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| 1 // Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file | |
| 2 // for details. All rights reserved. Use of this source code is governed by a | |
| 3 // BSD-style license that can be found in the LICENSE file. | |
| 4 | |
| 5 library barback.transformer.aggregate_transform; | |
| 6 | |
| 7 import 'dart:async'; | |
| 8 import 'dart:convert'; | |
| 9 | |
| 10 import '../asset/asset.dart'; | |
| 11 import '../asset/asset_id.dart'; | |
| 12 import '../asset/asset_set.dart'; | |
| 13 import '../errors.dart'; | |
| 14 import '../graph/transform_node.dart'; | |
| 15 import '../utils.dart'; | |
| 16 import 'base_transform.dart'; | |
| 17 | |
| 18 /// A transform for [AggregateTransformer]s that provides access to all of their | |
| 19 /// primary inputs. | |
| 20 class AggregateTransform extends BaseTransform { | |
| 21 final TransformNode _node; | |
| 22 | |
| 23 /// The set of outputs emitted by the transformer. | |
| 24 final _outputs = new AssetSet(); | |
| 25 | |
| 26 /// The transform key. | |
| 27 /// | |
| 28 /// This is the key returned by [AggregateTransformer.classifyPrimary] for all | |
| 29 /// the assets in this transform. | |
| 30 String get key => _node.key; | |
| 31 | |
| 32 /// The package in which this transform is running. | |
| 33 String get package => _node.phase.cascade.package; | |
| 34 | |
| 35 /// The stream of primary inputs that will be processed by this transform. | |
| 36 /// | |
| 37 /// This is exposed as a stream so that the transformer can start working | |
| 38 /// before all its inputs are available. The stream is closed not just when | |
| 39 /// all inputs are provided, but when barback is confident no more inputs will | |
| 40 /// be forthcoming. | |
| 41 /// | |
| 42 /// A transformer may complete its `apply` method before this stream is | |
| 43 /// closed. For example, it may know that each key will only have two inputs | |
| 44 /// associated with it, and so use `transform.primaryInputs.take(2)` to access | |
| 45 /// only those inputs. | |
| 46 Stream<Asset> get primaryInputs => _inputController.stream; | |
| 47 final _inputController = new StreamController<Asset>(); | |
| 48 | |
| 49 /// The set of all primary inputs that have been emitted by [primaryInputs]. | |
| 50 /// | |
| 51 /// This is populated by the transform's controller so that | |
| 52 /// [AggregateTransformController.addedId] synchronously returns the correct | |
| 53 /// result after [AggregateTransformController.addInput] is called. | |
| 54 final _emittedPrimaryInputs = new AssetSet(); | |
| 55 | |
| 56 AggregateTransform._(TransformNode node) | |
| 57 : _node = node, | |
| 58 super(node); | |
| 59 | |
| 60 /// Gets the asset for an input [id]. | |
| 61 /// | |
| 62 /// If an input with [id] cannot be found, throws an [AssetNotFoundException]. | |
| 63 Future<Asset> getInput(AssetId id) { | |
| 64 if (_emittedPrimaryInputs.containsId(id)) { | |
| 65 return syncFuture(() => _emittedPrimaryInputs[id]); | |
| 66 } else { | |
| 67 return _node.getInput(id); | |
| 68 } | |
| 69 } | |
| 70 | |
| 71 /// A convenience method to the contents of the input with [id] as a string. | |
| 72 /// | |
| 73 /// This is equivalent to calling [getInput] followed by [Asset.readAsString]. | |
| 74 /// | |
| 75 /// If the asset was created from a [String] the original string is always | |
| 76 /// returned and [encoding] is ignored. Otherwise, the binary data of the | |
| 77 /// asset is decoded using [encoding], which defaults to [UTF8]. | |
| 78 /// | |
| 79 /// If an input with [id] cannot be found, throws an [AssetNotFoundException]. | |
| 80 Future<String> readInputAsString(AssetId id, {Encoding encoding}) { | |
| 81 if (encoding == null) encoding = UTF8; | |
| 82 return getInput(id).then((input) => input.readAsString(encoding: encoding)); | |
| 83 } | |
| 84 | |
| 85 /// A convenience method to the contents of the input with [id]. | |
| 86 /// | |
| 87 /// This is equivalent to calling [getInput] followed by [Asset.read]. | |
| 88 /// | |
| 89 /// If the asset was created from a [String], this returns its UTF-8 encoding. | |
| 90 /// | |
| 91 /// If an input with [id] cannot be found, throws an [AssetNotFoundException]. | |
| 92 Stream<List<int>> readInput(AssetId id) => | |
| 93 futureStream(getInput(id).then((input) => input.read())); | |
| 94 | |
| 95 /// A convenience method to return whether or not an asset exists. | |
| 96 /// | |
| 97 /// This is equivalent to calling [getInput] and catching an | |
| 98 /// [AssetNotFoundException]. | |
| 99 Future<bool> hasInput(AssetId id) { | |
| 100 return getInput(id).then((_) => true).catchError((error) { | |
| 101 if (error is AssetNotFoundException && error.id == id) return false; | |
| 102 throw error; | |
| 103 }); | |
| 104 } | |
| 105 | |
| 106 /// Stores [output] as the output created by this transformation. | |
| 107 /// | |
| 108 /// A transformation can output as many assets as it wants. | |
| 109 void addOutput(Asset output) { | |
| 110 // TODO(rnystrom): This should immediately throw if an output with that ID | |
| 111 // has already been created by this transformer. | |
| 112 _outputs.add(output); | |
| 113 } | |
| 114 | |
| 115 void consumePrimary(AssetId id) { | |
| 116 if (!_emittedPrimaryInputs.containsId(id)) { | |
| 117 throw new StateError( | |
| 118 "$id can't be consumed because it's not a primary input."); | |
| 119 } | |
| 120 | |
| 121 super.consumePrimary(id); | |
| 122 } | |
| 123 } | |
| 124 | |
| 125 /// The controller for [AggregateTransform]. | |
| 126 class AggregateTransformController extends BaseTransformController { | |
| 127 AggregateTransform get transform => super.transform; | |
| 128 | |
| 129 /// The set of assets that the transformer has emitted. | |
| 130 AssetSet get outputs => transform._outputs; | |
| 131 | |
| 132 bool get isDone => transform._inputController.isClosed; | |
| 133 | |
| 134 AggregateTransformController(TransformNode node) | |
| 135 : super(new AggregateTransform._(node)); | |
| 136 | |
| 137 /// Adds a primary input asset to the [AggregateTransform.primaryInputs] | |
| 138 /// stream. | |
| 139 void addInput(Asset input) { | |
| 140 transform._emittedPrimaryInputs.add(input); | |
| 141 transform._inputController.add(input); | |
| 142 } | |
| 143 | |
| 144 /// Returns whether an input with the given [id] was added via [addInput]. | |
| 145 bool addedId(AssetId id) => | |
| 146 transform._emittedPrimaryInputs.containsId(id); | |
| 147 | |
| 148 void done() { | |
| 149 transform._inputController.close(); | |
| 150 } | |
| 151 } | |
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Chromium Code Reviews
Issue 808713003:
Remove barback from the repo. (Closed)
Base URL: https://dart.googlecode.com/svn/branches/bleeding_edge/dart