1/*
2 *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
3 *
4 *  Use of this source code is governed by a BSD-style license
5 *  that can be found in the LICENSE file in the root of the source
6 *  tree. An additional intellectual property rights grant can be found
7 *  in the file PATENTS.  All contributing project authors may
8 *  be found in the AUTHORS file in the root of the source tree.
9 */
10
11#include "webrtc/base/worker.h"
12
13#include "webrtc/base/common.h"
14#include "webrtc/base/logging.h"
15#include "webrtc/base/thread.h"
16
17namespace rtc {
18
19enum {
20  MSG_HAVEWORK = 0,
21};
22
23Worker::Worker() : worker_thread_(NULL) {}
24
25Worker::~Worker() {
26  // We need to already be stopped before being destroyed. We cannot call
27  // StopWork() from here because the subclass's data has already been
28  // destructed, so OnStop() cannot be called.
29  ASSERT(!worker_thread_);
30}
31
32bool Worker::StartWork() {
33  rtc::Thread *me = rtc::Thread::Current();
34  if (worker_thread_) {
35    if (worker_thread_ == me) {
36      // Already working on this thread, so nothing to do.
37      return true;
38    } else {
39      LOG(LS_ERROR) << "Automatically switching threads is not supported";
40      ASSERT(false);
41      return false;
42    }
43  }
44  worker_thread_ = me;
45  OnStart();
46  return true;
47}
48
49bool Worker::StopWork() {
50  if (!worker_thread_) {
51    // Already not working, so nothing to do.
52    return true;
53  } else if (worker_thread_ != rtc::Thread::Current()) {
54    LOG(LS_ERROR) << "Stopping from a different thread is not supported";
55    ASSERT(false);
56    return false;
57  }
58  OnStop();
59  worker_thread_->Clear(this, MSG_HAVEWORK);
60  worker_thread_ = NULL;
61  return true;
62}
63
64void Worker::HaveWork() {
65  ASSERT(worker_thread_ != NULL);
66  worker_thread_->Post(this, MSG_HAVEWORK);
67}
68
69void Worker::OnMessage(rtc::Message *msg) {
70  ASSERT(msg->message_id == MSG_HAVEWORK);
71  ASSERT(worker_thread_ == rtc::Thread::Current());
72  OnHaveWork();
73}
74
75}  // namespace rtc
76