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| 1 // Copyright 2017 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 "mojo/edk/system/watch.h" | |
| 6 | |
| 7 #include "mojo/edk/system/request_context.h" | |
| 8 #include "mojo/edk/system/watcher_dispatcher.h" | |
| 9 | |
| 10 namespace mojo { | |
| 11 namespace edk { | |
| 12 | |
| 13 Watch::Watch(const scoped_refptr<WatcherDispatcher>& watcher, | |
| 14 const scoped_refptr<Dispatcher>& dispatcher, | |
| 15 uintptr_t context, | |
| 16 MojoHandleSignals signals) | |
| 17 : watcher_(watcher), | |
| 18 dispatcher_(dispatcher), | |
| 19 context_(context), | |
| 20 signals_(signals) {} | |
| 21 | |
| 22 bool Watch::NotifyState(const HandleSignalsState& state, | |
| 23 bool allowed_to_call_callback) { | |
| 24 AssertWatcherLockAcquired(); | |
| 25 | |
| 26 // NOTE: This method must NEVER call into |dispatcher_| directly, because it | |
| 27 // may be called while |dispatcher_| holds a lock. | |
| 28 | |
| 29 MojoResult rv = MOJO_RESULT_SHOULD_WAIT; | |
| 30 RequestContext* const request_context = RequestContext::current(); | |
| 31 if (state.satisfies(signals_)) { | |
| 32 rv = MOJO_RESULT_OK; | |
| 33 if (allowed_to_call_callback && rv != last_known_result_) { | |
| 34 request_context->AddWatchNotifyFinalizer(this, MOJO_RESULT_OK, state); | |
| 35 } | |
| 36 } else if (!state.can_satisfy(signals_)) { | |
| 37 rv = MOJO_RESULT_FAILED_PRECONDITION; | |
| 38 if (allowed_to_call_callback && rv != last_known_result_) { | |
| 39 request_context->AddWatchNotifyFinalizer( | |
| 40 this, MOJO_RESULT_FAILED_PRECONDITION, state); | |
| 41 } | |
| 42 } | |
| 43 | |
| 44 last_known_signals_state_ = | |
| 45 *static_cast<const MojoHandleSignalsState*>(&state); | |
| 46 last_known_result_ = rv; | |
| 47 return ready(); | |
| 48 } | |
| 49 | |
| 50 void Watch::Cancel() { | |
| 51 RequestContext::current()->AddWatchCancelFinalizer(this); | |
| 52 } | |
| 53 | |
| 54 void Watch::InvokeCallback(MojoResult result, | |
| 55 const HandleSignalsState& state, | |
| 56 MojoWatcherNotificationFlags flags) { | |
| 57 // We hold the lock through invocation to ensure that only one notification | |
| 58 // callback runs for this context at any given time. | |
| 59 base::AutoLock lock(notification_lock_); | |
| 60 if (result == MOJO_RESULT_CANCELLED) { | |
| 61 // Make sure cancellation is the last notification we dispatch. | |
| 62 DCHECK(!is_cancelled_); | |
| 63 is_cancelled_ = true; | |
| 64 } else if (is_cancelled_) { | |
| 65 return; | |
| 66 } | |
| 67 | |
| 68 // NOTE: This will acquire |watcher_|'s internal lock. It's safe because a | |
| 69 // thread can only enter InvokeCallback() from within a RequestContext | |
| 70 // destructor where no dispatcher locks are held. | |
| 71 watcher_->InvokeWatchCallback(context_, result, state, flags); | |
| 72 } | |
| 73 | |
| 74 Watch::~Watch() {} | |
| 75 | |
| 76 #if DCHECK_IS_ON() | |
| 77 void Watch::AssertWatcherLockAcquired() const { | |
| 78 watcher_->lock_.AssertAcquired(); | |
| 79 } | |
| 80 #endif | |
| 81 | |
| 82 } // namespace edk | |
| 83 } // namespace mojo | |
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Chromium Code Reviews
Issue 2750373002:
Revert of Mojo: Armed Watchers (Closed)
