1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/ipc/glue/CrossProcessMutex.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,113 @@
1.4 +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
1.5 + * This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +#ifndef mozilla_CrossProcessMutex_h
1.10 +#define mozilla_CrossProcessMutex_h
1.11 +
1.12 +#include "base/process.h"
1.13 +#include "mozilla/Mutex.h"
1.14 +
1.15 +#if defined(OS_LINUX)
1.16 +#include <pthread.h>
1.17 +#include "SharedMemoryBasic.h"
1.18 +#include "mozilla/Atomics.h"
1.19 +#endif
1.20 +
1.21 +namespace IPC {
1.22 +template<typename T>
1.23 +struct ParamTraits;
1.24 +}
1.25 +
1.26 +//
1.27 +// Provides:
1.28 +//
1.29 +// - CrossProcessMutex, a non-recursive mutex that can be shared across processes
1.30 +// - CrossProcessMutexAutoLock, an RAII class for ensuring that Mutexes are
1.31 +// properly locked and unlocked
1.32 +//
1.33 +// Using CrossProcessMutexAutoLock/CrossProcessMutexAutoUnlock is MUCH
1.34 +// preferred to making bare calls to CrossProcessMutex.Lock and Unlock.
1.35 +//
1.36 +namespace mozilla {
1.37 +#ifdef XP_WIN
1.38 +typedef HANDLE CrossProcessMutexHandle;
1.39 +#elif defined(OS_LINUX)
1.40 +typedef mozilla::ipc::SharedMemoryBasic::Handle CrossProcessMutexHandle;
1.41 +#else
1.42 +// Stub for other platforms. We can't use uintptr_t here since different
1.43 +// processes could disagree on its size.
1.44 +typedef uintptr_t CrossProcessMutexHandle;
1.45 +#endif
1.46 +
1.47 +class NS_COM_GLUE CrossProcessMutex
1.48 +{
1.49 +public:
1.50 + /**
1.51 + * CrossProcessMutex
1.52 + * @param name A name which can reference this lock (currently unused)
1.53 + **/
1.54 + CrossProcessMutex(const char* aName);
1.55 + /**
1.56 + * CrossProcessMutex
1.57 + * @param handle A handle of an existing cross process mutex that can be
1.58 + * opened.
1.59 + */
1.60 + CrossProcessMutex(CrossProcessMutexHandle aHandle);
1.61 +
1.62 + /**
1.63 + * ~CrossProcessMutex
1.64 + **/
1.65 + ~CrossProcessMutex();
1.66 +
1.67 + /**
1.68 + * Lock
1.69 + * This will lock the mutex. Any other thread in any other process that
1.70 + * has access to this mutex calling lock will block execution until the
1.71 + * initial caller of lock has made a call to Unlock.
1.72 + *
1.73 + * If the owning process is terminated unexpectedly the mutex will be
1.74 + * released.
1.75 + **/
1.76 + void Lock();
1.77 +
1.78 + /**
1.79 + * Unlock
1.80 + * This will unlock the mutex. A single thread currently waiting on a lock
1.81 + * call will resume execution and aquire ownership of the lock. No
1.82 + * guarantees are made as to the order in which waiting threads will resume
1.83 + * execution.
1.84 + **/
1.85 + void Unlock();
1.86 +
1.87 + /**
1.88 + * ShareToProcess
1.89 + * This function is called to generate a serializable structure that can
1.90 + * be sent to the specified process and opened on the other side.
1.91 + *
1.92 + * @returns A handle that can be shared to another process
1.93 + */
1.94 + CrossProcessMutexHandle ShareToProcess(base::ProcessHandle aTarget);
1.95 +
1.96 +private:
1.97 + friend struct IPC::ParamTraits<CrossProcessMutex>;
1.98 +
1.99 + CrossProcessMutex();
1.100 + CrossProcessMutex(const CrossProcessMutex&);
1.101 + CrossProcessMutex &operator=(const CrossProcessMutex&);
1.102 +
1.103 +#ifdef XP_WIN
1.104 + HANDLE mMutex;
1.105 +#elif defined(OS_LINUX)
1.106 + mozilla::ipc::SharedMemoryBasic* mSharedBuffer;
1.107 + pthread_mutex_t* mMutex;
1.108 + mozilla::Atomic<int32_t>* mCount;
1.109 +#endif
1.110 +};
1.111 +
1.112 +typedef BaseAutoLock<CrossProcessMutex> CrossProcessMutexAutoLock;
1.113 +typedef BaseAutoUnlock<CrossProcessMutex> CrossProcessMutexAutoUnlock;
1.114 +
1.115 +}
1.116 +#endif
