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authorMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
committerMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
commit5f8de423f190bbb79a62f804151bc24824fa32d8 (patch)
tree10027f336435511475e392454359edea8e25895d /ipc/chromium/src/base/lock.h
parent49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff)
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Add m-esr52 at 52.6.0
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diff --git a/ipc/chromium/src/base/lock.h 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_