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// Copyright 2015 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.
#ifndef MOJO_PUBLIC_CPP_BINDINGS_LIB_MULTIPLEX_ROUTER_H_
#define MOJO_PUBLIC_CPP_BINDINGS_LIB_MULTIPLEX_ROUTER_H_
#include <stdint.h>
#include <map>
#include <memory>
#include <string>
#include "base/compiler_specific.h"
#include "base/containers/queue.h"
#include "base/containers/small_map.h"
#include "base/logging.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"
#include "base/optional.h"
#include "base/sequence_checker.h"
#include "base/sequenced_task_runner.h"
#include "base/synchronization/lock.h"
#include "mojo/public/cpp/bindings/associated_group_controller.h"
#include "mojo/public/cpp/bindings/bindings_export.h"
#include "mojo/public/cpp/bindings/connector.h"
#include "mojo/public/cpp/bindings/filter_chain.h"
#include "mojo/public/cpp/bindings/interface_id.h"
#include "mojo/public/cpp/bindings/message_header_validator.h"
#include "mojo/public/cpp/bindings/pipe_control_message_handler.h"
#include "mojo/public/cpp/bindings/pipe_control_message_handler_delegate.h"
#include "mojo/public/cpp/bindings/pipe_control_message_proxy.h"
#include "mojo/public/cpp/bindings/scoped_interface_endpoint_handle.h"
namespace base {
class SequencedTaskRunner;
}
namespace mojo {
namespace internal {
// MultiplexRouter supports routing messages for multiple interfaces over a
// single message pipe.
//
// It is created on the sequence where the master interface of the message pipe
// lives. Although it is ref-counted, it is guarateed to be destructed on the
// same sequence.
// Some public methods are only allowed to be called on the creating sequence;
// while the others are safe to call from any sequence. Please see the method
// comments for more details.
//
// NOTE: CloseMessagePipe() or PassMessagePipe() MUST be called on |runner|'s
// sequence before this object is destroyed.
class MOJO_CPP_BINDINGS_EXPORT MultiplexRouter
: public MessageReceiver,
public AssociatedGroupController,
public PipeControlMessageHandlerDelegate {
public:
enum Config {
// There is only the master interface running on this router. Please note
// that because of interface versioning, the other side of the message pipe
// may use a newer master interface definition which passes associated
// interfaces. In that case, this router may still receive pipe control
// messages or messages targetting associated interfaces.
SINGLE_INTERFACE,
// Similar to the mode above, there is only the master interface running on
// this router. Besides, the master interface has sync methods.
SINGLE_INTERFACE_WITH_SYNC_METHODS,
// There may be associated interfaces running on this router.
MULTI_INTERFACE
};
// If |set_interface_id_namespace_bit| is true, the interface IDs generated by
// this router will have the highest bit set.
MultiplexRouter(ScopedMessagePipeHandle message_pipe,
Config config,
bool set_interface_id_namespace_bit,
scoped_refptr<base::SequencedTaskRunner> runner);
// Adds a MessageReceiver which can filter a message after validation but
// before dispatch.
void AddIncomingMessageFilter(std::unique_ptr<MessageReceiver> filter);
// Sets the master interface name for this router. Only used when reporting
// message header or control message validation errors.
// |name| must be a string literal.
void SetMasterInterfaceName(const char* name);
// ---------------------------------------------------------------------------
// The following public methods are safe to call from any sequence.
// AssociatedGroupController implementation:
InterfaceId AssociateInterface(
ScopedInterfaceEndpointHandle handle_to_send) override;
ScopedInterfaceEndpointHandle CreateLocalEndpointHandle(
InterfaceId id) override;
void CloseEndpointHandle(
InterfaceId id,
const base::Optional<DisconnectReason>& reason) override;
InterfaceEndpointController* AttachEndpointClient(
const ScopedInterfaceEndpointHandle& handle,
InterfaceEndpointClient* endpoint_client,
scoped_refptr<base::SequencedTaskRunner> runner) override;
void DetachEndpointClient(
const ScopedInterfaceEndpointHandle& handle) override;
void RaiseError() override;
bool PrefersSerializedMessages() override;
// ---------------------------------------------------------------------------
// The following public methods are called on the creating sequence.
// Please note that this method shouldn't be called unless it results from an
// explicit request of the user of bindings (e.g., the user sets an
// InterfacePtr to null or closes a Binding).
void CloseMessagePipe();
// Extracts the underlying message pipe.
ScopedMessagePipeHandle PassMessagePipe() {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
DCHECK(!HasAssociatedEndpoints());
return connector_.PassMessagePipe();
}
// Blocks the current sequence until the first incoming message, or
// |deadline|.
bool WaitForIncomingMessage(MojoDeadline deadline) {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
return connector_.WaitForIncomingMessage(deadline);
}
// See Binding for details of pause/resume.
void PauseIncomingMethodCallProcessing();
void ResumeIncomingMethodCallProcessing();
// Whether there are any associated interfaces running currently.
bool HasAssociatedEndpoints() const;
// Sets this object to testing mode.
// In testing mode, the object doesn't disconnect the underlying message pipe
// when it receives unexpected or invalid messages.
void EnableTestingMode();
// Is the router bound to a message pipe handle?
bool is_valid() const {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
return connector_.is_valid();
}
// TODO(yzshen): consider removing this getter.
MessagePipeHandle handle() const {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
return connector_.handle();
}
bool SimulateReceivingMessageForTesting(Message* message) {
return filters_.Accept(message);
}
private:
class InterfaceEndpoint;
class MessageWrapper;
struct Task;
~MultiplexRouter() override;
// MessageReceiver implementation:
bool Accept(Message* message) override;
// PipeControlMessageHandlerDelegate implementation:
bool OnPeerAssociatedEndpointClosed(
InterfaceId id,
const base::Optional<DisconnectReason>& reason) override;
void OnPipeConnectionError();
// Specifies whether we are allowed to directly call into
// InterfaceEndpointClient (given that we are already on the same sequence as
// the client).
enum ClientCallBehavior {
// Don't call any InterfaceEndpointClient methods directly.
NO_DIRECT_CLIENT_CALLS,
// Only call InterfaceEndpointClient::HandleIncomingMessage directly to
// handle sync messages.
ALLOW_DIRECT_CLIENT_CALLS_FOR_SYNC_MESSAGES,
// Allow to call any InterfaceEndpointClient methods directly.
ALLOW_DIRECT_CLIENT_CALLS
};
// Processes enqueued tasks (incoming messages and error notifications).
// |current_task_runner| is only used when |client_call_behavior| is
// ALLOW_DIRECT_CLIENT_CALLS to determine whether we are on the right task
// runner to make client calls for async messages or connection error
// notifications.
//
// Note: Because calling into InterfaceEndpointClient may lead to destruction
// of this object, if direct calls are allowed, the caller needs to hold on to
// a ref outside of |lock_| before calling this method.
void ProcessTasks(ClientCallBehavior client_call_behavior,
base::SequencedTaskRunner* current_task_runner);
// Processes the first queued sync message for the endpoint corresponding to
// |id|; returns whether there are more sync messages for that endpoint in the
// queue.
//
// This method is only used by enpoints during sync watching. Therefore, not
// all sync messages are handled by it.
bool ProcessFirstSyncMessageForEndpoint(InterfaceId id);
// Returns true to indicate that |task|/|message| has been processed.
bool ProcessNotifyErrorTask(Task* task,
ClientCallBehavior client_call_behavior,
base::SequencedTaskRunner* current_task_runner);
bool ProcessIncomingMessage(MessageWrapper* message_wrapper,
ClientCallBehavior client_call_behavior,
base::SequencedTaskRunner* current_task_runner);
void MaybePostToProcessTasks(base::SequencedTaskRunner* task_runner);
void LockAndCallProcessTasks();
// Updates the state of |endpoint|. If both the endpoint and its peer have
// been closed, removes it from |endpoints_|.
// NOTE: The method may invalidate |endpoint|.
enum EndpointStateUpdateType { ENDPOINT_CLOSED, PEER_ENDPOINT_CLOSED };
void UpdateEndpointStateMayRemove(InterfaceEndpoint* endpoint,
EndpointStateUpdateType type);
void RaiseErrorInNonTestingMode();
InterfaceEndpoint* FindOrInsertEndpoint(InterfaceId id, bool* inserted);
InterfaceEndpoint* FindEndpoint(InterfaceId id);
// Returns false if some interface IDs are invalid or have been used.
bool InsertEndpointsForMessage(const Message& message);
void CloseEndpointsForMessage(const Message& message);
void AssertLockAcquired();
// Whether to set the namespace bit when generating interface IDs. Please see
// comments of kInterfaceIdNamespaceMask.
const bool set_interface_id_namespace_bit_;
scoped_refptr<base::SequencedTaskRunner> task_runner_;
// Owned by |filters_| below.
MessageHeaderValidator* header_validator_ = nullptr;
FilterChain filters_;
Connector connector_;
SEQUENCE_CHECKER(sequence_checker_);
// Protects the following members.
// Not set in Config::SINGLE_INTERFACE* mode.
mutable base::Optional<base::Lock> lock_;
PipeControlMessageHandler control_message_handler_;
// NOTE: It is unsafe to call into this object while holding |lock_|.
PipeControlMessageProxy control_message_proxy_;
base::small_map<std::map<InterfaceId, scoped_refptr<InterfaceEndpoint>>, 1>
endpoints_;
uint32_t next_interface_id_value_ = 1;
base::circular_deque<std::unique_ptr<Task>> tasks_;
// It refers to tasks in |tasks_| and doesn't own any of them.
std::map<InterfaceId, base::circular_deque<Task*>> sync_message_tasks_;
bool posted_to_process_tasks_ = false;
scoped_refptr<base::SequencedTaskRunner> posted_to_task_runner_;
bool encountered_error_ = false;
bool paused_ = false;
bool testing_mode_ = false;
bool being_destructed_ = false;
DISALLOW_COPY_AND_ASSIGN(MultiplexRouter);
};
} // namespace internal
} // namespace mojo
#endif // MOJO_PUBLIC_CPP_BINDINGS_LIB_MULTIPLEX_ROUTER_H_