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comparison: ipc/glue/CrossProcessMutex.h
ipc/glue/CrossProcessMutex.h
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| 1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- | |
| 2 * This Source Code Form is subject to the terms of the Mozilla Public | |
| 3 * License, v. 2.0. If a copy of the MPL was not distributed with this | |
| 4 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ | |
| 5 | |
| 6 #ifndef mozilla_CrossProcessMutex_h | |
| 7 #define mozilla_CrossProcessMutex_h | |
| 8 | |
| 9 #include "base/process.h" | |
| 10 #include "mozilla/Mutex.h" | |
| 11 | |
| 12 #if defined(OS_LINUX) | |
| 13 #include <pthread.h> | |
| 14 #include "SharedMemoryBasic.h" | |
| 15 #include "mozilla/Atomics.h" | |
| 16 #endif | |
| 17 | |
| 18 namespace IPC { | |
| 19 template<typename T> | |
| 20 struct ParamTraits; | |
| 21 } | |
| 22 | |
| 23 // | |
| 24 // Provides: | |
| 25 // | |
| 26 // - CrossProcessMutex, a non-recursive mutex that can be shared across processes | |
| 27 // - CrossProcessMutexAutoLock, an RAII class for ensuring that Mutexes are | |
| 28 // properly locked and unlocked | |
| 29 // | |
| 30 // Using CrossProcessMutexAutoLock/CrossProcessMutexAutoUnlock is MUCH | |
| 31 // preferred to making bare calls to CrossProcessMutex.Lock and Unlock. | |
| 32 // | |
| 33 namespace mozilla { | |
| 34 #ifdef XP_WIN | |
| 35 typedef HANDLE CrossProcessMutexHandle; | |
| 36 #elif defined(OS_LINUX) | |
| 37 typedef mozilla::ipc::SharedMemoryBasic::Handle CrossProcessMutexHandle; | |
| 38 #else | |
| 39 // Stub for other platforms. We can't use uintptr_t here since different | |
| 40 // processes could disagree on its size. | |
| 41 typedef uintptr_t CrossProcessMutexHandle; | |
| 42 #endif | |
| 43 | |
| 44 class NS_COM_GLUE CrossProcessMutex | |
| 45 { | |
| 46 public: | |
| 47 /** | |
| 48 * CrossProcessMutex | |
| 49 * @param name A name which can reference this lock (currently unused) | |
| 50 **/ | |
| 51 CrossProcessMutex(const char* aName); | |
| 52 /** | |
| 53 * CrossProcessMutex | |
| 54 * @param handle A handle of an existing cross process mutex that can be | |
| 55 * opened. | |
| 56 */ | |
| 57 CrossProcessMutex(CrossProcessMutexHandle aHandle); | |
| 58 | |
| 59 /** | |
| 60 * ~CrossProcessMutex | |
| 61 **/ | |
| 62 ~CrossProcessMutex(); | |
| 63 | |
| 64 /** | |
| 65 * Lock | |
| 66 * This will lock the mutex. Any other thread in any other process that | |
| 67 * has access to this mutex calling lock will block execution until the | |
| 68 * initial caller of lock has made a call to Unlock. | |
| 69 * | |
| 70 * If the owning process is terminated unexpectedly the mutex will be | |
| 71 * released. | |
| 72 **/ | |
| 73 void Lock(); | |
| 74 | |
| 75 /** | |
| 76 * Unlock | |
| 77 * This will unlock the mutex. A single thread currently waiting on a lock | |
| 78 * call will resume execution and aquire ownership of the lock. No | |
| 79 * guarantees are made as to the order in which waiting threads will resume | |
| 80 * execution. | |
| 81 **/ | |
| 82 void Unlock(); | |
| 83 | |
| 84 /** | |
| 85 * ShareToProcess | |
| 86 * This function is called to generate a serializable structure that can | |
| 87 * be sent to the specified process and opened on the other side. | |
| 88 * | |
| 89 * @returns A handle that can be shared to another process | |
| 90 */ | |
| 91 CrossProcessMutexHandle ShareToProcess(base::ProcessHandle aTarget); | |
| 92 | |
| 93 private: | |
| 94 friend struct IPC::ParamTraits<CrossProcessMutex>; | |
| 95 | |
| 96 CrossProcessMutex(); | |
| 97 CrossProcessMutex(const CrossProcessMutex&); | |
| 98 CrossProcessMutex &operator=(const CrossProcessMutex&); | |
| 99 | |
| 100 #ifdef XP_WIN | |
| 101 HANDLE mMutex; | |
| 102 #elif defined(OS_LINUX) | |
| 103 mozilla::ipc::SharedMemoryBasic* mSharedBuffer; | |
| 104 pthread_mutex_t* mMutex; | |
| 105 mozilla::Atomic<int32_t>* mCount; | |
| 106 #endif | |
| 107 }; | |
| 108 | |
| 109 typedef BaseAutoLock<CrossProcessMutex> CrossProcessMutexAutoLock; | |
| 110 typedef BaseAutoUnlock<CrossProcessMutex> CrossProcessMutexAutoUnlock; | |
| 111 | |
| 112 } | |
| 113 #endif |
