Modify WaitableEvent::Wait() to return void

base/synchronization/waitable_event_posix.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/synchronization/waitable_event.h"
 
 #include "base/synchronization/condition_variable.h"
 #include "base/synchronization/lock.h"
 #include "base/message_loop.h"
 
@@ skipping 131 matching lines @@
     return &cv_;
   }
 
  private:
   bool fired_;
   WaitableEvent* signaling_event_;  // The WaitableEvent which woke us
   base::Lock lock_;
   base::ConditionVariable cv_;
 };
 
-bool WaitableEvent::Wait() {
-  return TimedWait(TimeDelta::FromSeconds(-1));
+void WaitableEvent::Wait() {
+  bool result = TimedWait(TimeDelta::FromSeconds(-1));
+  DCHECK(result) << "TimedWait() should never fail with infinite timeout";
 }
 
 bool WaitableEvent::TimedWait(const TimeDelta& max_time) {
   const Time end_time(Time::Now() + max_time);
   const bool finite_time = max_time.ToInternalValue() >= 0;
 
   kernel_->lock_.Acquire();
-    if (kernel_->signaled_) {
-      if (!kernel_->manual_reset_) {
-        // In this case we were signaled when we had no waiters. Now that
-        // someone has waited upon us, we can automatically reset.
-        kernel_->signaled_ = false;
-      }
-
-      kernel_->lock_.Release();
-      return true;
+  if (kernel_->signaled_) {
+    if (!kernel_->manual_reset_) {
+      // In this case we were signaled when we had no waiters. Now that
+      // someone has waited upon us, we can automatically reset.
+      kernel_->signaled_ = false;
     }
 
-    SyncWaiter sw;
-    sw.lock()->Acquire();
+    kernel_->lock_.Release();
+    return true;
+  }
 
-    Enqueue(&sw);
+  SyncWaiter sw;
+  sw.lock()->Acquire();
+
+  Enqueue(&sw);
   kernel_->lock_.Release();
   // We are violating locking order here by holding the SyncWaiter lock but not
   // the WaitableEvent lock. However, this is safe because we don't lock @lock_
   // again before unlocking it.
 
   for (;;) {
     const Time current_time(Time::Now());
 
     if (sw.fired() || (finite_time && current_time >= end_time)) {
       const bool return_value = sw.fired();
 
       // We can't acquire @lock_ before releasing the SyncWaiter lock (because
       // of locking order), however, in between the two a signal could be fired
       // and @sw would accept it, however we will still return false, so the
       // signal would be lost on an auto-reset WaitableEvent. Thus we call
       // Disable which makes sw::Fire return false.
       sw.Disable();
       sw.lock()->Release();
 
       kernel_->lock_.Acquire();
-        kernel_->Dequeue(&sw, &sw);
+      kernel_->Dequeue(&sw, &sw);
       kernel_->lock_.Release();
 
       return return_value;
     }
 
     if (finite_time) {
       const TimeDelta max_wait(end_time - current_time);
       sw.cv()->TimedWait(max_wait);
     } else {
       sw.cv()->Wait();
@@ skipping 185 matching lines @@
       return true;
     }
   }
 
   return false;
 }
 
 // -----------------------------------------------------------------------------
 
 }  // namespace base