blob: 3b2a05b6433853b4459d1ab5272c5c906b6b1c1f [file] [log] [blame]
// Copyright (c) 2016, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
import 'dart:io';
import 'constants.dart';
import 'sync_message_grouper.dart';
import 'utils.dart';
import 'worker_connection.dart';
import 'worker_loop.dart';
import 'worker_protocol.pb.dart';
/// Connection between a worker and input / output.
abstract class SyncWorkerConnection implements WorkerConnection {
/// Read a new [WorkRequest]. Returns [null] when there are no more requests.
WorkRequest readRequest();
/// Write the given [response] as bytes to the output.
void writeResponse(WorkResponse response);
/// Persistent Bazel worker loop.
/// Extend this class and implement the `performRequest` method.
abstract class SyncWorkerLoop implements WorkerLoop {
final SyncWorkerConnection connection;
SyncWorkerLoop({SyncWorkerConnection connection})
: this.connection = connection ?? new StdSyncWorkerConnection();
/// Perform a single [WorkRequest], and return a [WorkResponse].
WorkResponse performRequest(WorkRequest request);
/// Run the worker loop. Blocks until [connection#readRequest] returns `null`.
void run() {
while (true) {
WorkResponse response;
try {
var request = connection.readRequest();
if (request == null) break;
response = performRequest(request);
// In case they forget to set this.
response.exitCode ??= EXIT_CODE_OK;
} catch (e, s) {
response = new WorkResponse()
..exitCode = EXIT_CODE_ERROR
..output = '$e\n$s';
/// Default implementation of [SyncWorkerConnection] that works with [Stdin] and
/// [Stdout].
class StdSyncWorkerConnection implements SyncWorkerConnection {
final SyncMessageGrouper _messageGrouper;
final Stdout _stdoutStream;
StdSyncWorkerConnection({Stdin stdinStream, Stdout stdoutStream})
: _messageGrouper = new SyncMessageGrouper(stdinStream ?? stdin),
_stdoutStream = stdoutStream ?? stdout;
WorkRequest readRequest() {
var buffer =;
if (buffer == null) return null;
return new WorkRequest.fromBuffer(buffer);
void writeResponse(WorkResponse response) {