Update the streams interfaces

runtime/bin/string_stream.dart

+// Copyright (c) 2011, the Dart 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 file.
+
+// Utility class which can deliver bytes one by one from a number of
+// buffers added.
+class _BufferList {
+  _BufferList() : _index = 0, _length = 0, _buffers = new Queue();
+
+  void add(List<int> buffer) {
+    _buffers.addLast(buffer);
+    _length += buffer.length;
+  }
+
+  int peek() {
+    return _buffers.first()[_index];
+  }
+
+  int next() {
+    int value = _buffers.first()[_index++];
+    _length--;
+    if (_index == _buffers.first().length) {
+      _buffers.removeFirst();
+      _index = 0;
+    }
+    return value;
+  }
+
+  int get length() => _length;
+
+  int _length;
+  Queue<List<int>> _buffers;
+  int _index;
+}
+
+
+// Interface for decoders decoding binary data into objects of type T.
+interface _Decoder<T> {
+  // Add more binary data to be decoded. The ownership of the buffer
+  // is transfered to the decoder and the caller most not modify it any more.
+  int write(List<int> buffer);
+
+  // Returns whether any decoded data is available.
+  bool isEmpty();
+
+  // Get the data decoded since the last call to decode.
+  T get decoded();
+}
+
+
+class DecoderException implements Exception {
+  const DecoderException([String this.message]);
+  String toString() => "DecoderException: $message";
+  final String message;
+}
+
+
+// Utility class for decoding UTF-8 from data delivered as a stream of
+// bytes.
+class _StringDecoderBase implements _Decoder<String> {
+  _StringDecoderBase()
+      : _bufferList = new _BufferList(),
+        _result = new StringBuffer();
+
+  // Add UTF-8 encoded data.
+  int write(List<int> buffer) {
+    _bufferList.add(buffer);
+    // Decode as many bytes into characters as possible.
+    while (_bufferList.length > 0) {
+      if (!_processNext()) {
+        break;
+      }
+    }
+    return buffer.length;
+  }
+
+  // Check if any characters have been decoded since the last call to decode.
+  bool isEmpty() {
+    return _result.isEmpty();
+  }
+
+  // Return the string decoded since the last call to decode.
+  String get decoded() {
+    if (isEmpty()) {
+      return null;
+    } else {
+      String result =  _result.toString();
+      _result = new StringBuffer();
+      return result;
+    }
+  }
+
+  abstract bool _processNext();
+
+  _BufferList _bufferList;
+  StringBuffer _result;
+}
+
+
+// Utility class for decoding ascii data delivered as a stream of
+// bytes.
+class _AsciiDecoder extends _StringDecoderBase {
+  // Process the next ascii encoded character.
+  bool _processNext() {
+    while (_bufferList.length > 0) {
+      int byte = _bufferList.next();
+      if (byte > 127) {
+        throw new DecoderException("Illegal ASCII character $byte");
+      }
+      _result.addCharCode(byte);
+    }
+    return true;
+  }
+}
+
+
+// Utility class for decoding Latin-1 data delivered as a stream of
+// bytes.
+class _Latin1Decoder extends _StringDecoderBase {
+  // Process the next Latin-1 encoded character.
+  bool _processNext() {
+    while (_bufferList.length > 0) {
+      int byte = _bufferList.next();
+      _result.addCharCode(byte);
+    }
+    return true;
+  }
+}
+
+
+// Utility class for decoding UTF-8 from data delivered as a stream of
+// bytes.
+class _UTF8Decoder extends _StringDecoderBase {
+  // Process the next UTF-8 encoded character.
+  bool _processNext() {
+    // Peek the next byte to calculate the number of bytes required for
+    // the next character.
+    int value = _bufferList.peek() & 0xFF;
+    if ((value & 0x80) == 0x80) {
+      int additionalBytes;
+      if ((value & 0xe0) == 0xc0) {  // 110xxxxx
+        value = value & 0x1F;
+        additionalBytes = 1;
+      } else if ((value & 0xf0) == 0xe0) {  // 1110xxxx
+        value = value & 0x0F;
+        additionalBytes = 2;
+      } else {  // 11110xxx
+        value = value & 0x07;
+        additionalBytes = 3;
+      }
+      // Check if there are enough bytes to decode the character. Otherwise
+      // return false.
+      if (_bufferList.length < additionalBytes + 1) {
+        return false;
+      }
+      // Remove the value peeked from the buffer list.
+      _bufferList.next();
+      for (int i = 0; i < additionalBytes; i++) {
+        int byte = _bufferList.next();
+        value = value << 6 | (byte & 0x3F);
+      }
+    } else {
+      // Remove the value peeked from the buffer list.
+      _bufferList.next();
+    }
+    _result.addCharCode(value);
+    return true;
+  }
+}
+
+
+class _StringInputStream implements StringInputStream {
+  _StringInputStream(InputStream this._input, [String this._encoding]) {
+    if (_encoding == null) {
+      _encoding = "UTF-8";
+    }
+    if (_encoding == "UTF-8") {
+      _decoder = new _UTF8Decoder();
+    } else if (_encoding == "ISO-8859-1") {
+      _decoder = new _Latin1Decoder();
+    } else if (_encoding == "ASCII") {
+      _decoder = new _AsciiDecoder();
+    } else {
+      throw new StreamException("Unsupported encoding $_encoding");
+    }
+    _input.dataHandler = _dataHandler;
+    _input.closeHandler = _closeHandler;
+  }
+
+  String read() {
+    // If there is buffered data return that first.
+    var decodedString = _decoder.decoded;
+    if (_buffer != null) {
+      var result = _buffer;
+      _resetBuffer();
+      if (decodedString != null) result += decodedString;
+      return result;
+    } else {
+      if (decodedString != null) {
+        return decodedString;
+      } else {
+        _readData();
+        return _decoder.decoded;
+      }
+    }
+  }
+
+  String readLine() {
+    // Get line from the buffer if possible.
+    if (_buffer != null) {
+      var result = _readLineFromBuffer();
+      if (result != null) return result;
+    }
+    // Try to fill more data into the buffer and read a line.
+    if (_fillBuffer()) {
+      if (_eof && _buffer == null) return null;
+      return _readLineFromBuffer();
+    }
+    return null;
+  }
+
+  String get encoding() => _encoding;
+
+  bool get closed() => _closed;
+
+  void set dataHandler(void callback()) {
+    _clientDataHandler = callback;
+  }
+
+  void set closeHandler(void callback()) {
+    _clientCloseHandler = callback;
+  }
+
+  void _dataHandler() {
+    _readData();
+    if (!_decoder.isEmpty() && _clientDataHandler != null) {
+      _clientDataHandler();
+    }
+  }
+
+  void _closeHandler() {
+    _closed = true;
+    if (_clientDataHandler != null) _clientDataHandler();
+    if (_clientCloseHandler != null) _clientCloseHandler();
+  }
+
+  void _readData() {
+    List<int> data = _input.read();
+    if (data != null) {
+      _decoder.write(data);
+    }
+  }
+
+  String _readLineFromBuffer() {
+    // Both \n or \r indicates a new line. If \r is followed by \n the
+    // \n is part of the line breaking character.
+    for (int i = _bufferLineStart; i < _buffer.length; i++) {
+      String char = _buffer[i];
+      if (char == '\r') {
+        if (i == _buffer.length - 1) {
+          if (_eof) {
+            var result = _buffer.substring(_bufferLineStart, i);
+            _resetBuffer();
+            return result;
+          } else {
+            return null;
+          }
+        }
+        var result = _buffer.substring(_bufferLineStart, i);
+        _bufferLineStart = i + 1;
+        if (_buffer[_bufferLineStart] == '\n') _bufferLineStart++;
+        return result;
+      } else if (char == '\n') {
+        var result = _buffer.substring(_bufferLineStart, i);
+        _bufferLineStart = i + 1;
+        return result;
+      }
+    }
+    if (_eof) {
+      var result = _buffer;
+      _resetBuffer();
+      return result;
+    }
+    return null;
+  }
+
+  void _resetBuffer() {
+    _buffer = null;
+    _bufferLineStart = null;
+  }
+
+  // Fill decoded data into the buffer. Returns true if more data was
+  // added or end of file was reached.
+  bool _fillBuffer() {
+    if (_eof) return false;
+    if (_buffer != null && _bufferLineStart == _buffer.length) {
+      _buffer = null;
+      _bufferLineStart = null;
+    }
+    _readData();
+    var decodedString = _decoder.decoded;
+    if (decodedString == null && _closed) {
+      _eof = true;
+      return true;
+    }
+    if (_buffer == null) {
+      _buffer = decodedString;
+      if (_buffer != null) {
+        _bufferLineStart = 0;
+        return true;
+      }
+    } else if (decodedString != null) {
+      _buffer = _buffer.substring(_bufferLineStart) + decodedString;
+      _bufferLineStart = 0;
+      return true;
+    }
+    return false;
+  }
+
+  InputStream _input;
+  String _encoding;
+  _Decoder _decoder;
+  String _buffer;  // String can be buffered here if readLine is used.
+  int _bufferLineStart;  // Current offset into _buffer if any.
+  bool _closed = false;
+  bool _eof = false;  // Has all data been read from the decoder?
+  var _clientDataHandler;
+  var _clientCloseHandler;
+}