ITreeViewDataProvider } from 'vs/workbench/common/views';
+import { Emitter, Event } from 'vs/base/common/event';
+import { ITreeItem } from 'sql/workbench/common/views';
+
+export interface IConnectionTreeService {
+	_serviceBrand: undefined;
+	registerTreeProvider(id: string, provider: ITreeViewDataProvider): IDisposable;
+	registerTreeDescriptor(descriptor: IConnectionTreeDescriptor): IDisposable;
+	setView(view: IView): void;
+	readonly onDidAddProvider: Event<ITreeViewDataProvider>;
+	readonly providers: Iterable<[string, ITreeViewDataProvider]>;
+	readonly descriptors: Iterable<IConnectionTreeDescriptor>;
+	readonly view: IView | undefined;
+}
+
+export const IConnectionTreeService = createDecorator<IConnectionTreeService>('connectionTreeService');
+
+export interface IView {
+	refresh(items?: ITreeItem[])
+}
+
+export interface IConnectionTreeDescriptor {
+	readonly id: string;
+	readonly name: string;
+	readonly icon: string;
+}
+
+export class ConnectionTreeService implements IConnectionTreeService {
+	_serviceBrand;
+	private readonly _onDidAddProvider = new Emitter<ITreeViewDataProvider>();
+	public readonly onDidAddProvider = this._onDidAddProvider.event;
+
+	private readonly _onDidRemoveProvider = new Emitter<void>();
+	public readonly onDidRemoveProvider = this._onDidRemoveProvider.event;
+
+	private _providers = new Map<string, ITreeViewDataProvider>();
+	private _descriptors = new Set<IConnectionTreeDescriptor>();
+
+	private _view: IView | undefined;
+
+	registerTreeProvider(id: string, provider: ITreeViewDataProvider): IDisposable {
+		this._providers.set(id, provider);
+		this._onDidAddProvider.fire(provider);
+		return toDisposable(() => {
+			this._providers.delete(id);
+			this._onDidRemoveProvider.fire();
+		});
+	}
+
+	registerTreeDescriptor(descriptor: IConnectionTreeDescriptor): IDisposable {
+		this._descriptors.add(descriptor);
+		return toDisposable(() => {
+			this._descriptors.delete(descriptor);
+		});
+	}
+
+	get descriptors(): Iterable<IConnectionTreeDescriptor> {
+		return this._descriptors.values();
+	}
+
+	get providers(): Iterable<[string, ITreeViewDataProvider]> {
+		return this._providers.entries();
+	}
+
+	get view(): IView | undefined {
+		return this._view;
+	}
+
+	setView(view: IView): void {
+		this._view = view;
+	}
+}
+
+registerSingleton(IConnectionTreeService, ConnectionTreeService, false);