Share LibrarySpecificUnits when possible

pkg/analyzer/lib/src/context/context.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 analyzer.src.context.context;
 
 import 'dart:async';
 import 'dart:collection';
 
 import 'package:analyzer/dart/ast/ast.dart';
@@ skipping 626 matching lines @@
     }
     _onSourcesChangedController.add(new SourcesChangedEvent(changeSet));
     return new ApplyChangesStatus(changeSet.addedSources.isNotEmpty ||
         changeSet.changedContents.isNotEmpty ||
         changeSet.deletedSources.isNotEmpty ||
         changedSources.isNotEmpty ||
         removedSources.isNotEmpty);
   }
 
   @override
+  AnalysisTarget canonicalizeTarget(AnalysisTarget target) {
+    if (target is LibrarySpecificUnit) {
+      return getLibrarySpecificUnit(target.library, target.unit);
+    }
+    return target;
+  }
+
+  @override
   String computeDocumentationComment(Element element) =>
       element?.documentationComment;
 
   @override
   List<AnalysisError> computeErrors(Source source) {
     String name = source.shortName;
     if (AnalysisEngine.isHtmlFileName(name)) {
       return computeResult(source, HTML_ERRORS);
     }
     return computeResult(source, DART_ERRORS);
@@ skipping 192 matching lines @@
     if (_contentCache.getContents(source) != null) {
       return true;
     }
     return source.exists();
   }
 
   @override
   CacheEntry getCacheEntry(AnalysisTarget target) {
     CacheEntry entry = _cache.get(target);
     if (entry == null) {
+      target = canonicalizeTarget(target);
       entry = new CacheEntry(target);
       ImplicitAnalysisEvent event = null;
       if (target is Source) {
         entry.modificationTime = getModificationStamp(target);
         event = new ImplicitAnalysisEvent(target, true);
       }
       _cache.put(entry);
       if (event != null) {
         _implicitAnalysisEventsController.add(event);
       }
@@ skipping 131 matching lines @@
       return entry.getValue(REFERENCED_LIBRARIES);
     }
     return Source.EMPTY_LIST;
   }
 
   @override
   LibraryElement getLibraryElement(Source source) =>
       getResult(source, LIBRARY_ELEMENT);
 
   @override
+  LibrarySpecificUnit getLibrarySpecificUnit(Source library, Source unit) {
+    CacheEntry entry = analysisCache.get(unit);
+    if (entry != null) {
+      LibrarySpecificUnit lsu = entry.librarySpecificUnit;
+      if (lsu == null) {
+        lsu = new LibrarySpecificUnit(library, unit);
+        entry.librarySpecificUnit = lsu;
+        return lsu;
+      } else if (lsu.library == library && lsu.unit == unit) {
+        return lsu;
+      }
+    }
+    return new LibrarySpecificUnit(library, unit);
+  }
+
+  @override
   LineInfo getLineInfo(Source source) => getResult(source, LINE_INFO);
 
   @override
   int getModificationStamp(Source source) {
     int stamp = _contentCache.getModificationStamp(source);
     if (stamp != null) {
       return stamp;
     }
     return source.modificationStamp;
   }
@@ skipping 1276 matching lines @@
     }
     DartSdk sdk = factory.dartSdk;
     if (sdk == null) {
       throw new IllegalArgumentException(
           "The source factory for an SDK analysis context must have a DartUriResolver");
     }
     return new AnalysisCache(
         <CachePartition>[AnalysisEngine.instance.partitionManager.forSdk(sdk)]);
   }
 }