WaitableEvent is the replacement for Windows events. Previously in the code, a HANDLE from CreateEvent was used for signaling, both within a process and across processes.

WaitableEvent is the cross platform replacement for this. To convert:
  * HANDLE -> base::WaitableEvent*
  * ScopedHandle -> scoped_ptr<base::WaitableEvent>
  * CreateEvent -> new base::WaitableEvent
  * SetEvent -> base::WaitableEvent::Signal
  * ResetEvent -> base::WaitableEvent::Reset
  * ObjectWatcher -> base::WaitableEventWatcher
  * WaitForMultipleObjects -> static base::WaitableEvent::WaitMany

ObjectWatcher remains for Windows specific code. WaitableEventWatcher has an identical interface save,
  * It uses WaitableEvents, not HANDLEs
  * It returns void from StartWatching and StopWatcher, rather than errors. System internal errors are fatal to the address space

IMPORTANT: There are semantic differences between the different platforms. WaitableEvents on Windows are implemented on top of events. Windows events work across process and this is used mostly for modal dialog support. Windows events can be duplicated with DuplicateHandle.

On other platforms, WaitableEvent works only within a single process. In the future we shall have to replace the current uses of cross-process events with IPCs.

BEWARE: HANDLE, on Windows, is a void *. Since any pointer type coerces to void *, you can pass a WaitableEvent * where a HANDLE is expected without any build-time errors.

Review URL: http://codereview.chromium.org/16554


git-svn-id: svn://svn.chromium.org/chrome/trunk/src@8126 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 0 insertions, 71 deletions

diff --git a/base/waitable_event_generic.cc b/base/waitable_event_generic.cc
deleted file mode 100644
index 61eeeb8..0000000
--- a/base/waitable_event_generic.cc
+++ /dev/null
@@ -1,71 +0,0 @@
-// Copyright (c) 2006-2008 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/waitable_event.h"
-
-namespace base {
-
-WaitableEvent::WaitableEvent(bool manual_reset, bool signaled)
-    : lock_(),
-      cvar_(&lock_),
-      signaled_(signaled),
-      manual_reset_(manual_reset) {
-}
-
-WaitableEvent::~WaitableEvent() {
-  // Members are destroyed in the reverse of their initialization order, so we
-  // should not have to worry about lock_ being destroyed before cvar_.
-}
-
-void WaitableEvent::Reset() {
-  AutoLock locked(lock_);
-  signaled_ = false;
-}
-
-void WaitableEvent::Signal() {
-  AutoLock locked(lock_);
-  if (!signaled_) {
-    signaled_ = true;
-    if (manual_reset_) {
-      cvar_.Broadcast(); 
-    } else {
-      cvar_.Signal();
-    }
-  }
-}
-
-bool WaitableEvent::IsSignaled() {
-  return TimedWait(TimeDelta::FromMilliseconds(0));
-}
-
-bool WaitableEvent::Wait() {
-  AutoLock locked(lock_);
-  while (!signaled_)
-    cvar_.Wait();
-  if (!manual_reset_)
-    signaled_ = false;
-  return true;
-}
-
-bool WaitableEvent::TimedWait(const TimeDelta& max_time) {
-  AutoLock locked(lock_);
-  // In case of spurious wake-ups, we need to adjust the amount of time that we
-  // spend sleeping.
-  TimeDelta total_time;
-  for (;;) {
-    TimeTicks start = TimeTicks::Now();
-    cvar_.TimedWait(max_time - total_time);
-    if (signaled_)
-      break;
-    total_time += TimeTicks::Now() - start;
-    if (total_time >= max_time)
-      break;
-  }
-  bool result = signaled_;
-  if (!manual_reset_)
-    signaled_ = false;
-  return result;
-}
-
-}  // namespace base