| // 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; |
| |
| /** |
| * A [Converter] converts data from one representation into another. |
| * |
| * It is recommended that implementations of `Converter` extend this class, |
| * to inherit any further methods that may be added to the class. |
| */ |
| abstract class Converter<S, T> implements StreamTransformer<S, T> { |
| const Converter(); |
| |
| /** |
| * Converts [input] and returns the result of the conversion. |
| */ |
| T convert(S input); |
| |
| /** |
| * Fuses `this` with [other]. |
| * |
| * Encoding with the resulting converter is equivalent to converting with |
| * `this` before converting with `other`. |
| */ |
| Converter<S, TT> fuse<TT>(Converter<T, TT> other) { |
| return new _FusedConverter<S, T, TT>(this, other); |
| } |
| |
| /** |
| * Starts a chunked conversion. |
| * |
| * The returned sink serves as input for the long-running conversion. The |
| * given [sink] serves as output. |
| */ |
| Sink/*<S>*/ startChunkedConversion(Sink/*<T>*/ sink) { |
| throw new UnsupportedError( |
| "This converter does not support chunked conversions: $this"); |
| } |
| |
| Stream<T> bind(Stream<S> stream) { |
| return new Stream<T>.eventTransformed( |
| stream, (EventSink sink) => new _ConverterStreamEventSink(this, sink)); |
| } |
| } |
| |
| /** |
| * Fuses two converters. |
| * |
| * For a non-chunked conversion converts the input in sequence. |
| */ |
| class _FusedConverter<S, M, T> extends Converter<S, T> { |
| final Converter<S, M> _first; |
| final Converter<M, T> _second; |
| |
| _FusedConverter(this._first, this._second); |
| |
| T convert(S input) => _second.convert(_first.convert(input)); |
| |
| Sink/*<S>*/ startChunkedConversion(Sink/*<T>*/ sink) { |
| return _first.startChunkedConversion(_second.startChunkedConversion(sink)); |
| } |
| } |