Use CondVar+Lock+bool instead of WaitableEvent for MessagePumpDefault on posix

base/message_loop/message_pump_default.cc

Index: base/message_loop/message_pump_default.cc
diff --git a/base/message_loop/message_pump_default.cc b/base/message_loop/message_pump_default.cc
index 27c19e0227bc6f9d6c0f0d71562a2d14c466a42c..aca56bc802747f7bad9c7a31e7e28a9c113c77bc 100644
--- a/base/message_loop/message_pump_default.cc
+++ b/base/message_loop/message_pump_default.cc
@@ -15,7 +15,12 @@ namespace base {
 
 MessagePumpDefault::MessagePumpDefault()
     : keep_running_(true),
+#if defined(OS_WIN)
       event_(false, false) {
+#elif defined(OS_POSIX)
+      needs_wake_up_(false),
+      cv_(&lock_) {
+#endif
 }
 
 MessagePumpDefault::~MessagePumpDefault() {
@@ -49,11 +54,11 @@ void MessagePumpDefault::Run(Delegate* delegate) {
 
     ThreadRestrictions::ScopedAllowWait allow_wait;
     if (delayed_work_time_.is_null()) {
-      event_.Wait();
+      Wait();
     } else {
       TimeDelta delay = delayed_work_time_ - TimeTicks::Now();
       if (delay > TimeDelta()) {
-        event_.TimedWait(delay);
+        TimedWait(delay);
       } else {
         // It looks like delayed_work_time_ indicates a time in the past, so we
         // need to call DoDelayedWork now.
@@ -74,7 +79,7 @@ void MessagePumpDefault::Quit() {
 void MessagePumpDefault::ScheduleWork() {
   // Since this can be called on any thread, we need to ensure that our Run
   // loop wakes up.
-  event_.Signal();
+  Signal();
 }
 
 void MessagePumpDefault::ScheduleDelayedWork(
@@ -85,4 +90,37 @@ void MessagePumpDefault::ScheduleDelayedWork(
   delayed_work_time_ = delayed_work_time;
 }
 
+void MessagePumpDefault::Wait() {
+#if defined(OS_WIN)
+  event_.Wait();
+#else
+  AutoLock lock(lock_);
+  while (!needs_wake_up_)
+    cv_.Wait();
+  needs_wake_up_ = false;
+#endif
+}
+
+void MessagePumpDefault::TimedWait(const TimeDelta& max_time) {
+#if defined(OS_WIN)
+  event_.TimedWait(max_time);
+#else
+  AutoLock lock(lock_);
+  cv_.TimedWait(max_time);

[darin (slow to review), 2014/09/09 06:21:07]

TODO: you'll need to protect this against spurious wake-ups.

+  needs_wake_up_ = false;
+#endif
+}
+
+void MessagePumpDefault::Signal() {
+#if defined(OS_WIN)
+  event_.Signal();
+#else
+  {
+    AutoLock lock(lock_);
+    needs_wake_up_ = true;

[jamesr, 2014/09/22 17:42:28]

try adding:

if (needs_wake_up_)
  return;

to avoid the CV signal

+  }
+  cv_.Signal();
+#endif
+}
+
 }  // namespace base