Index: mojo/public/dart/third_party/barback/lib/src/transformer/aggregate_transform.dart |
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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+// 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; |
+ |
+import 'dart:async'; |
+import 'dart:convert'; |
+ |
+import '../asset/asset.dart'; |
+import '../asset/asset_id.dart'; |
+import '../asset/asset_set.dart'; |
+import '../errors.dart'; |
+import '../graph/transform_node.dart'; |
+import '../utils.dart'; |
+import 'base_transform.dart'; |
+ |
+/// A transform for [AggregateTransformer]s that provides access to all of their |
+/// primary inputs. |
+class AggregateTransform extends BaseTransform { |
+ final TransformNode _node; |
+ |
+ /// The set of outputs emitted by the transformer. |
+ final _outputs = new AssetSet(); |
+ |
+ /// The transform key. |
+ /// |
+ /// This is the key returned by [AggregateTransformer.classifyPrimary] for all |
+ /// the assets in this transform. |
+ String get key => _node.key; |
+ |
+ /// The package in which this transform is running. |
+ String get package => _node.phase.cascade.package; |
+ |
+ /// The stream of primary inputs that will be processed by this transform. |
+ /// |
+ /// This is exposed as a stream so that the transformer can start working |
+ /// before all its inputs are available. The stream is closed not just when |
+ /// all inputs are provided, but when barback is confident no more inputs will |
+ /// be forthcoming. |
+ /// |
+ /// A transformer may complete its `apply` method before this stream is |
+ /// closed. For example, it may know that each key will only have two inputs |
+ /// associated with it, and so use `transform.primaryInputs.take(2)` to access |
+ /// only those inputs. |
+ Stream<Asset> get primaryInputs => _inputController.stream; |
+ final _inputController = new StreamController<Asset>(); |
+ |
+ /// The set of all primary inputs that have been emitted by [primaryInputs]. |
+ /// |
+ /// This is populated by the transform's controller so that |
+ /// [AggregateTransformController.addedId] synchronously returns the correct |
+ /// result after [AggregateTransformController.addInput] is called. |
+ final _emittedPrimaryInputs = new AssetSet(); |
+ |
+ AggregateTransform._(TransformNode node) |
+ : _node = node, |
+ super(node); |
+ |
+ /// Gets the asset for an input [id]. |
+ /// |
+ /// If an input with [id] cannot be found, throws an [AssetNotFoundException]. |
+ Future<Asset> getInput(AssetId id) { |
+ if (_emittedPrimaryInputs.containsId(id)) { |
+ return syncFuture(() => _emittedPrimaryInputs[id]); |
+ } else { |
+ return _node.getInput(id); |
+ } |
+ } |
+ |
+ /// A convenience method to the contents of the input with [id] as a string. |
+ /// |
+ /// This is equivalent to calling [getInput] followed by [Asset.readAsString]. |
+ /// |
+ /// If the asset was created from a [String] the original string is always |
+ /// returned and [encoding] is ignored. Otherwise, the binary data of the |
+ /// asset is decoded using [encoding], which defaults to [UTF8]. |
+ /// |
+ /// If an input with [id] cannot be found, throws an [AssetNotFoundException]. |
+ Future<String> readInputAsString(AssetId id, {Encoding encoding}) { |
+ if (encoding == null) encoding = UTF8; |
+ return getInput(id).then((input) => input.readAsString(encoding: encoding)); |
+ } |
+ |
+ /// A convenience method to the contents of the input with [id]. |
+ /// |
+ /// This is equivalent to calling [getInput] followed by [Asset.read]. |
+ /// |
+ /// If the asset was created from a [String], this returns its UTF-8 encoding. |
+ /// |
+ /// If an input with [id] cannot be found, throws an [AssetNotFoundException]. |
+ Stream<List<int>> readInput(AssetId id) => |
+ futureStream(getInput(id).then((input) => input.read())); |
+ |
+ /// A convenience method to return whether or not an asset exists. |
+ /// |
+ /// This is equivalent to calling [getInput] and catching an |
+ /// [AssetNotFoundException]. |
+ Future<bool> hasInput(AssetId id) { |
+ return getInput(id).then((_) => true).catchError((error) { |
+ if (error is AssetNotFoundException && error.id == id) return false; |
+ throw error; |
+ }); |
+ } |
+ |
+ /// Stores [output] as an output created by this transformation. |
+ /// |
+ /// A transformation can output as many assets as it wants. |
+ void addOutput(Asset output) { |
+ // TODO(rnystrom): This should immediately throw if an output with that ID |
+ // has already been created by this transformer. |
+ _outputs.add(output); |
+ } |
+ |
+ void consumePrimary(AssetId id) { |
+ if (!_emittedPrimaryInputs.containsId(id)) { |
+ throw new StateError( |
+ "$id can't be consumed because it's not a primary input."); |
+ } |
+ |
+ super.consumePrimary(id); |
+ } |
+} |
+ |
+/// The controller for [AggregateTransform]. |
+class AggregateTransformController extends BaseTransformController { |
+ AggregateTransform get transform => super.transform; |
+ |
+ /// The set of assets that the transformer has emitted. |
+ AssetSet get outputs => transform._outputs; |
+ |
+ bool get isDone => transform._inputController.isClosed; |
+ |
+ AggregateTransformController(TransformNode node) |
+ : super(new AggregateTransform._(node)); |
+ |
+ /// Adds a primary input asset to the [AggregateTransform.primaryInputs] |
+ /// stream. |
+ void addInput(Asset input) { |
+ transform._emittedPrimaryInputs.add(input); |
+ transform._inputController.add(input); |
+ } |
+ |
+ /// Returns whether an input with the given [id] was added via [addInput]. |
+ bool addedId(AssetId id) => |
+ transform._emittedPrimaryInputs.containsId(id); |
+ |
+ void done() { |
+ transform._inputController.close(); |
+ } |
+} |