Support all Transform methods on ForeignTransform.

R=alanknight@google.com

Review URL: https://codereview.chromium.org//29343004

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@28895 260f80e4-7a28-3924-810f-c04153c831b5

sdk/lib/_internal/pub/lib/src/barback/load_transformers.dart

@@ -19,8 +19,8 @@ import 'server.dart';
 
 /// A Dart script to run in an isolate.
 ///
-/// This script serializes one or more transformers defined in a Dart library and
-/// marhsals calls to and from them with the host isolate.
+/// This script serializes one or more transformers defined in a Dart library
+/// and marshals calls to and from them with the host isolate.
 const _TRANSFORMER_ISOLATE = """
 import 'dart:async';
 import 'dart:isolate';
@@ -116,6 +116,14 @@ class ForeignTransform implements Transform {
     })).then(_deserializeAsset);
   }
 
+  Future<String> readInputAsString(AssetId id, {Encoding encoding}) {
+    if (encoding == null) encoding = UTF8;
+    return getInput(id).then((input) => input.readAsString(encoding: encoding));
+  }
+
+  Stream<List<int>> readInput(AssetId id) =>
+      _futureStream(getInput(id).then((input) => input.read()));
+
   void addOutput(Asset output) {
     _port.send({
       'type': 'addOutput',
@@ -335,6 +343,23 @@ String getErrorMessage(error) {
     return error.toString();
   }
 }
+
+/// Returns a buffered stream that will emit the same values as the stream
+/// returned by [future] once [future] completes. If [future] completes to an
+/// error, the return value will emit that error and then close.
+Stream _futureStream(Future<Stream> future) {
+  var controller = new StreamController(sync: true);
+  future.then((stream) {
+    stream.listen(
+        controller.add,
+        onError: controller.addError,
+        onDone: controller.close);
+  }).catchError((e, stackTrace) {
+    controller.addError(e, stackTrace);
+    controller.close();
+  });
+  return controller.stream;
+}
 """;
 
 /// Load and return all transformers and groups from the library identified by

sdk/lib/_internal/pub/test/transformer/can_use_read_input_as_string_test.dart

@@ -0,0 +1,53 @@
+// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS d.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 pub_tests;
+
+import '../descriptor.dart' as d;
+import '../test_pub.dart';
+import '../serve/utils.dart';
+
+const TRANSFORMER = """
+import 'dart:async';
+
+import 'package:barback/barback.dart';
+
+class RewriteTransformer extends Transformer {
+  RewriteTransformer.asPlugin();
+
+  String get allowedExtensions => '.txt';
+
+  Future apply(Transform transform) {
+    return transform.readInputAsString(transform.primaryInput.id)
+        .then((contents) {
+      var id = transform.primaryInput.id.changeExtension(".out");
+      transform.addOutput(new Asset.fromString(id, "\$contents.out"));
+    });
+  }
+}
+""";
+
+main() {
+  initConfig();
+  integration("a transform can use readInputAsString", () {
+    d.dir(appPath, [
+      d.pubspec({
+        "name": "myapp",
+        "transformers": ["myapp/src/transformer"]
+      }),
+      d.dir("lib", [d.dir("src", [
+        d.file("transformer.dart", TRANSFORMER)
+      ])]),
+      d.dir("web", [
+        d.file("foo.txt", "foo")
+      ])
+    ]).create();
+
+    createLockFile('myapp', pkg: ['barback']);
+
+    startPubServe();
+    requestShouldSucceed("foo.out", "foo.out");
+    endPubServe();
+  });
+}

sdk/lib/_internal/pub/test/transformer/can_use_read_input_test.dart

@@ -0,0 +1,54 @@
+// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS d.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 pub_tests;
+
+import '../descriptor.dart' as d;
+import '../test_pub.dart';
+import '../serve/utils.dart';
+
+const TRANSFORMER = """
+import 'dart:async';
+
+import 'package:barback/barback.dart';
+
+class RewriteTransformer extends Transformer {
+  RewriteTransformer.asPlugin();
+
+  String get allowedExtensions => '.txt';
+
+  Future apply(Transform transform) {
+    return transform.readInput(transform.primaryInput.id).toList()
+        .then((contents) {
+      var id = transform.primaryInput.id.changeExtension(".out");
+      var asset = new Asset.fromString(id, "\$contents.out");
+      transform.addOutput(asset);
+    });
+  }
+}
+""";
+
+main() {
+  initConfig();
+  integration("a transform can use readInputAsString", () {
+    d.dir(appPath, [
+      d.pubspec({
+        "name": "myapp",
+        "transformers": ["myapp/src/transformer"]
+      }),
+      d.dir("lib", [d.dir("src", [
+        d.file("transformer.dart", TRANSFORMER)
+      ])]),
+      d.dir("web", [
+        d.file("foo.txt", "foo")
+      ])
+    ]).create();
+
+    createLockFile('myapp', pkg: ['barback']);
+
+    startPubServe();
+    requestShouldSucceed("foo.out", "[[102 111 111]].out");
+    endPubServe();
+  });
+}