Add multi_process_lock to chrome/common

chrome/common/multi_process_lock_win.cc

+// 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 "chrome/common/multi_process_lock.h"
+
+#include "base/logging.h"
+#include "base/utf_string_conversions.h"
+#include "base/win/scoped_handle.h"
+
+class MultiProcessLockWin : public MultiProcessLock {
+ public:
+  explicit MultiProcessLockWin(const std::string& name)
+      : name_(name), count_(0) { }
+
+  virtual ~MultiProcessLockWin() {
+    if (count_ > 0) {
+      Unlock();
+    }
+  }
+
+  virtual bool TryLock() {
+    if (count_ > 0) {
+      count_ += 1;
+      return true;
+    }
+    string16 wname = UTF8ToUTF16(name_);
+    HANDLE event = CreateEvent(NULL, FALSE, FALSE, wname.c_str());
+    if (event && GetLastError() != ERROR_ALREADY_EXISTS) {
+      event_.Set(event);
+      count_ = 1;
+      return true;
+    } else {
+      if (event) {
+        CloseHandle(event);
+      }
+      return false;
+    }
+  }
+
+  virtual void Unlock() {
+    if (count_ == 0) {
+      DLOG(ERROR) << "Over unlocked MultiProcessLock " << name_;

[Mark Mentovai, 2010/11/11 23:45:24]

hypheny
(and the Linux file too.)

[dmac, 2010/11/12 00:36:26]

Done.

+      return;
+    }
+    count_ -= 1;
+    if (count_ == 0) {
+      event_.Set(NULL);
+    }
+  }
+
+ private:
+  std::string name_;
+  int count_;

[Mark Mentovai, 2010/11/11 23:45:24]

packy

[dmac, 2010/11/12 00:36:26]

Done.

+  base::win::ScopedHandle event_;
+  DISALLOW_COPY_AND_ASSIGN(MultiProcessLockWin);
+};
+
+MultiProcessLock* MultiProcessLock::Create(const std::string &name) {
+  return new MultiProcessLockWin(name);
+}