| // Copyright 2008, Google Inc. |
| // All rights reserved. |
| // |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are |
| // met: |
| // |
| // * Redistributions of source code must retain the above copyright |
| // notice, this list of conditions and the following disclaimer. |
| // * Redistributions in binary form must reproduce the above |
| // copyright notice, this list of conditions and the following disclaimer |
| // in the documentation and/or other materials provided with the |
| // distribution. |
| // * Neither the name of Google Inc. nor the names of its |
| // contributors may be used to endorse or promote products derived from |
| // this software without specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| #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" |
| |
| // 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(); |
| |
| // Return the native underlying lock. |
| // TODO(awalker): refactor lock and condition variables so that this is |
| // unnecessary. |
| OSLockType* os_lock() { return &os_lock_; } |
| |
| private: |
| OSLockType os_lock_; |
| |
| DISALLOW_COPY_AND_ASSIGN(LockImpl); |
| }; |
| |
| class AutoLockImpl { |
| public: |
| AutoLockImpl(LockImpl* lock_impl) |
| : lock_impl_(lock_impl) { |
| lock_impl_->Lock(); |
| } |
| |
| ~AutoLockImpl() { |
| lock_impl_->Unlock(); |
| } |
| |
| private: |
| DISALLOW_EVIL_CONSTRUCTORS(AutoLockImpl); |
| |
| LockImpl* lock_impl_; |
| }; |
| |
| #endif // BASE_LOCK_IMPL_H_ |