Rename fletch -> dartino

pkg/fletchc/lib/src/shared_command_infrastructure.dart

-// Copyright (c) 2015, the Dartino project authors. Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE.md file.
-
-/// Provides common infrastructure for reading commads from a [Stream].
-///
-/// We have two independent command kinds that follow the same scheme:
-///
-///   1. ../vm_commands.dart
-///   2. hub/client_commands.dart
-///
-/// Both commands are serialized in this format (using little endian):
-///
-///   * Byte offset 0: one byte (code) which corresponds to an enum value.
-///   * Byte offset 1: four bytes payload length (unsigned int).
-///   * Byte offset 5: payload length bytes of payload.
-library fletchc.src.command_transformer_builder;
-
-import 'dart:async' show
-    EventSink,
-    StreamTransformer;
-
-import 'dart:convert' show
-    ASCII;
-
-import 'dart:io' show
-    BytesBuilder;
-
-import 'dart:typed_data' show
-    ByteData,
-    Endianness,
-    TypedData,
-    Uint32List,
-    Uint8List;
-
-const Endianness commandEndianness = Endianness.LITTLE_ENDIAN;
-
-/// 32 bit package length + 8 bit code is 5 bytes.
-const headerSize = 5;
-
-/// [C] is the command implementation class.
-abstract class CommandTransformerBuilder<C> {
-  StreamTransformer<List<int>, C> build() {
-    BytesBuilder builder = new BytesBuilder(copy: false);
-
-    ByteData toByteData(TypedData data, [int offset = 0, int length]) {
-      return data.buffer.asByteData(data.offsetInBytes + offset, length);
-    }
-
-    void handleData(Uint8List data, EventSink<C> sink) {
-      builder.add(toUint8ListView(data));
-      Uint8List list = builder.takeBytes();
-
-      ByteData view = toByteData(list);
-
-      while (view.lengthInBytes >= headerSize) {
-        int length = view.getUint32(0, commandEndianness);
-        if ((view.lengthInBytes - headerSize) < length) {
-          // Not all of the payload has arrived yet.
-          break;
-        }
-        int code = view.getUint8(4);
-
-        ByteData payload = toByteData(view, headerSize, length);
-
-        C command = makeCommand(code, payload);
-
-        if (command != null) {
-          sink.add(command);
-        } else {
-          sink.addError("Command not implemented yet: $code");
-        }
-
-        view = toByteData(payload, length);
-      }
-
-      if (view.lengthInBytes > 0) {
-        builder.add(toUint8ListView(view));
-      }
-    }
-
-    void handleError(error, StackTrace stackTrace, EventSink<C> sink) {
-      sink.addError(error, stackTrace);
-    }
-
-    void handleDone(EventSink<C> sink) {
-      List trailing = builder.takeBytes();
-      if (trailing.length != 0) {
-        sink.addError(
-            new StateError("Stream closed with trailing bytes : $trailing"));
-      }
-      sink.close();
-    }
-
-    return new StreamTransformer<List<int>, C>.fromHandlers(
-        handleData: handleData,
-        handleError: handleError,
-        handleDone: handleDone);
-  }
-
-  C makeCommand(int code, ByteData payload);
-}
-
-Uint8List toUint8ListView(TypedData list, [int offset = 0, int length]) {
-  if (length == null) {
-    length = list.lengthInBytes;
-  }
-  return new Uint8List.view(list.buffer, list.offsetInBytes + offset, length);
-}
-
-/// [E] is an enum.
-class CommandBuffer<E> {
-  int position = headerSize;
-
-  Uint8List list = new Uint8List(16);
-
-  ByteData view;
-
-  CommandBuffer() {
-    view = new ByteData.view(list.buffer, list.offsetInBytes);
-  }
-
-  void growBytes(int size) {
-    while (position + size >= list.length) {
-      list = new Uint8List(list.length * 2)
-          ..setRange(0, list.length, list);
-      view = new ByteData.view(list.buffer, list.offsetInBytes);
-    }
-  }
-
-  void addUint8(int value) {
-    growBytes(1);
-    view.setUint8(position++, value);
-  }
-
-  void addUint32(int value) {
-    // TODO(ahe): The C++ appears to often read 32-bit values into a signed
-    // integer. Figure which is signed and which is unsigned.
-    growBytes(4);
-    view.setUint32(position, value, commandEndianness);
-    position += 4;
-  }
-
-  void addUint64(int value) {
-    growBytes(8);
-    view.setUint64(position, value, commandEndianness);
-    position += 8;
-  }
-
-  void addDouble(double value) {
-    growBytes(8);
-    view.setFloat64(position, value, commandEndianness);
-    position += 8;
-  }
-
-  void addUint8List(List<int> value) {
-    growBytes(value.length);
-    list.setRange(position, position + value.length, value);
-    position += value.length;
-  }
-
-  void addAsciiString(String value) {
-    addUint8List(ASCII.encode(value));
-  }
-
-  void addBool(bool value) {
-    addUint8(value ? 1 : 0);
-  }
-
-  void sendOn(Sink<List<int>> sink, E code) {
-    view.setUint32(0, position - headerSize, commandEndianness);
-    view.setUint8(4, (code as dynamic).index);
-    sink.add(new Uint8List.view(list.buffer, list.offsetInBytes, position));
-  }
-
-  static bool readBoolFromBuffer(Uint8List buffer, int offset) {
-    return buffer[offset] != 0;
-  }
-
-  static String readStringFromBuffer(Uint8List buffer, int offset, int length) {
-    const bytesPerCharacter = 4;
-    int numberOfCharacters = length ~/ bytesPerCharacter;
-    assert(length == numberOfCharacters * bytesPerCharacter);
-    if (((buffer.offsetInBytes + offset) % Uint32List.BYTES_PER_ELEMENT) != 0) {
-      // Uint32List.view throws ArgumentError if offset isn't muliple of 4.
-      buffer = new Uint8List.fromList(buffer);
-    }
-    return new String.fromCharCodes(
-        new Uint32List.view(
-            buffer.buffer, buffer.offsetInBytes + offset, numberOfCharacters));
-  }
-
-  static String readAsciiStringFromBuffer(
-      Uint8List buffer, int offset, int length) {
-    return new String.fromCharCodes(
-        new Uint8List.view(
-            buffer.buffer, buffer.offsetInBytes + offset, length));
-  }
-
-  static int readInt32FromBuffer(Uint8List buffer, int offset) {
-    return buffer.buffer.asByteData(buffer.offsetInBytes)
-        .getInt32(offset, commandEndianness);
-  }
-
-  static int readInt64FromBuffer(Uint8List buffer, int offset) {
-    return buffer.buffer.asByteData(buffer.offsetInBytes)
-        .getInt64(offset, commandEndianness);
-  }
-
-  static double readDoubleFromBuffer(Uint8List buffer, int offset) {
-    {
-      // TODO(ahe): On ARM the Dart VM might crash when reading a double from
-      // an unaligned address. Remove this block when this bug is fixed:
-      // https://github.com/dart-lang/sdk/issues/23953
-      buffer = new Uint8List.fromList(
-          buffer.buffer.asUint8List(buffer.offsetInBytes + offset));
-      assert(buffer.offsetInBytes == 0);
-      offset = 0;
-    }
-    return buffer.buffer.asByteData(buffer.offsetInBytes)
-        .getFloat64(offset, commandEndianness);
-  }
-}