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1 // Copyright (c) 2013, 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.package_graph; | |
6 | |
7 import 'dart:async'; | |
8 import 'dart:collection'; | |
9 | |
10 import 'asset_cascade.dart'; | |
11 import 'asset_id.dart'; | |
12 import 'asset_node.dart'; | |
13 import 'asset_set.dart'; | |
14 import 'build_result.dart'; | |
15 import 'errors.dart'; | |
16 import 'log.dart'; | |
17 import 'node_status.dart'; | |
18 import 'package_provider.dart'; | |
19 import 'transformer.dart'; | |
20 import 'utils.dart'; | |
21 | |
22 /// The collection of [AssetCascade]s for an entire application. | |
23 /// | |
24 /// This tracks each package's [AssetCascade] and routes asset requests between | |
25 /// them. | |
26 class PackageGraph { | |
27 /// The provider that exposes asset and package information. | |
28 final PackageProvider provider; | |
29 | |
30 /// The [AssetCascade] for each package. | |
31 final _cascades = <String, AssetCascade>{}; | |
32 | |
33 /// A stream that emits a [BuildResult] each time the build is completed, | |
34 /// whether or not it succeeded. | |
35 /// | |
36 /// This will emit a result only once every package's [AssetCascade] has | |
37 /// finished building. | |
38 /// | |
39 /// If an unexpected error in barback itself occurs, it will be emitted | |
40 /// through this stream's error channel. | |
41 Stream<BuildResult> get results => _resultsController.stream; | |
42 final _resultsController = | |
43 new StreamController<BuildResult>.broadcast(sync: true); | |
44 | |
45 /// A stream that emits any errors from the graph or the transformers. | |
46 /// | |
47 /// This emits errors as they're detected. If an error occurs in one part of | |
48 /// the graph, unrelated parts will continue building. | |
49 /// | |
50 /// This will not emit programming errors from barback itself. Those will be | |
51 /// emitted through the [results] stream's error channel. | |
52 Stream<BarbackException> get errors => _errors; | |
53 Stream<BarbackException> _errors; | |
54 | |
55 /// The stream of [LogEntry] objects used to report transformer log entries. | |
56 Stream<LogEntry> get log => _logController.stream; | |
57 final _logController = new StreamController<LogEntry>.broadcast(sync: true); | |
58 | |
59 /// How far along [this] is in processing its assets. | |
60 NodeStatus get _status => NodeStatus.dirtiest( | |
61 _cascades.values.map((cascade) => cascade.status)); | |
62 | |
63 /// Whether a [BuildResult] is scheduled to be emitted on [results] (see | |
64 /// [_tryScheduleResult]). | |
65 bool _resultScheduled = false; | |
66 | |
67 /// The most recent [BuildResult] emitted on [results]. | |
68 BuildResult _lastResult; | |
69 | |
70 // TODO(nweiz): This can have bogus errors if an error is created and resolved | |
71 // in the space of one build. | |
72 /// The errors that have occurred since the current build started. | |
73 /// | |
74 /// This will be empty if no build is occurring. | |
75 final _accumulatedErrors = new Queue<BarbackException>(); | |
76 | |
77 /// The most recent error emitted from a cascade's result stream. | |
78 /// | |
79 /// This is used to pipe an unexpected error from a build to the resulting | |
80 /// [Future] returned by [getAllAssets]. | |
81 var _lastUnexpectedError; | |
82 | |
83 /// The stack trace for [_lastUnexpectedError]. | |
84 StackTrace _lastUnexpectedErrorTrace; | |
85 | |
86 /// Creates a new [PackageGraph] that will transform assets in all packages | |
87 /// made available by [provider]. | |
88 PackageGraph(this.provider) { | |
89 _inErrorZone(() { | |
90 for (var package in provider.packages) { | |
91 var cascade = new AssetCascade(this, package); | |
92 _cascades[package] = cascade; | |
93 cascade.onLog.listen(_onLog); | |
94 cascade.onStatusChange.listen((status) { | |
95 if (status == NodeStatus.IDLE) _tryScheduleResult(); | |
96 }); | |
97 } | |
98 | |
99 _errors = mergeStreams(_cascades.values.map((cascade) => cascade.errors), | |
100 broadcast: true); | |
101 _errors.listen(_accumulatedErrors.add); | |
102 }); | |
103 } | |
104 | |
105 /// Gets the asset node identified by [id]. | |
106 /// | |
107 /// If [id] is for a generated or transformed asset, this will wait until it | |
108 /// has been created and return it. This means that the returned asset will | |
109 /// always be [AssetState.AVAILABLE]. | |
110 /// | |
111 /// If the asset cannot be found, returns null. | |
112 Future<AssetNode> getAssetNode(AssetId id) { | |
113 return _inErrorZone(() { | |
114 var cascade = _cascades[id.package]; | |
115 if (cascade != null) return cascade.getAssetNode(id); | |
116 return new Future.value(null); | |
117 }); | |
118 } | |
119 | |
120 /// Gets all output assets. | |
121 /// | |
122 /// If a build is currently in progress, waits until it completes. The | |
123 /// returned future will complete with an error if the build is not | |
124 /// successful. | |
125 /// | |
126 /// Any transforms using [LazyTransformer]s will be forced to generate | |
127 /// concrete outputs, and those outputs will be returned. | |
128 Future<AssetSet> getAllAssets() { | |
129 for (var cascade in _cascades.values) { | |
130 _inErrorZone(() => cascade.forceAllTransforms()); | |
131 } | |
132 | |
133 if (_status != NodeStatus.IDLE) { | |
134 // A build is still ongoing, so wait for it to complete and try again. | |
135 return results.first.then((_) => getAllAssets()); | |
136 } | |
137 | |
138 // If an unexpected error occurred, complete with that. | |
139 if (_lastUnexpectedError != null) { | |
140 var error = _lastUnexpectedError; | |
141 _lastUnexpectedError = null; | |
142 return new Future.error(error, _lastUnexpectedErrorTrace); | |
143 } | |
144 | |
145 // If the last build completed with an error, complete the future with it. | |
146 if (!_lastResult.succeeded) { | |
147 return new Future.error(BarbackException.aggregate(_lastResult.errors)); | |
148 } | |
149 | |
150 // Otherwise, return all of the final output assets. | |
151 var assets = unionAll(_cascades.values.map( | |
152 (cascade) => cascade.availableOutputs.toSet())); | |
153 | |
154 return new Future.value(new AssetSet.from(assets)); | |
155 } | |
156 | |
157 /// Adds [sources] to the graph's known set of source assets. | |
158 /// | |
159 /// Begins applying any transforms that can consume any of the sources. If a | |
160 /// given source is already known, it is considered modified and all | |
161 /// transforms that use it will be re-applied. | |
162 void updateSources(Iterable<AssetId> sources) { | |
163 groupBy(sources, (id) => id.package).forEach((package, ids) { | |
164 var cascade = _cascades[package]; | |
165 if (cascade == null) throw new ArgumentError("Unknown package $package."); | |
166 _inErrorZone(() => cascade.updateSources(ids)); | |
167 }); | |
168 | |
169 // It's possible for adding sources not to cause any processing. The user | |
170 // still expects there to be a build, though, so we emit one immediately. | |
171 _tryScheduleResult(); | |
172 } | |
173 | |
174 /// Removes [removed] from the graph's known set of source assets. | |
175 void removeSources(Iterable<AssetId> sources) { | |
176 groupBy(sources, (id) => id.package).forEach((package, ids) { | |
177 var cascade = _cascades[package]; | |
178 if (cascade == null) throw new ArgumentError("Unknown package $package."); | |
179 _inErrorZone(() => cascade.removeSources(ids)); | |
180 }); | |
181 | |
182 // It's possible for removing sources not to cause any processing. The user | |
183 // still expects there to be a build, though, so we emit one immediately. | |
184 _tryScheduleResult(); | |
185 } | |
186 | |
187 void updateTransformers(String package, | |
188 Iterable<Iterable<Transformer>> transformers) { | |
189 _inErrorZone(() => _cascades[package].updateTransformers(transformers)); | |
190 | |
191 // It's possible for updating transformers not to cause any processing. The | |
192 // user still expects there to be a build, though, so we emit one | |
193 // immediately. | |
194 _tryScheduleResult(); | |
195 } | |
196 | |
197 /// A handler for a log entry from an [AssetCascade]. | |
198 void _onLog(LogEntry entry) { | |
199 if (entry.level == LogLevel.ERROR) { | |
200 // TODO(nweiz): keep track of stack chain. | |
201 _accumulatedErrors.add( | |
202 new TransformerException(entry.transform, entry.message, null)); | |
203 } | |
204 | |
205 if (_logController.hasListener) { | |
206 _logController.add(entry); | |
207 } else if (entry.level != LogLevel.FINE) { | |
208 // No listeners, so just print entry. | |
209 var buffer = new StringBuffer(); | |
210 buffer.write("[${entry.level} ${entry.transform}] "); | |
211 | |
212 if (entry.span != null) { | |
213 buffer.write(entry.span.getLocationMessage(entry.message)); | |
214 } else { | |
215 buffer.write(entry.message); | |
216 } | |
217 | |
218 print(buffer); | |
219 } | |
220 } | |
221 | |
222 /// If [this] is done processing, schedule a [BuildResult] to be emitted on | |
223 /// [results]. | |
224 /// | |
225 /// This schedules the result (as opposed to just emitting one directly on | |
226 /// [BuildResult]) to ensure that calling multiple functions synchronously | |
227 /// produces only a single [BuildResult]. | |
228 void _tryScheduleResult() { | |
229 if (_status != NodeStatus.IDLE) return; | |
230 if (_resultScheduled) return; | |
231 | |
232 _resultScheduled = true; | |
233 newFuture(() { | |
234 _resultScheduled = false; | |
235 if (_status != NodeStatus.IDLE) return; | |
236 | |
237 _lastResult = new BuildResult(_accumulatedErrors); | |
238 _accumulatedErrors.clear(); | |
239 _resultsController.add(_lastResult); | |
240 }); | |
241 } | |
242 | |
243 /// Run [body] in an error-handling [Zone] and pipe any unexpected errors to | |
244 /// the error channel of [results]. | |
245 /// | |
246 /// [body] can return a value or a [Future] that will be piped to the returned | |
247 /// [Future]. If it throws a [BarbackException], that exception will be piped | |
248 /// to the returned [Future] as well. Any other exceptions will be piped to | |
249 /// [results]. | |
250 Future _inErrorZone(body()) { | |
251 var completer = new Completer.sync(); | |
252 runZoned(() { | |
253 syncFuture(body).then(completer.complete).catchError((error, stackTrace) { | |
254 if (error is! BarbackException) throw error; | |
255 completer.completeError(error, stackTrace); | |
256 }); | |
257 }, onError: (error, stackTrace) { | |
258 _lastUnexpectedError = error; | |
259 _lastUnexpectedErrorTrace = stackTrace; | |
260 _resultsController.addError(error, stackTrace); | |
261 }); | |
262 return completer.future; | |
263 } | |
264 } | |
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