Support source maps in server mode

lib/src/server/server.dart

 // Copyright (c) 2015, 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.
 
 /// Development server that compiles Dart to JS on the fly.
 library dev_compiler.src.server;
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
@@ skipping 116 matching lines @@
         resourceOutputPath(node.uri, _entryNode.uri, options.runtimeDir);
     assert(filepath != null);
     filepath = path.join(outputDir, filepath);
     var dir = path.dirname(filepath);
     new Directory(dir).createSync(recursive: true);
     new File.fromUri(node.source.uri).copySync(filepath);
     if (_hashing) node.cachingHash = computeHashFromFile(filepath);
   }
 
   void _buildDartLibrary(DartSourceNode node) {
+    print('Compiling ${node.uri}');
     var source = node.source;
     // TODO(sigmund): find out from analyzer team if there is a better way
     context.applyChanges(new ChangeSet()..changedSource(source));
     var entryUnit = context.resolveCompilationUnit2(source, source);
     var lib = entryUnit.element.enclosingElement;
     if (!options.checkSdk && lib.source.uri.scheme == 'dart') return;
     var current = node.info;
     if (current != null) {
       assert(current.library == lib);
     } else {
@@ skipping 99 matching lines @@
         // TODO(jmesserly): this logic is duplicated in a few places
         this._entryPath = compiler.options.sourceOptions.useImplicitHtml
             ? SourceResolverOptions.implicitHtmlFile
             : entryPath;
 
   Future start() async {
     // Create output directory if needed. shelf_static will fail otherwise.
     var out = new Directory(outDir);
     if (!await out.exists()) await out.create(recursive: true);
 
+    var mainHandler =
+        shelf_static.createStaticHandler(outDir, defaultDocument: _entryPath);
+    var sourceHandler = shelf_static.createStaticHandler(compiler.inputBaseDir,
+        serveFilesOutsidePath: true);
+    var topLevelHandler = (shelf.Request request) {
+      var path = request.url.path;
+      if (path.endsWith('.dart')) {
+        return sourceHandler(request);
+      } else {
+        return mainHandler(request);
+      }
+    };
+
     var handler = const shelf.Pipeline()
         .addMiddleware(rebuildAndCache)
-        .addHandler(shelf_static.createStaticHandler(outDir,
-            defaultDocument: _entryPath));
+        .addHandler(topLevelHandler);
     await shelf.serve(handler, host, port);
     print('Serving $_entryPath at http://$host:$port/');
     // Give the compiler a head start. This is not needed for correctness,
     // but will likely speed up the first load. Regardless of whether compile
     // succeeds we should still start the server.
     compiler.run();
     // Server has started so this future will complete.
   }
 
   shelf.Handler rebuildAndCache(shelf.Handler handler) => (request) {
-        print('requested $GREEN_COLOR${request.url}$NO_COLOR');
         // Trigger recompile only when requesting the HTML page.
         var segments = request.url.pathSegments;
         bool isEntryPage = segments.length == 0 || segments[0] == _entryPath;
         if (isEntryPage) compiler._runAgain();
 
         // To help browsers cache resources that don't change, we serve these
         // resources by adding a query parameter containing their hash:
         //    /{path-to-file.js}?____cached={hash}
         var hash = request.url.queryParameters['____cached'];
         var response = handler(request);
@@ skipping 27 matching lines @@
   Source resolveAbsolute(Uri uri, [Uri actualUri]) {
     var src = resolver.resolveAbsolute(uri, actualUri);
     return src.exists() ? src : null;
   }
 
   Uri restoreAbsolute(Source source) => resolver.restoreAbsolute(source);
 }
 
 final _log = new Logger('dev_compiler.src.server');
 final _earlyErrorResult = new CheckerResults(const [], true);