1 // Copyright (c) 2011 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_SYNCHRONIZATION_LOCK_IMPL_H_ 6 #define BASE_SYNCHRONIZATION_LOCK_IMPL_H_ 7 8 #include "base/base_export.h" 9 #include "base/macros.h" 10 #include "build/build_config.h" 11 12 #if defined(OS_WIN) 13 #include <windows.h> 14 #elif defined(OS_POSIX) 15 #include <pthread.h> 16 #endif 17 18 namespace base { 19 namespace internal { 20 21 // This class implements the underlying platform-specific spin-lock mechanism 22 // used for the Lock class. Most users should not use LockImpl directly, but 23 // should instead use Lock. 24 class BASE_EXPORT LockImpl { 25 public: 26 #if defined(OS_WIN) 27 using NativeHandle = SRWLOCK; 28 #elif defined(OS_POSIX) 29 using NativeHandle = pthread_mutex_t; 30 #endif 31 32 LockImpl(); 33 ~LockImpl(); 34 35 // If the lock is not held, take it and return true. If the lock is already 36 // held by something else, immediately return false. 37 bool Try(); 38 39 // Take the lock, blocking until it is available if necessary. 40 void Lock(); 41 42 // Release the lock. This must only be called by the lock's holder: after 43 // a successful call to Try, or a call to Lock. 44 void Unlock(); 45 46 // Return the native underlying lock. 47 // TODO(awalker): refactor lock and condition variables so that this is 48 // unnecessary. 49 NativeHandle* native_handle() { return &native_handle_; } 50 51 private: 52 NativeHandle native_handle_; 53 54 DISALLOW_COPY_AND_ASSIGN(LockImpl); 55 }; 56 57 } // namespace internal 58 } // namespace base 59 60 #endif // BASE_SYNCHRONIZATION_LOCK_IMPL_H_ 61
