Add support for adding/removing pubspec.yaml files.

pkg/analysis_server/lib/src/context_directory_manager.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 context.directory.manager;
 
 import 'dart:async';
 import 'dart:collection';
 
 import 'package:analysis_server/src/resource.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:watcher/watcher.dart';
 
 /**
  * Information tracked by the [ContextDirectoryManager] for each context.
  */
 class _ContextDirectoryInfo {
   /**
    * Stream subscription we are using to watch the context's directory for
    * changes.
    */
   StreamSubscription<WatchEvent> changeSubscription;
 
   /**
    * Map from full path to the [Source] object, for each source that has been
    * added to the context.
    */
   Map<String, Source> sources = new HashMap<String, Source>();
+
+  /**
+   * Pubspec file for this context, if there is one.  Otherwise null.
+   */
+  File pubspecFile = null;

[scheglov, 2014/06/18 18:32:04]

Do we need "= null"?

[Paul Berry, 2014/06/19 14:55:15]

Technically, it's redundant, since uninitialized variables always have null as
their initial value.  However, since there is a code path that relies on this
initial value, I thought it would be nice to be explicit.

+
+  /**
+   * Path to that the pubspec file for this context would have, if it has one.
+   * Otherwise path that the pubspec file would have.
+   */
+  String pubspecPath;
 }
 
 /**
  * Class that maintains a mapping from included/excluded paths to a set of
  * folders that should correspond to analysis contexts.
  */
 abstract class ContextDirectoryManager {
   /**
+   * File name of pubspec files.
+   */
+  static String PUBSPEC_NAME = 'pubspec.yaml';

[scheglov, 2014/06/18 18:32:04]

static const?

[Paul Berry, 2014/06/19 14:55:15]

Done.

+
+  /**
    * [_ContextDirectoryInfo] object for each included directory in the most
    * recent successful call to [setRoots].
    */
   Map<Folder, _ContextDirectoryInfo> _currentDirectoryInfo =
       new HashMap<Folder, _ContextDirectoryInfo>();
 
   /**
    * The [ResourceProvider] using which paths are converted into [Resource]s.
    */
   final ResourceProvider resourceProvider;
@@ skipping 24 matching lines @@
     // TODO(scheglov) remove when implemented
     if (excludedPaths.isNotEmpty) {
       throw new UnimplementedError(
           'Excluded paths are not supported yet');
     }
     Set<Folder> excludedFolders = new HashSet<Folder>();
     // diff
     Set<Folder> currentFolders = _currentDirectoryInfo.keys.toSet();
     Set<Folder> newFolders = includedFolders.difference(currentFolders);
     Set<Folder> oldFolders = currentFolders.difference(includedFolders);
     // remove old contexts

[scheglov, 2014/06/18 18:32:04]

"destroy old contexts" ?

[Paul Berry, 2014/06/19 14:55:15]

Done.

     for (Folder folder in oldFolders) {
-      _currentDirectoryInfo.remove(folder);
-      removeContext(folder);
+      _destroyContext(folder);
     }
     // add new contexts

[scheglov, 2014/06/18 18:32:04]

"create new contexts"?

[Paul Berry, 2014/06/19 14:55:15]

Done.

     for (Folder folder in newFolders) {
-      _ContextDirectoryInfo info = new _ContextDirectoryInfo();
-      _currentDirectoryInfo[folder] = info;
-      info.changeSubscription = folder.changes.listen((WatchEvent event) {
-        _handleWatchEvent(folder, info, event);
-      });
-      File pubspecFile = folder.getChild('pubspec.yaml');
-      addContext(folder, pubspecFile.exists ? pubspecFile : null);
-      ChangeSet changeSet = new ChangeSet();
-      _addSourceFiles(changeSet, folder, info);
-      applyChangesToContext(folder, changeSet);
+      _createContext(folder);
     }
   }
 
+  /**
+   * Create a new context associated with the given folder.
+   */
+  void _createContext(Folder folder) {
+    _ContextDirectoryInfo info = new _ContextDirectoryInfo();
+    _currentDirectoryInfo[folder] = info;
+    info.changeSubscription = folder.changes.listen((WatchEvent event) {
+      _handleWatchEvent(folder, info, event);
+    });
+    File pubspecFile = folder.getChild(PUBSPEC_NAME);
+    info.pubspecPath = pubspecFile.path;
+    if (pubspecFile.exists) {
+      info.pubspecFile = pubspecFile;
+    }
+    addContext(folder, info.pubspecFile);
+    ChangeSet changeSet = new ChangeSet();
+    _addSourceFiles(changeSet, folder, info);
+    applyChangesToContext(folder, changeSet);
+  }
+
+  /**
+   * Clean up and destroy the context associated with the given folder.
+   */
+  void _destroyContext(Folder folder) {
+    _currentDirectoryInfo[folder].changeSubscription.cancel();
+    _currentDirectoryInfo.remove(folder);
+    removeContext(folder);
+  }
+
   void _handleWatchEvent(Folder folder, _ContextDirectoryInfo info, WatchEvent event) {
     switch (event.type) {
       case ChangeType.ADD:
         if (_isInPackagesDir(event.path, folder)) {
           // TODO(paulberry): perhaps we should only skip packages dirs if
           // there is a pubspec.yaml?
           break;
         }
-        // TODO(paulberry): handle adding pubspec.yaml
+        if (info.pubspecFile == null && event.path == info.pubspecPath) {
+          // Pubspec file added.  This is likely to be such a rare event that
+          // there's no need to try to be clever.  Just destroy the old context
+          // and create a new one.
+          _destroyContext(folder);
+          _createContext(folder);
+          return;
+        }
         if (_shouldFileBeAnalyzed(event.path)) {
           ChangeSet changeSet = new ChangeSet();
           Resource resource = resourceProvider.getResource(event.path);
           // If the file went away and was replaced by a folder before we
           // had a chance to process the event, resource might be a Folder.  In
           // that case don't add it.
           if (resource is File) {
             File file = resource;
             Source source = file.createSource(UriKind.FILE_URI);
             changeSet.addedSource(source);
             applyChangesToContext(folder, changeSet);
             info.sources[event.path]= source;
           }
         }
         break;
       case ChangeType.REMOVE:
+        if (info.pubspecFile != null && event.path == info.pubspecPath) {
+          // Pubspec file removed.  This is likely to be such a rare event that
+          // there's no need to try to be clever.  Just destroy the old context
+          // and create a new one.
+          _destroyContext(folder);
+          _createContext(folder);
+          return;
+        }
         // TODO(paulberry): handle removing pubspec.yaml
         Source source = info.sources[event.path];
         if (source != null) {
           ChangeSet changeSet = new ChangeSet();
           changeSet.removedSource(source);
           applyChangesToContext(folder, changeSet);
           info.sources.remove(event.path);
         }
         break;
       case ChangeType.MODIFY:
@@ skipping 62 matching lines @@
    * some of those files have been modified).  [changeSet] is the set of
    * changes that need to be applied to the context.
    */
   void applyChangesToContext(Folder contextFolder, ChangeSet changeSet);
 
   /**
    * Remove the context associated with the given [folder].
    */
   void removeContext(Folder folder);
 }