| Index: mojo/public/dart/third_party/barback/lib/src/transformer/transform.dart
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| diff --git a/mojo/public/dart/third_party/barback/lib/src/transformer/transform.dart b/mojo/public/dart/third_party/barback/lib/src/transformer/transform.dart
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| new file mode 100644
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| index 0000000000000000000000000000000000000000..2da73eee043a147f43a1a4d80713be1755b14d85
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| --- /dev/null
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| +++ b/mojo/public/dart/third_party/barback/lib/src/transformer/transform.dart
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| @@ -0,0 +1,104 @@
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| +// Copyright (c) 2014, 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.
|
| +
|
| +library barback.transformer.transform;
|
| +
|
| +import 'dart:async';
|
| +import 'dart:convert';
|
| +
|
| +import '../asset/asset.dart';
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| +import '../asset/asset_id.dart';
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| +import '../errors.dart';
|
| +import 'aggregate_transform.dart';
|
| +import 'transform_logger.dart';
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| +
|
| +/// Creates a new [Transform] wrapping an [AggregateTransform].
|
| +///
|
| +/// Although barback internally works in terms of [AggregateTransformer]s, most
|
| +/// transformers only work on individual primary inputs in isolation. We want to
|
| +/// allow those transformers to implement the more user-friendly [Transformer]
|
| +/// interface which takes the more user-friendly [Transform] object. This method
|
| +/// wraps the more general [AggregateTransform] to return a [Transform] instead.
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| +Future<Transform> newTransform(AggregateTransform aggregate) {
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| + // A wrapped [Transformer] will assign each primary input a unique transform
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| + // key, so we can safely get the first asset emitted. We don't want to wait
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| + // for the stream to close, since that requires barback to prove that no more
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| + // new assets will be generated.
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| + return aggregate.primaryInputs.first.then((primaryInput) =>
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| + new Transform._(aggregate, primaryInput));
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| +}
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| +
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| +/// While a [Transformer] represents a *kind* of transformation, this defines
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| +/// one specific usage of it on a set of files.
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| +///
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| +/// This ephemeral object exists only during an actual transform application to
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| +/// facilitate communication between the [Transformer] and the code hosting
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| +/// the transformation. It lets the [Transformer] access inputs and generate
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| +/// outputs.
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| +class Transform {
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| + /// The underlying aggregate transform.
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| + final AggregateTransform _aggregate;
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| +
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| + /// Gets the primary input asset.
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| + ///
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| + /// While a transformation can use multiple input assets, one must be a
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| + /// special "primary" asset. This will be the "entrypoint" or "main" input
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| + /// file for a transformation.
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| + ///
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| + /// For example, with a dart2js transform, the primary input would be the
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| + /// entrypoint Dart file. All of the other Dart files that that imports
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| + /// would be secondary inputs.
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| + final Asset primaryInput;
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| +
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| + /// A logger so that the [Transformer] can report build details.
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| + TransformLogger get logger => _aggregate.logger;
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| +
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| + Transform._(this._aggregate, this.primaryInput);
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| +
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| + /// Gets the asset for an input [id].
|
| + ///
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| + /// If an input with [id] cannot be found, throws an [AssetNotFoundException].
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| + Future<Asset> getInput(AssetId id) => _aggregate.getInput(id);
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| +
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| + /// A convenience method to the contents of the input with [id] as a string.
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| + ///
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| + /// This is equivalent to calling [getInput] followed by [Asset.readAsString].
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| + ///
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| + /// If the asset was created from a [String] the original string is always
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| + /// returned and [encoding] is ignored. Otherwise, the binary data of the
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| + /// asset is decoded using [encoding], which defaults to [UTF8].
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| + ///
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| + /// If an input with [id] cannot be found, throws an [AssetNotFoundException].
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| + Future<String> readInputAsString(AssetId id, {Encoding encoding}) =>
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| + _aggregate.readInputAsString(id, encoding: encoding);
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| +
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| + /// A convenience method to the contents of the input with [id].
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| + ///
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| + /// This is equivalent to calling [getInput] followed by [Asset.read].
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| + ///
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| + /// If the asset was created from a [String], this returns its UTF-8 encoding.
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| + ///
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| + /// If an input with [id] cannot be found, throws an [AssetNotFoundException].
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| + Stream<List<int>> readInput(AssetId id) => _aggregate.readInput(id);
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| +
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| + /// A convenience method to return whether or not an asset exists.
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| + ///
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| + /// This is equivalent to calling [getInput] and catching an
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| + /// [AssetNotFoundException].
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| + Future<bool> hasInput(AssetId id) => _aggregate.hasInput(id);
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| +
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| + /// Stores [output] as an output created by this transformation.
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| + ///
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| + /// A transformation can output as many assets as it wants.
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| + void addOutput(Asset output) => _aggregate.addOutput(output);
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| +
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| + /// Consume the primary input so that it doesn't get processed by future
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| + /// phases or emitted once processing has finished.
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| + ///
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| + /// Normally the primary input will automatically be forwarded unless the
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| + /// transformer overwrites it by emitting an input with the same id. This
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| + /// allows the transformer to tell barback not to forward the primary input
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| + /// even if it's not overwritten.
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| + void consumePrimary() => _aggregate.consumePrimary(primaryInput.id);
|
| +}
|
|
|