sdk/dart/fidl/lib/src/message.dart

// Copyright 2018 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import 'dart:typed_data';

import 'package:zircon/zircon.dart';

// ignore_for_file: public_member_api_docs

const int kMessageHeaderSize = 16;
const int kMessageTxidOffset = 0;
const int kMessageFlagOffset = 4;
const int kMessageMagicOffset = 7;
const int kMessageOrdinalOffset = 8;

const int kMagicNumberInitial = 1;

class Message {
  Message(this.data, this.handles);
  Message.fromReadResult(ReadResult result)
      : data = result.bytes,
        handles = result.handles,
        assert(result.status == ZX.OK);

  final ByteData data;
  final List<Handle> handles;

  int get txid => data.getUint32(kMessageTxidOffset, Endian.little);
  set txid(int value) =>
      data.setUint32(kMessageTxidOffset, value, Endian.little);

  int get ordinal => data.getUint64(kMessageOrdinalOffset, Endian.little);
  int get magic => data.getUint8(kMessageMagicOffset);

  bool isCompatible() => magic == kMagicNumberInitial;

  void hexDump() {
    const int width = 16;
    Uint8List list = Uint8List.view(data.buffer, 0);
    StringBuffer buffer = StringBuffer();
    final RegExp isPrintable = RegExp(r'\w');
    for (int i = 0; i < data.lengthInBytes; i += width) {
      StringBuffer hex = StringBuffer();
      StringBuffer printable = StringBuffer();
      for (int j = 0; j < width && i + j < data.lengthInBytes; j++) {
        int v = list[i + j];
        String s = v.toRadixString(16);
        if (s.length == 1)
          hex.write('0$s ');
        else
          hex.write('$s ');

        s = String.fromCharCode(v);
        if (isPrintable.hasMatch(s)) {
          printable.write(s);
        } else {
          printable.write('.');
        }
      }
      buffer.write('${hex.toString().padRight(3 * width)} $printable\n');
    }

    print('==================================================\n'
        '$buffer'
        '==================================================');
  }

  void closeHandles() {
    if (handles != null) {
      for (int i = 0; i < handles.length; ++i) {
        handles[i].close();
      }
    }
  }

  @override
  String toString() {
    return 'Message(numBytes=${data.lengthInBytes}, numHandles=${handles.length})';
  }
}

typedef MessageSink = void Function(Message message);