data workspace extension batch 2 (#12208)

* work in progress

* load projects in view and test cases

* update scope

* make the sql proj menu available in workspace view

* add extension unit test

* address comments

* fix errors

extensions/data-workspace/src/common/interfaces.ts

@@ -0,0 +1,70 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the Source EULA. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import { IProjectProvider, IProjectType } from 'dataworkspace';
+import * as vscode from 'vscode';
+
+/**
+ * Defines the project provider registry
+ */
+export interface IProjectProviderRegistry {
+	/**
+	 * Registers a new project provider
+	 * @param provider The project provider
+	 */
+	registerProvider(provider: IProjectProvider): vscode.Disposable;
+
+	/**
+	 * Clear the providers
+	 */
+	clear(): void;
+
+	/**
+	 * Gets all the registered providers
+	 */
+	readonly providers: IProjectProvider[];
+
+	/**
+	 * Gets the project provider for the specified project type
+	 * @param projectType The project type, file extension of the project
+	 */
+	getProviderByProjectType(projectType: string): IProjectProvider | undefined;
+}
+
+/**
+ * Defines the project service
+ */
+export interface IWorkspaceService {
+	/**
+	 * Gets all supported project types
+	 */
+	getAllProjectTypes(): Promise<IProjectType[]>;
+
+	/**
+	 * Gets the project files in current workspace
+	 */
+	getProjectsInWorkspace(): Promise<string[]>;
+
+	/**
+	 * Gets the project provider by project file
+	 * @param projectFilePath The full path of the project file
+	 */
+	getProjectProvider(projectFilePath: string): Promise<IProjectProvider | undefined>;
+}
+
+/**
+ * Represents the item for the workspace tree
+ */
+export interface WorkspaceTreeItem {
+	/**
+	 * Gets the tree data provider
+	 */
+	treeDataProvider: vscode.TreeDataProvider<any>;
+
+	/**
+	 * Gets the raw element returned by the tree data provider
+	 */
+	element: any;
+}