parts of

pkg/docgen/lib/docgen.dart

 // Copyright (c) 2013, 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.
 
 /**
  * **docgen** is a tool for creating machine readable representations of Dart
  * code metadata, including: classes, members, comments and annotations.
  *
  * docgen is run on a `.dart` file or a directory containing `.dart` files.
  *
@@ skipping 95 matching lines @@
       return true;
     });
 }
 
 List<String> _listLibraries(List<String> args) {
   if (args.length != 1) throw new UnsupportedError(USAGE);
   var libraries = new List<String>();
   var type = FileSystemEntity.typeSync(args[0]);
 
   if (type == FileSystemEntityType.FILE) {
-    libraries.add(path.absolute(args[0]));
-    logger.info('Added to libraries: ${libraries.last}');
+    if (args[0].endsWith('.dart')) {
+      libraries.add(path.absolute(args[0]));
+      logger.info('Added to libraries: ${libraries.last}');
+    }
   } else {
     libraries.addAll(_listDartFromDir(args[0]));
   }
   return libraries;
 }
 
 List<String> _listDartFromDir(String args) {
-  var files = listDir(args, recursive: true);
+  var libraries = [];
   // To avoid anaylzing package files twice, only files with paths not
   // containing '/packages' will be added. The only exception is if the file to
   // analyze already has a '/package' in its path.
-  return files.where((f) => f.endsWith('.dart') &&
+  var files = listDir(args, recursive: true).where((f) => f.endsWith('.dart') &&
       (!f.contains('${path.separator}packages') ||
-          args.contains('${path.separator}packages'))).toList()
-      ..forEach((lib) => logger.info('Added to libraries: $lib'));
+          args.contains('${path.separator}packages'))).toList();
+  
+  files.forEach((f) {
+    // Only add the file if it does not contain 'part of' 
+    // TODO(janicejl): Remove when Issue(12406) is resolved.
+    var contents = new File(f).readAsStringSync();
+    if (!(contents.contains(new RegExp('\npart of ')) || 
+        contents.startsWith(new RegExp('part of ')))) {
+      libraries.add(f);
+      logger.info('Added to libraries: $f');
+    }
+  });
+  return libraries;
 }
 
 String _findPackageRoot(String directory) {
   var files = listDir(directory, recursive: true);
   // Return '' means that there was no pubspec.yaml and therefor no packageRoot.
   String packageRoot = files.firstWhere((f) =>
       f.endsWith('${path.separator}pubspec.yaml'), orElse: () => '');
   if (packageRoot != '') {
     packageRoot = path.join(path.dirname(packageRoot), 'packages');
   }
@@ skipping 918 matching lines @@
   String qualifiedName;
   List<String> parameters;
 
   Annotation(this.qualifiedName, this.parameters);
 
   Map toMap() => {
     'name': qualifiedName,
     'parameters': parameters
   };
 }