Only reload libraries when they may have been modified.

runtime/bin/vmservice/loader.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.
 
 part of vmservice_io;
 
 _sanitizeWindowsPath(path) {
   // For Windows we need to massage the paths a bit according to
   // http://blogs.msdn.com/b/ie/archive/2006/12/06/file-uris-in-windows.aspx
   //
@@ skipping 301 matching lines @@
 _log(msg) {
   print("% $msg");
 }
 
 var _httpClient;
 
 // Send a response to the requesting isolate.
 void _sendResourceResponse(SendPort sp,
                            int tag,
                            Uri uri,
+                           Uri resolvedUri,
                            String libraryUrl,
                            dynamic data) {
   assert((data is List<int>) || (data is String));
-  var msg = new List(4);
+  var msg = new List(5);
   if (data is String) {
     // We encountered an error, flip the sign of the tag to indicate that.
     tag = -tag;
     if (libraryUrl == null) {
       data = 'Could not load "$uri": $data';
     } else {
       data = 'Could not import "$uri" from "$libraryUrl": $data';
     }
   }
   msg[0] = tag;
   msg[1] = uri.toString();
-  msg[2] = libraryUrl;
-  msg[3] = data;
+  msg[2] = resolvedUri.toString();
+  msg[3] = libraryUrl;
+  msg[4] = data;
   sp.send(msg);
 }
 
 // Send a response to the requesting isolate.
 void _sendExtensionImportResponse(SendPort sp,
                                   Uri uri,
                                   String libraryUrl,
                                   String resolvedUri) {
   var msg = new List(4);
   int tag = _Dart_kImportExtension;
@@ skipping 20 matching lines @@
   _httpClient.getUrl(resolvedUri)
     .then((HttpClientRequest request) => request.close())
     .then((HttpClientResponse response) {
       var builder = new BytesBuilder(copy: false);
       response.listen(
           builder.add,
           onDone: () {
             if (response.statusCode != 200) {
               var msg = "Failure getting $resolvedUri:\n"
                         "  ${response.statusCode} ${response.reasonPhrase}";
-              _sendResourceResponse(sp, tag, uri, libraryUrl, msg);
+              _sendResourceResponse(sp, tag, uri, resolvedUri, libraryUrl, msg);
             } else {
-              _sendResourceResponse(sp, tag, uri, libraryUrl,
+              _sendResourceResponse(sp, tag, uri, resolvedUri, libraryUrl,
                                     builder.takeBytes());
             }
           },
           onError: (e) {
-            _sendResourceResponse(sp, tag, uri, libraryUrl, e.toString());
+            _sendResourceResponse(
+                sp, tag, uri, resolvedUri, libraryUrl, e.toString());
           });
     })
     .catchError((e) {
-      _sendResourceResponse(sp, tag, uri, libraryUrl, e.toString());
+      _sendResourceResponse(
+        sp, tag, uri, resolvedUri, libraryUrl, e.toString());
     });
   // It's just here to push an event on the event loop so that we invoke the
   // scheduled microtasks.
   Timer.run(() {});
 }
 
 void _loadFile(SendPort sp,
                int tag,
                Uri uri,
                Uri resolvedUri,
                String libraryUrl) {
   var path = resolvedUri.toFilePath();
   var sourceFile = new File(path);
   sourceFile.readAsBytes().then((data) {
-    _sendResourceResponse(sp, tag, uri, libraryUrl, data);
+    _sendResourceResponse(sp, tag, uri, resolvedUri, libraryUrl, data);
   },
   onError: (e) {
-    _sendResourceResponse(sp, tag, uri, libraryUrl, e.toString());
+    _sendResourceResponse(sp, tag, uri, resolvedUri, libraryUrl, e.toString());
   });
 }
 
 void _loadDataUri(SendPort sp,
                   int tag,
                   Uri uri,
                   Uri resolvedUri,
                   String libraryUrl) {
   try {
     var mime = uri.data.mimeType;
     if ((mime != "application/dart") &&
         (mime != "text/plain")) {
       throw "MIME-type must be application/dart or text/plain: $mime given.";
     }
     var charset = uri.data.charset;
     if ((charset != "utf-8") &&
         (charset != "US-ASCII")) {
       // The C++ portion of the embedder assumes UTF-8.
       throw "Only utf-8 or US-ASCII encodings are supported: $charset given.";
     }
-    _sendResourceResponse(sp, tag, uri, libraryUrl, uri.data.contentAsBytes());
+    _sendResourceResponse(
+        sp, tag, uri, resolvedUri, libraryUrl, uri.data.contentAsBytes());
   } catch (e) {
-    _sendResourceResponse(sp, tag, uri, libraryUrl,
+    _sendResourceResponse(sp, tag, uri, resolvedUri, libraryUrl,
                           "Invalid data uri ($uri):\n  $e");
   }
 }
 
 // Loading a package URI needs to first map the package name to a loadable
 // URI.
 _loadPackage(IsolateLoaderState loaderState,
              SendPort sp,
              bool traceLoading,
              int tag,
              Uri uri,
              Uri resolvedUri,
              String libraryUrl) {
   if (loaderState._packagesReady) {
     var resolvedUri;
     try {
       resolvedUri = loaderState._resolvePackageUri(uri);
     } catch (e, s) {
       if (traceLoading) {
         _log("Exception ($e) when resolving package URI: $uri");
       }
       // Report error.
       _sendResourceResponse(sp,
                             tag,
                             uri,
+                            resolvedUri,
                             libraryUrl,
                             e.toString());
       return;
     }
     // Recursively call with the new resolved uri.
     _handleResourceRequest(loaderState,
                            sp,
                            traceLoading,
                            tag,
                            uri,
@@ skipping 43 matching lines @@
     _loadPackage(loaderState,
                  sp,
                  traceLoading,
                  tag,
                  uri,
                  resolvedUri,
                  libraryUrl);
   } else {
     _sendResourceResponse(sp, tag,
                           uri,
+                          resolvedUri,
                           libraryUrl,
                           'Unknown scheme (${resolvedUri.scheme}) for '
                           '$resolvedUri');
   }
 }
 
 // Handling of packages requests. Finding and parsing of .packages file or
 // packages/ directories.
 const _LF    = 0x0A;
 const _CR    = 0x0D;
@@ skipping 528 matching lines @@
             _log('Unknown scheme (${pathUri.scheme}) in $pathUri.');
           }
           _sendExtensionImportResponse(sp, uri, libraryUri, null);
         break;
       }
     break;
     default:
       _log('Unknown loader request tag=$tag from $isolateId');
   }
 }