1 // Copyright 2014 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 MOJO_PUBLIC_CPP_UTILITY_MUTEX_H_ 6 #define MOJO_PUBLIC_CPP_UTILITY_MUTEX_H_ 7 8 #ifdef _WIN32 9 #error "Not implemented: See crbug.com/342893." 10 #endif 11 12 #include <pthread.h> 13 14 #include "mojo/public/cpp/system/macros.h" 15 16 namespace mojo { 17 18 #ifdef NDEBUG 19 // Note: Make a C++ constant for |PTHREAD_MUTEX_INITIALIZER|. (We can't directly 20 // use the C macro in an initializer list, since it might expand to |{ ... }|.) 21 namespace internal { 22 const pthread_mutex_t kPthreadMutexInitializer = PTHREAD_MUTEX_INITIALIZER; 23 } 24 #endif 25 26 class Mutex { 27 public: 28 #ifdef NDEBUG Mutex()29 Mutex() : mutex_(internal::kPthreadMutexInitializer) {} ~Mutex()30 ~Mutex() { pthread_mutex_destroy(&mutex_); } 31 Lock()32 void Lock() { pthread_mutex_lock(&mutex_); } Unlock()33 void Unlock() { pthread_mutex_unlock(&mutex_); } TryLock()34 bool TryLock() { return pthread_mutex_trylock(&mutex_) == 0; } 35 AssertHeld()36 void AssertHeld() {} 37 #else 38 Mutex(); 39 ~Mutex(); 40 41 void Lock(); 42 void Unlock(); 43 bool TryLock(); 44 45 void AssertHeld(); 46 #endif 47 48 private: 49 pthread_mutex_t mutex_; 50 51 MOJO_DISALLOW_COPY_AND_ASSIGN(Mutex); 52 }; 53 54 class MutexLock { 55 public: MutexLock(Mutex * mutex)56 explicit MutexLock(Mutex* mutex) : mutex_(mutex) { mutex_->Lock(); } ~MutexLock()57 ~MutexLock() { mutex_->Unlock(); } 58 59 private: 60 Mutex* const mutex_; 61 62 MOJO_DISALLOW_COPY_AND_ASSIGN(MutexLock); 63 }; 64 65 // Catch bug where variable name is omitted (e.g., |MutexLock (&mu)|). 66 #define MutexLock(x) MOJO_COMPILE_ASSERT(0, mutex_lock_missing_variable_name); 67 68 } // namespace mojo 69 70 #endif // MOJO_PUBLIC_CPP_UTILITY_MUTEX_H_ 71