Mojo cpp bindings: add support for validating incoming messages.

mojo/public/tools/bindings/generators/mojom_cpp_generator.py

 # 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.
 
 """Generates C++ source files from a mojom.Module."""
 
 import mojom.generate.generator as generator
 import mojom.generate.module as mojom
 import mojom.generate.pack as pack
 from mojom.generate.template_expander import UseJinja
@@ skipping 153 matching lines @@
     name.append(token.name)
     return "::".join(name)
   return token
 
 def ExpressionToText(value, module):
   if value[0] != "EXPRESSION":
     raise Exception("Expected EXPRESSION, got" + value)
   return "".join(generator.ExpressionMapper(value,
       lambda token: TranslateConstants(token, module)))
 
+def HasCallbacks(interface):
+  for method in interface.methods:
+    if method.response_parameters != None:
+      return True
+  return False
+
 _HEADER_SIZE = 8
 
 class Generator(generator.Generator):
 
   cpp_filters = {
     "cpp_const_wrapper_type": GetCppConstWrapperType,
     "cpp_field_type": GetCppFieldType,
     "cpp_pod_type": GetCppPodType,
     "cpp_result_type": GetCppResultWrapperType,
     "cpp_type": GetCppType,
     "cpp_wrapper_type": GetCppWrapperType,
     "expression_to_text": ExpressionToText,
     "get_pad": pack.GetPad,
+    "has_callbacks": HasCallbacks,
     "is_enum_kind": generator.IsEnumKind,
     "is_handle_kind": generator.IsHandleKind,
     "is_interface_kind": generator.IsInterfaceKind,
     "is_object_kind": generator.IsObjectKind,
     "is_string_kind": generator.IsStringKind,
     "is_array_kind": lambda kind: isinstance(kind, mojom.Array),
     "is_struct_with_handles": IsStructWithHandles,
     "struct_size": lambda ps: ps.GetTotalSize() + _HEADER_SIZE,
     "struct_from_method": generator.GetStructFromMethod,
     "response_struct_from_method": generator.GetResponseStructFromMethod,
@@ skipping 23 matching lines @@
 
   @UseJinja("cpp_templates/module.cc.tmpl", filters=cpp_filters)
   def GenerateModuleSource(self):
     return self.GetJinjaExports()
 
   def GenerateFiles(self, args):
     self.Write(self.GenerateModuleHeader(), "%s.h" % self.module.name)
     self.Write(self.GenerateModuleInternalHeader(),
         "%s-internal.h" % self.module.name)
     self.Write(self.GenerateModuleSource(), "%s.cc" % self.module.name)