2406ce261c
Backed out changeset 8d9053f1c203 (bug 1942129) Backed out changeset 393e3c507c27 (bug 1942129) Backed out changeset 8240d353d224 (bug 1942129) Backed out changeset 8c4cd026b720 (bug 1942129) Backed out changeset 742634b0d6e9 (bug 1942129) Backed out changeset d16857f9812f (bug 1942129) Backed out changeset 7ff7af041ee7 (bug 1942129) Backed out changeset ef41d9e4c7de (bug 1942129)
120 lines
3.2 KiB
C++
120 lines
3.2 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef mozilla_CrossProcessSemaphore_h
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#define mozilla_CrossProcessSemaphore_h
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#include "base/process.h"
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#include "mozilla/TimeStamp.h"
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#include "mozilla/Maybe.h"
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#if defined(XP_WIN) || defined(XP_DARWIN)
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# include "mozilla/UniquePtrExtensions.h"
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#else
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# include <pthread.h>
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# include <semaphore.h>
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# include "mozilla/ipc/SharedMemory.h"
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# include "mozilla/Atomics.h"
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#endif
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namespace IPC {
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template <typename T>
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struct ParamTraits;
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} // namespace IPC
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//
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// Provides:
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//
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// - CrossProcessSemaphore, a semaphore that can be shared across processes
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namespace mozilla {
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template <typename T>
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inline bool IsHandleValid(const T& handle) {
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return bool(handle);
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}
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#if defined(XP_WIN)
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typedef mozilla::UniqueFileHandle CrossProcessSemaphoreHandle;
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#elif defined(XP_DARWIN)
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typedef mozilla::UniqueMachSendRight CrossProcessSemaphoreHandle;
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#else
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typedef mozilla::ipc::SharedMemory::Handle CrossProcessSemaphoreHandle;
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template <>
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inline bool IsHandleValid<CrossProcessSemaphoreHandle>(
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const CrossProcessSemaphoreHandle& handle) {
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return !(handle == mozilla::ipc::SharedMemory::NULLHandle());
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}
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#endif
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class CrossProcessSemaphore {
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public:
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/**
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* CrossProcessSemaphore
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* @param name A name which can reference this lock (currently unused)
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**/
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static CrossProcessSemaphore* Create(const char* aName,
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uint32_t aInitialValue);
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/**
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* CrossProcessSemaphore
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* @param handle A handle of an existing cross process semaphore that can be
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* opened.
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*/
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static CrossProcessSemaphore* Create(CrossProcessSemaphoreHandle aHandle);
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~CrossProcessSemaphore();
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/**
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* Decrements the current value of the semaphore. This will block if the
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* current value of the semaphore is 0, up to a maximum of aWaitTime (if
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* specified).
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* Returns true if the semaphore was succesfully decremented, false otherwise.
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**/
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bool Wait(const Maybe<TimeDuration>& aWaitTime = Nothing());
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/**
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* Increments the current value of the semaphore.
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**/
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void Signal();
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/**
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* CloneHandle
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* This function is called to generate a serializable structure that can
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* be sent to the specified process and opened on the other side.
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*
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* @returns A handle that can be shared to another process
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*/
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CrossProcessSemaphoreHandle CloneHandle();
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void CloseHandle();
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private:
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friend struct IPC::ParamTraits<CrossProcessSemaphore>;
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CrossProcessSemaphore();
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CrossProcessSemaphore(const CrossProcessSemaphore&);
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CrossProcessSemaphore& operator=(const CrossProcessSemaphore&);
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#if defined(XP_WIN)
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explicit CrossProcessSemaphore(HANDLE aSemaphore);
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HANDLE mSemaphore;
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#elif defined(XP_DARWIN)
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explicit CrossProcessSemaphore(CrossProcessSemaphoreHandle aSemaphore);
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CrossProcessSemaphoreHandle mSemaphore;
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#else
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RefPtr<mozilla::ipc::SharedMemory> mSharedBuffer;
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sem_t* mSemaphore;
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mozilla::Atomic<int32_t>* mRefCount;
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#endif
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};
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} // namespace mozilla
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#endif
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