Manage known file paths set in FileSystemState.

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

 // Copyright (c) 2016, 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:convert';
 import 'dart:typed_data';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/error/listener.dart';
@@ skipping 530 matching lines @@
   final AnalysisOptions _analysisOptions;
   final Uint32List _salt;
   final String _sdkApiSignature;
 
   /**
    * Mapping from a URI to the corresponding [FileState].
    */
   final Map<Uri, FileState> _uriToFile = {};
 
   /**
+   * All known file paths.
+   */
+  final Set<String> knownFilePaths = new Set<String>();
+
+  /**
    * Mapping from a path to the corresponding [FileState]s, canonical or not.
    */
   final Map<String, List<FileState>> _pathToFiles = {};
 
   /**
    * Mapping from a path to the corresponding canonical [FileState].
    */
   final Map<String, FileState> _pathToCanonicalFile = {};
 
   /**
    * Mapping from a part to the libraries it is a part of.
    */
   final Map<FileState, List<FileState>> _partToLibraries = {};
 
   FileSystemStateTestView _testView;
 
   FileSystemState(
       this._logger,
       this._byteStore,
       this._contentOverlay,
       this._resourceProvider,
       this._sourceFactory,
       this._analysisOptions,
       this._salt,
       this._sdkApiSignature) {
     _testView = new FileSystemStateTestView(this);
   }
 
   /**
-   * Return the set of known file paths.
-   */
-  Set<String> get knownFilePaths => _pathToFiles.keys.toSet();
-
-  /**
    * Return the known files.
    */
   Iterable<FileState> get knownFiles =>
       _pathToFiles.values.map((files) => files.first);
 
   @visibleForTesting
   FileSystemStateTestView get test => _testView;
 
   /**
    * Return the canonical [FileState] for the given absolute [path]. The
@@ skipping 12 matching lines @@
       file = _uriToFile[uri];
       // If we have a file, call it the canonical one and return it.
       if (file != null) {
         _pathToCanonicalFile[path] = file;
         return file;
       }
       // Create a new file.
       FileSource uriSource = new FileSource(resource, uri);
       file = new FileState._(this, path, uri, uriSource);
       _uriToFile[uri] = file;
-      _pathToFiles.putIfAbsent(path, () => <FileState>[]).add(file);
+      _addFileWithPath(path, file);
       _pathToCanonicalFile[path] = file;
       file.refresh();
     }
     return file;
   }
 
   /**
    * Return the [FileState] for the given absolute [uri]. May return `null` if
    * the [uri] is invalid, e.g. a `package:` URI without a package name. The
    * returned file has the last known state since if was last refreshed.
    */
   FileState getFileForUri(Uri uri) {
     FileState file = _uriToFile[uri];
     if (file == null) {
       Source uriSource = _sourceFactory.resolveUri(null, uri.toString());
       // If the URI is invalid, for example package:/test/d.dart (note the
       // leading '/'), then `null` is returned. We should ignore this URI.
       if (uriSource == null) {
         return null;
       }
       String path = uriSource.fullName;
       File resource = _resourceProvider.getFile(path);
       FileSource source = new FileSource(resource, uri);
       file = new FileState._(this, path, uri, source);
       _uriToFile[uri] = file;
-      _pathToFiles.putIfAbsent(path, () => <FileState>[]).add(file);
+      _addFileWithPath(path, file);
       file.refresh();
     }
     return file;
   }
 
   /**
    * Return the list of all [FileState]s corresponding to the given [path]. The
    * list has at least one item, and the first item is the canonical file.
    */
   List<FileState> getFilesForPath(String path) {
     FileState canonicalFile = getFileForPath(path);
     List<FileState> allFiles = _pathToFiles[path].toList();
     if (allFiles.length == 1) {
       return allFiles;
     }
     return allFiles
       ..remove(canonicalFile)
       ..insert(0, canonicalFile);
   }
+
+  void _addFileWithPath(String path, FileState file) {
+    var files = _pathToFiles[path];
+    if (files == null) {
+      knownFilePaths.add(path);
+      files = <FileState>[];
+      _pathToFiles[path] = files;
+    }
+    files.add(file);
+  }
 }
 
 @visibleForTesting
 class FileSystemStateTestView {
   final FileSystemState state;
 
   FileSystemStateTestView(this.state);
 
   Set<FileState> get filesWithoutTransitiveFiles {
     return state._uriToFile.values
         .where((f) => f._transitiveFiles == null)
         .toSet();
   }
 
   Set<FileState> get filesWithoutTransitiveSignature {
     return state._uriToFile.values
         .where((f) => f._transitiveSignature == null)
         .toSet();
   }
 }