ipc/glue/CrossProcessSemaphore_windows.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include <windows.h>
   8
   9 #include "base/process_util.h"
  10 #include "CrossProcessSemaphore.h"
  11 #include "nsDebug.h"
  12 #include "nsISupportsImpl.h"
  13 #include "ProtocolUtils.h"
  14
  15 using base::GetCurrentProcessHandle;
  16 using base::ProcessHandle;
  17
  18 namespace mozilla {
  19
  20 /* static */
  21 CrossProcessSemaphore* CrossProcessSemaphore::Create(const char*,
  22                                                      uint32_t aInitialValue) {
  23   // We explicitly share this using DuplicateHandle, we do -not- want this to
  24   // be inherited by child processes by default! So no security attributes are
  25   // given.
  26   HANDLE semaphore =
  27       ::CreateSemaphoreA(nullptr, aInitialValue, 0x7fffffff, nullptr);
  28   if (!semaphore) {
  29     return nullptr;
  30   }
  31   return new CrossProcessSemaphore(semaphore);
  32 }
  33
  34 /* static */
  35 CrossProcessSemaphore* CrossProcessSemaphore::Create(
  36     CrossProcessSemaphoreHandle aHandle) {
  37   DWORD flags;
  38   if (!::GetHandleInformation(aHandle.get(), &flags)) {
  39     return nullptr;
  40   }
  41
  42   return new CrossProcessSemaphore(aHandle.release());
  43 }
  44
  45 CrossProcessSemaphore::CrossProcessSemaphore(HANDLE aSemaphore)
  46     : mSemaphore(aSemaphore) {
  47   MOZ_COUNT_CTOR(CrossProcessSemaphore);
  48 }
  49
  50 CrossProcessSemaphore::~CrossProcessSemaphore() {
  51   MOZ_ASSERT(mSemaphore, "Improper construction of semaphore or double free.");
  52   ::CloseHandle(mSemaphore);
  53   MOZ_COUNT_DTOR(CrossProcessSemaphore);
  54 }
  55
  56 bool CrossProcessSemaphore::Wait(const Maybe<TimeDuration>& aWaitTime) {
  57   MOZ_ASSERT(mSemaphore, "Improper construction of semaphore.");
  58   HRESULT hr = ::WaitForSingleObject(
  59       mSemaphore, aWaitTime.isSome() ? aWaitTime->ToMilliseconds() : INFINITE);
  60   return hr == WAIT_OBJECT_0;
  61 }
  62
  63 void CrossProcessSemaphore::Signal() {
  64   MOZ_ASSERT(mSemaphore, "Improper construction of semaphore.");
  65   ::ReleaseSemaphore(mSemaphore, 1, nullptr);
  66 }
  67
  68 CrossProcessSemaphoreHandle CrossProcessSemaphore::CloneHandle() {
  69   HANDLE newHandle;
  70   bool succeeded =
  71       ::DuplicateHandle(GetCurrentProcess(), mSemaphore, GetCurrentProcess(),
  72                         &newHandle, 0, false, DUPLICATE_SAME_ACCESS);
  73
  74   if (!succeeded) {
  75     return nullptr;
  76   }
  77
  78   return UniqueFileHandle(newHandle);
  79 }
  80
  81 void CrossProcessSemaphore::CloseHandle() {}
  82
  83 }  // namespace mozilla