Compute exported top-level declarations.

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

Index: pkg/analyzer/lib/src/dart/analysis/file_state.dart
diff --git a/pkg/analyzer/lib/src/dart/analysis/file_state.dart b/pkg/analyzer/lib/src/dart/analysis/file_state.dart
index 9381aa264841a98ad2a004f0ba0b366ed7c57946..514828423ce55b7b3a9fe6d53885a5ff6f02c01d 100644
--- a/pkg/analyzer/lib/src/dart/analysis/file_state.dart
+++ b/pkg/analyzer/lib/src/dart/analysis/file_state.dart
@@ -102,6 +102,7 @@ class FileState {
   String _transitiveSignature;
 
   List<TopLevelDeclaration> _topLevelDeclarations;
+  List<TopLevelDeclaration> _exportTopLevelDeclarations;
 
   FileState._(this._fsState, this.path, this.uri, this.source);
 
@@ -131,6 +132,52 @@ class FileState {
    */
   List<FileState> get exportedFiles => _exportedFiles;
 
+  /**
+   * Return [TopLevelDeclaration]s exported from the this library file.
+   */
+  List<TopLevelDeclaration> get exportTopLevelDeclarations {

[Paul Berry, 2016/12/01 21:16:10]

This sounds like the name of a method with takes some top level declarations and
exports them.  Consider renaming to "exportedTopLevelDeclarations".

[scheglov, 2016/12/01 21:39:56]

Done.

+    if (_exportTopLevelDeclarations == null) {
+      _exportTopLevelDeclarations = <TopLevelDeclaration>[];
+
+      Set<FileState> seenLibraries = new Set<FileState>();
+
+      /**
+       * Compute [TopLevelDeclaration]s exported from the [library].
+       */
+      List<TopLevelDeclaration> computeExported(FileState library) {

[Paul Berry, 2016/12/01 21:16:10]

I think there's a bug.  Consider the following:

a.dart:
export 'b.dart' show Foo;
export 'c.dart' show Bar;

b.dart:
export 'd.dart';

c.dart:
export 'd.dart';

d.dart:
class Foo {}
class Bar {}

The first time we call computeExported() for d.dart, we're calling in the
context of b.dart, so we'll filter out Bar and only find Foo.  The second time
we call computeExported() for d.dart, we're calling in the context of c.dart. 
But since seenLibraries already contains d.dart at that point, we'll return an
empty list.  So Bar will get missed.

[scheglov, 2016/12/01 21:39:56]

You're right.
Fixed.

+        var declarations = <String, TopLevelDeclaration>{};
+        if (seenLibraries.add(library)) {
+          // Append the library declarations.
+          for (TopLevelDeclaration t in library.topLevelDeclarations) {
+            declarations[t.name] = t;

[Brian Wilkerson, 2016/12/01 21:07:47]

I think we need to test for private names both here and on line 156.

[scheglov, 2016/12/01 21:39:56]

Done.

+          }
+          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;
+              }
+            }
+          }
+        }
+
+        return declarations.values.toList();
+      }
+
+      _exportTopLevelDeclarations = computeExported(this);
+    }
+    return _exportTopLevelDeclarations;
+  }
+
   @override
   int get hashCode => uri.hashCode;
 
@@ -352,18 +399,24 @@ 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._exportTopLevelDeclarations = null;
       }
     }