1 files changed, 77 insertions, 0 deletions
diff --git a/ipc/chromium/src/base/lock.h b/ipc/chromium/src/base/lock.h
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+++ b/ipc/chromium/src/base/lock.h
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+// Copyright (c) 2006-2009 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.
+
+#ifndef BASE_LOCK_H_
+#define BASE_LOCK_H_
+
+#include "base/lock_impl.h"
+
+// A convenient wrapper for an OS specific critical section.
+
+class Lock {
+ public:
+  Lock() : lock_() {}
+  ~Lock() {}
+  void Acquire() { lock_.Lock(); }
+  void Release() { lock_.Unlock(); }
+  // If the lock is not held, take it and return true. If the lock is already
+  // held by another thread, immediately return false.
+  bool Try() { return lock_.Try(); }
+
+  // In debug builds this method checks that the lock has been acquired by the
+  // calling thread.  If the lock has not been acquired, then the method
+  // will DCHECK().  In non-debug builds, the LockImpl's implementation of
+  // AssertAcquired() is an empty inline method.
+  void AssertAcquired() const { return lock_.AssertAcquired(); }
+
+  // Return the underlying lock implementation.
+  // TODO(awalker): refactor lock and condition variables so that this is
+  // unnecessary.
+  LockImpl* lock_impl() { return &lock_; }
+
+ private:
+  LockImpl lock_;  // Platform specific underlying lock implementation.
+
+  DISALLOW_COPY_AND_ASSIGN(Lock);
+};
+
+// A helper class that acquires the given Lock while the AutoLock is in scope.
+class AutoLock {
+ public:
+  explicit AutoLock(Lock& lock) : lock_(lock) {
+    lock_.Acquire();
+  }
+
+  ~AutoLock() {
+    lock_.AssertAcquired();
+    lock_.Release();
+  }
+
+ private:
+  Lock& lock_;
+  DISALLOW_COPY_AND_ASSIGN(AutoLock);
+};
+
+// AutoUnlock is a helper that will Release() the |lock| argument in the
+// constructor, and re-Acquire() it in the destructor.
+class AutoUnlock {
+ public:
+  explicit AutoUnlock(Lock& lock) : lock_(lock) {
+    // We require our caller to have the lock.
+    lock_.AssertAcquired();
+    lock_.Release();
+  }
+
+  ~AutoUnlock() {
+    lock_.Acquire();
+  }
+
+ private:
+  Lock& lock_;
+  DISALLOW_COPY_AND_ASSIGN(AutoUnlock);
+};
+
+#endif  // BASE_LOCK_H_