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barback/lib/src/errors.dart

Index: barback/lib/src/errors.dart
diff --git a/barback/lib/src/errors.dart b/barback/lib/src/errors.dart
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index 3488e31459528b3c9ac40c140715eb7b552774a4..0000000000000000000000000000000000000000
--- a/barback/lib/src/errors.dart
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-// 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/asset_id.dart';
-import 'transformer/wrapping_aggregate_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;
-
-  String get message => "$_message: ${getErrorMessage(error)}";
-
-  String get _message;
-
-  _WrappedException(error, StackTrace stackTrace)
-      : this.error = error,
-        this.stackTrace = _getChain(error, stackTrace);
-
-  String toString() {
-    var result = message;
-    if (stackTrace != null) result = "$result\n${stackTrace.terse}";
-    return result;
-  }
-}
-
-/// Returns the stack chain for [error] and [stackTrace].
-Chain _getChain(error, StackTrace stackTrace) {
-  if (error is Error && stackTrace == null) stackTrace = error.stackTrace;
-  if (stackTrace != null) return new Chain.forTrace(stackTrace);
-  return null;
-}
-
-/// 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 $id";
-}
-
-/// Information about a single transform in the barback graph.
-///
-/// Identifies a single transformation in the barback graph.
-///
-/// A transformation is uniquely identified by the ID of its primary input, and
-/// the transformer that is applied to it.
-class TransformInfo {
-  /// The transformer that's run for this transform.
-  ///
-  /// This may be a [Transformer] or a [WrappingAggregateTransformer]. It may
-  /// also return additional types in the future.
-  final transformer;
-
-  /// The id of this transform's primary asset.
-  final AssetId primaryId;
-
-  TransformInfo(transformer, this.primaryId)
-      : transformer = transformer is WrappingAggregateTransformer ?
-            transformer.transformer : transformer;
-
-  bool operator==(other) =>
-      other is TransformInfo &&
-      other.transformer == transformer &&
-      other.primaryId == primaryId;
-
-  int get hashCode => transformer.hashCode ^ primaryId.hashCode;
-
-  String toString() => "$transformer on $primaryId";
-}