| // Copyright (c) 2006-2008 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_IMPL_H_ |
| #define BASE_LOCK_IMPL_H_ |
| |
| #include "build/build_config.h" |
| |
| #if defined(OS_WIN) |
| #include <windows.h> |
| #elif defined(OS_POSIX) |
| #include <pthread.h> |
| #endif |
| |
| #include "base/basictypes.h" |
| #include "base/platform_thread.h" |
| |
| // This class implements the underlying platform-specific spin-lock mechanism |
| // used for the Lock class. Most users should not use LockImpl directly, but |
| // should instead use Lock. |
| class LockImpl { |
| public: |
| #if defined(OS_WIN) |
| typedef CRITICAL_SECTION OSLockType; |
| #elif defined(OS_POSIX) |
| typedef pthread_mutex_t OSLockType; |
| #endif |
| |
| LockImpl(); |
| ~LockImpl(); |
| |
| // If the lock is not held, take it and return true. If the lock is already |
| // held by something else, immediately return false. |
| bool Try(); |
| |
| // Take the lock, blocking until it is available if necessary. |
| void Lock(); |
| |
| // Release the lock. This must only be called by the lock's holder: after |
| // a successful call to Try, or a call to Lock. |
| void Unlock(); |
| |
| // Debug-only method that will DCHECK() if the lock is not acquired by the |
| // current thread. In non-debug builds, no check is performed. |
| // Because linux and mac condition variables modify the underlyning lock |
| // through the os_lock() method, runtime assertions can not be done on those |
| // builds. |
| #if defined(NDEBUG) || !defined(OS_WIN) |
| void AssertAcquired() const {} |
| #else |
| void AssertAcquired() const; |
| #endif |
| |
| // Return the native underlying lock. Not supported for Windows builds. |
| // TODO(awalker): refactor lock and condition variables so that this is |
| // unnecessary. |
| #if !defined(OS_WIN) |
| OSLockType* os_lock() { return &os_lock_; } |
| #endif |
| |
| private: |
| OSLockType os_lock_; |
| |
| #if !defined(NDEBUG) && defined(OS_WIN) |
| // All private data is implicitly protected by lock_. |
| // Be VERY careful to only access members under that lock. |
| PlatformThreadId owning_thread_id_; |
| int32 recursion_count_shadow_; |
| bool recursion_used_; // Allow debugging to continued after a DCHECK(). |
| #endif // NDEBUG |
| |
| DISALLOW_COPY_AND_ASSIGN(LockImpl); |
| }; |
| |
| |
| #endif // BASE_LOCK_IMPL_H_ |