Source/bindings/scripts/unstable/v8_methods.py

# Copyright (C) 2013 Google Inc. All rights reserved.
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"""Generate template values for methods.

FIXME: Not currently used in build.
This is a rewrite of the Perl IDL compiler in Python, but is not complete.
Once it is complete, we will switch all IDL files over to Python at once.
Until then, please work on the Perl IDL compiler.
For details, see bug http://crbug.com/239771
"""

import v8_types
import v8_utilities


def generate_method(method):
    arguments = method.arguments
    contents = {
        'arguments': [generate_argument(method, argument, index)
                      for index, argument in enumerate(arguments)],
        'cpp_method': cpp_method(method, len(arguments)),
        'custom_signature': custom_signature(arguments),
        'idl_type': method.idl_type,
        'name': method.name,
        'number_of_required_arguments': len([
            argument for argument in arguments
            if not (argument.is_optional or argument.is_variadic)]),
        'number_of_required_or_variadic_arguments': len([
            argument for argument in arguments
            if not argument.is_optional]),
    }
    return contents


def generate_argument(method, argument, index):
    idl_type = argument.idl_type
    return {
        'cpp_method': cpp_method(method, index),
        'cpp_type': v8_types.cpp_type(idl_type),
        'enum_validation_expression': v8_utilities.enum_validation_expression(idl_type),
        'idl_type': argument.idl_type,
        'index': index,
        'is_optional': argument.is_optional,
        'is_variadic_wrapper_type': argument.is_variadic and v8_types.is_wrapper_type(idl_type),
        'name': argument.name,
        'v8_value_to_local_cpp_value': v8_value_to_local_cpp_value(argument, index),
    }


def cpp_method(method, number_of_arguments):
    def cpp_argument(argument):
        if argument.idl_type in ('NodeFilter', 'XPathNSResolver'):
            # FIXME: remove this special case
            return '%s.get()' % argument.name
        return argument.name

    # Truncate omitted optional arguments
    arguments = method.arguments[:number_of_arguments]
    cpp_arguments = [cpp_argument(argument) for argument in arguments]
    cpp_value = 'imp->%s(%s)' % (method.name, ', '.join(cpp_arguments))

    idl_type = method.idl_type
    if idl_type == 'void':
        return cpp_value
    return v8_types.v8_set_return_value(idl_type, cpp_value, callback_info='args', isolate='args.GetIsolate()')


def custom_signature(arguments):
    def argument_template(argument):
        idl_type = argument.idl_type
        if (v8_types.is_wrapper_type(idl_type) and
            not v8_types.is_typed_array_type(idl_type) and
            # Compatibility: all other browsers accepts a callable for
            # XPathNSResolver, despite it being against spec.
            not idl_type == 'XPathNSResolver'):
            return 'V8PerIsolateData::from(isolate)->rawTemplate(&V8{idl_type}::wrapperTypeInfo, currentWorldType)'.format(idl_type=idl_type)
        return 'v8::Handle<v8::FunctionTemplate>()'

    if (any(argument.is_optional for argument in arguments) or
        all(not v8_types.is_wrapper_type(argument.idl_type)
            for argument in arguments)):
        return None
    return ', '.join([argument_template(argument) for argument in arguments])


def v8_value_to_local_cpp_value(argument, index):
    idl_type = argument.idl_type
    name = argument.name
    if argument.is_variadic:
        return 'V8TRYCATCH_VOID(Vector<{cpp_type}>, {name}, toNativeArguments<{cpp_type}>(args, {index}))'.format(
                cpp_type=v8_types.cpp_type(idl_type), name=name, index=index)
    return v8_types.v8_value_to_local_cpp_value(
        idl_type, argument.extended_attributes,
        'args[%s]' % index, name, 'args.GetIsolate()', index=index)