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      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
    123