| // Copyright 2013 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "mojo/public/cpp/bindings/connector.h" |
| |
| #include <stdint.h> |
| |
| #include "base/bind.h" |
| #include "base/lazy_instance.h" |
| #include "base/location.h" |
| #include "base/logging.h" |
| #include "base/macros.h" |
| #include "base/memory/ptr_util.h" |
| #include "base/message_loop/message_loop.h" |
| #include "base/run_loop.h" |
| #include "base/synchronization/lock.h" |
| #include "base/threading/thread_local.h" |
| #include "base/trace_event/trace_event.h" |
| #include "mojo/public/cpp/bindings/lib/may_auto_lock.h" |
| #include "mojo/public/cpp/bindings/sync_handle_watcher.h" |
| #include "mojo/public/cpp/system/wait.h" |
| |
| namespace mojo { |
| |
| namespace { |
| |
| // The NestingObserver for each thread. Note that this is always a |
| // Connector::RunLoopNestingObserver; we use the base type here because that |
| // subclass is private to Connector. |
| base::LazyInstance<base::ThreadLocalPointer<base::RunLoop::NestingObserver>>:: |
| Leaky g_tls_nesting_observer = LAZY_INSTANCE_INITIALIZER; |
| |
| // The default outgoing serialization mode for new Connectors. |
| Connector::OutgoingSerializationMode g_default_outgoing_serialization_mode = |
| Connector::OutgoingSerializationMode::kLazy; |
| |
| // The default incoming serialization mode for new Connectors. |
| Connector::IncomingSerializationMode g_default_incoming_serialization_mode = |
| Connector::IncomingSerializationMode::kDispatchAsIs; |
| |
| } // namespace |
| |
| // Used to efficiently maintain a doubly-linked list of all Connectors |
| // currently dispatching on any given thread. |
| class Connector::ActiveDispatchTracker { |
| public: |
| explicit ActiveDispatchTracker(const base::WeakPtr<Connector>& connector); |
| ~ActiveDispatchTracker(); |
| |
| void NotifyBeginNesting(); |
| |
| private: |
| const base::WeakPtr<Connector> connector_; |
| RunLoopNestingObserver* const nesting_observer_; |
| ActiveDispatchTracker* outer_tracker_ = nullptr; |
| ActiveDispatchTracker* inner_tracker_ = nullptr; |
| |
| DISALLOW_COPY_AND_ASSIGN(ActiveDispatchTracker); |
| }; |
| |
| // Watches the MessageLoop on the current thread. Notifies the current chain of |
| // ActiveDispatchTrackers when a nested run loop is started. |
| class Connector::RunLoopNestingObserver |
| : public base::RunLoop::NestingObserver, |
| public base::MessageLoop::DestructionObserver { |
| public: |
| RunLoopNestingObserver() { |
| base::RunLoop::AddNestingObserverOnCurrentThread(this); |
| base::MessageLoop::current()->AddDestructionObserver(this); |
| } |
| |
| ~RunLoopNestingObserver() override {} |
| |
| // base::RunLoop::NestingObserver: |
| void OnBeginNestedRunLoop() override { |
| if (top_tracker_) |
| top_tracker_->NotifyBeginNesting(); |
| } |
| |
| // base::MessageLoop::DestructionObserver: |
| void WillDestroyCurrentMessageLoop() override { |
| base::RunLoop::RemoveNestingObserverOnCurrentThread(this); |
| base::MessageLoop::current()->RemoveDestructionObserver(this); |
| DCHECK_EQ(this, g_tls_nesting_observer.Get().Get()); |
| g_tls_nesting_observer.Get().Set(nullptr); |
| delete this; |
| } |
| |
| static RunLoopNestingObserver* GetForThread() { |
| if (!base::MessageLoop::current() || |
| !base::RunLoop::IsNestingAllowedOnCurrentThread()) { |
| return nullptr; |
| } |
| auto* observer = static_cast<RunLoopNestingObserver*>( |
| g_tls_nesting_observer.Get().Get()); |
| if (!observer) { |
| observer = new RunLoopNestingObserver; |
| g_tls_nesting_observer.Get().Set(observer); |
| } |
| return observer; |
| } |
| |
| private: |
| friend class ActiveDispatchTracker; |
| |
| ActiveDispatchTracker* top_tracker_ = nullptr; |
| |
| DISALLOW_COPY_AND_ASSIGN(RunLoopNestingObserver); |
| }; |
| |
| Connector::ActiveDispatchTracker::ActiveDispatchTracker( |
| const base::WeakPtr<Connector>& connector) |
| : connector_(connector), nesting_observer_(connector_->nesting_observer_) { |
| DCHECK(nesting_observer_); |
| if (nesting_observer_->top_tracker_) { |
| outer_tracker_ = nesting_observer_->top_tracker_; |
| outer_tracker_->inner_tracker_ = this; |
| } |
| nesting_observer_->top_tracker_ = this; |
| } |
| |
| Connector::ActiveDispatchTracker::~ActiveDispatchTracker() { |
| if (nesting_observer_->top_tracker_ == this) |
| nesting_observer_->top_tracker_ = outer_tracker_; |
| else if (inner_tracker_) |
| inner_tracker_->outer_tracker_ = outer_tracker_; |
| if (outer_tracker_) |
| outer_tracker_->inner_tracker_ = inner_tracker_; |
| } |
| |
| void Connector::ActiveDispatchTracker::NotifyBeginNesting() { |
| if (connector_ && connector_->handle_watcher_) |
| connector_->handle_watcher_->ArmOrNotify(); |
| if (outer_tracker_) |
| outer_tracker_->NotifyBeginNesting(); |
| } |
| |
| Connector::Connector(ScopedMessagePipeHandle message_pipe, |
| ConnectorConfig config, |
| scoped_refptr<base::SequencedTaskRunner> runner) |
| : message_pipe_(std::move(message_pipe)), |
| task_runner_(std::move(runner)), |
| outgoing_serialization_mode_(g_default_outgoing_serialization_mode), |
| incoming_serialization_mode_(g_default_incoming_serialization_mode), |
| nesting_observer_(RunLoopNestingObserver::GetForThread()), |
| weak_factory_(this) { |
| if (config == MULTI_THREADED_SEND) |
| lock_.emplace(); |
| |
| weak_self_ = weak_factory_.GetWeakPtr(); |
| // Even though we don't have an incoming receiver, we still want to monitor |
| // the message pipe to know if is closed or encounters an error. |
| WaitToReadMore(); |
| } |
| |
| Connector::~Connector() { |
| { |
| // Allow for quick destruction on any sequence if the pipe is already |
| // closed. |
| base::AutoLock lock(connected_lock_); |
| if (!connected_) |
| return; |
| } |
| |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| CancelWait(); |
| } |
| |
| void Connector::SetOutgoingSerializationMode(OutgoingSerializationMode mode) { |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| outgoing_serialization_mode_ = mode; |
| } |
| |
| void Connector::SetIncomingSerializationMode(IncomingSerializationMode mode) { |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| incoming_serialization_mode_ = mode; |
| } |
| |
| void Connector::CloseMessagePipe() { |
| // Throw away the returned message pipe. |
| PassMessagePipe(); |
| } |
| |
| ScopedMessagePipeHandle Connector::PassMessagePipe() { |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| |
| CancelWait(); |
| internal::MayAutoLock locker(&lock_); |
| ScopedMessagePipeHandle message_pipe = std::move(message_pipe_); |
| weak_factory_.InvalidateWeakPtrs(); |
| sync_handle_watcher_callback_count_ = 0; |
| |
| base::AutoLock lock(connected_lock_); |
| connected_ = false; |
| return message_pipe; |
| } |
| |
| void Connector::RaiseError() { |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| |
| HandleError(true, true); |
| } |
| |
| bool Connector::WaitForIncomingMessage(MojoDeadline deadline) { |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| |
| if (error_) |
| return false; |
| |
| ResumeIncomingMethodCallProcessing(); |
| |
| // TODO(rockot): Use a timed Wait here. Nobody uses anything but 0 or |
| // INDEFINITE deadlines at present, so we only support those. |
| DCHECK(deadline == 0 || deadline == MOJO_DEADLINE_INDEFINITE); |
| |
| MojoResult rv = MOJO_RESULT_UNKNOWN; |
| if (deadline == 0 && !message_pipe_->QuerySignalsState().readable()) |
| return false; |
| |
| if (deadline == MOJO_DEADLINE_INDEFINITE) { |
| rv = Wait(message_pipe_.get(), MOJO_HANDLE_SIGNAL_READABLE); |
| if (rv != MOJO_RESULT_OK) { |
| // Users that call WaitForIncomingMessage() should expect their code to be |
| // re-entered, so we call the error handler synchronously. |
| HandleError(rv != MOJO_RESULT_FAILED_PRECONDITION, false); |
| return false; |
| } |
| } |
| |
| ignore_result(ReadSingleMessage(&rv)); |
| return (rv == MOJO_RESULT_OK); |
| } |
| |
| void Connector::PauseIncomingMethodCallProcessing() { |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| |
| if (paused_) |
| return; |
| |
| paused_ = true; |
| CancelWait(); |
| } |
| |
| void Connector::ResumeIncomingMethodCallProcessing() { |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| |
| if (!paused_) |
| return; |
| |
| paused_ = false; |
| WaitToReadMore(); |
| } |
| |
| bool Connector::PrefersSerializedMessages() { |
| if (outgoing_serialization_mode_ == OutgoingSerializationMode::kEager) |
| return true; |
| DCHECK_EQ(OutgoingSerializationMode::kLazy, outgoing_serialization_mode_); |
| return peer_remoteness_tracker_ && |
| peer_remoteness_tracker_->last_known_state().peer_remote(); |
| } |
| |
| bool Connector::Accept(Message* message) { |
| if (!lock_) |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| |
| // It shouldn't hurt even if |error_| may be changed by a different sequence |
| // at the same time. The outcome is that we may write into |message_pipe_| |
| // after encountering an error, which should be fine. |
| if (error_) |
| return false; |
| |
| internal::MayAutoLock locker(&lock_); |
| |
| if (!message_pipe_.is_valid() || drop_writes_) |
| return true; |
| |
| MojoResult rv = |
| WriteMessageNew(message_pipe_.get(), message->TakeMojoMessage(), |
| MOJO_WRITE_MESSAGE_FLAG_NONE); |
| |
| switch (rv) { |
| case MOJO_RESULT_OK: |
| break; |
| case MOJO_RESULT_FAILED_PRECONDITION: |
| // There's no point in continuing to write to this pipe since the other |
| // end is gone. Avoid writing any future messages. Hide write failures |
| // from the caller since we'd like them to continue consuming any backlog |
| // of incoming messages before regarding the message pipe as closed. |
| drop_writes_ = true; |
| break; |
| case MOJO_RESULT_BUSY: |
| // We'd get a "busy" result if one of the message's handles is: |
| // - |message_pipe_|'s own handle; |
| // - simultaneously being used on another sequence; or |
| // - in a "busy" state that prohibits it from being transferred (e.g., |
| // a data pipe handle in the middle of a two-phase read/write, |
| // regardless of which sequence that two-phase read/write is happening |
| // on). |
| // TODO(vtl): I wonder if this should be a |DCHECK()|. (But, until |
| // crbug.com/389666, etc. are resolved, this will make tests fail quickly |
| // rather than hanging.) |
| CHECK(false) << "Race condition or other bug detected"; |
| return false; |
| default: |
| // This particular write was rejected, presumably because of bad input. |
| // The pipe is not necessarily in a bad state. |
| return false; |
| } |
| return true; |
| } |
| |
| void Connector::AllowWokenUpBySyncWatchOnSameThread() { |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| |
| allow_woken_up_by_others_ = true; |
| |
| EnsureSyncWatcherExists(); |
| sync_watcher_->AllowWokenUpBySyncWatchOnSameThread(); |
| } |
| |
| bool Connector::SyncWatch(const bool* should_stop) { |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| |
| if (error_) |
| return false; |
| |
| ResumeIncomingMethodCallProcessing(); |
| |
| EnsureSyncWatcherExists(); |
| return sync_watcher_->SyncWatch(should_stop); |
| } |
| |
| void Connector::SetWatcherHeapProfilerTag(const char* tag) { |
| if (tag) { |
| heap_profiler_tag_ = tag; |
| if (handle_watcher_) |
| handle_watcher_->set_heap_profiler_tag(tag); |
| } |
| } |
| |
| // static |
| void Connector::OverrideDefaultSerializationBehaviorForTesting( |
| OutgoingSerializationMode outgoing_mode, |
| IncomingSerializationMode incoming_mode) { |
| g_default_outgoing_serialization_mode = outgoing_mode; |
| g_default_incoming_serialization_mode = incoming_mode; |
| } |
| |
| void Connector::OnWatcherHandleReady(MojoResult result) { |
| OnHandleReadyInternal(result); |
| } |
| |
| void Connector::OnSyncHandleWatcherHandleReady(MojoResult result) { |
| base::WeakPtr<Connector> weak_self(weak_self_); |
| |
| sync_handle_watcher_callback_count_++; |
| OnHandleReadyInternal(result); |
| // At this point, this object might have been deleted. |
| if (weak_self) { |
| DCHECK_LT(0u, sync_handle_watcher_callback_count_); |
| sync_handle_watcher_callback_count_--; |
| } |
| } |
| |
| void Connector::OnHandleReadyInternal(MojoResult result) { |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| |
| if (result != MOJO_RESULT_OK) { |
| HandleError(result != MOJO_RESULT_FAILED_PRECONDITION, false); |
| return; |
| } |
| |
| ReadAllAvailableMessages(); |
| // At this point, this object might have been deleted. Return. |
| } |
| |
| void Connector::WaitToReadMore() { |
| CHECK(!paused_); |
| DCHECK(!handle_watcher_); |
| |
| handle_watcher_.reset(new SimpleWatcher( |
| FROM_HERE, SimpleWatcher::ArmingPolicy::MANUAL, task_runner_)); |
| handle_watcher_->set_heap_profiler_tag(heap_profiler_tag_); |
| MojoResult rv = handle_watcher_->Watch( |
| message_pipe_.get(), MOJO_HANDLE_SIGNAL_READABLE, |
| base::Bind(&Connector::OnWatcherHandleReady, base::Unretained(this))); |
| |
| if (message_pipe_.is_valid()) { |
| peer_remoteness_tracker_.emplace(message_pipe_.get(), |
| MOJO_HANDLE_SIGNAL_PEER_REMOTE); |
| } |
| |
| if (rv != MOJO_RESULT_OK) { |
| // If the watch failed because the handle is invalid or its conditions can |
| // no longer be met, we signal the error asynchronously to avoid reentry. |
| task_runner_->PostTask( |
| FROM_HERE, |
| base::Bind(&Connector::OnWatcherHandleReady, weak_self_, rv)); |
| } else { |
| handle_watcher_->ArmOrNotify(); |
| } |
| |
| if (allow_woken_up_by_others_) { |
| EnsureSyncWatcherExists(); |
| sync_watcher_->AllowWokenUpBySyncWatchOnSameThread(); |
| } |
| } |
| |
| bool Connector::ReadSingleMessage(MojoResult* read_result) { |
| CHECK(!paused_); |
| |
| bool receiver_result = false; |
| |
| // Detect if |this| was destroyed or the message pipe was closed/transferred |
| // during message dispatch. |
| base::WeakPtr<Connector> weak_self = weak_self_; |
| |
| Message message; |
| const MojoResult rv = ReadMessage(message_pipe_.get(), &message); |
| *read_result = rv; |
| |
| if (rv == MOJO_RESULT_OK) { |
| base::Optional<ActiveDispatchTracker> dispatch_tracker; |
| if (!is_dispatching_ && nesting_observer_) { |
| is_dispatching_ = true; |
| dispatch_tracker.emplace(weak_self); |
| } |
| |
| if (incoming_serialization_mode_ == |
| IncomingSerializationMode::kSerializeBeforeDispatchForTesting) { |
| message.SerializeIfNecessary(); |
| } else { |
| DCHECK_EQ(IncomingSerializationMode::kDispatchAsIs, |
| incoming_serialization_mode_); |
| } |
| |
| TRACE_EVENT0("mojom", heap_profiler_tag_); |
| receiver_result = |
| incoming_receiver_ && incoming_receiver_->Accept(&message); |
| |
| if (!weak_self) |
| return false; |
| |
| if (dispatch_tracker) { |
| is_dispatching_ = false; |
| dispatch_tracker.reset(); |
| } |
| } else if (rv == MOJO_RESULT_SHOULD_WAIT) { |
| return true; |
| } else { |
| HandleError(rv != MOJO_RESULT_FAILED_PRECONDITION, false); |
| return false; |
| } |
| |
| if (enforce_errors_from_incoming_receiver_ && !receiver_result) { |
| HandleError(true, false); |
| return false; |
| } |
| return true; |
| } |
| |
| void Connector::ReadAllAvailableMessages() { |
| while (!error_) { |
| base::WeakPtr<Connector> weak_self = weak_self_; |
| MojoResult rv; |
| |
| // May delete |this.| |
| if (!ReadSingleMessage(&rv)) |
| return; |
| |
| if (!weak_self || paused_) |
| return; |
| |
| DCHECK(rv == MOJO_RESULT_OK || rv == MOJO_RESULT_SHOULD_WAIT); |
| |
| if (rv == MOJO_RESULT_SHOULD_WAIT) { |
| // Attempt to re-arm the Watcher. |
| MojoResult ready_result; |
| MojoResult arm_result = handle_watcher_->Arm(&ready_result); |
| if (arm_result == MOJO_RESULT_OK) |
| return; |
| |
| // The watcher is already ready to notify again. |
| DCHECK_EQ(MOJO_RESULT_FAILED_PRECONDITION, arm_result); |
| |
| if (ready_result == MOJO_RESULT_FAILED_PRECONDITION) { |
| HandleError(false, false); |
| return; |
| } |
| |
| // There's more to read now, so we'll just keep looping. |
| DCHECK_EQ(MOJO_RESULT_OK, ready_result); |
| } |
| } |
| } |
| |
| void Connector::CancelWait() { |
| peer_remoteness_tracker_.reset(); |
| handle_watcher_.reset(); |
| sync_watcher_.reset(); |
| } |
| |
| void Connector::HandleError(bool force_pipe_reset, bool force_async_handler) { |
| if (error_ || !message_pipe_.is_valid()) |
| return; |
| |
| if (paused_) { |
| // Enforce calling the error handler asynchronously if the user has paused |
| // receiving messages. We need to wait until the user starts receiving |
| // messages again. |
| force_async_handler = true; |
| } |
| |
| if (!force_pipe_reset && force_async_handler) |
| force_pipe_reset = true; |
| |
| if (force_pipe_reset) { |
| CancelWait(); |
| internal::MayAutoLock locker(&lock_); |
| message_pipe_.reset(); |
| MessagePipe dummy_pipe; |
| message_pipe_ = std::move(dummy_pipe.handle0); |
| } else { |
| CancelWait(); |
| } |
| |
| if (force_async_handler) { |
| if (!paused_) |
| WaitToReadMore(); |
| } else { |
| error_ = true; |
| if (connection_error_handler_) |
| std::move(connection_error_handler_).Run(); |
| } |
| } |
| |
| void Connector::EnsureSyncWatcherExists() { |
| if (sync_watcher_) |
| return; |
| sync_watcher_.reset(new SyncHandleWatcher( |
| message_pipe_.get(), MOJO_HANDLE_SIGNAL_READABLE, |
| base::Bind(&Connector::OnSyncHandleWatcherHandleReady, |
| base::Unretained(this)))); |
| } |
| |
| } // namespace mojo |