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 40 Worker::Worker() : worker_thread_(NULL) {} 41 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 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 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 81 void Worker::HaveWork() { 82 ASSERT(worker_thread_ != NULL); 83 worker_thread_->Post(this, MSG_HAVEWORK); 84 } 85 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