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pkg/dev_compiler/tool/input_sdk/lib/convert/string_conversion.dart

-// Copyright (c) 2013, 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.
-
-part of dart.convert;
-
-/**
- * This class provides an interface for converters to
- * efficiently transmit String data.
- *
- * Instead of limiting the interface to one non-chunked String it accepts
- * partial strings or can be transformed into a byte sink that
- * accepts UTF-8 code units.
- *
- * This abstract class will likely get more methods over time. Implementers are
- * urged to extend [StringConversionSinkBase] or to mix in
- * [StringConversionSinkMixin], to ensure that their class covers the newly
- * added methods.
- */
-abstract class StringConversionSink extends ChunkedConversionSink<String> {
-  StringConversionSink();
-  factory StringConversionSink.withCallback(void callback(String accumulated))
-      = _StringCallbackSink;
-  factory StringConversionSink.from(Sink<String> sink)
-      = _StringAdapterSink;
-
-  /**
-   * Creates a new instance wrapping the given [sink].
-   *
-   * Every string that is added to the returned instance is forwarded to
-   * the [sink]. The instance is allowed to buffer and is not required to
-   * forward immediately.
-   */
-  factory StringConversionSink.fromStringSink(StringSink sink) =
-      _StringSinkConversionSink;
-
-  /**
-   * Adds the next [chunk] to `this`.
-   *
-   * Adds the substring defined by [start] and [end]-exclusive to `this`.
-   *
-   * If [isLast] is `true` closes `this`.
-   */
-  void addSlice(String chunk, int start, int end, bool isLast);
-
-  /**
-   * Returns `this` as a sink that accepts UTF-8 input.
-   *
-   * If used, this method must be the first and only call to `this`. It
-   * invalidates `this`. All further operations must be performed on the result.
-   */
-  ByteConversionSink asUtf8Sink(bool allowMalformed);
-  // - asRuneSink
-  // - asCodeUnitsSink
-
-  /**
-   * Returns `this` as a [ClosableStringSink].
-   *
-   * If used, this method must be the first and only call to `this`. It
-   * invalidates `this`. All further operations must be performed on the result.
-   */
-  ClosableStringSink asStringSink();
-}
-
-/**
- * A [ClosableStringSink] extends the [StringSink] interface by adding a
- * `close` method.
- */
-abstract class ClosableStringSink extends StringSink {
-  /**
-   * Creates a new instance combining a [StringSink] [sink] and a callback
-   * [onClose] which is invoked when the returned instance is closed.
-   */
-  factory ClosableStringSink.fromStringSink(StringSink sink, void onClose())
-      = _ClosableStringSink;
-
-  /**
-   * Closes `this` and flushes any outstanding data.
-   */
-  void close();
-}
-
-typedef void _StringSinkCloseCallback();
-
-/**
- * This class wraps an existing [StringSink] and invokes a
- * closure when [close] is invoked.
- */
-class _ClosableStringSink implements ClosableStringSink {
-  final _StringSinkCloseCallback _callback;
-  final StringSink _sink;
-
-  _ClosableStringSink(this._sink, this._callback);
-
-  void close() { _callback(); }
-
-  void writeCharCode(int charCode) { _sink.writeCharCode(charCode); }
-  void write(Object o) { _sink.write(o); }
-  void writeln([Object o = ""]) { _sink.writeln(o); }
-  void writeAll(Iterable objects, [String separator = ""]) {
-    _sink.writeAll(objects, separator);
-  }
-}
-
-/**
- * This class wraps an existing [StringConversionSink] and exposes a
- * [ClosableStringSink] interface. The wrapped sink only needs to implement
- * `add` and `close`.
- */
-// TODO(floitsch): make this class public?
-class _StringConversionSinkAsStringSinkAdapter implements ClosableStringSink {
-  static const _MIN_STRING_SIZE = 16;
-
-  StringBuffer _buffer;
-  StringConversionSink _chunkedSink;
-
-  _StringConversionSinkAsStringSinkAdapter(this._chunkedSink)
-      : _buffer = new StringBuffer();
-
-  void close() {
-    if (_buffer.isNotEmpty) _flush();
-    _chunkedSink.close();
-  }
-
-  void writeCharCode(int charCode) {
-    _buffer.writeCharCode(charCode);
-    if (_buffer.length > _MIN_STRING_SIZE) _flush();
-  }
-
-  void write(Object o) {
-    if (_buffer.isNotEmpty) _flush();
-    _chunkedSink.add(o.toString());
-  }
-
-  void writeln([Object o = ""]) {
-    _buffer.writeln(o);
-    if (_buffer.length > _MIN_STRING_SIZE) _flush();
-  }
-
-  void writeAll(Iterable objects, [String separator = ""]) {
-    if (_buffer.isNotEmpty) _flush();
-    Iterator iterator = objects.iterator;
-    if (!iterator.moveNext()) return;
-    if (separator.isEmpty) {
-      do {
-        _chunkedSink.add(iterator.current.toString());
-      } while (iterator.moveNext());
-    } else {
-      _chunkedSink.add(iterator.current.toString());
-      while (iterator.moveNext()) {
-        write(separator);
-        _chunkedSink.add(iterator.current.toString());
-      }
-    }
-  }
-
-  void _flush() {
-    String accumulated = _buffer.toString();
-    _buffer.clear();
-    _chunkedSink.add(accumulated);
-  }
-}
-
-/**
- * This class provides a base-class for converters that need to accept String
- * inputs.
- */
-abstract class StringConversionSinkBase extends StringConversionSinkMixin {
-}
-
-/**
- * This class provides a mixin for converters that need to accept String
- * inputs.
- */
-abstract class StringConversionSinkMixin implements StringConversionSink {
-
-  void addSlice(String str, int start, int end, bool isLast);
-  void close();
-
-  void add(String str) { addSlice(str, 0, str.length, false); }
-
-  ByteConversionSink asUtf8Sink(bool allowMalformed) {
-    return new _Utf8ConversionSink(this, allowMalformed);
-  }
-
-  ClosableStringSink asStringSink() {
-    return new _StringConversionSinkAsStringSinkAdapter(this);
-  }
-}
-
-/**
- * This class is a [StringConversionSink] that wraps a [StringSink].
- */
-class _StringSinkConversionSink extends StringConversionSinkBase {
-  StringSink _stringSink;
-  _StringSinkConversionSink(StringSink this._stringSink);
-
-  void close() {}
-  void addSlice(String str, int start, int end, bool isLast) {
-    if (start != 0 || end != str.length) {
-      for (int i = start; i < end; i++) {
-        _stringSink.writeCharCode(str.codeUnitAt(i));
-      }
-    } else {
-      _stringSink.write(str);
-    }
-    if (isLast) close();
-  }
-
-  void add(String str) { _stringSink.write(str); }
-
-  ByteConversionSink asUtf8Sink(bool allowMalformed) {
-    return new _Utf8StringSinkAdapter(this, _stringSink, allowMalformed);
-  }
-
-  ClosableStringSink asStringSink() {
-    return new ClosableStringSink.fromStringSink(_stringSink, this.close);
-  }
-}
-
-/**
- * This class accumulates all chunks into one string
- * and invokes a callback when the sink is closed.
- *
- * This class can be used to terminate a chunked conversion.
- */
-class _StringCallbackSink extends _StringSinkConversionSink {
-  final _ChunkedConversionCallback<String> _callback;
-  _StringCallbackSink(this._callback) : super(new StringBuffer());
-
-  void close() {
-    StringBuffer buffer = _stringSink;
-    String accumulated = buffer.toString();
-    buffer.clear();
-    _callback(accumulated);
-  }
-
-  ByteConversionSink asUtf8Sink(bool allowMalformed) {
-    return new _Utf8StringSinkAdapter(
-        this, _stringSink, allowMalformed);
-  }
-}
-
-/**
- * This class adapts a simple [ChunkedConversionSink] to a
- * [StringConversionSink].
- *
- * All additional methods of the [StringConversionSink] (compared to the
- * ChunkedConversionSink) are redirected to the `add` method.
- */
-class _StringAdapterSink extends StringConversionSinkBase {
-  final Sink<String> _sink;
-
-  _StringAdapterSink(this._sink);
-
-  void add(String str) { _sink.add(str); }
-
-  void addSlice(String str, int start, int end, bool isLast) {
-    if (start == 0 && end == str.length) {
-      add(str);
-    } else {
-      add(str.substring(start, end));
-    }
-    if (isLast) close();
-  }
-
-  void close() { _sink.close(); }
-}
-
-
-/**
- * Decodes UTF-8 code units and stores them in a [StringSink].
- */
-class _Utf8StringSinkAdapter extends ByteConversionSink {
-  final _Utf8Decoder _decoder;
-  final Sink _sink;
-
-  _Utf8StringSinkAdapter(this._sink,
-                         StringSink stringSink, bool allowMalformed)
-      : _decoder = new _Utf8Decoder(stringSink, allowMalformed);
-
-  void close() {
-    _decoder.close();
-    if(_sink != null) _sink.close();
-  }
-
-  void add(List<int> chunk) {
-    addSlice(chunk, 0, chunk.length, false);
-  }
-
-  void addSlice(List<int> codeUnits, int startIndex, int endIndex,
-                bool isLast) {
-    _decoder.convert(codeUnits, startIndex, endIndex);
-    if (isLast) close();
-  }
-}
-
-/**
- * Decodes UTF-8 code units.
- *
- * Forwards the decoded strings to the given [StringConversionSink].
- */
-// TODO(floitsch): make this class public?
-class _Utf8ConversionSink extends ByteConversionSink {
-
-  final _Utf8Decoder _decoder;
-  final StringConversionSink _chunkedSink;
-  final StringBuffer _buffer;
-  _Utf8ConversionSink(StringConversionSink sink, bool allowMalformed)
-      : this._(sink, new StringBuffer(), allowMalformed);
-
-  _Utf8ConversionSink._(this._chunkedSink, StringBuffer stringBuffer,
-                       bool allowMalformed)
-      : _decoder = new _Utf8Decoder(stringBuffer, allowMalformed),
-        _buffer = stringBuffer;
-
-  void close() {
-    _decoder.close();
-    if (_buffer.isNotEmpty) {
-      String accumulated = _buffer.toString();
-      _buffer.clear();
-      _chunkedSink.addSlice(accumulated, 0, accumulated.length, true);
-    } else  {
-      _chunkedSink.close();
-    }
-  }
-
-  void add(List<int> chunk) {
-    addSlice(chunk, 0, chunk.length, false);
-  }
-
-  void addSlice(List<int> chunk, int startIndex, int endIndex, bool isLast) {
-    _decoder.convert(chunk, startIndex, endIndex);
-    if (_buffer.isNotEmpty) {
-      String accumulated = _buffer.toString();
-      _chunkedSink.addSlice(accumulated, 0, accumulated.length, isLast);
-      _buffer.clear();
-      return;
-    }
-    if (isLast) close();
-  }
-}