Add multi_process_lock to chrome/common

base/shared_mutex_win.cc

Index: base/shared_mutex_win.cc
diff --git a/base/shared_mutex_win.cc b/base/shared_mutex_win.cc
new file mode 100644
index 0000000000000000000000000000000000000000..324d3930db1b8d64a4a1d8da0d671db10a46717c
--- /dev/null
+++ b/base/shared_mutex_win.cc
@@ -0,0 +1,33 @@
+// Copyright (c) 2010 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/shared_mutex.h"
+
+#include <string>
+#include <algorithm>
+
+#include "base/string_piece.h"
+#include "base/sys_string_conversions.h"
+
+namespace base {
+
+SharedMutex::SharedMutex(const std::string& name) : event_(NULL), name_(name) {
+}
+
+bool SharedMutex::TryLock() {
+  std::wstring wname = base::SysUTF8ToWide(name_);

[sanjeevr, 2010/11/09 06:21:05]

Please use string16 instead of wstring.

[dmac, 2010/11/11 21:47:59]

Done.

+  std::replace(wname.begin(), wname.end(), '\\', '!');

[sanjeevr, 2010/11/09 06:21:05]

Not sure whether the escaping belongs here or outside this class. This is
especially important in might of my next comment.

[dmac, 2010/11/11 21:47:59]

Pulled escaping out.

+  wname = L"Global\\" + wname;

[sanjeevr, 2010/11/09 06:21:05]

You should not add the "Global\\". We want the event to be scoped to the current
session. If the caller wants global scoping, they can specify that in the name.

[dmac, 2010/11/11 21:47:59]

removed, and added comment in header about it.

+  event_ = CreateEvent(NULL, FALSE, FALSE, wname.c_str());
+  return event_ != NULL;
+}
+
+void SharedMutex::Unlock() {
+  if (event_) {

[Mark Mentovai, 2010/11/09 17:43:14]

Don’t we have a ScopedHandle you could use?

[dmac, 2010/11/11 21:47:59]

Done.

+    CloseHandle(event_);
+    event_ = NULL;
+  }
+}
+
+}  // namespace base