remoting/protocol/message_reader.cc

   1 // Copyright (c) 2012 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 "remoting/protocol/message_reader.h"
   6
   7 #include "base/bind.h"
   8 #include "base/callback.h"
   9 #include "base/compiler_specific.h"
  10 #include "base/location.h"
  11 #include "base/thread_task_runner_handle.h"
  12 #include "base/single_thread_task_runner.h"
  13 #include "net/base/io_buffer.h"
  14 #include "net/base/net_errors.h"
  15 #include "net/socket/socket.h"
  16 #include "remoting/base/compound_buffer.h"
  17 #include "remoting/proto/internal.pb.h"
  18
  19 namespace remoting {
  20 namespace protocol {
  21
  22 static const int kReadBufferSize = 4096;
  23
  24 MessageReader::MessageReader()
  25     : socket_(NULL),
  26       read_pending_(false),
  27       pending_messages_(0),
  28       closed_(false),
  29       weak_factory_(this) {
  30 }
  31
  32 void MessageReader::Init(net::Socket* socket,
  33                          const MessageReceivedCallback& callback) {
  34   DCHECK(CalledOnValidThread());
  35   message_received_callback_ = callback;
  36   DCHECK(socket);
  37   socket_ = socket;
  38   DoRead();
  39 }
  40
  41 MessageReader::~MessageReader() {
  42 }
  43
  44 void MessageReader::DoRead() {
  45   DCHECK(CalledOnValidThread());
  46   // Don't try to read again if there is another read pending or we
  47   // have messages that we haven't finished processing yet.
  48   while (!closed_ && !read_pending_ && pending_messages_ == 0) {
  49     read_buffer_ = new net::IOBuffer(kReadBufferSize);
  50     int result = socket_->Read(
  51         read_buffer_.get(),
  52         kReadBufferSize,
  53         base::Bind(&MessageReader::OnRead, weak_factory_.GetWeakPtr()));
  54     HandleReadResult(result);
  55   }
  56 }
  57
  58 void MessageReader::OnRead(int result) {
  59   DCHECK(CalledOnValidThread());
  60   DCHECK(read_pending_);
  61   read_pending_ = false;
  62
  63   if (!closed_) {
  64     HandleReadResult(result);
  65     DoRead();
  66   }
  67 }
  68
  69 void MessageReader::HandleReadResult(int result) {
  70   DCHECK(CalledOnValidThread());
  71   if (closed_)
  72     return;
  73
  74   if (result > 0) {
  75     OnDataReceived(read_buffer_.get(), result);
  76   } else if (result == net::ERR_IO_PENDING) {
  77     read_pending_ = true;
  78   } else {
  79     if (result != net::ERR_CONNECTION_CLOSED) {
  80       LOG(ERROR) << "Read() returned error " << result;
  81     }
  82     // Stop reading after any error.
  83     closed_ = true;
  84   }
  85 }
  86
  87 void MessageReader::OnDataReceived(net::IOBuffer* data, int data_size) {
  88   DCHECK(CalledOnValidThread());
  89   message_decoder_.AddData(data, data_size);
  90
  91   // Get list of all new messages first, and then call the callback
  92   // for all of them.
  93   while (true) {
  94     CompoundBuffer* buffer = message_decoder_.GetNextMessage();
  95     if (!buffer)
  96       break;
  97     pending_messages_++;
  98     base::ThreadTaskRunnerHandle::Get()->PostTask(
  99         FROM_HERE,
 100         base::Bind(&MessageReader::RunCallback,
 101                    weak_factory_.GetWeakPtr(),
 102                    base::Passed(scoped_ptr<CompoundBuffer>(buffer))));
 103   }
 104 }
 105
 106 void MessageReader::RunCallback(scoped_ptr<CompoundBuffer> message) {
 107   message_received_callback_.Run(
 108       message.Pass(), base::Bind(&MessageReader::OnMessageDone,
 109                                  weak_factory_.GetWeakPtr()));
 110 }
 111
 112 void MessageReader::OnMessageDone() {
 113   DCHECK(CalledOnValidThread());
 114   pending_messages_--;
 115   DCHECK_GE(pending_messages_, 0);
 116
 117   // Start next read if necessary.
 118   DoRead();
 119 }
 120
 121 }  // namespace protocol
 122 }  // namespace remoting