terminal: standardize on customPtyImplementation

I initially was doing a larger refactor where the `onInstanceRequestStartExtensionTerminal`
event was removed from the terminalService and instead events would only
be fired in the proxy instance itself, which would be encapsulated better.
However, the task system depends on the global even firing so that the
MainThreadTerminalService can get the terminal for tasks that create
pseudoterminals, so this didn't work out. Kept a more focus refactor
for now.

src/vs/platform/terminal/common/terminal.ts

@@ -238,16 +238,10 @@ export interface IShellLaunchConfig {
 	 */
 	initialText?: string;
 
-	/**
-	 * Whether an extension is controlling the terminal via a `vscode.Pseudoterminal`.
-	 */
-	isExtensionCustomPtyTerminal?: boolean;
-
 	/**
 	 * Custom PTY/pseudoterminal process to use.
-	 * @todo should `TerminalProcessExtHostProxy` be passed to here and remove `isExtensionCustomPtyTerminal`?
 	 */
-	customPtyImplementation?: ITerminalChildProcess;
+	customPtyImplementation?: (terminalId: number, cols: number, rows: number) => ITerminalChildProcess;
 
 	/**
 	 * A UUID generated by the extension host process for terminals created on the extension host process.

src/vs/workbench/api/browser/mainThreadTerminalService.ts

@@ -13,6 +13,7 @@ import { TerminalDataBufferer } from 'vs/platform/terminal/common/terminalDataBu
 import { ExtHostContext, ExtHostTerminalServiceShape, IExtHostContext, ITerminalDimensionsDto, MainContext, MainThreadTerminalServiceShape, TerminalIdentifier, TerminalLaunchConfig } from 'vs/workbench/api/common/extHost.protocol';
 import { extHostNamedCustomer } from 'vs/workbench/api/common/extHostCustomers';
 import { ITerminalExternalLinkProvider, ITerminalInstance, ITerminalInstanceService, ITerminalLink, ITerminalService } from 'vs/workbench/contrib/terminal/browser/terminal';
+import { TerminalProcessExtHostProxy } from 'vs/workbench/contrib/terminal/browser/terminalProcessExtHostProxy';
 import { IEnvironmentVariableService, ISerializableEnvironmentVariableCollection } from 'vs/workbench/contrib/terminal/common/environmentVariable';
 import { deserializeEnvironmentVariableCollection, serializeEnvironmentVariableCollection } from 'vs/workbench/contrib/terminal/common/environmentVariableShared';
 import { IAvailableProfilesRequest as IAvailableProfilesRequest, IDefaultShellAndArgsRequest, IStartExtensionTerminalRequest, ITerminalProcessExtHostProxy } from 'vs/workbench/contrib/terminal/common/terminal';
@@ -130,7 +131,7 @@ export class MainThreadTerminalService implements MainThreadTerminalServiceShape
 			env: launchConfig.env,
 			strictEnv: launchConfig.strictEnv,
 			hideFromUser: launchConfig.hideFromUser,
-			isExtensionCustomPtyTerminal: launchConfig.isExtensionCustomPtyTerminal,
+			customPtyImplementation: (id, rows, cols) => new TerminalProcessExtHostProxy(id, cols, rows, this._terminalService),
 			extHostTerminalId: extHostTerminalId,
 			isFeatureTerminal: launchConfig.isFeatureTerminal,
 			isExtensionOwnedTerminal: launchConfig.isExtensionOwnedTerminal

src/vs/workbench/contrib/tasks/browser/terminalTaskSystem.ts

@@ -48,6 +48,7 @@ import { IViewsService, IViewDescriptorService, ViewContainerLocation } from 'vs
 import { ILogService } from 'vs/platform/log/common/log';
 import { IConfigurationService } from 'vs/platform/configuration/common/configuration';
 import { IShellLaunchConfig } from 'vs/platform/terminal/common/terminal';
+import { TerminalProcessExtHostProxy } from 'vs/workbench/contrib/terminal/browser/terminalProcessExtHostProxy';
 
 interface TerminalData {
 	terminal: ITerminalInstance;
@@ -1163,7 +1164,7 @@ export class TerminalTaskSystem implements ITaskSystem {
 
 		if (task.command.runtime === RuntimeType.CustomExecution) {
 			this.currentTask.shellLaunchConfig = launchConfigs = {
-				isExtensionCustomPtyTerminal: true,
+				customPtyImplementation: (id, rows, cols) => new TerminalProcessExtHostProxy(id, cols, rows, this.terminalService),
 				waitOnExit,
 				name: this.createTerminalName(task),
 				initialText: task.command.presentation && task.command.presentation.echo ? `\x1b[1m> Executing task: ${task._label} <\x1b[0m\n` : undefined,

src/vs/workbench/contrib/terminal/browser/terminalInstance.ts

@@ -1621,7 +1621,7 @@ export class TerminalInstance extends Disposable implements ITerminalInstance {
 			this._configHelper.config.environmentChangesRelaunch &&
 			!this._processManager.hasWrittenData &&
 			!this._shellLaunchConfig.isFeatureTerminal &&
-			!this._shellLaunchConfig.isExtensionCustomPtyTerminal
+			!this._shellLaunchConfig.customPtyImplementation
 			&& !this._shellLaunchConfig.isExtensionOwnedTerminal &&
 			!this._shellLaunchConfig.attachPersistentProcess
 		) {

src/vs/workbench/contrib/terminal/browser/terminalProcessExtHostProxy.ts

@@ -54,10 +54,9 @@ export class TerminalProcessExtHostProxy extends Disposable implements ITerminal
 
 	constructor(
 		public instanceId: number,
-		private _shellLaunchConfig: IShellLaunchConfig,
 		private _cols: number,
 		private _rows: number,
-		@ITerminalService private readonly _terminalService: ITerminalService
+		@ITerminalService private readonly _terminalService: ITerminalService,
 	) {
 		super();
 	}
@@ -106,9 +105,6 @@ export class TerminalProcessExtHostProxy extends Disposable implements ITerminal
 	}
 
 	public async start(): Promise<ITerminalLaunchError | undefined> {
-		if (!this._shellLaunchConfig.isExtensionCustomPtyTerminal) {
-			throw new Error('Attempt to start an ext host process that is not an extension terminal');
-		}
 		return this._terminalService.requestStartExtensionTerminal(this, this._cols, this._rows);
 	}
 

src/vs/workbench/contrib/terminal/browser/terminalProcessManager.ts

@@ -10,7 +10,6 @@ import { ProcessState, ITerminalProcessManager, ITerminalConfigHelper, IBeforePr
 import { ILogService } from 'vs/platform/log/common/log';
 import { Emitter, Event } from 'vs/base/common/event';
 import { IHistoryService } from 'vs/workbench/services/history/common/history';
-import { TerminalProcessExtHostProxy } from 'vs/workbench/contrib/terminal/browser/terminalProcessExtHostProxy';
 import { IInstantiationService, optional } from 'vs/platform/instantiation/common/instantiation';
 import { IWorkspaceContextService } from 'vs/platform/workspace/common/workspace';
 import { IConfigurationResolverService } from 'vs/workbench/services/configurationResolver/common/configurationResolver';
@@ -191,9 +190,9 @@ export class TerminalProcessManager extends Disposable implements ITerminalProce
 
 		let newProcess: ITerminalChildProcess;
 
-		if (shellLaunchConfig.isExtensionCustomPtyTerminal || shellLaunchConfig.customPtyImplementation) {
+		if (shellLaunchConfig.customPtyImplementation) {
 			this._processType = ProcessType.PsuedoTerminal;
-			newProcess = shellLaunchConfig.customPtyImplementation || this._instantiationService.createInstance(TerminalProcessExtHostProxy, this._instanceId, shellLaunchConfig, cols, rows);
+			newProcess = shellLaunchConfig.customPtyImplementation(this._instanceId, cols, rows);
 		} else {
 			const forceExtHostProcess = (this._configHelper.config as any).extHostProcess;
 			if (shellLaunchConfig.cwd && typeof shellLaunchConfig.cwd === 'object') {

src/vs/workbench/contrib/terminal/browser/terminalService.ts

@@ -996,7 +996,7 @@ export class TerminalService implements ITerminalService {
 	public createTerminal(shellLaunchConfigOrProfile: IShellLaunchConfig | ITerminalProfile): ITerminalInstance {
 		const shellLaunchConfig = this._convertProfileToShellLaunchConfig(shellLaunchConfigOrProfile);
 
-		if (!shellLaunchConfig.isExtensionCustomPtyTerminal && !this.isProcessSupportRegistered) {
+		if (!shellLaunchConfig.customPtyImplementation && !this.isProcessSupportRegistered) {
 			throw new Error('Could not create terminal when process support is not registered');
 		}
 		if (shellLaunchConfig.hideFromUser) {

src/vs/workbench/contrib/testing/browser/testingOutputTerminalService.ts

@@ -66,7 +66,7 @@ export class TestingOutputTerminalService implements ITestingOutputTerminalServi
 			output = new TestOutputProcess();
 			terminal = this.terminalService.createTerminal({
 				isFeatureTerminal: true,
-				customPtyImplementation: output,
+				customPtyImplementation: () => output,
 				name: title,
 			}) as TestOutputTerminalInstance;
 		}