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| 1 // Copyright 2007-2009 Google Inc. | |
| 2 // | |
| 3 // Licensed under the Apache License, Version 2.0 (the "License"); | |
| 4 // you may not use this file except in compliance with the License. | |
| 5 // You may obtain a copy of the License at | |
| 6 // | |
| 7 // http://www.apache.org/licenses/LICENSE-2.0 | |
| 8 // | |
| 9 // Unless required by applicable law or agreed to in writing, software | |
| 10 // distributed under the License is distributed on an "AS IS" BASIS, | |
| 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
| 12 // See the License for the specific language governing permissions and | |
| 13 // limitations under the License. | |
| 14 // ======================================================================== | |
| 15 | |
| 16 | |
| 17 #include "omaha/base/reactor.h" | |
| 18 | |
| 19 #include <vector> | |
| 20 #include "base/scoped_ptr.h" | |
| 21 #include "omaha/base/debug.h" | |
| 22 #include "omaha/base/error.h" | |
| 23 #include "omaha/base/logging.h" | |
| 24 #include "omaha/base/event_handler.h" | |
| 25 | |
| 26 namespace omaha { | |
| 27 | |
| 28 Reactor::Reactor() { | |
| 29 CORE_LOG(L4, (_T("[Reactor::Reactor]"))); | |
| 30 ::InitializeCriticalSection(&cs_); | |
| 31 } | |
| 32 | |
| 33 Reactor::~Reactor() { | |
| 34 CORE_LOG(L4, (_T("[Reactor::~Reactor]"))); | |
| 35 | |
| 36 // Each handle must be unregistered before destroying the reactor. | |
| 37 ASSERT1(handlers_.empty()); | |
| 38 ::DeleteCriticalSection(&cs_); | |
| 39 } | |
| 40 | |
| 41 // The reactor loop is just an efficient wait, as the demultiplexing of the | |
| 42 // events is actually done by the OS thread pool. | |
| 43 // TODO(omaha): replace the alertable wait with waiting on an event and provide | |
| 44 // a method for the reactor to stop handling events. | |
| 45 HRESULT Reactor::HandleEvents() { | |
| 46 CORE_LOG(L1, (_T("[Reactor::HandleEvents]"))); | |
| 47 VERIFY1(::SleepEx(INFINITE, true) == WAIT_IO_COMPLETION); | |
| 48 CORE_LOG(L1, (_T("[Reactor::HandleEvents exit]"))); | |
| 49 return S_OK; | |
| 50 } | |
| 51 | |
| 52 void __stdcall Reactor::Callback(void* param, BOOLEAN timer_or_wait) { | |
| 53 ASSERT1(param); | |
| 54 | |
| 55 // Since we wait an INFINITE the wait handle is always signaled. | |
| 56 VERIFY1(!timer_or_wait); | |
| 57 RegistrationState* state = static_cast<RegistrationState*>(param); | |
| 58 ASSERT1(state->reactor); | |
| 59 state->reactor->DoCallback(state); | |
| 60 } | |
| 61 | |
| 62 // Method does not check to see if the same handle is registered twice. | |
| 63 HRESULT Reactor::RegisterHandle(HANDLE handle, | |
| 64 EventHandler* event_handler, | |
| 65 uint32 flags) { | |
| 66 ASSERT1(handle); | |
| 67 ASSERT1(event_handler); | |
| 68 | |
| 69 if (!handle || !event_handler) { | |
| 70 return E_INVALIDARG; | |
| 71 } | |
| 72 | |
| 73 scoped_ptr<RegistrationState> state(new RegistrationState); | |
| 74 state->event_handler = event_handler; | |
| 75 state->handle = handle; | |
| 76 state->reactor = this; | |
| 77 state->flags = flags | WT_EXECUTEONLYONCE; | |
| 78 | |
| 79 // The reactor only calls the handler once. | |
| 80 ASSERT1(WT_EXECUTEDEFAULT == 0); | |
| 81 | |
| 82 // As soon as the handle is registered, the thread pool can queue up a | |
| 83 // callback and reenter the reactor on a different thread. | |
| 84 // Acquire the critical section before registering the handle. | |
| 85 ::EnterCriticalSection(&cs_); | |
| 86 #if DEBUG | |
| 87 // The same handle should not be registered multiple times. | |
| 88 std::vector<RegistrationState*>::iterator it = handlers_.begin(); | |
| 89 for (; it != handlers_.end(); ++it) { | |
| 90 ASSERT((*it)->handle != handle, (_T("[already registered %d]"), handle)); | |
| 91 } | |
| 92 #endif | |
| 93 bool res = !!::RegisterWaitForSingleObject(&state->wait_handle, | |
| 94 state->handle, | |
| 95 &Reactor::Callback, | |
| 96 state.get(), | |
| 97 INFINITE, | |
| 98 state->flags); | |
| 99 HRESULT hr = res ? S_OK : HRESULTFromLastError(); | |
| 100 if (SUCCEEDED(hr)) { | |
| 101 handlers_.push_back(state.release()); | |
| 102 } | |
| 103 ::LeaveCriticalSection(&cs_); | |
| 104 | |
| 105 return hr; | |
| 106 } | |
| 107 | |
| 108 HRESULT Reactor::RegisterHandle(HANDLE handle) { | |
| 109 ::EnterCriticalSection(&cs_); | |
| 110 HRESULT hr = DoRegisterHandle(handle); | |
| 111 ::LeaveCriticalSection(&cs_); | |
| 112 return hr; | |
| 113 } | |
| 114 | |
| 115 HRESULT Reactor::DoRegisterHandle(HANDLE handle) { | |
| 116 ASSERT1(handle); | |
| 117 std::vector<RegistrationState*>::iterator it = handlers_.begin(); | |
| 118 for (; it != handlers_.end(); ++it) { | |
| 119 if ((*it)->handle == handle) { | |
| 120 break; | |
| 121 } | |
| 122 } | |
| 123 if (it == handlers_.end()) { | |
| 124 // The handle is not registered with the reactor anymore. Registering the | |
| 125 // the handle again is not possible. | |
| 126 return E_FAIL; | |
| 127 } | |
| 128 | |
| 129 // Unregister and register the handle again. Unregistering is an non blocking | |
| 130 // call. | |
| 131 RegistrationState* state = *it; | |
| 132 bool res = !!::UnregisterWaitEx(state->wait_handle, NULL); | |
| 133 if (!res && ::GetLastError() != ERROR_IO_PENDING) { | |
| 134 return HRESULTFromLastError(); | |
| 135 } | |
| 136 if (!::RegisterWaitForSingleObject(&state->wait_handle, | |
| 137 state->handle, | |
| 138 &Reactor::Callback, | |
| 139 state, | |
| 140 INFINITE, | |
| 141 state->flags)) { | |
| 142 return HRESULTFromLastError(); | |
| 143 } | |
| 144 return S_OK; | |
| 145 } | |
| 146 | |
| 147 HRESULT Reactor::UnregisterHandle(HANDLE handle) { | |
| 148 ASSERT1(handle); | |
| 149 if (!handle) { | |
| 150 return E_INVALIDARG; | |
| 151 } | |
| 152 | |
| 153 // Attempts to take the ownership of the registration state for the handle. | |
| 154 // If taking the ownership does not succeed, it means the handle has already | |
| 155 // been unregistered. | |
| 156 scoped_ptr<RegistrationState> state(ReleaseHandlerState(handle)); | |
| 157 if (!state.get()) { | |
| 158 return E_UNEXPECTED; | |
| 159 } | |
| 160 | |
| 161 // Unregisters the wait handle from the thread pool. The call blocks waiting | |
| 162 // for any pending callbacks to finish. No lock is being held while waiting | |
| 163 // here. If there is no callback pending, the call will succeed right away. | |
| 164 // Otherwise, if a callback has already started, the call waits for the | |
| 165 // callback to complete. | |
| 166 bool res = !!::UnregisterWaitEx(state->wait_handle, INVALID_HANDLE_VALUE); | |
| 167 | |
| 168 // Clear the registration state, as a defensive programming measure and | |
| 169 // for debugging purposes. | |
| 170 state->reactor = NULL; | |
| 171 state->handle = NULL; | |
| 172 state->wait_handle = NULL; | |
| 173 state->event_handler = NULL; | |
| 174 | |
| 175 return res ? S_OK : HRESULTFromLastError(); | |
| 176 } | |
| 177 | |
| 178 void Reactor::DoCallback(RegistrationState* state) { | |
| 179 ASSERT1(state); | |
| 180 ASSERT1(state->event_handler); | |
| 181 ASSERT1(state->handle); | |
| 182 state->event_handler->HandleEvent(state->handle); | |
| 183 } | |
| 184 | |
| 185 // Looks up the registration state for a handle and releases the ownership | |
| 186 // of it to the caller. As the clean up of the state can happen from multiple | |
| 187 // places, the transfer of ownership ensures the clean up happens once and | |
| 188 // only once. | |
| 189 Reactor::RegistrationState* Reactor::ReleaseHandlerState(HANDLE handle) { | |
| 190 RegistrationState* registration_state = NULL; | |
| 191 ::EnterCriticalSection(&cs_); | |
| 192 std::vector<RegistrationState*>::iterator it = handlers_.begin(); | |
| 193 for (; it != handlers_.end(); ++it) { | |
| 194 if ((*it)->handle == handle) { | |
| 195 registration_state = *it; | |
| 196 handlers_.erase(it); | |
| 197 break; | |
| 198 } | |
| 199 } | |
| 200 ::LeaveCriticalSection(&cs_); | |
| 201 return registration_state; | |
| 202 } | |
| 203 | |
| 204 } // namespace omaha | |
| 205 | |
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Chromium Code Reviews
Issue 624713003:
Keep only base/extractor.[cc|h]. (Closed)
Base URL: https://chromium.googlesource.com/external/omaha.git@master