tools/android/forwarder2/command.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 "tools/android/forwarder2/command.h"
   6
   7 #include <errno.h>
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10 #include <string.h>
  11
  12 #include "base/logging.h"
  13 #include "base/posix/safe_strerror.h"
  14 #include "base/strings/string_number_conversions.h"
  15 #include "base/strings/string_piece.h"
  16 #include "tools/android/forwarder2/socket.h"
  17
  18 using base::StringPiece;
  19
  20 namespace {
  21
  22
  23 // Command format:
  24 //      <port>:<type>
  25 //
  26 // Where:
  27 //   <port> is a 5-chars zero-padded ASCII decimal integer
  28 //          matching the target port for the command (e.g.
  29 //          '08080' for port 8080)
  30 //   <type> is a 3-char zero-padded ASCII decimal integer
  31 //          matching a command::Type value (e.g. 002 for
  32 //          ACK).
  33 // The column (:) is used as a separator for easier reading.
  34 const int kPortStringSize = 5;
  35 const int kCommandTypeStringSize = 2;
  36 // Command string size also includes the ':' separator char.
  37 const int kCommandStringSize = kPortStringSize + kCommandTypeStringSize + 1;
  38
  39 }  // namespace
  40
  41 namespace forwarder2 {
  42
  43 bool ReadCommand(Socket* socket,
  44                  int* port_out,
  45                  command::Type* command_type_out) {
  46   char command_buffer[kCommandStringSize + 1];
  47   // To make logging easier.
  48   command_buffer[kCommandStringSize] = '\0';
  49
  50   int bytes_read = socket->ReadNumBytes(command_buffer, kCommandStringSize);
  51   if (bytes_read != kCommandStringSize) {
  52     if (bytes_read < 0)
  53       LOG(ERROR) << "Read() error: " << base::safe_strerror(errno);
  54     else if (!bytes_read)
  55       LOG(ERROR) << "Read() error, endpoint was unexpectedly closed.";
  56     else
  57       LOG(ERROR) << "Read() error, not enough data received from the socket.";
  58     return false;
  59   }
  60
  61   StringPiece port_str(command_buffer, kPortStringSize);
  62   if (!StringToInt(port_str, port_out)) {
  63     LOG(ERROR) << "Could not parse the command port string: "
  64                << port_str;
  65     return false;
  66   }
  67
  68   StringPiece command_type_str(
  69       &command_buffer[kPortStringSize + 1], kCommandTypeStringSize);
  70   int command_type;
  71   if (!StringToInt(command_type_str, &command_type)) {
  72     LOG(ERROR) << "Could not parse the command type string: "
  73                << command_type_str;
  74     return false;
  75   }
  76   *command_type_out = static_cast<command::Type>(command_type);
  77   return true;
  78 }
  79
  80 bool SendCommand(command::Type command, int port, Socket* socket) {
  81   char buffer[kCommandStringSize + 1];
  82   int len = snprintf(buffer, sizeof(buffer), "%05d:%02d", port, command);
  83   CHECK_EQ(len, kCommandStringSize);
  84   // Write the full command minus the leading \0 char.
  85   return socket->WriteNumBytes(buffer, len) == len;
  86 }
  87
  88 bool ReceivedCommand(command::Type command, Socket* socket) {
  89   int port;
  90   command::Type received_command;
  91   if (!ReadCommand(socket, &port, &received_command))
  92     return false;
  93   return received_command == command;
  94 }
  95
  96 }  // namespace forwarder