| // Copyright (c) 2013, 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.errors; |
| |
| import 'package:stack_trace/stack_trace.dart'; |
| |
| import 'asset_id.dart'; |
| import 'transformer.dart'; |
| import 'utils.dart'; |
| |
| /// Error thrown when an asset with [id] cannot be found. |
| class AssetNotFoundException implements Exception { |
| final AssetId id; |
| |
| AssetNotFoundException(this.id); |
| |
| String toString() => "Could not find asset $id."; |
| } |
| |
| /// Replaces any occurrences of [AggregateException] in [errors] with the list |
| /// of errors it contains. |
| Iterable<BarbackException> flattenAggregateExceptions( |
| Iterable<BarbackException> errors) { |
| return errors.expand((error) { |
| if (error is! AggregateException) return [error]; |
| return error.errors; |
| }); |
| } |
| |
| /// The interface for exceptions from the barback graph or its transformers. |
| /// |
| /// These exceptions are never produced by programming errors in barback. |
| abstract class BarbackException implements Exception { |
| /// Takes a collection of [BarbackExceptions] and returns a single exception |
| /// that contains them all. |
| /// |
| /// If [errors] is empty, returns `null`. If it only has one error, that |
| /// error is returned. Otherwise, an [AggregateException] is returned. |
| static BarbackException aggregate(Iterable<BarbackException> errors) { |
| if (errors.isEmpty) return null; |
| if (errors.length == 1) return errors.single; |
| return new AggregateException(errors); |
| } |
| } |
| |
| /// An error that wraps a collection of other [BarbackException]s. |
| /// |
| /// It implicitly flattens any [AggregateException]s that occur in the list of |
| /// exceptions it wraps. |
| class AggregateException implements BarbackException { |
| final Set<BarbackException> errors; |
| |
| AggregateException(Iterable<BarbackException> errors) |
| : errors = flattenAggregateExceptions(errors).toSet(); |
| |
| String toString() { |
| var buffer = new StringBuffer(); |
| buffer.writeln("Multiple errors occurred:\n"); |
| |
| for (var error in errors) { |
| buffer.writeln(prefixLines(error.toString(), |
| prefix: " ", firstPrefix: "- ")); |
| } |
| |
| return buffer.toString(); |
| } |
| } |
| |
| /// Error thrown when two or more transformers both output an asset with [id]. |
| class AssetCollisionException implements BarbackException { |
| /// All the transforms that output an asset with [id]. |
| /// |
| /// If this only contains a single transform, that indicates that a |
| /// transformer produced an output that collides with a source asset or an |
| /// asset from a previous phase. |
| final Set<TransformInfo> transforms; |
| final AssetId id; |
| |
| AssetCollisionException(Iterable<TransformInfo> transforms, this.id) |
| : transforms = new Set.from(transforms); |
| |
| String toString() => "Transforms $transforms all emitted asset $id."; |
| } |
| |
| /// Error thrown when a transformer requests an input [id] which cannot be |
| /// found. |
| class MissingInputException implements BarbackException { |
| /// The transform that requested [id]. |
| final TransformInfo transform; |
| final AssetId id; |
| |
| MissingInputException(this.transform, this.id); |
| |
| String toString() => "Transform $transform tried to load missing input $id."; |
| } |
| |
| /// Error thrown when a transformer outputs an asset to a different package than |
| /// the primary input's. |
| class InvalidOutputException implements BarbackException { |
| /// The transform that output the asset. |
| final TransformInfo transform; |
| final AssetId id; |
| |
| InvalidOutputException(this.transform, this.id); |
| |
| String toString() => "Transform $transform emitted $id, which wasn't in the " |
| "same package (${transform.primaryId.package})."; |
| } |
| |
| /// Base class for an error that wraps another. |
| abstract class _WrappedException implements BarbackException { |
| /// The wrapped exception. |
| final error; |
| final Chain stackTrace; |
| |
| _WrappedException(this.error, StackTrace stackTrace) |
| : this.stackTrace = stackTrace == null ? null : |
| new Chain.forTrace(stackTrace); |
| |
| String get _message; |
| |
| String toString() { |
| var result = "$_message: $error"; |
| |
| var stack = stackTrace; |
| if (stack == null && error is Error) stack = error.stackTrace; |
| if (stack != null) { |
| result = "$result\n${stackTrace.terse}"; |
| } |
| |
| return result; |
| } |
| } |
| |
| /// Error wrapping an exception thrown by a transform. |
| class TransformerException extends _WrappedException { |
| /// The transform that threw the exception. |
| final TransformInfo transform; |
| |
| TransformerException(this.transform, error, StackTrace stackTrace) |
| : super(error, stackTrace); |
| |
| String get _message => "Transform $transform threw error"; |
| } |
| |
| /// Error thrown when a source asset [id] fails to load. |
| /// |
| /// This can be thrown either because the source asset was expected to exist and |
| /// did not or because reading it failed somehow. |
| class AssetLoadException extends _WrappedException { |
| final AssetId id; |
| |
| AssetLoadException(this.id, error, [StackTrace stackTrace]) |
| : super(error, stackTrace); |
| |
| String get _message => "Failed to load source asset $id"; |
| } |
| |
| /// Information about a single transform in the barback graph. |
| /// |
| /// Identifies a single transformation in the barback graph. |
| /// |
| /// A transformation is uniquely identified by the ID of its primary input, and |
| /// the transformer that is applied to it. |
| class TransformInfo { |
| /// The transformer that's run for this transform. |
| final Transformer transformer; |
| |
| /// The id of this transform's primary asset. |
| final AssetId primaryId; |
| |
| TransformInfo(this.transformer, this.primaryId); |
| |
| bool operator==(other) => |
| other is TransformInfo && |
| other.transformer == transformer && |
| other.primaryId == primaryId; |
| |
| int get hashCode => transformer.hashCode ^ primaryId.hashCode; |
| |
| String toString() => "$transformer on $primaryId"; |
| } |