Properly set UnlinkedReference.prefixReference in summaries.

pkg/analyzer/lib/src/summary/summarize_elements.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.
 
 library serialization.elements;
 
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
 import 'package:analyzer/src/dart/element/type.dart';
 import 'package:analyzer/src/generated/resolver.dart';
@@ skipping 120 matching lines @@
    * closure of exports.
    */
   final Set<LibraryElement> librariesAddedToTransitiveExportClosure =
       new Set<LibraryElement>();
 
   /**
    * [BuilderContext] used to serialize the output summary.
    */
   final BuilderContext ctx;
 
+  /**
+   * Map from imported element to the prefix which may be used to refer to that
+   * element, or null if no prefix is needed.
+   */
+  final Map<Element, PrefixElement> prefixMap = <Element, PrefixElement>{};
+
   _LibrarySerializer(this.ctx, this.libraryElement, this.typeProvider) {
     dependencies.add(encodePrelinkedDependency(ctx));
     dependencyMap[libraryElement] = 0;
   }
 
   /**
    * Retrieve the library element for `dart:core`.
    */
   LibraryElement get coreLibrary => typeProvider.objectType.element.library;
 
@@ skipping 118 matching lines @@
     if (librariesAddedToTransitiveExportClosure.add(exportedLibrary)) {
       serializeDependency(exportedLibrary);
       for (LibraryElement transitiveExport
           in exportedLibrary.exportedLibraries) {
         addTransitiveExportClosure(transitiveExport);
       }
     }
   }
 
   /**
+   * Fill in [prefixMap] using information from [libraryElement.imports].
+   */
+  void computePrefixMap() {
+    for (ImportElement import in libraryElement.imports) {

[scheglov, 2016/01/09 22:51:31]

We could skip analyzing an import if it does not have any prefix.

[Paul Berry, 2016/01/10 02:08:28]

Done.

+      import.importedLibrary.exportNamespace.definedNames
+          .forEach((String name, Element e) {
+        if (import.combinators.any((NamespaceCombinator combinator) =>
+            doesCombinatorReject(combinator, name))) {
+          return;
+        }
+        prefixMap[e] = import.prefix;
+      });
+    }
+  }
+
+  /**
+   * Determine if the given [combinator] would reject an element having the
+   * given [name].
+   */
+  bool doesCombinatorReject(NamespaceCombinator combinator, String name) {
+    if (combinator is ShowElementCombinator) {
+      return !combinator.shownNames.contains(name);
+    } else if (combinator is HideElementCombinator) {
+      return combinator.hiddenNames.contains(name);
+    } else {
+      throw new StateError(
+          'Unexpected combinator type ${combinator.runtimeType}');
+    }
+  }
+
+  /**
    * Compute the appropriate De Bruijn index to represent the given type
    * parameter [type].
    */
   int findTypeParameterIndex(TypeParameterType type, Element context) {
     int index = 0;
     while (context != null) {
       List<TypeParameterElement> typeParameters;
       if (context is ClassElement) {
         typeParameters = context.typeParameters;
       } else if (context is FunctionTypeAliasElement) {
@@ skipping 223 matching lines @@
   }
 
   /**
    * Serialize the whole library element into a [PrelinkedLibrary].  Should be
    * called exactly once for each instance of [_LibrarySerializer].
    *
    * The unlinked compilation units are stored in [unlinkedUnits], and their
    * absolute URIs are stored in [unitUris].
    */
   PrelinkedLibraryBuilder serializeLibrary() {
+    computePrefixMap();
     PrelinkedLibraryBuilder pb = new PrelinkedLibraryBuilder(ctx);
     addCompilationUnitElements(libraryElement.definingCompilationUnit, 0);
     for (int i = 0; i < libraryElement.parts.length; i++) {
       addCompilationUnitElements(libraryElement.parts[i], i + 1);
     }
     pb.units = prelinkedUnits;
     pb.dependencies = dependencies;
     pb.importDependencies = prelinkedImports;
     return pb;
   }
@@ skipping 104 matching lines @@
           assert(unlinkedReferences.length == prelinkedReferences.length);
           CompilationUnitElement unitElement =
               element.getAncestor((Element e) => e is CompilationUnitElement);
           int unit = dependentLibrary.units.indexOf(unitElement);
           assert(unit != -1);
           int numTypeParameters = 0;
           if (element is TypeParameterizedElement) {
             numTypeParameters = element.typeParameters.length;
           }
           int index = unlinkedReferences.length;
-          // TODO(paulberry): set UnlinkedReference.prefix.
-          unlinkedReferences
-              .add(encodeUnlinkedReference(ctx, name: element.name));
+          // Figure out a prefix that may be used to refer to the given type.
+          // TODO(paulberry): to avoid subtle relinking inconsistencies we
+          // should use the actual prefix from the AST (a given type may be
+          // reachable via multiple prefixes), but sadly, this information is
+          // not recorded in the element model.
+          int prefixReference = 0;
+          PrefixElement prefix = prefixMap[element];
+          if (prefix != null) {
+            prefixReference = serializePrefix(prefix);
+          }
+          unlinkedReferences.add(encodeUnlinkedReference(ctx,
+              name: element.name, prefixReference: prefixReference));
           prelinkedReferences.add(encodePrelinkedReference(ctx,
               dependency: serializeDependency(dependentLibrary),
               kind: element is FunctionTypeAliasElement
                   ? PrelinkedReferenceKind.typedef
                   : PrelinkedReferenceKind.classOrEnum,
               unit: unit,
               numTypeParameters: numTypeParameters));
           return index;
         });
       }
@@ skipping 42 matching lines @@
     b.nameOffset = variable.nameOffset;
     b.type = serializeTypeRef(variable.type, variable);
     b.isStatic = variable.isStatic && variable.enclosingElement is ClassElement;
     b.isFinal = variable.isFinal;
     b.isConst = variable.isConst;
     b.hasImplicitType = variable.hasImplicitType;
     b.documentationComment = serializeDocumentation(variable);
     return b;
   }
 }