Rationalize Dart mojo and sky package structure

mojo/public/dart/src/message.dart

-// Copyright 2014 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.
-
-part of bindings;
-
-class MessageHeader {
-  static const int kSimpleMessageSize = 16;
-  static const int kSimpleMessageVersion = 0;
-  static const int kMessageWithRequestIdSize = 24;
-  static const int kMessageWithRequestIdVersion = 1;
-  static const int kMessageTypeOffset = StructDataHeader.kHeaderSize;
-  static const int kMessageFlagsOffset = kMessageTypeOffset + 4;
-  static const int kMessageRequestIdOffset = kMessageFlagsOffset + 4;
-  static const int kMessageExpectsResponse = 1 << 0;
-  static const int kMessageIsResponse = 1 << 1;
-
-  StructDataHeader _header;
-  int type;
-  int flags;
-  int requestId;
-
-  static bool mustHaveRequestId(int flags) =>
-      (flags & (kMessageExpectsResponse | kMessageIsResponse)) != 0;
-
-  MessageHeader(this.type)
-      : _header = new StructDataHeader(
-          kSimpleMessageSize, kSimpleMessageVersion),
-        flags = 0,
-        requestId = 0;
-
-  MessageHeader.withRequestId(this.type, this.flags, this.requestId)
-      : _header = new StructDataHeader(
-          kMessageWithRequestIdSize, kMessageWithRequestIdVersion);
-
-  MessageHeader.fromMessage(Message message) {
-    var decoder = new Decoder(message);
-    _header = decoder.decodeStructDataHeader();
-    if (_header.size < kSimpleMessageSize) {
-      throw new MojoCodecError('Incorrect message size. Got: ${_header.size} '
-          'wanted $kSimpleMessageSize');
-    }
-    type = decoder.decodeUint32(kMessageTypeOffset);
-    flags = decoder.decodeUint32(kMessageFlagsOffset);
-    if (mustHaveRequestId(flags)) {
-      if (_header.size < kMessageWithRequestIdSize) {
-        throw new MojoCodecError('Incorrect message size. Got: ${_header.size} '
-            'wanted $kMessageWithRequestIdSize');
-      }
-      requestId = decoder.decodeUint64(kMessageRequestIdOffset);
-    } else {
-      requestId = 0;
-    }
-  }
-
-  int get size => _header.size;
-  bool get hasRequestId => mustHaveRequestId(flags);
-
-  void encode(Encoder encoder) {
-    encoder.encodeStructDataHeader(_header);
-    encoder.encodeUint32(type, kMessageTypeOffset);
-    encoder.encodeUint32(flags, kMessageFlagsOffset);
-    if (hasRequestId) {
-      encoder.encodeUint64(requestId, kMessageRequestIdOffset);
-    }
-  }
-
-  String toString() => "MessageHeader($_header, $type, $flags, $requestId)";
-
-  bool validateHeaderFlags(expectedFlags) =>
-      (flags & (kMessageExpectsResponse | kMessageIsResponse)) == expectedFlags;
-
-  bool validateHeader(int expectedType, int expectedFlags) =>
-      (type == expectedType) && validateHeaderFlags(expectedFlags);
-
-  static void _validateDataHeader(StructDataHeader dataHeader) {
-    if (dataHeader.version < kSimpleMessageVersion) {
-      throw 'Incorrect version, expecting at least '
-          '$kSimpleMessageVersion, but got: ${dataHeader.version}.';
-    }
-    if (dataHeader.size < kSimpleMessageSize) {
-      throw 'Incorrect message size, expecting at least $kSimpleMessageSize, '
-          'but got: ${dataHeader.size}';
-    }
-    if ((dataHeader.version == kSimpleMessageVersion) &&
-        (dataHeader.size != kSimpleMessageSize)) {
-      throw 'Incorrect message size for a message of version '
-          '$kSimpleMessageVersion, expecting $kSimpleMessageSize, '
-          'but got ${dataHeader.size}';
-    }
-    if ((dataHeader.version == kMessageWithRequestIdVersion) &&
-        (dataHeader.size != kMessageWithRequestIdSize)) {
-      throw 'Incorrect message size for a message of version '
-          '$kMessageWithRequestIdVersion, expecting '
-          '$kMessageWithRequestIdSize, but got ${dataHeader.size}';
-    }
-  }
-}
-
-class Message {
-  final ByteData buffer;
-  final List<core.MojoHandle> handles;
-  Message(this.buffer, this.handles);
-  String toString() =>
-      "Message(numBytes=${buffer.lengthInBytes}, numHandles=${handles.length})";
-}
-
-class ServiceMessage extends Message {
-  final MessageHeader header;
-  Message _payload;
-
-  ServiceMessage(Message message, this.header)
-      : super(message.buffer, message.handles);
-
-  ServiceMessage.fromMessage(Message message)
-      : this(message, new MessageHeader.fromMessage(message));
-
-  Message get payload {
-    if (_payload == null) {
-      var truncatedBuffer = new ByteData.view(buffer.buffer, header.size);
-      _payload = new Message(truncatedBuffer, handles);
-    }
-    return _payload;
-  }
-
-  String toString() => "ServiceMessage($header, $_payload)";
-}