Fix a bug with mojom imports where 2 imports with the same namespace would

mojo/public/bindings/mojom_bindings_generator.py

 #!/usr/bin/env python
 # Copyright 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """The frontend for the Mojo bindings system."""
 
 
 import argparse
 import imp
@@ skipping 28 matching lines @@
     else:
       print "Unknown generator name %s" % generator_name
       sys.exit(1)
     generator_module = imp.load_source(os.path.basename(generator_name)[:-3],
                                        generator_name)
     generators.append(generator_module)
   return generators
 
 def ProcessFile(args, generator_modules, filename, processed_files):
   # Ensure we only visit each file once.
-  processed_files.append(filename)
+  if filename in processed_files:
+    if processed_files[filename] is None:
+      raise Exception("Circular dependency: " + filename)
+    return processed_files[filename]
+  processed_files[filename] = None
 
   dirname, name = os.path.split(filename)
   name = os.path.splitext(name)[0]
   # TODO(darin): There's clearly too many layers of translation here!  We can
   # at least avoid generating the serialized Mojom IR.
   tree = mojo_parser.Parse(filename)
   mojom = mojo_translate.Translate(tree, name)
   if args.debug_print_intermediate:
     pprint.PrettyPrinter().pprint(mojom)
 
   # Process all our imports first and collect the module object for each.
   # We use these to generate proper type info.
   for import_data in mojom['imports']:
     import_filename = os.path.join(dirname, import_data['filename'])
-    if import_filename not in processed_files:
-      import_data['module'] = ProcessFile(
-          args, generator_modules, import_filename, processed_files)
+    import_data['module'] = ProcessFile(
+        args, generator_modules, import_filename, processed_files)
 
   module = mojom_data.OrderedModuleFromData(mojom)
   for generator_module in generator_modules:
     generator = generator_module.Generator(module, args.include_dir,
                                            args.output_dir)
     generator.GenerateFiles()
 
+  processed_files[filename] = module
   return module
 
 def Main():
   parser = argparse.ArgumentParser(
       description="Generate bindings from mojom files.")
   parser.add_argument("filename", nargs="+",
                       help="mojom input file")
   parser.add_argument("-i", "--include_dir", dest="include_dir", default=".",
                       help="include path for #includes")
   parser.add_argument("-o", "--output_dir", dest="output_dir", default=".",
                       help="output directory for generated files")
   parser.add_argument("-g", "--generators", dest="generators_string",
                       metavar="GENERATORS", default="c++,javascript",
                       help="comma-separated list of generators")
   parser.add_argument("--debug_print_intermediate", action="store_true",
                       help="print the intermediate representation")
   args = parser.parse_args()
 
   generator_modules = LoadGenerators(args.generators_string)
 
   if not os.path.exists(args.output_dir):
     os.makedirs(args.output_dir)
 
   for filename in args.filename:
-    ProcessFile(args, generator_modules, filename, [])
+    ProcessFile(args, generator_modules, filename, {})
 
   return 0
 
 
 if __name__ == "__main__":
   sys.exit(Main())