A basic wrapper for a windows event object that encapsulates the way we often use windows events. This API is not meant to be compatible with ObjectWatcher or MessageLoop::WatchObject. This API is meant to be easily ported to Mac & Linux using a traditional mutex and condition variable pairing.

There's nothing to test here since the implementation is such a thin wrapper around Win32 APIs.  However, once we go off to implement a posix version, we'll need some tests.

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@620 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 84 insertions, 0 deletions

diff --git a/base/waitable_event_win.cc b/base/waitable_event_win.cc
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+// Copyright 2008, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//    * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//    * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//    * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "base/waitable_event.h"
+
+#include <windows.h>
+#include "base/logging.h"
+
+namespace base {
+
+WaitableEvent::WaitableEvent(bool manual_reset, bool signaled)
+    : event_(CreateEvent(NULL, manual_reset, signaled, NULL)) {
+  // We're probably going to crash anyways if this is ever NULL, so we might as
+  // well make our stack reports more informative by crashing here.
+  CHECK(event_);
+}
+
+WaitableEvent::~WaitableEvent() {
+  CloseHandle(event_);
+}
+
+void WaitableEvent::Reset() {
+  ResetEvent(event_);
+}
+
+void WaitableEvent::Signal() {
+  SetEvent(event_);
+}
+
+bool WaitableEvent::IsSignaled() {
+  return TimedWait(TimeDelta::FromMilliseconds(0));
+}
+
+bool WaitableEvent::Wait() {
+  DWORD result = WaitForSingleObject(event_, INFINITE);
+  // It is most unexpected that this should ever fail.  Help consumers learn
+  // about it if it should ever fail.
+  DCHECK(result == WAIT_OBJECT_0) << "WaitForSingleObject failed";
+  return result == WAIT_OBJECT_0;
+}
+
+bool WaitableEvent::TimedWait(const TimeDelta& max_time) {
+  int32 timeout = static_cast<int32>(max_time.InMilliseconds());
+  DWORD result = WaitForSingleObject(event_, timeout);
+  switch (result) {
+    case WAIT_OBJECT_0:
+      return true;
+    case WAIT_TIMEOUT:
+      return false;
+  }
+  // It is most unexpected that this should ever fail.  Help consumers learn
+  // about it if it should ever fail.
+  NOTREACHED() << "WaitForSingleObject failed";
+  return false;
+
+}
+
+}  // namespace base