Load patches via callback.

sdk/lib/_internal/compiler/implementation/library_loader.dart

Index: sdk/lib/_internal/compiler/implementation/library_loader.dart
diff --git a/sdk/lib/_internal/compiler/implementation/library_loader.dart b/sdk/lib/_internal/compiler/implementation/library_loader.dart
index c9b2d5c4f3938fed74fcefb0f1b57f879876c97f..bc6eac33022dc6a9e2df00962e2215e2e18a83fd 100644
--- a/sdk/lib/_internal/compiler/implementation/library_loader.dart
+++ b/sdk/lib/_internal/compiler/implementation/library_loader.dart
@@ -2,7 +2,30 @@
 // 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 dart2js;
+library dart2js.library_loader;
+
+import 'dart:async';
+import 'dart2jslib.dart'
+    show Compiler,
+         CompilerTask,
+         MessageKind,
+         Script,
+         invariant;
+import 'elements/elements.dart'
+    show CompilationUnitElement,
+         Element,
+         LibraryElement,
+         PrefixElement;
+import 'elements/modelx.dart'
+    show CompilationUnitElementX,
+         DeferredLoaderGetterElementX,
+         ErroneousElementX,
+         LibraryElementX,
+         PrefixElementX;
+import 'helpers/helpers.dart';
+import 'native_handler.dart' as native;
+import 'tree/tree.dart';
+import 'util/util.dart' show Link, LinkBuilder;
 
 /**
  * [CompilerTask] for loading libraries and setting up the import/export scopes.
@@ -112,11 +135,21 @@ abstract class LibraryLoader extends CompilerTask {
    * This is the main entry point for [LibraryLoader].
    */
   Future<LibraryElement> loadLibrary(Uri resolvedUri);
+}
 
-  // TODO(johnniwinther): Remove this when patches don't need special parsing.
-  Future registerLibraryFromTag(LibraryDependencyHandler handler,
-                                LibraryElement library,
-                                LibraryDependency tag);
+/// Callback for creating synthesized/patch libraries during library loading.
+abstract class LibraryLoaderCallback {

[floitsch, 2014/06/23 19:12:33]

Don't call this "callback". It took me some time to realize that the
LibraryLoaderCallback is not just a function typedef.

[Johnni Winther, 2014/06/24 08:11:20]

Done.

+  /// Call this when a new synthesized/patch library has been created.

[floitsch, 2014/06/23 19:12:33]

This is ambiguous.
Who needs to call this method? The implementer of the interface? The user of it?
The framework (in this file)?

"Must be called when a ..."


Why not "registerLibrary" and "processTags" ?
This should make it clearer what the purpose of these methods are.

[Johnni Winther, 2014/06/24 08:11:20]

Done.

+  ///
+  /// This call ensures that [library] will part of library dependency graph
+  /// used for computing import/export scopes.
+  void onLibraryCreated(LibraryElement library);
+
+  /// Call this when a new synthesized/patch library has been scanned.
+  ///
+  /// On this call library tags in [library] will be processed, allowing for
+  /// imports/exports/parts in the synthesized/patch library.
+  Future onLibraryScanned(LibraryElement library);
 }
 
 /**
@@ -221,7 +254,7 @@ class LibraryLoaderTask extends LibraryLoader {
       assert(currentHandler == null);
       // TODO(johnniwinther): Ensure that currentHandler correctly encloses the
       // loading of a library cluster.
-      currentHandler = new LibraryDependencyHandler(compiler);
+      currentHandler = new LibraryDependencyHandler(this);
       return createLibrary(currentHandler, null, resolvedUri)
           .then((LibraryElement library) {
         return compiler.withCurrentElement(library, () {
@@ -301,17 +334,11 @@ class LibraryLoaderTask extends LibraryLoader {
         }
       });
     }).then((_) {
-      // TODO(johnniwinther): Move callback to after patching.
-      compiler.onLibraryScanned(library);
-      return compiler.withCurrentElement(library, () {
-        checkDuplicatedLibraryName(library);
-        // Apply patch, if any.
-        if (library.isPlatformLibrary) {
-          return patchDartLibrary(handler, library, library.canonicalUri.path);
-        }
-      });
+      return compiler.onLibraryScanned(library, handler);
     }).then((_) {
       return compiler.withCurrentElement(library, () {
+        checkDuplicatedLibraryName(library);
+
         // Import dart:core if not already imported.
         if (!importsDartCore && !isDartCore(library.canonicalUri)) {
           return loadCoreLibrary(handler).then((LibraryElement coreLibrary) {
@@ -386,16 +413,6 @@ class LibraryLoaderTask extends LibraryLoader {
     });
   }
 
-  Future patchDartLibrary(LibraryDependencyHandler handler,
-                          LibraryElement library,
-                          String dartLibraryPath) {
-    if (library.isPatched) return new Future.value();
-    Uri patchUri = compiler.resolvePatchUri(dartLibraryPath);
-    if (patchUri == null) return new Future.value();
-
-    return compiler.patchParser.patchLibrary(handler, patchUri, library);
-  }
-
   /**
    * Handle a part tag in the scope of [library]. The [resolvedUri] given is
    * used as is, any URI resolution should be done beforehand.
@@ -465,8 +482,7 @@ class LibraryLoaderTask extends LibraryLoader {
             if (script == null) return null;
             LibraryElement element = new LibraryElementX(script, resolvedUri);
             compiler.withCurrentElement(element, () {
-              compiler.onLibraryCreated(element);
-              handler.registerNewLibrary(element);
+              handler.onLibraryCreated(element);
               native.maybeEnableNative(compiler, element);
               compiler.libraries[resolvedUri.toString()] = element;
               compiler.scanner.scanLibrary(element);
@@ -807,8 +823,8 @@ class LibraryDependencyNode {
  * libraries and to compute their import/export scopes through a fixed-point
  * algorithm.
  */
-class LibraryDependencyHandler {
-  final Compiler compiler;
+class LibraryDependencyHandler implements LibraryLoaderCallback {
+  final LibraryLoaderTask task;
 
   /**
    * Newly loaded libraries and their corresponding node in the library
@@ -819,7 +835,9 @@ class LibraryDependencyHandler {
   Map<LibraryElement, LibraryDependencyNode> nodeMap =
       new Map<LibraryElement, LibraryDependencyNode>();
 
-  LibraryDependencyHandler(Compiler this.compiler);
+  LibraryDependencyHandler(LibraryLoaderTask this.task);
+
+  Compiler get compiler => task.compiler;
 
   /// The libraries loaded with this handler.
   Iterable<LibraryElement> get loadedLibraries => nodeMap.keys;
@@ -917,4 +935,13 @@ class LibraryDependencyHandler {
   void registerLibraryExports(LibraryElement library) {
     nodeMap[library].registerInitialExports();
   }
+
+  void onLibraryCreated(LibraryElement library) {
+    compiler.onLibraryCreated(library);
+    registerNewLibrary(library);
+  }
+
+  Future onLibraryScanned(LibraryElement library) {
+    return task.processLibraryTags(this, library);
+  }
 }