Enhance DirectiveListener to collect import/exports with combinators.

pkg/front_end/lib/src/incremental/file_state.dart

 // Copyright (c) 2017, 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.
 
 import 'dart:async';
 import 'dart:typed_data';
 
 import 'package:crypto/crypto.dart';
 import 'package:front_end/file_system.dart';
 import 'package:front_end/src/dependency_walker.dart' as graph;
@@ skipping 17 matching lines @@
   /// The absolute URI of the file.
   final Uri uri;
 
   /// The resolved URI of the file in the file system.
   final Uri fileUri;
 
   bool _exists;
   List<int> _content;
   List<int> _contentHash;
 
+  List<NamespaceExport> _exports;
   List<FileState> _importedLibraries;
   List<FileState> _exportedLibraries;
   List<FileState> _partFiles;
 
   Set<FileState> _directReferencedFiles = new Set<FileState>();
   List<FileState> _directReferencedLibraries = <FileState>[];
 
   FileState._(this._fsState, this.uri, this.fileUri);
 
   /// The content of the file.
   List<int> get content => _content;
 
   /**
    * The MD5 hash of the [content].
    */
   List<int> get contentHash => _contentHash;
 
   /// Libraries that this library file directly imports or exports.
   List<FileState> get directReferencedLibraries => _directReferencedLibraries;
 
   /// Whether the file exists.
   bool get exists => _exists;
 
   /// The list of the libraries exported by this library.
   List<FileState> get exportedLibraries => _exportedLibraries;
 
+  /// The list of the exported files with combinators.
+  List<NamespaceExport> get exports => _exports;
+
   @override
   int get hashCode => uri.hashCode;
 
   /// The list of the libraries imported by this library.
   List<FileState> get importedLibraries => _importedLibraries;
 
   /// The list of files this library file references as parts.
   List<FileState> get partFiles => _partFiles;
 
   /// Return topologically sorted cycles of dependencies for this library.
@@ skipping 42 matching lines @@
 
     // Parse directives.
     ScannerResult scannerResults = _scan();
     var listener = new _DirectiveListenerWithNative();
     new TopLevelParser(listener).parseUnit(scannerResults.tokens);
 
     // Build the graph.
     _importedLibraries = <FileState>[];
     _exportedLibraries = <FileState>[];
     _partFiles = <FileState>[];
-    await _addFileForRelativeUri(_importedLibraries, 'dart:core');
-    for (String uri in listener.imports) {
-      await _addFileForRelativeUri(_importedLibraries, uri);
+    _exports = <NamespaceExport>[];
+    {
+      FileState coreFile = await _getFileForRelativeUri('dart:core');
+      if (coreFile != null) {
+        _importedLibraries.add(coreFile);

[Paul Berry, 2017/05/15 20:28:30]

Should we report an error?  It seems like this should never happen if we are
pointing to a proper SDK.

+      }
+    }
+    for (ImportDirective import_ in listener.imports) {
+      FileState file = await _getFileForRelativeUri(import_.uri);
+      if (file != null) {
+        _importedLibraries.add(file);
+      }
     }
     await _addVmTargetImportsForCore();
-    for (String uri in listener.exports) {
-      await _addFileForRelativeUri(_exportedLibraries, uri);
+    for (ExportDirective export_ in listener.exports) {
+      FileState file = await _getFileForRelativeUri(export_.uri);
+      if (file != null) {
+        _exportedLibraries.add(file);
+        _exports.add(new NamespaceExport(file, export_.combinators));
+      }
     }
     for (String uri in listener.parts) {
-      await _addFileForRelativeUri(_partFiles, uri);
+      FileState file = await _getFileForRelativeUri(uri);
+      if (file != null) {
+        _partFiles.add(file);
+      }
     }
 
     // Compute referenced files.
     _directReferencedFiles = new Set<FileState>()
       ..addAll(_importedLibraries)
       ..addAll(_exportedLibraries)
       ..addAll(_partFiles);
     _directReferencedLibraries = (new Set<FileState>()
           ..addAll(_importedLibraries)
           ..addAll(_exportedLibraries))
         .toList();
   }
 
   @override
   String toString() {
     if (fileUri.scheme == 'file') return fileUri.path;
     return fileUri.toString();
   }
 
-  /// Add the [FileState] for the given [relativeUri] to the [files].
-  /// Do nothing if the URI cannot be parsed, cannot correspond any file, etc.
-  Future<Null> _addFileForRelativeUri(
-      List<FileState> files, String relativeUri) async {
-    if (relativeUri.isEmpty) return;
+  /// Fasta unconditionally loads all VM libraries.  In order to be able to
+  /// serve them using the file system view, pretend that all of them were
+  /// imported into `dart:core`.
+  /// TODO(scheglov) Ask VM people whether all these libraries are required.
+  Future<Null> _addVmTargetImportsForCore() async {
+    if (uri.toString() != 'dart:core') return;
+    for (String uri in new VmTarget(null).extraRequiredLibraries) {
+      FileState file = await _getFileForRelativeUri(uri);
+      if (file != null) {
+        _importedLibraries.add(file);

[Paul Berry, 2017/05/15 20:28:30]

Similar question here.

+      }
+    }
+  }
+
+  /// Return the [FileState] for the given [relativeUri] or `null` if the URI
+  /// cannot be parsed, cannot correspond any file, etc.
+  Future<FileState> _getFileForRelativeUri(String relativeUri) async {
+    if (relativeUri.isEmpty) return null;
 
     // Resolve the relative URI into absolute.
     // The result is either:
     //   1) The absolute file URI.
     //   2) The absolute non-file URI, e.g. `package:foo/foo.dart`.
     Uri absoluteUri;
     try {
       absoluteUri = fileUri.resolve(relativeUri);
     } on FormatException {
-      return;
+      return null;
     }
 
-    FileState file = await _fsState.getFile(absoluteUri);
-    if (file == null) return;
-    files.add(file);
-  }
-
-  /// Fasta unconditionally loads all VM libraries.  In order to be able to
-  /// serve them using the file system view, pretend that all of them were
-  /// imported into `dart:core`.
-  /// TODO(scheglov) Ask VM people whether all these libraries are required.
-  Future<Null> _addVmTargetImportsForCore() async {
-    if (uri.toString() != 'dart:core') return;
-    for (String uri in new VmTarget(null).extraRequiredLibraries) {
-      await _addFileForRelativeUri(_importedLibraries, uri);
-    }
+    return await _fsState.getFile(absoluteUri);
   }
 
   /// Scan the content of the file.
   ScannerResult _scan() {
     var zeroTerminatedBytes = new Uint8List(_content.length + 1);
     zeroTerminatedBytes.setRange(0, _content.length, _content);
     return scan(zeroTerminatedBytes);
   }
 }
 
@@ skipping 54 matching lines @@
 
   @override
   String toString() {
     if (_isForVm) {
       return '[core + vm]';
     }
     return '[' + libraries.join(', ') + ']';
   }
 }
 
+/// Information about a single `export` directive.
+class NamespaceExport {
+  final FileState library;
+  final List<NamespaceCombinator> combinators;
+
+  NamespaceExport(this.library, this.combinators);
+
+  /// Return `true` if the [name] satisfies the sequence of the [combinators].
+  bool filter(String name) {
+    for (NamespaceCombinator combinator in combinators) {
+      if (combinator.isShow) {
+        if (!combinator.names.contains(name)) {
+          return false;
+        }
+      } else {
+        if (combinator.names.contains(name)) {
+          return false;
+        }
+      }
+    }
+    return true;
+  }
+}
+
 /// [DirectiveListener] that skips native clauses.
 class _DirectiveListenerWithNative extends DirectiveListener {
   @override
   Token handleNativeClause(Token token) => skipNativeClause(token);
 }
 
 /// [FileSystemState] based implementation of [FileSystem].
 /// It provides a consistent view on the known file system state.
 class _FileSystemView implements FileSystem {
   final FileSystemState fsState;
@@ skipping 76 matching lines @@
       node.isEvaluated = true;
       cycle.libraries.add(node.file);
     }
     topologicallySortedCycles.add(cycle);
   }
 
   _LibraryNode getNode(FileState file) {
     return nodesOfFiles.putIfAbsent(file, () => new _LibraryNode(this, file));
   }
 }