base/message_loop/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_loop/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 MessagePumpDefault::~MessagePumpDefault() {
  22 }
  23
  24 void MessagePumpDefault::Run(Delegate* delegate) {
  25   DCHECK(keep_running_) << "Quit must have been called outside of Run!";
  26
  27   for (;;) {
  28 #if defined(OS_MACOSX)
  29     mac::ScopedNSAutoreleasePool autorelease_pool;
  30 #endif
  31
  32     bool did_work = delegate->DoWork();
  33     if (!keep_running_)
  34       break;
  35
  36     did_work |= delegate->DoDelayedWork(&delayed_work_time_);
  37     if (!keep_running_)
  38       break;
  39
  40     if (did_work)
  41       continue;
  42
  43     did_work = delegate->DoIdleWork();
  44     if (!keep_running_)
  45       break;
  46
  47     if (did_work)
  48       continue;
  49
  50     ThreadRestrictions::ScopedAllowWait allow_wait;
  51     if (delayed_work_time_.is_null()) {
  52       event_.Wait();
  53     } else {
  54       TimeDelta delay = delayed_work_time_ - TimeTicks::Now();
  55       if (delay > TimeDelta()) {
  56         event_.TimedWait(delay);
  57       } else {
  58         // It looks like delayed_work_time_ indicates a time in the past, so we
  59         // need to call DoDelayedWork now.
  60         delayed_work_time_ = TimeTicks();
  61       }
  62     }
  63     // Since event_ is auto-reset, we don't need to do anything special here
  64     // other than service each delegate method.
  65   }
  66
  67   keep_running_ = true;
  68 }
  69
  70 void MessagePumpDefault::Quit() {
  71   keep_running_ = false;
  72 }
  73
  74 void MessagePumpDefault::ScheduleWork() {
  75   // Since this can be called on any thread, we need to ensure that our Run
  76   // loop wakes up.
  77   event_.Signal();
  78 }
  79
  80 void MessagePumpDefault::ScheduleDelayedWork(
  81     const TimeTicks& delayed_work_time) {
  82   // We know that we can't be blocked on Wait right now since this method can
  83   // only be called on the same thread as Run, so we only need to update our
  84   // record of how long to sleep when we do sleep.
  85   delayed_work_time_ = delayed_work_time;
  86 }
  87
  88 }  // namespace base