Start unification of overload dispatcher generation.

tools/dom/scripts/systemnative.py

 #!/usr/bin/python
 # Copyright (c) 2012, 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.
 
 """This module provides shared functionality for the systems to generate
 native binding from the IDL database."""
 
 import emitter
 import os
@@ skipping 433 matching lines @@
     if not needs_dispatcher:
       # Bind directly to native implementation
       argument_count = (0 if info.IsStatic() else 1) + len(info.param_infos)
       cpp_callback_name = self._GenerateNativeBinding(
           info.name, argument_count, dart_declaration, 'Callback', is_custom)
       if not is_custom:
         self._GenerateOperationNativeCallback(operation, operation.arguments, cpp_callback_name)
     else:
       self._GenerateDispatcher(info.operations, dart_declaration, [info.name for info in info.param_infos])
 
-  def _GenerateDispatcher(self, operations, dart_declaration, argument_names):
+  def _GenerateDispatcher(self, operations, dart_declaration, parameter_names):
 
     body = self._members_emitter.Emit(
         '\n'
         '  $DECLARATION {\n'
         '$!BODY'
         '  }\n',
         DECLARATION=dart_declaration)
 
     version = [1]
     def GenerateCall(operation, argument_count, checks):
       if checks:
         if operation.type.id != 'void':
           template = '    if ($CHECKS) {\n      return $CALL;\n    }\n'
         else:
           template = '    if ($CHECKS) {\n      $CALL;\n      return;\n    }\n'
       else:
         if operation.type.id != 'void':
           template = '    return $CALL;\n'
         else:
           template = '    $CALL;\n'
 
       overload_name = '%s_%s' % (operation.id, version[0])
       version[0] += 1
-      argument_list = ', '.join(argument_names[:argument_count])
+      argument_list = ', '.join(parameter_names[:argument_count])
       call = '_%s(%s)' % (overload_name, argument_list)
       body.Emit(template, CHECKS=' && '.join(checks), CALL=call)
 
       dart_declaration = '%s%s _%s(%s)' % (
           'static ' if operation.is_static else '',
           self.SecureOutputType(operation.type.id),
           overload_name, argument_list)
       cpp_callback_name = self._GenerateNativeBinding(
           overload_name, (0 if operation.is_static else 1) + argument_count,
           dart_declaration, 'Callback', False)
       self._GenerateOperationNativeCallback(operation, operation.arguments[:argument_count], cpp_callback_name)
 
     def GenerateChecksAndCall(operation, argument_count):
-      checks = []
-      for i in range(0, argument_count):
-        argument = operation.arguments[i]
-        argument_name = argument_names[i]
-        type = self._DartType(argument.type.id)
-        if type not in ['dynamic', 'Object']:
-          checks.append('(%s is %s || %s == null)' % (argument_name, type, argument_name))
-      checks.extend(['!?%s' % name for name in argument_names[argument_count:]])
-      GenerateCall(operation, argument_count, checks)
+      GenerateCall(operation, argument_count,
+          self._OverloadChecks(operation, parameter_names, argument_count))
 
     # TODO: Optimize the dispatch to avoid repeated checks.
     if len(operations) > 1:
       for operation in operations:
         for position, argument in enumerate(operation.arguments):
           if self._IsArgumentOptionalInWebCore(operation, argument):
             GenerateChecksAndCall(operation, position)
         GenerateChecksAndCall(operation, len(operation.arguments))
       body.Emit('    throw "Incorrect number or type of arguments";\n');
     else:
       operation = operations[0]
       argument_count = len(operation.arguments)
       for position, argument in list(enumerate(operation.arguments))[::-1]:
         if self._IsArgumentOptionalInWebCore(operation, argument):
-          check = '?%s' % argument_names[position]
+          check = '?%s' % parameter_names[position]
           # argument_count instead of position + 1 is used here to cover one
           # complicated case with the effectively optional argument in the middle.
           # Consider foo(x, [Optional] y, [Optional=DefaultIsNullString] z)
           # (as of now it's modelled after HTMLMediaElement.webkitAddKey).
           # y is optional in WebCore, while z is not.
           # In this case, if y was actually passed, we'd like to emit foo(x, y, z) invocation,
           # not foo(x, y).
           GenerateCall(operation, argument_count, [check])
           argument_count = position
       GenerateCall(operation, argument_count, [])
@@ skipping 388 matching lines @@
         LIBRARY_NAME=library_name)
 
       headers = self._library_headers[library_name]
       for header_file in headers:
         path = os.path.relpath(header_file, output_dir)
         includes_emitter.Emit('#include "$PATH"\n', PATH=path)
         body_emitter.Emit(
             '    if (Dart_NativeFunction func = $CLASS_NAME::resolver(name, argumentCount))\n'
             '        return func;\n',
             CLASS_NAME=os.path.splitext(os.path.basename(path))[0])