base/message_pump_default.cc

   1 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "base/message_pump_default.h"
   6
   7 #include "base/logging.h"
   8 #include "base/threading/thread_restrictions.h"
   9
  10 #if defined(OS_MACOSX)
  11 #include "base/mac/scoped_nsautorelease_pool.h"
  12 #endif
  13
  14 namespace base {
  15
  16 MessagePumpDefault::MessagePumpDefault()
  17     : keep_running_(true),
  18       event_(false, false) {
  19 }
  20
  21 void MessagePumpDefault::Run(Delegate* delegate) {
  22   DCHECK(keep_running_) << "Quit must have been called outside of Run!";
  23
  24   for (;;) {
  25 #if defined(OS_MACOSX)
  26     mac::ScopedNSAutoreleasePool autorelease_pool;
  27 #endif
  28
  29     bool did_work = delegate->DoWork();
  30     if (!keep_running_)
  31       break;
  32
  33     did_work |= delegate->DoDelayedWork(&delayed_work_time_);
  34     if (!keep_running_)
  35       break;
  36
  37     if (did_work)
  38       continue;
  39
  40     did_work = delegate->DoIdleWork();
  41     if (!keep_running_)
  42       break;
  43
  44     if (did_work)
  45       continue;
  46
  47     base::ThreadRestrictions::ScopedAllowWait allow_wait;
  48     if (delayed_work_time_.is_null()) {
  49       event_.Wait();
  50     } else {
  51       TimeDelta delay = delayed_work_time_ - TimeTicks::Now();
  52       if (delay > TimeDelta()) {
  53         event_.TimedWait(delay);
  54       } else {
  55         // It looks like delayed_work_time_ indicates a time in the past, so we
  56         // need to call DoDelayedWork now.
  57         delayed_work_time_ = TimeTicks();
  58       }
  59     }
  60     // Since event_ is auto-reset, we don't need to do anything special here
  61     // other than service each delegate method.
  62   }
  63
  64   keep_running_ = true;
  65 }
  66
  67 void MessagePumpDefault::Quit() {
  68   keep_running_ = false;
  69 }
  70
  71 void MessagePumpDefault::ScheduleWork() {
  72   // Since this can be called on any thread, we need to ensure that our Run
  73   // loop wakes up.
  74   event_.Signal();
  75 }
  76
  77 void MessagePumpDefault::ScheduleDelayedWork(
  78     const TimeTicks& delayed_work_time) {
  79   // We know that we can't be blocked on Wait right now since this method can
  80   // only be called on the same thread as Run, so we only need to update our
  81   // record of how long to sleep when we do sleep.
  82   delayed_work_time_ = delayed_work_time;
  83 }
  84
  85 }  // namespace base