Adds a repeatable --url_mapping flag to dartanalyzer

pkg/analyzer/lib/src/generated/source.dart

Index: pkg/analyzer/lib/src/generated/source.dart
===================================================================
--- pkg/analyzer/lib/src/generated/source.dart	(revision 43472)
+++ pkg/analyzer/lib/src/generated/source.dart	(working copy)
@@ -17,7 +17,9 @@
 import 'engine.dart';
 import 'java_core.dart';
 import 'java_engine.dart';
+import 'java_io.dart' show JavaFile;
 import 'sdk.dart' show DartSdk;
+import 'source_io.dart' show FileBasedSource;
 
 /**
  * A function that is used to handle [ContentCache] entries.
@@ -165,6 +167,24 @@
   static bool isDartUri(Uri uri) => DART_SCHEME == uri.scheme;
 }
 
+class CustomUriResolver extends UriResolver {

[Brian Wilkerson, 2015/02/13 23:56:13]

It would be good to have some tests for this class.

[zra, 2015/02/14 01:01:56]

Done.

+  final Map<String, String> _urlMappings;
+
+  CustomUriResolver(this._urlMappings);
+
+  @override
+  Source resolveAbsolute(Uri uri) {
+    var mapping = _urlMappings[uri.toString()];
+    if (mapping == null) return null;
+
+    var fileUri = new Uri.file(mapping);
+    if (!fileUri.isAbsolute) return null;

[Brian Wilkerson, 2015/02/13 23:56:13]

I don't have source available at the moment, but in Java, the method
isAbsolute() means "has a scheme". I believe Uri.file always provides a "file"
scheme, so I'm guessing this condition isn't doing what you think it is. (But
I'm not that familiar with Dart's Uri class yet, so it might work differently.)

[zra, 2015/02/14 01:01:56]

The docs for Uri.file say "If the path starts with a path separator an absolute
URI is created. Otherwise a relative URI is created." It looks like this meaning
of "absolute" is consistent other places in the docs.

+
+    var javaFile = new JavaFile.fromUri(fileUri);
+    return new FileBasedSource.con1(javaFile);
+  }
+}
+
 /**
  * Instances of the class `LineInfo` encapsulate information about line and column information
  * within a source file.