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- // Copyright 2014 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 COMPONENTS_CAST_CHANNEL_CAST_TRANSPORT_H_
- #define COMPONENTS_CAST_CHANNEL_CAST_TRANSPORT_H_
- #include <string>
- #include "base/containers/queue.h"
- #include "base/memory/raw_ptr.h"
- #include "base/memory/ref_counted.h"
- #include "base/sequence_checker.h"
- #include "base/threading/thread_checker.h"
- #include "components/cast_channel/cast_channel_enum.h"
- #include "components/cast_channel/logger.h"
- #include "net/base/completion_once_callback.h"
- #include "net/base/ip_endpoint.h"
- #include "third_party/openscreen/src/cast/common/channel/proto/cast_channel.pb.h"
- namespace net {
- class DrainableIOBuffer;
- class DrainableIOBuffer;
- class GrowableIOBuffer;
- class IOBuffer;
- class Socket;
- } // namespace net
- namespace cast_channel {
- using ::cast::channel::CastMessage;
- class MessageFramer;
- class CastTransport {
- public:
- virtual ~CastTransport() {}
- // Object to be informed of incoming messages and read errors.
- class Delegate {
- public:
- virtual ~Delegate() {}
- // Called once Transport is successfully initialized and started.
- // Owned read delegates are Start()ed automatically.
- virtual void Start() = 0;
- // An error occurred on the channel.
- // The caller is responsible for closing |socket| if an error occurred.
- virtual void OnError(ChannelError error_state) = 0;
- // A message was received on the channel.
- virtual void OnMessage(const CastMessage& message) = 0;
- };
- // Sends a CastMessage to |socket_|.
- // |message|: The message to send.
- // |callback|: Callback to be invoked when the write operation has finished.
- // Virtual for testing.
- virtual void SendMessage(const CastMessage& message,
- net::CompletionOnceCallback callback) = 0;
- // Initializes the reading state machine and starts reading from the
- // underlying socket.
- // Virtual for testing.
- virtual void Start() = 0;
- // Changes the delegate for processing read events. Pending reads remain
- // in-flight.
- // Ownership of the pointee of |delegate| is assumed by the transport.
- // Prior delegates are deleted automatically.
- virtual void SetReadDelegate(std::unique_ptr<Delegate> delegate) = 0;
- };
- // Manager class for reading and writing messages to/from a socket.
- class CastTransportImpl : public CastTransport {
- public:
- using ChannelError = ::cast_channel::ChannelError;
- // Interface to read/write data from a socket to ease unit-testing.
- class Channel {
- public:
- virtual ~Channel() {}
- virtual void Read(net::IOBuffer* buffer,
- int bytes,
- net::CompletionOnceCallback callback) = 0;
- virtual void Write(net::IOBuffer* buffer,
- int bytes,
- net::CompletionOnceCallback callback) = 0;
- };
- // Adds a CastMessage read/write layer to a socket.
- // Message read events are propagated to the owner via |read_delegate|.
- // |vlog_prefix| sets the prefix used for all VLOGged output.
- // |channel| and |logger| must all out-live the
- // CastTransportImpl instance.
- // |read_delegate| is owned by this CastTransportImpl object.
- CastTransportImpl(Channel* channel,
- int channel_id,
- const net::IPEndPoint& ip_endpoint_,
- scoped_refptr<Logger> logger);
- CastTransportImpl(const CastTransportImpl&) = delete;
- CastTransportImpl& operator=(const CastTransportImpl&) = delete;
- ~CastTransportImpl() override;
- // CastTransport interface.
- void SendMessage(const CastMessage& message,
- net::CompletionOnceCallback callback) override;
- void Start() override;
- void SetReadDelegate(std::unique_ptr<Delegate> delegate) override;
- private:
- // Holds a message to be written to the socket. |callback| is invoked when the
- // message is fully written or an error occurrs.
- struct WriteRequest {
- explicit WriteRequest(const std::string& namespace_,
- const std::string& payload,
- net::CompletionOnceCallback callback);
- WriteRequest(WriteRequest&& other);
- ~WriteRequest();
- // Namespace of the serialized message.
- std::string message_namespace;
- // Write completion callback, invoked when the operation has completed or
- // failed.
- net::CompletionOnceCallback callback;
- // Buffer with outgoing data.
- scoped_refptr<net::DrainableIOBuffer> io_buffer;
- };
- static bool IsTerminalReadState(ReadState read_state);
- static bool IsTerminalWriteState(WriteState write_state);
- void SetReadState(ReadState read_state);
- void SetWriteState(WriteState write_state);
- void SetErrorState(ChannelError error_state);
- // Terminates all in-flight write callbacks with error code ERR_FAILED.
- void FlushWriteQueue();
- // Main method that performs write flow state transitions.
- void OnWriteResult(int result);
- // Each of the below Do* method is executed in the corresponding
- // write state. For example when write state is WRITE_STATE_WRITE_COMPLETE
- // DowriteComplete is called, and so on.
- int DoWrite();
- int DoWriteComplete(int result);
- int DoWriteCallback();
- int DoWriteHandleError(int result);
- // Main method that performs write flow state transitions.
- void OnReadResult(int result);
- // Each of the below Do* method is executed in the corresponding
- // write state. For example when read state is READ_STATE_READ_COMPLETE
- // DoReadComplete is called, and so on.
- int DoRead();
- int DoReadComplete(int result);
- int DoReadCallback();
- int DoReadHandleError(int result);
- // Indicates that the transport object is started and may receive and send
- // messages.
- bool started_;
- // Queue of pending writes. The message at the front of the queue is the one
- // being written.
- base::queue<WriteRequest> write_queue_;
- // Buffer used for read operations. Reused for every read.
- scoped_refptr<net::GrowableIOBuffer> read_buffer_;
- // Constructs and parses the wire representation of message frames.
- std::unique_ptr<MessageFramer> framer_;
- // Last message received on the socket.
- std::unique_ptr<CastMessage> current_message_;
- // Channel used for I/O operations.
- const raw_ptr<Channel> channel_;
- // Methods for communicating message receipt and error status to client code.
- std::unique_ptr<Delegate> delegate_;
- // Write flow state machine state.
- WriteState write_state_;
- // Read flow state machine state.
- ReadState read_state_;
- // The last error encountered by the channel.
- ChannelError error_state_;
- // Connection metadata for logging purposes.
- // Socket ID assigned by ApiResourceManager.
- int channel_id_;
- // IP address of the remote end.
- const net::IPEndPoint ip_endpoint_;
- // Accumulates details of events and errors, for debugging purposes.
- scoped_refptr<Logger> logger_;
- SEQUENCE_CHECKER(sequence_checker_);
- };
- } // namespace cast_channel
- #endif // COMPONENTS_CAST_CHANNEL_CAST_TRANSPORT_H_
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