Support extensions with multiple periods in Transformer.allowedExtensions.

pkg/barback/lib/src/transformer.dart

 // 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.transformer;
 
 import 'dart:async';
 
 import 'asset.dart';
 import 'transform.dart';
+import 'utils.dart';
 
 /// A [Transformer] represents a processor that takes in one or more input
 /// assets and uses them to generate one or more output assets.
 ///
 /// Dart2js, a SASS->CSS processor, a CSS spriter, and a tool to concatenate
 /// files are all examples of transformers. To define your own transformation
 /// step, extend (or implement) this class.
 ///
 /// If possible, transformers should implement [DeclaringTransformer] as well to
 /// help barback optimize the package graph.
 abstract class Transformer {
   /// Override this to return a space-separated list of file extensions
   /// (with leading `.`) that are allowed for the primary inputs to this

[Bob Nystrom, 2014/03/12 23:25:28]

Remove the "(with leading `.`)" part.

[nweiz, 2014/03/12 23:30:48]

Done.

   /// transformer.
   ///
+  /// Each extension must begin with a leading `.`.
+  ///
   /// If you don't override [isPrimary] yourself, it defaults to allowing any
   /// asset whose extension matches one of the ones returned by this. If you
   /// don't override [isPrimary] *or* this, it allows all files.
   String get allowedExtensions => null;
 
+  Transformer() {
+    if (allowedExtensions == null) return;
+
+    var invalidExtensions = allowedExtensions.split(" ")
+        .where((extension) => !extension.startsWith("."))
+        .map((extension) => '"$extension"');
+    if (invalidExtensions.isEmpty) return;
+
+    throw new FormatException('Each extension in $this.allowedExtensions '
+        'must begin with a ".", but ${toSentence(invalidExtensions)} '
+        '${pluralize("doesn't", invalidExtensions.length, plural: "don't")}.');
+  }
+
   /// Returns `true` if [input] can be a primary input for this transformer.
   ///
   /// While a transformer can read from multiple input files, one must be the
   /// "primary" input. This asset determines whether the transformation should
   /// be run at all. If the primary input is removed, the transformer will no
   /// longer be run.
   ///
   /// A concrete example is dart2js. When you run dart2js, it will traverse
   /// all of the imports in your Dart source files and use the contents of all
   /// of those to generate the final JS. However you still run dart2js "on" a
   /// single file: the entrypoint Dart file that has your `main()` method.
   /// This entrypoint file would be the primary input.
   ///
   /// If this is not overridden, defaults to allow any asset whose extension
   /// matches one of the ones returned by [allowedExtensions]. If *that* is
   /// not overridden, allows all assets.
   Future<bool> isPrimary(Asset input) {
     // Allow all files if [primaryExtensions] is not overridden.
     if (allowedExtensions == null) return new Future.value(true);
 
     for (var extension in allowedExtensions.split(" ")) {
-      if (input.id.extension == extension) return new Future.value(true);
+      if (input.id.path.endsWith(extension)) return new Future.value(true);
     }
 
     return new Future.value(false);
   }
 
   /// Run this transformer on on the primary input specified by [transform].
   ///
   /// The [transform] is used by the [Transformer] for two purposes (in
   /// addition to accessing the primary input). It can call `getInput()` to
   /// request additional input assets. It also calls `addOutput()` to provide
   /// generated assets back to the system. Either can be called multiple times,
   /// in any order.
   ///
   /// In other words, a Transformer's job is to find all inputs for a
   /// transform, starting at the primary input, then generate all output assets
   /// and yield them back to the transform.
   Future apply(Transform transform);
 
   String toString() => runtimeType.toString().replaceAll("Transformer", "");
 }