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comparison: ipc/chromium/src/base/lock.h
ipc/chromium/src/base/lock.h
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| 1 // Copyright (c) 2006-2009 The Chromium Authors. All rights reserved. | |
| 2 // Use of this source code is governed by a BSD-style license that can be | |
| 3 // found in the LICENSE file. | |
| 4 | |
| 5 #ifndef BASE_LOCK_H_ | |
| 6 #define BASE_LOCK_H_ | |
| 7 | |
| 8 #include "base/lock_impl.h" | |
| 9 | |
| 10 // A convenient wrapper for an OS specific critical section. | |
| 11 | |
| 12 class Lock { | |
| 13 public: | |
| 14 Lock() : lock_() {} | |
| 15 ~Lock() {} | |
| 16 void Acquire() { lock_.Lock(); } | |
| 17 void Release() { lock_.Unlock(); } | |
| 18 // If the lock is not held, take it and return true. If the lock is already | |
| 19 // held by another thread, immediately return false. | |
| 20 bool Try() { return lock_.Try(); } | |
| 21 | |
| 22 // In debug builds this method checks that the lock has been acquired by the | |
| 23 // calling thread. If the lock has not been acquired, then the method | |
| 24 // will DCHECK(). In non-debug builds, the LockImpl's implementation of | |
| 25 // AssertAcquired() is an empty inline method. | |
| 26 void AssertAcquired() const { return lock_.AssertAcquired(); } | |
| 27 | |
| 28 // Return the underlying lock implementation. | |
| 29 // TODO(awalker): refactor lock and condition variables so that this is | |
| 30 // unnecessary. | |
| 31 LockImpl* lock_impl() { return &lock_; } | |
| 32 | |
| 33 private: | |
| 34 LockImpl lock_; // Platform specific underlying lock implementation. | |
| 35 | |
| 36 DISALLOW_COPY_AND_ASSIGN(Lock); | |
| 37 }; | |
| 38 | |
| 39 // A helper class that acquires the given Lock while the AutoLock is in scope. | |
| 40 class AutoLock { | |
| 41 public: | |
| 42 explicit AutoLock(Lock& lock) : lock_(lock) { | |
| 43 lock_.Acquire(); | |
| 44 } | |
| 45 | |
| 46 ~AutoLock() { | |
| 47 lock_.AssertAcquired(); | |
| 48 lock_.Release(); | |
| 49 } | |
| 50 | |
| 51 private: | |
| 52 Lock& lock_; | |
| 53 DISALLOW_COPY_AND_ASSIGN(AutoLock); | |
| 54 }; | |
| 55 | |
| 56 // AutoUnlock is a helper that will Release() the |lock| argument in the | |
| 57 // constructor, and re-Acquire() it in the destructor. | |
| 58 class AutoUnlock { | |
| 59 public: | |
| 60 explicit AutoUnlock(Lock& lock) : lock_(lock) { | |
| 61 // We require our caller to have the lock. | |
| 62 lock_.AssertAcquired(); | |
| 63 lock_.Release(); | |
| 64 } | |
| 65 | |
| 66 ~AutoUnlock() { | |
| 67 lock_.Acquire(); | |
| 68 } | |
| 69 | |
| 70 private: | |
| 71 Lock& lock_; | |
| 72 DISALLOW_COPY_AND_ASSIGN(AutoUnlock); | |
| 73 }; | |
| 74 | |
| 75 #endif // BASE_LOCK_H_ |
