| Index: mojo/public/dart/third_party/barback/lib/src/transformer/aggregate_transform.dart
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| diff --git a/mojo/public/dart/third_party/barback/lib/src/transformer/aggregate_transform.dart b/mojo/public/dart/third_party/barback/lib/src/transformer/aggregate_transform.dart
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| new file mode 100644
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| +++ b/mojo/public/dart/third_party/barback/lib/src/transformer/aggregate_transform.dart
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| @@ -0,0 +1,151 @@
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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.aggregate_transform;
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| +
|
| +import 'dart:async';
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| +import 'dart:convert';
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| +
|
| +import '../asset/asset.dart';
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| +import '../asset/asset_id.dart';
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| +import '../asset/asset_set.dart';
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| +import '../errors.dart';
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| +import '../graph/transform_node.dart';
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| +import '../utils.dart';
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| +import 'base_transform.dart';
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| +
|
| +/// A transform for [AggregateTransformer]s that provides access to all of their
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| +/// primary inputs.
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| +class AggregateTransform extends BaseTransform {
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| + final TransformNode _node;
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| +
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| + /// The set of outputs emitted by the transformer.
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| + final _outputs = new AssetSet();
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| +
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| + /// The transform key.
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| + ///
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| + /// This is the key returned by [AggregateTransformer.classifyPrimary] for all
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| + /// the assets in this transform.
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| + String get key => _node.key;
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| +
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| + /// The package in which this transform is running.
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| + String get package => _node.phase.cascade.package;
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| +
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| + /// The stream of primary inputs that will be processed by this transform.
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| + ///
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| + /// This is exposed as a stream so that the transformer can start working
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| + /// before all its inputs are available. The stream is closed not just when
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| + /// all inputs are provided, but when barback is confident no more inputs will
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| + /// be forthcoming.
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| + ///
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| + /// A transformer may complete its `apply` method before this stream is
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| + /// closed. For example, it may know that each key will only have two inputs
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| + /// associated with it, and so use `transform.primaryInputs.take(2)` to access
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| + /// only those inputs.
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| + Stream<Asset> get primaryInputs => _inputController.stream;
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| + final _inputController = new StreamController<Asset>();
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| +
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| + /// The set of all primary inputs that have been emitted by [primaryInputs].
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| + ///
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| + /// This is populated by the transform's controller so that
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| + /// [AggregateTransformController.addedId] synchronously returns the correct
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| + /// result after [AggregateTransformController.addInput] is called.
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| + final _emittedPrimaryInputs = new AssetSet();
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| +
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| + AggregateTransform._(TransformNode node)
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| + : _node = node,
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| + super(node);
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| +
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| + /// Gets the asset for an input [id].
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| + ///
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| + /// If an input with [id] cannot be found, throws an [AssetNotFoundException].
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| + Future<Asset> getInput(AssetId id) {
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| + if (_emittedPrimaryInputs.containsId(id)) {
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| + return syncFuture(() => _emittedPrimaryInputs[id]);
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| + } else {
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| + return _node.getInput(id);
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| + }
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| + }
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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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| + if (encoding == null) encoding = UTF8;
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| + return getInput(id).then((input) => input.readAsString(encoding: encoding));
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| + }
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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) =>
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| + futureStream(getInput(id).then((input) => input.read()));
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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) {
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| + return getInput(id).then((_) => true).catchError((error) {
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| + if (error is AssetNotFoundException && error.id == id) return false;
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| + throw error;
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| + });
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| + }
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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) {
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| + // TODO(rnystrom): This should immediately throw if an output with that ID
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| + // has already been created by this transformer.
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| + _outputs.add(output);
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| + }
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| +
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| + void consumePrimary(AssetId id) {
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| + if (!_emittedPrimaryInputs.containsId(id)) {
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| + throw new StateError(
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| + "$id can't be consumed because it's not a primary input.");
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| + }
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| +
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| + super.consumePrimary(id);
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| + }
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| +}
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| +
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| +/// The controller for [AggregateTransform].
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| +class AggregateTransformController extends BaseTransformController {
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| + AggregateTransform get transform => super.transform;
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| +
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| + /// The set of assets that the transformer has emitted.
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| + AssetSet get outputs => transform._outputs;
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| +
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| + bool get isDone => transform._inputController.isClosed;
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| +
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| + AggregateTransformController(TransformNode node)
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| + : super(new AggregateTransform._(node));
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| +
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| + /// Adds a primary input asset to the [AggregateTransform.primaryInputs]
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| + /// stream.
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| + void addInput(Asset input) {
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| + transform._emittedPrimaryInputs.add(input);
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| + transform._inputController.add(input);
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| + }
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| +
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| + /// Returns whether an input with the given [id] was added via [addInput].
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| + bool addedId(AssetId id) =>
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| + transform._emittedPrimaryInputs.containsId(id);
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| +
|
| + void done() {
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| + transform._inputController.close();
|
| + }
|
| +}
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|
|