blob: 6352bf0ef16a4ab5d0811ecbe17b38e081e36e9f [file] [log] [blame]
// 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.
#include <stddef.h>
#include <stdint.h>
#include <memory>
#include <string>
#include "base/macros.h"
#include "components/cast_channel/cast_channel_enum.h"
#include "net/base/io_buffer.h"
namespace cast_channel {
class CastMessage;
// Class for constructing and parsing CastMessage packet data.
class MessageFramer {
using ChannelError = ::cast_channel::ChannelError;
// |input_buffer|: The input buffer used by all socket read operations that
// feed data into the framer.
explicit MessageFramer(scoped_refptr<net::GrowableIOBuffer> input_buffer);
// The number of bytes required from |input_buffer| to complete the
// CastMessage being read.
// Returns zero if |error_| is true (framer is in an invalid state.)
size_t BytesRequested();
// Serializes |message_proto| into |message_data|.
// Returns true if the message was serialized successfully, false otherwise.
static bool Serialize(const CastMessage& message_proto,
std::string* message_data);
// Reads bytes from |input_buffer_| and returns a new CastMessage if one
// is fully read.
// |num_bytes| The number of bytes received by a read operation.
// Value must be <= BytesRequested().
// |message_length| Size of the deserialized message object, in bytes. For
// logging purposes. Set to zero if no message was parsed.
// |error| The result of the ingest operation. Set to CHANNEL_ERROR_NONE
// if no error occurred.
// Returns A pointer to a parsed CastMessage if a message was received
// in its entirety, nullptr otherwise.
std::unique_ptr<CastMessage> Ingest(size_t num_bytes,
size_t* message_length,
ChannelError* error);
// Message header struct. If fields are added, be sure to update
// header_size(). Public to allow use of *_size() methods in unit tests.
struct MessageHeader {
// Sets the message size.
void SetMessageSize(size_t message_size);
// Prepends this header to |str|.
void PrependToString(std::string* str);
// Reads |header| from the bytes specified by |data|.
static void Deserialize(char* data, MessageHeader* header);
// Size (in bytes) of the message header.
static size_t header_size();
// Maximum size (in bytes) of a message payload on the wire (does not
// include header).
static size_t max_body_size();
// Maximum size (in bytes) of a message (header + payload) on the wire.
static size_t max_message_size();
std::string ToString();
// The size of the following protocol message in bytes, in host byte order.
size_t message_size;
enum MessageElement { HEADER, BODY };
// Prepares the framer for ingesting a new message.
void Reset();
// The element of the message that will be read on the next call to Ingest().
MessageElement current_element_;
// Total size of the message, in bytes (head + body).
size_t message_bytes_received_;
// Size of the body alone, in bytes.
size_t body_size_;
// Input buffer which carries message data read from the socket.
// Caller is responsible for writing into this buffer.
scoped_refptr<net::GrowableIOBuffer> input_buffer_;
// Disables Ingest functionality is the parser receives invalid data.
bool error_;
} // namespace cast_channel