1 // Copyright (c) 2006, Google Inc. 2 // All rights reserved. 3 // 4 // Redistribution and use in source and binary forms, with or without 5 // modification, are permitted provided that the following conditions are 6 // met: 7 // 8 // * Redistributions of source code must retain the above copyright 9 // notice, this list of conditions and the following disclaimer. 10 // * Redistributions in binary form must reproduce the above 11 // copyright notice, this list of conditions and the following disclaimer 12 // in the documentation and/or other materials provided with the 13 // distribution. 14 // * Neither the name of Google Inc. nor the names of its 15 // contributors may be used to endorse or promote products derived from 16 // this software without specific prior written permission. 17 // 18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 30 #ifndef GOOGLE_PROTOBUF_STUBS_MUTEX_H_ 31 #define GOOGLE_PROTOBUF_STUBS_MUTEX_H_ 32 33 #include <mutex> 34 35 #ifdef GOOGLE_PROTOBUF_SUPPORT_WINDOWS_XP 36 37 #include <windows.h> 38 39 // GetMessage conflicts with GeneratedMessageReflection::GetMessage(). 40 #ifdef GetMessage 41 #undef GetMessage 42 #endif 43 44 #endif 45 46 #include <google/protobuf/stubs/macros.h> 47 48 // Define thread-safety annotations for use below, if we are building with 49 // Clang. 50 #if defined(__clang__) && !defined(SWIG) 51 #define GOOGLE_PROTOBUF_ACQUIRE(...) \ 52 __attribute__((acquire_capability(__VA_ARGS__))) 53 #define GOOGLE_PROTOBUF_RELEASE(...) \ 54 __attribute__((release_capability(__VA_ARGS__))) 55 #define GOOGLE_PROTOBUF_CAPABILITY(x) __attribute__((capability(x))) 56 #else 57 #define GOOGLE_PROTOBUF_ACQUIRE(...) 58 #define GOOGLE_PROTOBUF_RELEASE(...) 59 #define GOOGLE_PROTOBUF_CAPABILITY(x) 60 #endif 61 62 #include <google/protobuf/port_def.inc> 63 64 // =================================================================== 65 // emulates google3/base/mutex.h 66 namespace google { 67 namespace protobuf { 68 namespace internal { 69 70 #define GOOGLE_PROTOBUF_LINKER_INITIALIZED 71 72 #ifdef GOOGLE_PROTOBUF_SUPPORT_WINDOWS_XP 73 74 // This class is a lightweight replacement for std::mutex on Windows platforms. 75 // std::mutex does not work on Windows XP SP2 with the latest VC++ libraries, 76 // because it utilizes the Concurrency Runtime that is only supported on Windows 77 // XP SP3 and above. 78 class PROTOBUF_EXPORT CriticalSectionLock { 79 public: CriticalSectionLock()80 CriticalSectionLock() { InitializeCriticalSection(&critical_section_); } ~CriticalSectionLock()81 ~CriticalSectionLock() { DeleteCriticalSection(&critical_section_); } lock()82 void lock() { EnterCriticalSection(&critical_section_); } unlock()83 void unlock() { LeaveCriticalSection(&critical_section_); } 84 85 private: 86 CRITICAL_SECTION critical_section_; 87 88 GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(CriticalSectionLock); 89 }; 90 91 #endif 92 93 // Mutex is a natural type to wrap. As both google and other organization have 94 // specialized mutexes. gRPC also provides an injection mechanism for custom 95 // mutexes. 96 class PROTOBUF_EXPORT GOOGLE_PROTOBUF_CAPABILITY("mutex") WrappedMutex { 97 public: 98 WrappedMutex() = default; Lock()99 void Lock() GOOGLE_PROTOBUF_ACQUIRE() { mu_.lock(); } Unlock()100 void Unlock() GOOGLE_PROTOBUF_RELEASE() { mu_.unlock(); } 101 // Crash if this Mutex is not held exclusively by this thread. 102 // May fail to crash when it should; will never crash when it should not. AssertHeld()103 void AssertHeld() const {} 104 105 private: 106 #ifndef GOOGLE_PROTOBUF_SUPPORT_WINDOWS_XP 107 std::mutex mu_; 108 #else // ifndef GOOGLE_PROTOBUF_SUPPORT_WINDOWS_XP 109 CriticalSectionLock mu_; 110 #endif // #ifndef GOOGLE_PROTOBUF_SUPPORT_WINDOWS_XP 111 }; 112 113 using Mutex = WrappedMutex; 114 115 // MutexLock(mu) acquires mu when constructed and releases it when destroyed. 116 class PROTOBUF_EXPORT MutexLock { 117 public: MutexLock(Mutex * mu)118 explicit MutexLock(Mutex *mu) : mu_(mu) { this->mu_->Lock(); } ~MutexLock()119 ~MutexLock() { this->mu_->Unlock(); } 120 private: 121 Mutex *const mu_; 122 GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(MutexLock); 123 }; 124 125 // TODO(kenton): Implement these? Hard to implement portably. 126 typedef MutexLock ReaderMutexLock; 127 typedef MutexLock WriterMutexLock; 128 129 // MutexLockMaybe is like MutexLock, but is a no-op when mu is nullptr. 130 class PROTOBUF_EXPORT MutexLockMaybe { 131 public: MutexLockMaybe(Mutex * mu)132 explicit MutexLockMaybe(Mutex *mu) : 133 mu_(mu) { if (this->mu_ != nullptr) { this->mu_->Lock(); } } ~MutexLockMaybe()134 ~MutexLockMaybe() { if (this->mu_ != nullptr) { this->mu_->Unlock(); } } 135 private: 136 Mutex *const mu_; 137 GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(MutexLockMaybe); 138 }; 139 140 #if defined(GOOGLE_PROTOBUF_NO_THREADLOCAL) 141 template<typename T> 142 class ThreadLocalStorage { 143 public: ThreadLocalStorage()144 ThreadLocalStorage() { 145 pthread_key_create(&key_, &ThreadLocalStorage::Delete); 146 } ~ThreadLocalStorage()147 ~ThreadLocalStorage() { 148 pthread_key_delete(key_); 149 } Get()150 T* Get() { 151 T* result = static_cast<T*>(pthread_getspecific(key_)); 152 if (result == nullptr) { 153 result = new T(); 154 pthread_setspecific(key_, result); 155 } 156 return result; 157 } 158 private: Delete(void * value)159 static void Delete(void* value) { 160 delete static_cast<T*>(value); 161 } 162 pthread_key_t key_; 163 164 GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(ThreadLocalStorage); 165 }; 166 #endif 167 168 } // namespace internal 169 170 // We made these internal so that they would show up as such in the docs, 171 // but we don't want to stick "internal::" in front of them everywhere. 172 using internal::Mutex; 173 using internal::MutexLock; 174 using internal::ReaderMutexLock; 175 using internal::WriterMutexLock; 176 using internal::MutexLockMaybe; 177 178 } // namespace protobuf 179 } // namespace google 180 181 #undef GOOGLE_PROTOBUF_ACQUIRE 182 #undef GOOGLE_PROTOBUF_RELEASE 183 184 #include <google/protobuf/port_undef.inc> 185 186 #endif // GOOGLE_PROTOBUF_STUBS_MUTEX_H_ 187