First cut of #45664: Add API to query and execute tasks

src/vs/vscode.proposed.d.ts

@@ -739,4 +739,31 @@ declare module 'vscode' {
 	}
 
 	//#endregion
+
+	//#region Tasks
+
+	/**
+	 * A task handle represents a task in the system. It can be used to
+	 * present task and to execute them.
+	 */
+	export interface TaskHandle {
+
+		/**
+		 * A unique ID.
+		 */
+		id: string;
+
+		/**
+		 * A human readable label of the task.
+		 */
+		label: string;
+
+		/**
+		 * The workspace folder the task belongs to. Is undefined
+		 * to tasks that aren't scoped to a workspace folder.
+		 */
+		workspaceFolder: WorkspaceFolder | undefined;
+	}
+
+	//#endregion
 }

src/vs/workbench/api/node/extHostApiCommands.ts

@@ -17,6 +17,7 @@ import { ExtHostCommands } from 'vs/workbench/api/node/extHostCommands';
 import { IWorkspaceSymbolProvider } from 'vs/workbench/parts/search/common/search';
 import { Position as EditorPosition, ITextEditorOptions } from 'vs/platform/editor/common/editor';
 import { CustomCodeAction } from 'vs/workbench/api/node/extHostLanguageFeatures';
+import * as TaskSystem from 'vs/workbench/parts/tasks/common/tasks';
 
 export class ExtHostApiCommands {
 
@@ -169,6 +170,11 @@ export class ExtHostApiCommands {
 			],
 			returns: 'A promise that resolves to an array of DocumentLink-instances.'
 		});
+		this._register('vscode.executeTaskProvider', this._executeTaskProvider, {
+			description: 'Execute task provider',
+			args: [],
+			returns: 'An array of task handles'
+		});
 
 		this._register('vscode.previewHtml', (uri: URI, position?: vscode.ViewColumn, label?: string, options?: any) => {
 			return this._commands.executeCommand('_workbench.previewHtml',
@@ -465,6 +471,22 @@ export class ExtHostApiCommands {
 		return this._commands.executeCommand<modes.ILink[]>('_executeLinkProvider', resource)
 			.then(tryMapWith(typeConverters.DocumentLink.to));
 	}
+
+	private _executeTaskProvider(): Thenable<vscode.TaskHandle[]> {
+		return this._commands.executeCommand<TaskSystem.TaskHandleTransfer[]>('_executeTaskProvider').then<vscode.TaskHandle[]>((values) => {
+			return values.map(handle => {
+				return {
+					id: handle.id,
+					label: handle.label,
+					workspaceFolder: {
+						name: handle.workspaceFolder.name,
+						index: handle.workspaceFolder.index,
+						uri: URI.revive(handle.workspaceFolder.uri)
+					}
+				};
+			});
+		});
+	}
 }
 
 function tryMapWith<T, R>(f: (x: T) => R) {

src/vs/workbench/parts/tasks/common/tasks.ts

@@ -11,7 +11,7 @@ import * as Objects from 'vs/base/common/objects';
 
 import { IExtensionDescription } from 'vs/workbench/services/extensions/common/extensions';
 import { ProblemMatcher } from 'vs/workbench/parts/tasks/common/problemMatcher';
-import { IWorkspaceFolder } from 'vs/platform/workspace/common/workspace';
+import { IWorkspaceFolder, IWorkspaceFolderData } from 'vs/platform/workspace/common/workspace';
 
 
 export enum ShellQuoting {
@@ -594,6 +594,11 @@ export namespace Task {
 	}
 }
 
+export interface TaskHandleTransfer {
+	id: string;
+	label: string;
+	workspaceFolder: IWorkspaceFolderData;
+}
 
 export enum ExecutionEngine {
 	Process = 1,

src/vs/workbench/parts/tasks/electron-browser/task.contribution.ts

@@ -62,7 +62,7 @@ import Constants from 'vs/workbench/parts/markers/electron-browser/constants';
 import { IPartService } from 'vs/workbench/services/part/common/partService';
 import { IWorkbenchEditorService } from 'vs/workbench/services/editor/common/editorService';
 import { IConfigurationResolverService } from 'vs/workbench/services/configurationResolver/common/configurationResolver';
-import { IWorkspaceContextService, WorkbenchState, IWorkspaceFolder } from 'vs/platform/workspace/common/workspace';
+import { IWorkspaceContextService, WorkbenchState, IWorkspaceFolder, IWorkspaceFolderData } from 'vs/platform/workspace/common/workspace';
 
 import { ITextFileService } from 'vs/workbench/services/textfile/common/textfiles';
 import { IOutputService, IOutputChannelRegistry, Extensions as OutputExt, IOutputChannel } from 'vs/workbench/parts/output/common/output';
@@ -71,7 +71,11 @@ import { Scope, IActionBarRegistry, Extensions as ActionBarExtensions } from 'vs
 import { ITerminalService } from 'vs/workbench/parts/terminal/common/terminal';
 
 import { ITaskSystem, ITaskResolver, ITaskSummary, TaskExecuteKind, TaskError, TaskErrors, TaskTerminateResponse } from 'vs/workbench/parts/tasks/common/taskSystem';
-import { Task, CustomTask, ConfiguringTask, ContributedTask, InMemoryTask, TaskEvent, TaskEventKind, TaskSet, TaskGroup, GroupType, ExecutionEngine, JsonSchemaVersion, TaskSourceKind, TaskIdentifier, TaskSorter } from 'vs/workbench/parts/tasks/common/tasks';
+import {
+	Task, CustomTask, ConfiguringTask, ContributedTask, InMemoryTask, TaskEvent,
+	TaskEventKind, TaskSet, TaskGroup, GroupType, ExecutionEngine, JsonSchemaVersion, TaskSourceKind,
+	TaskIdentifier, TaskSorter, TaskHandleTransfer
+} from 'vs/workbench/parts/tasks/common/tasks';
 import { ITaskService, ITaskProvider, RunOptions, CustomizationProperties } from 'vs/workbench/parts/tasks/common/taskService';
 import { getTemplates as getTaskTemplates } from 'vs/workbench/parts/tasks/common/taskTemplates';
 
@@ -575,6 +579,27 @@ class TaskService implements ITaskService {
 		CommandsRegistry.registerCommand('workbench.action.tasks.showTasks', () => {
 			this.runShowTasks();
 		});
+
+		CommandsRegistry.registerCommand('_executeTaskProvider', (accessor, args) => {
+			return this.tasks().then((tasks) => {
+				let result: TaskHandleTransfer[] = [];
+				for (let task of tasks) {
+					let folder = Task.getWorkspaceFolder(task);
+					let folderData: IWorkspaceFolderData = folder ? {
+						name: folder.name,
+						uri: folder.uri,
+						index: folder.index
+					} : undefined;
+					let handle: TaskHandleTransfer = {
+						id: task._id,
+						label: task._label,
+						workspaceFolder: folderData
+					};
+					result.push(handle);
+				}
+				return result;
+			});
+		});
 	}
 
 	private get workspaceFolders(): IWorkspaceFolder[] {