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| 1 // Copyright 2015 The Chromium Authors. All rights reserved. | |
| 2 // Use of this source code is governed by a BSD-style license that can be | |
| 3 // found in the LICENSE file. | |
| 4 | |
| 5 #include "third_party/mojo/src/mojo/edk/system/wait_set_dispatcher.h" | |
| 6 | |
| 7 #include <algorithm> | |
| 8 #include <utility> | |
| 9 | |
| 10 #include "base/logging.h" | |
| 11 #include "third_party/mojo/src/mojo/edk/system/awakable.h" | |
| 12 | |
| 13 namespace mojo { | |
| 14 namespace system { | |
| 15 | |
| 16 class WaitSetDispatcher::Waiter final : public Awakable { | |
| 17 public: | |
| 18 explicit Waiter(WaitSetDispatcher* dispatcher) : dispatcher_(dispatcher) {} | |
| 19 ~Waiter() {} | |
| 20 | |
| 21 // |Awakable| implementation. | |
| 22 bool Awake(MojoResult result, uintptr_t context) override { | |
| 23 // Note: This is called with various Mojo locks held. | |
| 24 dispatcher_->WakeDispatcher(result, context); | |
| 25 // Removes |this| from the dispatcher's list of waiters. | |
| 26 return false; | |
| 27 } | |
| 28 | |
| 29 private: | |
| 30 WaitSetDispatcher* const dispatcher_; | |
| 31 }; | |
| 32 | |
| 33 WaitSetDispatcher::WaitSetDispatcher() | |
| 34 : waiter_(new WaitSetDispatcher::Waiter(this)) {} | |
| 35 | |
| 36 WaitSetDispatcher::~WaitSetDispatcher() { | |
| 37 DCHECK(waiting_dispatchers_.empty()); | |
| 38 DCHECK(awoken_queue_.empty()); | |
| 39 DCHECK(processed_dispatchers_.empty()); | |
| 40 } | |
| 41 | |
| 42 Dispatcher::Type WaitSetDispatcher::GetType() const { | |
| 43 return Type::WAIT_SET; | |
| 44 } | |
| 45 | |
| 46 void WaitSetDispatcher::CloseImplNoLock() { | |
| 47 mutex().AssertHeld(); | |
| 48 for (const auto& entry : waiting_dispatchers_) | |
| 49 entry.second.dispatcher->RemoveAwakable(waiter_.get(), nullptr); | |
| 50 waiting_dispatchers_.clear(); | |
| 51 | |
| 52 MutexLocker locker(&awoken_mutex_); | |
| 53 awoken_queue_.clear(); | |
| 54 processed_dispatchers_.clear(); | |
| 55 } | |
| 56 | |
| 57 MojoResult WaitSetDispatcher::AddWaitingDispatcherImplNoLock( | |
| 58 const scoped_refptr<Dispatcher>& dispatcher, | |
| 59 MojoHandleSignals signals, | |
| 60 uintptr_t context) { | |
| 61 mutex().AssertHeld(); | |
| 62 if (dispatcher == this) | |
| 63 return MOJO_RESULT_INVALID_ARGUMENT; | |
| 64 | |
| 65 uintptr_t dispatcher_handle = reinterpret_cast<uintptr_t>(dispatcher.get()); | |
| 66 auto it = waiting_dispatchers_.find(dispatcher_handle); | |
| 67 if (it != waiting_dispatchers_.end()) { | |
| 68 return MOJO_RESULT_ALREADY_EXISTS; | |
| 69 } | |
| 70 | |
| 71 const MojoResult result = dispatcher->AddAwakable(waiter_.get(), signals, | |
| 72 dispatcher_handle, nullptr); | |
| 73 if (result == MOJO_RESULT_INVALID_ARGUMENT) { | |
| 74 // Dispatcher is closed. | |
| 75 return result; | |
| 76 } else if (result != MOJO_RESULT_OK) { | |
| 77 WakeDispatcher(result, dispatcher_handle); | |
| 78 } | |
| 79 | |
| 80 WaitState state; | |
| 81 state.dispatcher = dispatcher; | |
| 82 state.context = context; | |
| 83 state.signals = signals; | |
| 84 bool inserted = | |
| 85 waiting_dispatchers_.insert(std::make_pair(dispatcher_handle, state)) | |
| 86 .second; | |
| 87 DCHECK(inserted); | |
| 88 | |
| 89 return MOJO_RESULT_OK; | |
| 90 } | |
| 91 | |
| 92 MojoResult WaitSetDispatcher::RemoveWaitingDispatcherImplNoLock( | |
| 93 const scoped_refptr<Dispatcher>& dispatcher) { | |
| 94 mutex().AssertHeld(); | |
| 95 uintptr_t dispatcher_handle = reinterpret_cast<uintptr_t>(dispatcher.get()); | |
| 96 auto it = waiting_dispatchers_.find(dispatcher_handle); | |
| 97 if (it == waiting_dispatchers_.end()) | |
| 98 return MOJO_RESULT_NOT_FOUND; | |
| 99 | |
| 100 dispatcher->RemoveAwakable(waiter_.get(), nullptr); | |
| 101 // At this point, it should not be possible for |waiter_| to be woken with | |
| 102 // |dispatcher|. | |
| 103 waiting_dispatchers_.erase(it); | |
| 104 | |
| 105 MutexLocker locker(&awoken_mutex_); | |
| 106 int num_erased = 0; | |
| 107 for (auto it = awoken_queue_.begin(); it != awoken_queue_.end();) { | |
| 108 if (it->first == dispatcher_handle) { | |
| 109 it = awoken_queue_.erase(it); | |
| 110 num_erased++; | |
| 111 } else { | |
| 112 ++it; | |
| 113 } | |
| 114 } | |
| 115 // The dispatcher should only exist in the queue once. | |
| 116 DCHECK_LE(num_erased, 1); | |
| 117 processed_dispatchers_.erase( | |
| 118 std::remove(processed_dispatchers_.begin(), processed_dispatchers_.end(), | |
| 119 dispatcher_handle), | |
| 120 processed_dispatchers_.end()); | |
| 121 | |
| 122 return MOJO_RESULT_OK; | |
| 123 } | |
| 124 | |
| 125 MojoResult WaitSetDispatcher::GetReadyDispatchersImplNoLock( | |
| 126 UserPointer<uint32_t> count, | |
| 127 DispatcherVector* dispatchers, | |
| 128 UserPointer<MojoResult> results, | |
| 129 UserPointer<uintptr_t> contexts) { | |
| 130 mutex().AssertHeld(); | |
| 131 dispatchers->clear(); | |
| 132 | |
| 133 // Re-queue any already retrieved dispatchers. These should be the dispatchers | |
| 134 // that were returned on the last call to this function. This loop is | |
| 135 // necessary to preserve the logically level-triggering behaviour of waiting | |
| 136 // in Mojo. In particular, if no action is taken on a signal, that signal | |
| 137 // continues to be satisfied, and therefore a |MojoWait()| on that | |
| 138 // handle/signal continues to return immediately. | |
| 139 std::deque<uintptr_t> pending; | |
| 140 { | |
| 141 MutexLocker locker(&awoken_mutex_); | |
| 142 pending.swap(processed_dispatchers_); | |
| 143 } | |
| 144 for (uintptr_t d : pending) { | |
| 145 auto it = waiting_dispatchers_.find(d); | |
| 146 // Anything in |processed_dispatchers_| should also be in | |
| 147 // |waiting_dispatchers_| since dispatchers are removed from both in | |
| 148 // |RemoveWaitingDispatcherImplNoLock()|. | |
| 149 DCHECK(it != waiting_dispatchers_.end()); | |
| 150 | |
| 151 // |awoken_mutex_| cannot be held here because | |
| 152 // |Dispatcher::AddAwakable()| acquires the Dispatcher's mutex. This | |
| 153 // mutex is held while running |WakeDispatcher()| below, which needs to | |
| 154 // acquire |awoken_mutex_|. Holding |awoken_mutex_| here would result in | |
| 155 // a deadlock. | |
| 156 const MojoResult result = it->second.dispatcher->AddAwakable( | |
| 157 waiter_.get(), it->second.signals, d, nullptr); | |
| 158 | |
| 159 if (result == MOJO_RESULT_INVALID_ARGUMENT) { | |
| 160 // Dispatcher is closed. Implicitly remove it from the wait set since | |
| 161 // it may be impossible to remove using |MojoRemoveHandle()|. | |
| 162 waiting_dispatchers_.erase(it); | |
| 163 } else if (result != MOJO_RESULT_OK) { | |
| 164 WakeDispatcher(result, d); | |
| 165 } | |
| 166 } | |
| 167 | |
| 168 const uint32_t max_woken = count.Get(); | |
| 169 uint32_t num_woken = 0; | |
| 170 | |
| 171 MutexLocker locker(&awoken_mutex_); | |
| 172 while (!awoken_queue_.empty() && num_woken < max_woken) { | |
| 173 uintptr_t d = awoken_queue_.front().first; | |
| 174 MojoResult result = awoken_queue_.front().second; | |
| 175 awoken_queue_.pop_front(); | |
| 176 | |
| 177 auto it = waiting_dispatchers_.find(d); | |
| 178 DCHECK(it != waiting_dispatchers_.end()); | |
| 179 | |
| 180 results.At(num_woken).Put(result); | |
| 181 dispatchers->push_back(it->second.dispatcher); | |
| 182 if (!contexts.IsNull()) | |
| 183 contexts.At(num_woken).Put(it->second.context); | |
| 184 | |
| 185 if (result != MOJO_RESULT_CANCELLED) { | |
| 186 processed_dispatchers_.push_back(d); | |
| 187 } else { | |
| 188 waiting_dispatchers_.erase(it); | |
| 189 } | |
| 190 | |
| 191 num_woken++; | |
| 192 } | |
| 193 | |
| 194 count.Put(num_woken); | |
| 195 if (!num_woken) | |
| 196 return MOJO_RESULT_SHOULD_WAIT; | |
| 197 | |
| 198 return MOJO_RESULT_OK; | |
| 199 } | |
| 200 | |
| 201 void WaitSetDispatcher::CancelAllAwakablesNoLock() { | |
| 202 mutex().AssertHeld(); | |
| 203 MutexLocker locker(&awakable_mutex_); | |
| 204 awakable_list_.CancelAll(); | |
| 205 } | |
| 206 | |
| 207 MojoResult WaitSetDispatcher::AddAwakableImplNoLock( | |
| 208 Awakable* awakable, | |
| 209 MojoHandleSignals signals, | |
| 210 uintptr_t context, | |
| 211 HandleSignalsState* signals_state) { | |
| 212 mutex().AssertHeld(); | |
| 213 | |
| 214 HandleSignalsState state(GetHandleSignalsStateImplNoLock()); | |
| 215 if (state.satisfies(signals)) { | |
| 216 if (signals_state) | |
| 217 *signals_state = state; | |
| 218 return MOJO_RESULT_ALREADY_EXISTS; | |
| 219 } | |
| 220 if (!state.can_satisfy(signals)) { | |
| 221 if (signals_state) | |
| 222 *signals_state = state; | |
| 223 return MOJO_RESULT_FAILED_PRECONDITION; | |
| 224 } | |
| 225 | |
| 226 MutexLocker locker(&awakable_mutex_); | |
| 227 awakable_list_.Add(awakable, signals, context); | |
| 228 return MOJO_RESULT_OK; | |
| 229 } | |
| 230 | |
| 231 void WaitSetDispatcher::RemoveAwakableImplNoLock( | |
| 232 Awakable* awakable, | |
| 233 HandleSignalsState* signals_state) { | |
| 234 mutex().AssertHeld(); | |
| 235 MutexLocker locker(&awakable_mutex_); | |
| 236 awakable_list_.Remove(awakable); | |
| 237 if (signals_state) | |
| 238 *signals_state = GetHandleSignalsStateImplNoLock(); | |
| 239 } | |
| 240 | |
| 241 HandleSignalsState WaitSetDispatcher::GetHandleSignalsStateImplNoLock() const { | |
| 242 mutex().AssertHeld(); | |
| 243 HandleSignalsState rv; | |
| 244 rv.satisfiable_signals = MOJO_HANDLE_SIGNAL_READABLE; | |
| 245 MutexLocker locker(&awoken_mutex_); | |
| 246 if (!awoken_queue_.empty() || !processed_dispatchers_.empty()) | |
| 247 rv.satisfied_signals = MOJO_HANDLE_SIGNAL_READABLE; | |
| 248 return rv; | |
| 249 } | |
| 250 | |
| 251 scoped_refptr<Dispatcher> | |
| 252 WaitSetDispatcher::CreateEquivalentDispatcherAndCloseImplNoLock() { | |
| 253 mutex().AssertHeld(); | |
| 254 LOG(ERROR) << "Attempting to serialize WaitSet"; | |
| 255 CloseImplNoLock(); | |
| 256 return new WaitSetDispatcher(); | |
| 257 } | |
| 258 | |
| 259 void WaitSetDispatcher::WakeDispatcher(MojoResult result, uintptr_t context) { | |
| 260 { | |
| 261 MutexLocker locker(&awoken_mutex_); | |
| 262 | |
| 263 if (result == MOJO_RESULT_ALREADY_EXISTS) | |
| 264 result = MOJO_RESULT_OK; | |
| 265 | |
| 266 awoken_queue_.push_back(std::make_pair(context, result)); | |
| 267 } | |
| 268 | |
| 269 MutexLocker locker(&awakable_mutex_); | |
| 270 HandleSignalsState signals_state; | |
| 271 signals_state.satisfiable_signals = MOJO_HANDLE_SIGNAL_READABLE; | |
| 272 signals_state.satisfied_signals = MOJO_HANDLE_SIGNAL_READABLE; | |
| 273 awakable_list_.AwakeForStateChange(signals_state); | |
| 274 } | |
| 275 | |
| 276 } // namespace system | |
| 277 } // namespace mojo | |
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Chromium Code Reviews
Issue 1676913002:
[mojo] Delete third_party/mojo (Closed)
Base URL: https://chromium.googlesource.com/chromium/src.git@master