Share LibrarySpecificUnits when possible

pkg/analyzer/test/src/context/context_test.dart

 // Copyright (c) 2014, 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.test.src.context.context_test;
 
 import 'dart:async';
 import 'dart:collection';
 
 import 'package:analyzer/dart/ast/ast.dart';
@@ skipping 1404 matching lines @@
     // must be in the "async" library - main context
     {
       List<Source> coreLibraries = context.getLibrariesContaining(intSource);
       expect(coreLibraries, hasLength(1));
       Source coreSource = coreLibraries[0];
       expect(coreSource.isInSystemLibrary, isTrue);
       expect(coreSource.shortName, 'async.dart');
     }
   }
 
+  void test_getLibrarySpecificUnit_definingCU_different() {
+    Source source1 = newSource('/lib1.dart');
+    Source source2 = newSource('/lib2.dart');
+    context.applyChanges(
+        new ChangeSet()..addedSource(source1)..addedSource(source2));
+    LibrarySpecificUnit lsu1 = context.getLibrarySpecificUnit(source1, source1);
+    expect(lsu1, isNotNull);
+    expect(lsu1.library, same(source1));
+    expect(lsu1.unit, same(source1));
+    LibrarySpecificUnit lsu2 = context.getLibrarySpecificUnit(source2, source2);
+    expect(lsu2, isNotNull);
+    expect(lsu2.library, same(source2));
+    expect(lsu2.unit, same(source2));
+  }
+
+  void test_getLibrarySpecificUnit_definingCU_explicit() {
+    Source source = newSource('/test.dart');
+    context.applyChanges(new ChangeSet()..addedSource(source));
+    LibrarySpecificUnit lsu1 = context.getLibrarySpecificUnit(source, source);
+    expect(lsu1, isNotNull);
+    expect(lsu1.library, same(source));
+    expect(lsu1.unit, same(source));
+    LibrarySpecificUnit lsu2 = context.getLibrarySpecificUnit(source, source);
+    expect(lsu2, same(lsu1));
+  }
+
+  void test_getLibrarySpecificUnit_definingCU_implicit() {
+    Source source = newSource('/test.dart');
+    LibrarySpecificUnit lsu1 = context.getLibrarySpecificUnit(source, source);
+    expect(lsu1, isNotNull);
+    expect(lsu1.library, same(source));
+    expect(lsu1.unit, same(source));
+    LibrarySpecificUnit lsu2 = context.getLibrarySpecificUnit(source, source);
+    expect(lsu2, equals(lsu1));
+  }
+
+  void test_getLibrarySpecificUnit_part_differentLibraries() {
+    Source library1 = newSource('/lib1.dart');
+    Source library2 = newSource('/lib2.dart');
+    Source part = newSource('/part.dart');
+    context.applyChanges(new ChangeSet()
+      ..addedSource(library1)
+      ..addedSource(library2)
+      ..addedSource(part));
+    LibrarySpecificUnit lsu1 = context.getLibrarySpecificUnit(library1, part);
+    expect(lsu1, isNotNull);
+    expect(lsu1.library, same(library1));
+    expect(lsu1.unit, same(part));
+    LibrarySpecificUnit lsu2 = context.getLibrarySpecificUnit(library2, part);
+    expect(lsu2, isNotNull);
+    expect(lsu2.library, same(library2));
+    expect(lsu2.unit, same(part));
+  }
+
+  void test_getLibrarySpecificUnit_part_differentParts() {
+    Source library = newSource('/lib.dart');
+    Source part1 = newSource('/part1.dart');
+    Source part2 = newSource('/part2.dart');
+    context.applyChanges(new ChangeSet()
+      ..addedSource(library)
+      ..addedSource(part1)
+      ..addedSource(part2));
+    LibrarySpecificUnit lsu1 = context.getLibrarySpecificUnit(library, part1);
+    expect(lsu1, isNotNull);
+    expect(lsu1.library, same(library));
+    expect(lsu1.unit, same(part1));
+    LibrarySpecificUnit lsu2 = context.getLibrarySpecificUnit(library, part2);
+    expect(lsu2, isNotNull);
+    expect(lsu2.library, same(library));
+    expect(lsu2.unit, same(part2));
+  }
+
+  void test_getLibrarySpecificUnit_part_explicit() {
+    Source library = newSource('/lib.dart');
+    Source part = newSource('/part.dart');
+    context
+        .applyChanges(new ChangeSet()..addedSource(library)..addedSource(part));
+    LibrarySpecificUnit lsu1 = context.getLibrarySpecificUnit(library, part);
+    expect(lsu1, isNotNull);
+    expect(lsu1.library, same(library));
+    expect(lsu1.unit, same(part));
+    LibrarySpecificUnit lsu2 = context.getLibrarySpecificUnit(library, part);
+    expect(lsu2, same(lsu1));
+  }
+
+  void test_getLibrarySpecificUnit_part_implicit() {
+    Source library = newSource('/lib.dart');
+    Source part = newSource('/part.dart');
+    LibrarySpecificUnit lsu1 = context.getLibrarySpecificUnit(library, part);
+    expect(lsu1, isNotNull);
+    expect(lsu1.library, same(library));
+    expect(lsu1.unit, same(part));
+    LibrarySpecificUnit lsu2 = context.getLibrarySpecificUnit(library, part);
+    expect(lsu2, isNotNull);
+    expect(lsu2.library, same(library));
+    expect(lsu2.unit, same(part));
+  }
+
   void test_getLineInfo() {
     Source source = addSource(
         "/test.dart",
         r'''
 library lib;
 
 main() {}''');
     LineInfo info = context.getLineInfo(source);
     expect(info, isNull);
     context.parseCompilationUnit(source);
@@ skipping 2540 matching lines @@
    * Initialize the visitor.
    */
   _ElementGatherer();
 
   @override
   void visitElement(Element element) {
     elements[element] = element;
     super.visitElement(element);
   }
 }