Compute exported top-level declarations.

R=brianwilkerson@google.com, paulberry@google.com
BUG=

Review URL: https://codereview.chromium.org/2542883003 .

pkg/analyzer/lib/src/dart/analysis/file_state.dart

@@ -102,6 +102,7 @@ class FileState {
   String _transitiveSignature;
 
   List<TopLevelDeclaration> _topLevelDeclarations;
+  List<TopLevelDeclaration> _exportedTopLevelDeclarations;
 
   FileState._(this._fsState, this.path, this.uri, this.source);
 
@@ -131,6 +132,55 @@ class FileState {
    */
   List<FileState> get exportedFiles => _exportedFiles;
 
+  /**
+   * Return [TopLevelDeclaration]s exported from the this library file.
+   */
+  List<TopLevelDeclaration> get exportedTopLevelDeclarations {
+    if (_exportedTopLevelDeclarations == null) {
+      _exportedTopLevelDeclarations = <TopLevelDeclaration>[];
+
+      Set<FileState> seenLibraries = new Set<FileState>();
+
+      /**
+       * Compute [TopLevelDeclaration]s exported from the [library].
+       */
+      List<TopLevelDeclaration> computeExported(FileState library) {
+        var declarations = <String, TopLevelDeclaration>{};
+        if (seenLibraries.add(library)) {
+          // Append the library declarations.
+          for (TopLevelDeclaration t in library.topLevelDeclarations) {
+            declarations[t.name] = t;
+          }
+          for (FileState part in library.partedFiles) {
+            for (TopLevelDeclaration t in part.topLevelDeclarations) {
+              declarations[t.name] = t;
+            }
+          }
+
+          // Append the exported declarations.
+          for (int i = 0; i < library._exportedFiles.length; i++) {
+            List<TopLevelDeclaration> exported =
+                computeExported(library._exportedFiles[i]);
+            for (TopLevelDeclaration t in exported) {
+              if (!declarations.containsKey(t.name) &&
+                  library._exportFilters[i].accepts(t.name)) {
+                declarations[t.name] = t;
+              }
+            }
+          }
+
+          // We're done with this library.
+          seenLibraries.remove(library);
+        }
+
+        return declarations.values.toList();
+      }
+
+      _exportedTopLevelDeclarations = computeExported(this);
+    }
+    return _exportedTopLevelDeclarations;
+  }
+
   @override
   int get hashCode => uri.hashCode;
 
@@ -353,18 +403,24 @@ class FileState {
     _referencedNames = new Set<String>.from(driverUnlinkedUnit.referencedNames);
     _unlinked = driverUnlinkedUnit.unit;
     _lineInfo = new LineInfo(_unlinked.lineStarts);
+    _topLevelDeclarations = null;
+
+    // Prepare API signature.
     List<int> newApiSignature = _unlinked.apiSignature;
     bool apiSignatureChanged = _apiSignature != null &&
         !_equalByteLists(_apiSignature, newApiSignature);
     _apiSignature = newApiSignature;
 
-    // If the API signature changed, flush transitive signatures.
+    // The API signature changed.
+    //   Flush transitive signatures of affected files.
+    //   Flush exported top-level declarations of all files.
     if (apiSignatureChanged) {
       for (FileState file in _fsState._uriToFile.values) {
         if (file._transitiveFiles != null &&
             file._transitiveFiles.contains(this)) {
           file._transitiveSignature = null;
         }
+        file._exportedTopLevelDeclarations = null;
       }
     }
 

pkg/analyzer/test/src/dart/analysis/file_state_test.dart

@@ -58,6 +58,199 @@ class FileSystemStateTest {
         provider, sourceFactory, analysisOptions, new Uint32List(0), '');
   }
 
+  test_exportedTopLevelDeclarations_export() {
+    String a = _p('/aaa/lib/a.dart');
+    String b = _p('/aaa/lib/b.dart');
+    provider.newFile(
+        a,
+        r'''
+class A {}
+''');
+    provider.newFile(
+        b,
+        r'''
+export 'a.dart';
+class B {}
+''');
+    FileState file = fileSystemState.getFileForPath(b);
+    List<TopLevelDeclaration> declarations = file.exportedTopLevelDeclarations;
+    expect(declarations.map((t) => t.name), unorderedEquals(['A', 'B']));
+  }
+
+  test_exportedTopLevelDeclarations_export2_show() {
+    String a = _p('/aaa/lib/a.dart');
+    String b = _p('/aaa/lib/b.dart');
+    String c = _p('/aaa/lib/c.dart');
+    provider.newFile(
+        a,
+        r'''
+class A1 {}
+class A2 {}
+class A3 {}
+''');
+    provider.newFile(
+        b,
+        r'''
+export 'a.dart' show A1, A2;
+class B1 {}
+class B2 {}
+''');
+    provider.newFile(
+        c,
+        r'''
+export 'b.dart' show A2, A3, B1;
+class C {}
+''');
+    _assertExportedTopLevelDeclarations(c, ['A2', 'B1', 'C']);
+  }
+
+  test_exportedTopLevelDeclarations_export_flushOnChange() {
+    String a = _p('/aaa/lib/a.dart');
+    String b = _p('/aaa/lib/b.dart');
+    provider.newFile(
+        a,
+        r'''
+class A {}
+''');
+    provider.newFile(
+        b,
+        r'''
+export 'a.dart';
+class B {}
+''');
+
+    // Initial exported declarations.
+    _assertExportedTopLevelDeclarations(b, ['A', 'B']);
+
+    // Update a.dart, so a.dart and b.dart exported declarations are flushed.
+    provider.newFile(a, 'class A {} class A2 {}');
+    fileSystemState.getFileForPath(a).refresh();
+    _assertExportedTopLevelDeclarations(b, ['A', 'A2', 'B']);
+  }
+
+  test_exportedTopLevelDeclarations_export_hide() {
+    String a = _p('/aaa/lib/a.dart');
+    String b = _p('/aaa/lib/b.dart');
+    provider.newFile(
+        a,
+        r'''
+class A1 {}
+class A2 {}
+class A3 {}
+''');
+    provider.newFile(
+        b,
+        r'''
+export 'a.dart' hide A2;
+class B {}
+''');
+    _assertExportedTopLevelDeclarations(b, ['A1', 'A3', 'B']);
+  }
+
+  test_exportedTopLevelDeclarations_export_preferLocal() {
+    String a = _p('/aaa/lib/a.dart');
+    String b = _p('/aaa/lib/b.dart');
+    provider.newFile(
+        a,
+        r'''
+class V {}
+''');
+    provider.newFile(
+        b,
+        r'''
+export 'a.dart';
+int V;
+''');
+    FileState file = fileSystemState.getFileForPath(b);
+    List<TopLevelDeclaration> declarations = file.exportedTopLevelDeclarations;
+    expect(declarations.map((t) => t.name), unorderedEquals(['V']));
+    expect(declarations.single.kind, TopLevelDeclarationKind.variable);
+  }
+
+  test_exportedTopLevelDeclarations_export_show() {
+    String a = _p('/aaa/lib/a.dart');
+    String b = _p('/aaa/lib/b.dart');
+    provider.newFile(
+        a,
+        r'''
+class A1 {}
+class A2 {}
+''');
+    provider.newFile(
+        b,
+        r'''
+export 'a.dart' show A2;
+class B {}
+''');
+    _assertExportedTopLevelDeclarations(b, ['A2', 'B']);
+  }
+
+  test_exportedTopLevelDeclarations_export_show2() {
+    String a = _p('/aaa/lib/a.dart');
+    String b = _p('/aaa/lib/b.dart');
+    String c = _p('/aaa/lib/c.dart');
+    String d = _p('/aaa/lib/d.dart');
+    provider.newFile(
+        a,
+        r'''
+export 'b.dart' show Foo;
+export 'c.dart' show Bar;
+''');
+    provider.newFile(
+        b,
+        r'''
+export 'd.dart';
+''');
+    provider.newFile(
+        c,
+        r'''
+export 'd.dart';
+''');
+    provider.newFile(
+        d,
+        r'''
+class Foo {}
+class Bar {}
+''');
+    _assertExportedTopLevelDeclarations(a, ['Foo', 'Bar']);
+  }
+
+  test_exportedTopLevelDeclarations_import() {
+    String a = _p('/aaa/lib/a.dart');
+    String b = _p('/aaa/lib/b.dart');
+    provider.newFile(
+        a,
+        r'''
+class A {}
+''');
+    provider.newFile(
+        b,
+        r'''
+import 'a.dart';
+class B {}
+''');
+    _assertExportedTopLevelDeclarations(b, ['B']);
+  }
+
+  test_exportedTopLevelDeclarations_parts() {
+    String a = _p('/aaa/lib/a.dart');
+    String a2 = _p('/aaa/lib/a2.dart');
+    provider.newFile(
+        a,
+        r'''
+library lib;
+part 'a2.dart';
+class A1 {}
+''');
+    provider.newFile(
+        a2,
+        r'''
+part of lib;
+class A2 {}
+''');
+    _assertExportedTopLevelDeclarations(a, ['A1', 'A2']);
+  }
+
   test_getFileForPath_doesNotExist() {
     String path = _p('/aaa/lib/a.dart');
     FileState file = fileSystemState.getFileForPath(path);
@@ -441,6 +634,12 @@ set _V3(_) {}
     _assertFilesWithoutTransitiveSignatures([fa, fb, fc]);
   }
 
+  void _assertExportedTopLevelDeclarations(String path, List<String> expected) {
+    FileState file = fileSystemState.getFileForPath(path);
+    List<TopLevelDeclaration> declarations = file.exportedTopLevelDeclarations;
+    expect(declarations.map((t) => t.name), unorderedEquals(expected));
+  }
+
   void _assertFilesWithoutTransitiveFiles(List<FileState> expected) {
     var actual = fileSystemState.test.filesWithoutTransitiveFiles;
     expect(actual, unorderedEquals(expected));