ipc/ipc_channel_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 "ipc/ipc_channel_reader.h"
   6
   7 #include "ipc/ipc_listener.h"
   8 #include "ipc/ipc_logging.h"
   9 #include "ipc/ipc_message_macros.h"
  10
  11 namespace IPC {
  12 namespace internal {
  13
  14 ChannelReader::ChannelReader(Listener* listener) : listener_(listener) {
  15   memset(input_buf_, 0, sizeof(input_buf_));
  16 }
  17
  18 ChannelReader::~ChannelReader() {
  19 }
  20
  21 bool ChannelReader::ProcessIncomingMessages() {
  22   while (true) {
  23     int bytes_read = 0;
  24     ReadState read_state = ReadData(input_buf_, Channel::kReadBufferSize,
  25                                     &bytes_read);
  26     if (read_state == READ_FAILED)
  27       return false;
  28     if (read_state == READ_PENDING)
  29       return true;
  30
  31     DCHECK(bytes_read > 0);
  32     if (!DispatchInputData(input_buf_, bytes_read))
  33       return false;
  34   }
  35 }
  36
  37 bool ChannelReader::AsyncReadComplete(int bytes_read) {
  38   return DispatchInputData(input_buf_, bytes_read);
  39 }
  40
  41 bool ChannelReader::IsHelloMessage(const Message& m) const {
  42   return m.routing_id() == MSG_ROUTING_NONE &&
  43          m.type() == Channel::HELLO_MESSAGE_TYPE;
  44 }
  45
  46 bool ChannelReader::DispatchInputData(const char* input_data,
  47                                       int input_data_len) {
  48   const char* p;
  49   const char* end;
  50
  51   // Possibly combine with the overflow buffer to make a larger buffer.
  52   if (input_overflow_buf_.empty()) {
  53     p = input_data;
  54     end = input_data + input_data_len;
  55   } else {
  56     if (input_overflow_buf_.size() + input_data_len >
  57         Channel::kMaximumMessageSize) {
  58       input_overflow_buf_.clear();
  59       LOG(ERROR) << "IPC message is too big";
  60       return false;
  61     }
  62     input_overflow_buf_.append(input_data, input_data_len);
  63     p = input_overflow_buf_.data();
  64     end = p + input_overflow_buf_.size();
  65   }
  66
  67   // Dispatch all complete messages in the data buffer.
  68   while (p < end) {
  69     const char* message_tail = Message::FindNext(p, end);
  70     if (message_tail) {
  71       int len = static_cast<int>(message_tail - p);
  72       Message m(p, len);
  73       if (!WillDispatchInputMessage(&m))
  74         return false;
  75
  76 #ifdef IPC_MESSAGE_LOG_ENABLED
  77       Logging* logger = Logging::GetInstance();
  78       std::string name;
  79       logger->GetMessageText(m.type(), &name, &m, NULL);
  80       TRACE_EVENT1("ipc", "ChannelReader::DispatchInputData", "name", name);
  81 #else
  82       TRACE_EVENT2("ipc", "ChannelReader::DispatchInputData",
  83                    "class", IPC_MESSAGE_ID_CLASS(m.type()),
  84                    "line", IPC_MESSAGE_ID_LINE(m.type()));
  85 #endif
  86       m.TraceMessageEnd();
  87       if (IsHelloMessage(m))
  88         HandleHelloMessage(m);
  89       else
  90         listener_->OnMessageReceived(m);
  91       p = message_tail;
  92     } else {
  93       // Last message is partial.
  94       break;
  95     }
  96   }
  97
  98   // Save any partial data in the overflow buffer.
  99   input_overflow_buf_.assign(p, end - p);
 100
 101   if (input_overflow_buf_.empty() && !DidEmptyInputBuffers())
 102     return false;
 103   return true;
 104 }
 105
 106
 107 }  // namespace internal
 108 }  // namespace IPC