1 /*
2 * libjingle
3 * Copyright 2004--2010, Google Inc.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright notice,
9 * this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright notice,
11 * this list of conditions and the following disclaimer in the documentation
12 * and/or other materials provided with the distribution.
13 * 3. The name of the author may not be used to endorse or promote products
14 * derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
17 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
18 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
19 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
20 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28 #include "talk/base/worker.h"
29
30 #include "talk/base/common.h"
31 #include "talk/base/logging.h"
32 #include "talk/base/thread.h"
33
34 namespace talk_base {
35
36 enum {
37 MSG_HAVEWORK = 0,
38 };
39
Worker()40 Worker::Worker() : worker_thread_(NULL) {}
41
~Worker()42 Worker::~Worker() {
43 // We need to already be stopped before being destroyed. We cannot call
44 // StopWork() from here because the subclass's data has already been
45 // destructed, so OnStop() cannot be called.
46 ASSERT(!worker_thread_);
47 }
48
StartWork()49 bool Worker::StartWork() {
50 talk_base::Thread *me = talk_base::Thread::Current();
51 if (worker_thread_) {
52 if (worker_thread_ == me) {
53 // Already working on this thread, so nothing to do.
54 return true;
55 } else {
56 LOG(LS_ERROR) << "Automatically switching threads is not supported";
57 ASSERT(false);
58 return false;
59 }
60 }
61 worker_thread_ = me;
62 OnStart();
63 return true;
64 }
65
StopWork()66 bool Worker::StopWork() {
67 if (!worker_thread_) {
68 // Already not working, so nothing to do.
69 return true;
70 } else if (worker_thread_ != talk_base::Thread::Current()) {
71 LOG(LS_ERROR) << "Stopping from a different thread is not supported";
72 ASSERT(false);
73 return false;
74 }
75 OnStop();
76 worker_thread_->Clear(this, MSG_HAVEWORK);
77 worker_thread_ = NULL;
78 return true;
79 }
80
HaveWork()81 void Worker::HaveWork() {
82 ASSERT(worker_thread_ != NULL);
83 worker_thread_->Post(this, MSG_HAVEWORK);
84 }
85
OnMessage(talk_base::Message * msg)86 void Worker::OnMessage(talk_base::Message *msg) {
87 ASSERT(msg->message_id == MSG_HAVEWORK);
88 ASSERT(worker_thread_ == talk_base::Thread::Current());
89 OnHaveWork();
90 }
91
92 } // namespace talk_base
93