root/dbus/message.cc

DEFINITIONS

1. AppendStringHeader
2. AppendUint32Header
3. IsDBusTypeUnixFdSupported
4. Init
5. GetMessageType
6. GetMessageTypeAsString
7. ToStringInternal
8. ToString
9. SetDestination
10. SetPath
11. SetInterface
12. SetMember
13. SetErrorName
14. SetSender
15. SetSerial
16. SetReplySerial
17. GetDestination
18. GetPath
19. GetInterface
20. GetMember
21. GetErrorName
22. GetSender
23. GetSignature
24. GetSerial
25. GetReplySerial
26. FromRawMessage
27. FromRawMessage
28. FromRawMessage
29. FromMethodCall
30. CreateEmpty
31. FromRawMessage
32. FromMethodCall
33. container_is_open_
34. AppendByte
35. AppendBool
36. AppendInt16
37. AppendUint16
38. AppendInt32
39. AppendUint32
40. AppendInt64
41. AppendUint64
42. AppendDouble
43. AppendString
44. AppendObjectPath
45. OpenArray
46. OpenVariant
47. OpenStruct
48. OpenDictEntry
49. CloseContainer
50. AppendArrayOfBytes
51. AppendArrayOfStrings
52. AppendArrayOfObjectPaths
53. AppendProtoAsArrayOfBytes
54. AppendVariantOfByte
55. AppendVariantOfBool
56. AppendVariantOfInt16
57. AppendVariantOfUint16
58. AppendVariantOfInt32
59. AppendVariantOfUint32
60. AppendVariantOfInt64
61. AppendVariantOfUint64
62. AppendVariantOfDouble
63. AppendVariantOfString
64. AppendVariantOfObjectPath
65. AppendBasic
66. AppendVariantOfBasic
67. AppendFileDescriptor
68. HasMoreData
69. PopByte
70. PopBool
71. PopInt16
72. PopUint16
73. PopInt32
74. PopUint32
75. PopInt64
76. PopUint64
77. PopDouble
78. PopString
79. PopObjectPath
80. PopArray
81. PopStruct
82. PopDictEntry
83. PopVariant
84. PopArrayOfBytes
85. PopArrayOfStrings
86. PopArrayOfObjectPaths
87. PopArrayOfBytesAsProto
88. PopVariantOfByte
89. PopVariantOfBool
90. PopVariantOfInt16
91. PopVariantOfUint16
92. PopVariantOfInt32
93. PopVariantOfUint32
94. PopVariantOfInt64
95. PopVariantOfUint64
96. PopVariantOfDouble
97. PopVariantOfString
98. PopVariantOfObjectPath
99. GetDataType
100. CheckDataType
101. PopBasic
102. PopContainer
103. PopVariantOfBasic
104. PopFileDescriptor

// Copyright (c) 2012 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 "dbus/message.h"

#include <string>

#include "base/basictypes.h"
#include "base/format_macros.h"
#include "base/logging.h"
#include "base/strings/string_util.h"
#include "base/strings/stringprintf.h"
#include "dbus/object_path.h"

#if defined(USE_SYSTEM_PROTOBUF)
#include <google/protobuf/message_lite.h>
#else
#include "third_party/protobuf/src/google/protobuf/message_lite.h"
#endif

namespace {

// Appends the header name and the value to |output|, if the value is
// not empty.
void AppendStringHeader(const std::string& header_name,
                        const std::string& header_value,
                        std::string* output) {
  if (!header_value.empty()) {
    *output += header_name + ": " + header_value + "\n";
  }
}

// Appends the header name and the value to |output|, if the value is
// nonzero.
void AppendUint32Header(const std::string& header_name,
                        uint32 header_value,
                        std::string* output) {
  if (header_value != 0) {
    *output += (header_name + ": " + base::StringPrintf("%u", header_value) +
                "\n");
  }
}

}  // namespace

namespace dbus {

bool IsDBusTypeUnixFdSupported() {
  int major = 0, minor = 0, micro = 0;
  dbus_get_version(&major, &minor, &micro);
  return major >= 1 && minor >= 4;
}

Message::Message()
    : raw_message_(NULL) {
}

Message::~Message() {
  if (raw_message_)
    dbus_message_unref(raw_message_);
}

void Message::Init(DBusMessage* raw_message) {
  DCHECK(!raw_message_);
  raw_message_ = raw_message;
}

Message::MessageType Message::GetMessageType() {
  if (!raw_message_)
    return MESSAGE_INVALID;
  const int type = dbus_message_get_type(raw_message_);
  return static_cast<Message::MessageType>(type);
}

std::string Message::GetMessageTypeAsString() {
  switch (GetMessageType()) {
    case MESSAGE_INVALID:
      return "MESSAGE_INVALID";
    case MESSAGE_METHOD_CALL:
      return "MESSAGE_METHOD_CALL";
    case MESSAGE_METHOD_RETURN:
      return "MESSAGE_METHOD_RETURN";
    case MESSAGE_SIGNAL:
      return "MESSAGE_SIGNAL";
    case MESSAGE_ERROR:
      return "MESSAGE_ERROR";
  }
  NOTREACHED();
  return std::string();
}

std::string Message::ToStringInternal(const std::string& indent,
                                      MessageReader* reader) {
  const char* kBrokenMessage = "[broken message]";
  std::string output;
  while (reader->HasMoreData()) {
    const DataType type = reader->GetDataType();
    switch (type) {
      case BYTE: {
        uint8 value = 0;
        if (!reader->PopByte(&value))
          return kBrokenMessage;
        output += indent + "byte " + base::StringPrintf("%d", value) + "\n";
        break;
      }
      case BOOL: {
        bool value = false;
        if (!reader->PopBool(&value))
          return kBrokenMessage;
        output += indent + "bool " + (value ? "true" : "false") + "\n";
        break;
      }
      case INT16: {
        int16 value = 0;
        if (!reader->PopInt16(&value))
          return kBrokenMessage;
        output += indent + "int16 " + base::StringPrintf("%d", value) + "\n";
        break;
      }
      case UINT16: {
        uint16 value = 0;
        if (!reader->PopUint16(&value))
          return kBrokenMessage;
        output += indent + "uint16 " + base::StringPrintf("%d", value) + "\n";
        break;
      }
      case INT32: {
        int32 value = 0;
        if (!reader->PopInt32(&value))
          return kBrokenMessage;
        output += indent + "int32 " + base::StringPrintf("%d", value) + "\n";
        break;
      }
      case UINT32: {
        uint32 value = 0;
        if (!reader->PopUint32(&value))
          return kBrokenMessage;
        output += indent + "uint32 " + base::StringPrintf("%u", value) + "\n";
        break;
      }
      case INT64: {
        int64 value = 0;
        if (!reader->PopInt64(&value))
          return kBrokenMessage;
        output += (indent + "int64 " +
                   base::StringPrintf("%" PRId64, value) + "\n");
        break;
      }
      case UINT64: {
        uint64 value = 0;
        if (!reader->PopUint64(&value))
          return kBrokenMessage;
        output += (indent + "uint64 " +
                   base::StringPrintf("%" PRIu64, value) + "\n");
        break;
      }
      case DOUBLE: {
        double value = 0;
        if (!reader->PopDouble(&value))
          return kBrokenMessage;
        output += indent + "double " + base::StringPrintf("%f", value) + "\n";
        break;
      }
      case STRING: {
        std::string value;
        if (!reader->PopString(&value))
          return kBrokenMessage;
        // Truncate if the string is longer than the limit.
        const size_t kTruncateLength = 100;
        if (value.size() < kTruncateLength) {
          output += indent + "string \"" + value + "\"\n";
        } else {
          std::string truncated;
          base::TruncateUTF8ToByteSize(value, kTruncateLength, &truncated);
          base::StringAppendF(&truncated, "... (%" PRIuS " bytes in total)",
                              value.size());
          output += indent + "string \"" + truncated + "\"\n";
        }
        break;
      }
      case OBJECT_PATH: {
        ObjectPath value;
        if (!reader->PopObjectPath(&value))
          return kBrokenMessage;
        output += indent + "object_path \"" + value.value() + "\"\n";
        break;
      }
      case ARRAY: {
        MessageReader sub_reader(this);
        if (!reader->PopArray(&sub_reader))
          return kBrokenMessage;
        output += indent + "array [\n";
        output += ToStringInternal(indent + "  ", &sub_reader);
        output += indent + "]\n";
        break;
      }
      case STRUCT: {
        MessageReader sub_reader(this);
        if (!reader->PopStruct(&sub_reader))
          return kBrokenMessage;
        output += indent + "struct {\n";
        output += ToStringInternal(indent + "  ", &sub_reader);
        output += indent + "}\n";
        break;
      }
      case DICT_ENTRY: {
        MessageReader sub_reader(this);
        if (!reader->PopDictEntry(&sub_reader))
          return kBrokenMessage;
        output += indent + "dict entry {\n";
        output += ToStringInternal(indent + "  ", &sub_reader);
        output += indent + "}\n";
        break;
      }
      case VARIANT: {
        MessageReader sub_reader(this);
        if (!reader->PopVariant(&sub_reader))
          return kBrokenMessage;
        output += indent + "variant ";
        output += ToStringInternal(indent + "  ", &sub_reader);
        break;
      }
      case UNIX_FD: {
        CHECK(IsDBusTypeUnixFdSupported());

        FileDescriptor file_descriptor;
        if (!reader->PopFileDescriptor(&file_descriptor))
          return kBrokenMessage;
        output += indent + "fd#" +
                  base::StringPrintf("%d", file_descriptor.value()) + "\n";
        break;
      }
      default:
        LOG(FATAL) << "Unknown type: " << type;
    }
  }
  return output;
}

// The returned string consists of message headers such as
// destination if any, followed by a blank line, and the message
// payload. For example, a MethodCall's ToString() will look like:
//
// destination: com.example.Service
// path: /com/example/Object
// interface: com.example.Interface
// member: SomeMethod
//
// string \"payload\"
// ...
std::string Message::ToString() {
  if (!raw_message_)
    return std::string();

  // Generate headers first.
  std::string headers;
  AppendStringHeader("message_type", GetMessageTypeAsString(), &headers);
  AppendStringHeader("destination", GetDestination(), &headers);
  AppendStringHeader("path", GetPath().value(), &headers);
  AppendStringHeader("interface", GetInterface(), &headers);
  AppendStringHeader("member", GetMember(), &headers);
  AppendStringHeader("error_name", GetErrorName(), &headers);
  AppendStringHeader("sender", GetSender(), &headers);
  AppendStringHeader("signature", GetSignature(), &headers);
  AppendUint32Header("serial", GetSerial(), &headers);
  AppendUint32Header("reply_serial", GetReplySerial(), &headers);

  // Generate the payload.
  MessageReader reader(this);
  return headers + "\n" + ToStringInternal(std::string(), &reader);
}

bool Message::SetDestination(const std::string& destination) {
  return dbus_message_set_destination(raw_message_, destination.c_str());
}

bool Message::SetPath(const ObjectPath& path) {
  return dbus_message_set_path(raw_message_, path.value().c_str());
}

bool Message::SetInterface(const std::string& interface) {
  return dbus_message_set_interface(raw_message_, interface.c_str());
}

bool Message::SetMember(const std::string& member) {
  return dbus_message_set_member(raw_message_, member.c_str());
}

bool Message::SetErrorName(const std::string& error_name) {
  return dbus_message_set_error_name(raw_message_, error_name.c_str());
}

bool Message::SetSender(const std::string& sender) {
  return dbus_message_set_sender(raw_message_, sender.c_str());
}

void Message::SetSerial(uint32 serial) {
  dbus_message_set_serial(raw_message_, serial);
}

void Message::SetReplySerial(uint32 reply_serial) {
  dbus_message_set_reply_serial(raw_message_, reply_serial);
}

std::string Message::GetDestination() {
  const char* destination = dbus_message_get_destination(raw_message_);
  return destination ? destination : "";
}

ObjectPath Message::GetPath() {
  const char* path = dbus_message_get_path(raw_message_);
  return ObjectPath(path ? path : "");
}

std::string Message::GetInterface() {
  const char* interface = dbus_message_get_interface(raw_message_);
  return interface ? interface : "";
}

std::string Message::GetMember() {
  const char* member = dbus_message_get_member(raw_message_);
  return member ? member : "";
}

std::string Message::GetErrorName() {
  const char* error_name = dbus_message_get_error_name(raw_message_);
  return error_name ? error_name : "";
}

std::string Message::GetSender() {
  const char* sender = dbus_message_get_sender(raw_message_);
  return sender ? sender : "";
}

std::string Message::GetSignature() {
  const char* signature = dbus_message_get_signature(raw_message_);
  return signature ? signature : "";
}

uint32 Message::GetSerial() {
  return dbus_message_get_serial(raw_message_);
}

uint32 Message::GetReplySerial() {
  return dbus_message_get_reply_serial(raw_message_);
}

//
// MethodCall implementation.
//

MethodCall::MethodCall(const std::string& interface_name,
                       const std::string& method_name)
    : Message() {
  Init(dbus_message_new(DBUS_MESSAGE_TYPE_METHOD_CALL));

  CHECK(SetInterface(interface_name));
  CHECK(SetMember(method_name));
}

MethodCall::MethodCall() : Message() {
}

MethodCall* MethodCall::FromRawMessage(DBusMessage* raw_message) {
  DCHECK_EQ(DBUS_MESSAGE_TYPE_METHOD_CALL, dbus_message_get_type(raw_message));

  MethodCall* method_call = new MethodCall;
  method_call->Init(raw_message);
  return method_call;
}

//
// Signal implementation.
//
Signal::Signal(const std::string& interface_name,
               const std::string& method_name)
    : Message() {
  Init(dbus_message_new(DBUS_MESSAGE_TYPE_SIGNAL));

  CHECK(SetInterface(interface_name));
  CHECK(SetMember(method_name));
}

Signal::Signal() : Message() {
}

Signal* Signal::FromRawMessage(DBusMessage* raw_message) {
  DCHECK_EQ(DBUS_MESSAGE_TYPE_SIGNAL, dbus_message_get_type(raw_message));

  Signal* signal = new Signal;
  signal->Init(raw_message);
  return signal;
}

//
// Response implementation.
//

Response::Response() : Message() {
}

scoped_ptr<Response> Response::FromRawMessage(DBusMessage* raw_message) {
  DCHECK_EQ(DBUS_MESSAGE_TYPE_METHOD_RETURN,
            dbus_message_get_type(raw_message));

  scoped_ptr<Response> response(new Response);
  response->Init(raw_message);
  return response.Pass();
}

scoped_ptr<Response> Response::FromMethodCall(MethodCall* method_call) {
  scoped_ptr<Response> response(new Response);
  response->Init(dbus_message_new_method_return(method_call->raw_message()));
  return response.Pass();
}

scoped_ptr<Response> Response::CreateEmpty() {
  scoped_ptr<Response> response(new Response);
  response->Init(dbus_message_new(DBUS_MESSAGE_TYPE_METHOD_RETURN));
  return response.Pass();
}

//
// ErrorResponse implementation.
//

ErrorResponse::ErrorResponse() : Response() {
}

scoped_ptr<ErrorResponse> ErrorResponse::FromRawMessage(
    DBusMessage* raw_message) {
  DCHECK_EQ(DBUS_MESSAGE_TYPE_ERROR, dbus_message_get_type(raw_message));

  scoped_ptr<ErrorResponse> response(new ErrorResponse);
  response->Init(raw_message);
  return response.Pass();
}

scoped_ptr<ErrorResponse> ErrorResponse::FromMethodCall(
    MethodCall* method_call,
    const std::string& error_name,
    const std::string& error_message) {
  scoped_ptr<ErrorResponse> response(new ErrorResponse);
  response->Init(dbus_message_new_error(method_call->raw_message(),
                                        error_name.c_str(),
                                        error_message.c_str()));
  return response.Pass();
}

//
// MessageWriter implementation.
//

MessageWriter::MessageWriter(Message* message)
    : message_(message),
      container_is_open_(false) {
  memset(&raw_message_iter_, 0, sizeof(raw_message_iter_));
  if (message)
    dbus_message_iter_init_append(message_->raw_message(), &raw_message_iter_);
}

MessageWriter::~MessageWriter() {
}

void MessageWriter::AppendByte(uint8 value) {
  AppendBasic(DBUS_TYPE_BYTE, &value);
}

void MessageWriter::AppendBool(bool value) {
  // The size of dbus_bool_t and the size of bool are different. The
  // former is always 4 per dbus-types.h, whereas the latter is usually 1.
  // dbus_message_iter_append_basic() used in AppendBasic() expects four
  // bytes for DBUS_TYPE_BOOLEAN, so we must pass a dbus_bool_t, instead
  // of a bool, to AppendBasic().
  dbus_bool_t dbus_value = value;
  AppendBasic(DBUS_TYPE_BOOLEAN, &dbus_value);
}

void MessageWriter::AppendInt16(int16 value) {
  AppendBasic(DBUS_TYPE_INT16, &value);
}

void MessageWriter::AppendUint16(uint16 value) {
  AppendBasic(DBUS_TYPE_UINT16, &value);
}

void MessageWriter::AppendInt32(int32 value) {
  AppendBasic(DBUS_TYPE_INT32, &value);
}

void MessageWriter::AppendUint32(uint32 value) {
  AppendBasic(DBUS_TYPE_UINT32, &value);
}

void MessageWriter::AppendInt64(int64 value) {
  AppendBasic(DBUS_TYPE_INT64, &value);
}

void MessageWriter::AppendUint64(uint64 value) {
  AppendBasic(DBUS_TYPE_UINT64, &value);
}

void MessageWriter::AppendDouble(double value) {
  AppendBasic(DBUS_TYPE_DOUBLE, &value);
}

void MessageWriter::AppendString(const std::string& value) {
  // D-Bus Specification (0.19) says a string "must be valid UTF-8".
  CHECK(IsStringUTF8(value));
  const char* pointer = value.c_str();
  AppendBasic(DBUS_TYPE_STRING, &pointer);
  // TODO(satorux): It may make sense to return an error here, as the
  // input string can be large. If needed, we could add something like
  // bool AppendStringWithErrorChecking().
}

void MessageWriter::AppendObjectPath(const ObjectPath& value) {
  CHECK(value.IsValid());
  const char* pointer = value.value().c_str();
  AppendBasic(DBUS_TYPE_OBJECT_PATH, &pointer);
}

// Ideally, client shouldn't need to supply the signature string, but
// the underlying D-Bus library requires us to supply this before
// appending contents to array and variant. It's technically possible
// for us to design API that doesn't require the signature but it will
// complicate the implementation so we decided to have the signature
// parameter. Hopefully, variants are less used in request messages from
// client side than response message from server side, so this should
// not be a big issue.
void MessageWriter::OpenArray(const std::string& signature,
                              MessageWriter* writer) {
  DCHECK(!container_is_open_);

  const bool success = dbus_message_iter_open_container(
      &raw_message_iter_,
      DBUS_TYPE_ARRAY,
      signature.c_str(),
      &writer->raw_message_iter_);
  CHECK(success) << "Unable to allocate memory";
  container_is_open_ = true;
}

void MessageWriter::OpenVariant(const std::string& signature,
                                MessageWriter* writer) {
  DCHECK(!container_is_open_);

  const bool success = dbus_message_iter_open_container(
      &raw_message_iter_,
      DBUS_TYPE_VARIANT,
      signature.c_str(),
      &writer->raw_message_iter_);
  CHECK(success) << "Unable to allocate memory";
  container_is_open_ = true;
}

void MessageWriter::OpenStruct(MessageWriter* writer) {
  DCHECK(!container_is_open_);

  const bool success = dbus_message_iter_open_container(
      &raw_message_iter_,
      DBUS_TYPE_STRUCT,
      NULL,  // Signature should be NULL.
      &writer->raw_message_iter_);
  CHECK(success) << "Unable to allocate memory";
  container_is_open_ = true;
}

void MessageWriter::OpenDictEntry(MessageWriter* writer) {
  DCHECK(!container_is_open_);

  const bool success = dbus_message_iter_open_container(
      &raw_message_iter_,
      DBUS_TYPE_DICT_ENTRY,
      NULL,  // Signature should be NULL.
      &writer->raw_message_iter_);
  CHECK(success) << "Unable to allocate memory";
  container_is_open_ = true;
}

void MessageWriter::CloseContainer(MessageWriter* writer) {
  DCHECK(container_is_open_);

  const bool success = dbus_message_iter_close_container(
      &raw_message_iter_, &writer->raw_message_iter_);
  CHECK(success) << "Unable to allocate memory";
  container_is_open_ = false;
}

void MessageWriter::AppendArrayOfBytes(const uint8* values, size_t length) {
  DCHECK(!container_is_open_);
  MessageWriter array_writer(message_);
  OpenArray("y", &array_writer);
  const bool success = dbus_message_iter_append_fixed_array(
      &(array_writer.raw_message_iter_),
      DBUS_TYPE_BYTE,
      &values,
      static_cast<int>(length));
  CHECK(success) << "Unable to allocate memory";
  CloseContainer(&array_writer);
}

void MessageWriter::AppendArrayOfStrings(
    const std::vector<std::string>& strings) {
  DCHECK(!container_is_open_);
  MessageWriter array_writer(message_);
  OpenArray("s", &array_writer);
  for (size_t i = 0; i < strings.size(); ++i) {
    array_writer.AppendString(strings[i]);
  }
  CloseContainer(&array_writer);
}

void MessageWriter::AppendArrayOfObjectPaths(
    const std::vector<ObjectPath>& object_paths) {
  DCHECK(!container_is_open_);
  MessageWriter array_writer(message_);
  OpenArray("o", &array_writer);
  for (size_t i = 0; i < object_paths.size(); ++i) {
    array_writer.AppendObjectPath(object_paths[i]);
  }
  CloseContainer(&array_writer);
}

bool MessageWriter::AppendProtoAsArrayOfBytes(
    const google::protobuf::MessageLite& protobuf) {
  std::string serialized_proto;
  if (!protobuf.SerializeToString(&serialized_proto)) {
    LOG(ERROR) << "Unable to serialize supplied protocol buffer";
    return false;
  }
  AppendArrayOfBytes(reinterpret_cast<const uint8*>(serialized_proto.data()),
                     serialized_proto.size());
  return true;
}

void MessageWriter::AppendVariantOfByte(uint8 value) {
  AppendVariantOfBasic(DBUS_TYPE_BYTE, &value);
}

void MessageWriter::AppendVariantOfBool(bool value) {
  // See the comment at MessageWriter::AppendBool().
  dbus_bool_t dbus_value = value;
  AppendVariantOfBasic(DBUS_TYPE_BOOLEAN, &dbus_value);
}

void MessageWriter::AppendVariantOfInt16(int16 value) {
  AppendVariantOfBasic(DBUS_TYPE_INT16, &value);
}

void MessageWriter::AppendVariantOfUint16(uint16 value) {
  AppendVariantOfBasic(DBUS_TYPE_UINT16, &value);
}

void MessageWriter::AppendVariantOfInt32(int32 value) {
  AppendVariantOfBasic(DBUS_TYPE_INT32, &value);
}

void MessageWriter::AppendVariantOfUint32(uint32 value) {
  AppendVariantOfBasic(DBUS_TYPE_UINT32, &value);
}

void MessageWriter::AppendVariantOfInt64(int64 value) {
  AppendVariantOfBasic(DBUS_TYPE_INT64, &value);
}

void MessageWriter::AppendVariantOfUint64(uint64 value) {
  AppendVariantOfBasic(DBUS_TYPE_UINT64, &value);
}

void MessageWriter::AppendVariantOfDouble(double value) {
  AppendVariantOfBasic(DBUS_TYPE_DOUBLE, &value);
}

void MessageWriter::AppendVariantOfString(const std::string& value) {
  const char* pointer = value.c_str();
  AppendVariantOfBasic(DBUS_TYPE_STRING, &pointer);
}

void MessageWriter::AppendVariantOfObjectPath(const ObjectPath& value) {
  const char* pointer = value.value().c_str();
  AppendVariantOfBasic(DBUS_TYPE_OBJECT_PATH, &pointer);
}

void MessageWriter::AppendBasic(int dbus_type, const void* value) {
  DCHECK(!container_is_open_);

  const bool success = dbus_message_iter_append_basic(
      &raw_message_iter_, dbus_type, value);
  // dbus_message_iter_append_basic() fails only when there is not enough
  // memory. We don't return this error as there is nothing we can do when
  // it fails to allocate memory for a byte etc.
  CHECK(success) << "Unable to allocate memory";
}

void MessageWriter::AppendVariantOfBasic(int dbus_type, const void* value) {
  const std::string signature = base::StringPrintf("%c", dbus_type);
  MessageWriter variant_writer(message_);
  OpenVariant(signature, &variant_writer);
  variant_writer.AppendBasic(dbus_type, value);
  CloseContainer(&variant_writer);
}

void MessageWriter::AppendFileDescriptor(const FileDescriptor& value) {
  CHECK(IsDBusTypeUnixFdSupported());

  if (!value.is_valid()) {
    // NB: sending a directory potentially enables sandbox escape
    LOG(FATAL) << "Attempt to pass invalid file descriptor";
  }
  int fd = value.value();
  AppendBasic(DBUS_TYPE_UNIX_FD, &fd);
}

//
// MessageReader implementation.
//

MessageReader::MessageReader(Message* message)
    : message_(message) {
  memset(&raw_message_iter_, 0, sizeof(raw_message_iter_));
  if (message)
    dbus_message_iter_init(message_->raw_message(), &raw_message_iter_);
}


MessageReader::~MessageReader() {
}

bool MessageReader::HasMoreData() {
  const int dbus_type = dbus_message_iter_get_arg_type(&raw_message_iter_);
  return dbus_type != DBUS_TYPE_INVALID;
}

bool MessageReader::PopByte(uint8* value) {
  return PopBasic(DBUS_TYPE_BYTE, value);
}

bool MessageReader::PopBool(bool* value) {
  // Like MessageWriter::AppendBool(), we should copy |value| to
  // dbus_bool_t, as dbus_message_iter_get_basic() used in PopBasic()
  // expects four bytes for DBUS_TYPE_BOOLEAN.
  dbus_bool_t dbus_value = FALSE;
  const bool success = PopBasic(DBUS_TYPE_BOOLEAN, &dbus_value);
  *value = static_cast<bool>(dbus_value);
  return success;
}

bool MessageReader::PopInt16(int16* value) {
  return PopBasic(DBUS_TYPE_INT16, value);
}

bool MessageReader::PopUint16(uint16* value) {
  return PopBasic(DBUS_TYPE_UINT16, value);
}

bool MessageReader::PopInt32(int32* value) {
  return PopBasic(DBUS_TYPE_INT32, value);
}

bool MessageReader::PopUint32(uint32* value) {
  return PopBasic(DBUS_TYPE_UINT32, value);
}

bool MessageReader::PopInt64(int64* value) {
  return PopBasic(DBUS_TYPE_INT64, value);
}

bool MessageReader::PopUint64(uint64* value) {
  return PopBasic(DBUS_TYPE_UINT64, value);
}

bool MessageReader::PopDouble(double* value) {
  return PopBasic(DBUS_TYPE_DOUBLE, value);
}

bool MessageReader::PopString(std::string* value) {
  char* tmp_value = NULL;
  const bool success = PopBasic(DBUS_TYPE_STRING, &tmp_value);
  if (success)
    value->assign(tmp_value);
  return success;
}

bool MessageReader::PopObjectPath(ObjectPath* value) {
  char* tmp_value = NULL;
  const bool success = PopBasic(DBUS_TYPE_OBJECT_PATH, &tmp_value);
  if (success)
    *value = ObjectPath(tmp_value);
  return success;
}

bool MessageReader::PopArray(MessageReader* sub_reader) {
  return PopContainer(DBUS_TYPE_ARRAY, sub_reader);
}

bool MessageReader::PopStruct(MessageReader* sub_reader) {
  return PopContainer(DBUS_TYPE_STRUCT, sub_reader);
}

bool MessageReader::PopDictEntry(MessageReader* sub_reader) {
  return PopContainer(DBUS_TYPE_DICT_ENTRY, sub_reader);
}

bool MessageReader::PopVariant(MessageReader* sub_reader) {
  return PopContainer(DBUS_TYPE_VARIANT, sub_reader);
}

bool MessageReader::PopArrayOfBytes(const uint8** bytes, size_t* length) {
  MessageReader array_reader(message_);
  if (!PopArray(&array_reader))
      return false;
  // An empty array is allowed.
  if (!array_reader.HasMoreData()) {
    *length = 0;
    *bytes = NULL;
    return true;
  }
  if (!array_reader.CheckDataType(DBUS_TYPE_BYTE))
    return false;
  int int_length = 0;
  dbus_message_iter_get_fixed_array(&array_reader.raw_message_iter_,
                                    bytes,
                                    &int_length);
  *length = static_cast<int>(int_length);
  return true;
}

bool MessageReader::PopArrayOfStrings(
    std::vector<std::string> *strings) {
  strings->clear();
  MessageReader array_reader(message_);
  if (!PopArray(&array_reader))
    return false;
  while (array_reader.HasMoreData()) {
    std::string string;
    if (!array_reader.PopString(&string))
      return false;
    strings->push_back(string);
  }
  return true;
}

bool MessageReader::PopArrayOfObjectPaths(
    std::vector<ObjectPath> *object_paths) {
  object_paths->clear();
  MessageReader array_reader(message_);
  if (!PopArray(&array_reader))
    return false;
  while (array_reader.HasMoreData()) {
    ObjectPath object_path;
    if (!array_reader.PopObjectPath(&object_path))
      return false;
    object_paths->push_back(object_path);
  }
  return true;
}

bool MessageReader::PopArrayOfBytesAsProto(
    google::protobuf::MessageLite* protobuf) {
  DCHECK(protobuf != NULL);
  const char* serialized_buf = NULL;
  size_t buf_size = 0;
  if (!PopArrayOfBytes(
          reinterpret_cast<const uint8**>(&serialized_buf), &buf_size)) {
    LOG(ERROR) << "Error reading array of bytes";
    return false;
  }
  if (!protobuf->ParseFromArray(serialized_buf, buf_size)) {
    LOG(ERROR) << "Failed to parse protocol buffer from array";
    return false;
  }
  return true;
}

bool MessageReader::PopVariantOfByte(uint8* value) {
  return PopVariantOfBasic(DBUS_TYPE_BYTE, value);
}

bool MessageReader::PopVariantOfBool(bool* value) {
  // See the comment at MessageReader::PopBool().
  dbus_bool_t dbus_value = FALSE;
  const bool success = PopVariantOfBasic(DBUS_TYPE_BOOLEAN, &dbus_value);
  *value = static_cast<bool>(dbus_value);
  return success;
}

bool MessageReader::PopVariantOfInt16(int16* value) {
  return PopVariantOfBasic(DBUS_TYPE_INT16, value);
}

bool MessageReader::PopVariantOfUint16(uint16* value) {
  return PopVariantOfBasic(DBUS_TYPE_UINT16, value);
}

bool MessageReader::PopVariantOfInt32(int32* value) {
  return PopVariantOfBasic(DBUS_TYPE_INT32, value);
}

bool MessageReader::PopVariantOfUint32(uint32* value) {
  return PopVariantOfBasic(DBUS_TYPE_UINT32, value);
}

bool MessageReader::PopVariantOfInt64(int64* value) {
  return PopVariantOfBasic(DBUS_TYPE_INT64, value);
}

bool MessageReader::PopVariantOfUint64(uint64* value) {
  return PopVariantOfBasic(DBUS_TYPE_UINT64, value);
}

bool MessageReader::PopVariantOfDouble(double* value) {
  return PopVariantOfBasic(DBUS_TYPE_DOUBLE, value);
}

bool MessageReader::PopVariantOfString(std::string* value) {
  char* tmp_value = NULL;
  const bool success = PopVariantOfBasic(DBUS_TYPE_STRING, &tmp_value);
  if (success)
    value->assign(tmp_value);
  return success;
}

bool MessageReader::PopVariantOfObjectPath(ObjectPath* value) {
  char* tmp_value = NULL;
  const bool success = PopVariantOfBasic(DBUS_TYPE_OBJECT_PATH, &tmp_value);
  if (success)
    *value = ObjectPath(tmp_value);
  return success;
}

Message::DataType MessageReader::GetDataType() {
  const int dbus_type = dbus_message_iter_get_arg_type(&raw_message_iter_);
  return static_cast<Message::DataType>(dbus_type);
}

bool MessageReader::CheckDataType(int dbus_type) {
  const int actual_type = dbus_message_iter_get_arg_type(&raw_message_iter_);
  if (actual_type != dbus_type) {
    VLOG(1) << "Type " << dbus_type  << " is expected but got "
            << actual_type;
    return false;
  }
  return true;
}

bool MessageReader::PopBasic(int dbus_type, void* value) {
  if (!CheckDataType(dbus_type))
    return false;
  // dbus_message_iter_get_basic() here should always work, as we have
  // already checked the next item's data type in CheckDataType(). Note
  // that dbus_message_iter_get_basic() is a void function.
  dbus_message_iter_get_basic(&raw_message_iter_, value);
  DCHECK(value);
  dbus_message_iter_next(&raw_message_iter_);
  return true;
}

bool MessageReader::PopContainer(int dbus_type, MessageReader* sub_reader) {
  DCHECK_NE(this, sub_reader);

  if (!CheckDataType(dbus_type))
    return false;
  dbus_message_iter_recurse(&raw_message_iter_,
                            &sub_reader->raw_message_iter_);
  dbus_message_iter_next(&raw_message_iter_);
  return true;
}

bool MessageReader::PopVariantOfBasic(int dbus_type, void* value) {
  MessageReader variant_reader(message_);
  if (!PopVariant(&variant_reader))
    return false;
  return variant_reader.PopBasic(dbus_type, value);
}

bool MessageReader::PopFileDescriptor(FileDescriptor* value) {
  CHECK(IsDBusTypeUnixFdSupported());

  int fd = -1;
  const bool success = PopBasic(DBUS_TYPE_UNIX_FD, &fd);
  if (!success)
    return false;

  value->PutValue(fd);
  // NB: the caller must check validity before using the value
  return true;
}

}  // namespace dbus