src/vpp-api/vapi/vapi_cpp_gen.py

#!/usr/bin/env python3

import argparse
import os
import sys
import logging
from vapi_c_gen import CField, CStruct, CSimpleType, CStructType, CMessage, \
    json_to_c_header_name
from vapi_json_parser import JsonParser


class CppField(CField):
    def __init__(
            self,
            field_name,
            field_type,
            array_len=None,
            nelem_field=None):
        super().__init__(field_name, field_type, array_len, nelem_field)


class CppStruct(CStruct):
    def __init__(self, name, fields):
        super().__init__(name, fields)


class CppSimpleType (CSimpleType):

    def __init__(self, name):
        super().__init__(name)


class CppStructType (CStructType, CppStruct):
    def __init__(self, definition, typedict, field_class):
        super().__init__(definition, typedict, field_class)


class CppMessage (CMessage):
    def __init__(self, logger, definition, typedict,
                 struct_type_class, simple_type_class, field_class):
        super().__init__(logger, definition, typedict, struct_type_class,
                         simple_type_class, field_class)

    def get_swap_to_be_template_instantiation(self):
        return "\n".join([
            "template <> inline void vapi_swap_to_be<%s>(%s *msg)" %
            (self.get_c_name(), self.get_c_name()),
            "{",
            "  %s(msg);" % self.get_swap_to_be_func_name(),
            "}",
        ])

    def get_swap_to_host_template_instantiation(self):
        return "\n".join([
            "template <> inline void vapi_swap_to_host<%s>(%s *msg)" %
            (self.get_c_name(), self.get_c_name()),
            "{",
            "  %s(msg);" % self.get_swap_to_host_func_name(),
            "}",
        ])

    def get_alloc_template_instantiation(self):
        return "\n".join([
            "template <> inline %s* vapi_alloc<%s%s>"
            "(Connection &con%s)" %
            (self.get_c_name(), self.get_c_name(),
                ", size_t" * len(self.get_alloc_vla_param_names()),
                "".join([", size_t %s" % n for n in
                         self.get_alloc_vla_param_names()])
             ),
            "{",
            "  %s* result = %s(con.vapi_ctx%s);" %
            (self.get_c_name(), self.get_alloc_func_name(),
                "".join([", %s" % n
                         for n in self.get_alloc_vla_param_names()])),
            "#if VAPI_CPP_DEBUG_LEAKS",
            "  con.on_shm_data_alloc(result);",
            "#endif",
            "  return result;",
            "}",
        ])

    def get_cpp_name(self):
        return "%s%s" % (self.name[0].upper(), self.name[1:])

    def get_req_template_name(self):
        if self.is_dump():
            template = "Dump"
        else:
            template = "Request"

        return "%s<%s, %s%s>" % (
            template,
            self.get_c_name(),
            self.reply.get_c_name(),
            "".join([", size_t"] * len(self.get_alloc_vla_param_names()))
        )

    def get_req_template_instantiation(self):
        return "template class %s;" % self.get_req_template_name()

    def get_type_alias(self):
        return "using %s = %s;" % (
            self.get_cpp_name(), self.get_req_template_name())

    def get_reply_template_name(self):
        return "Msg<%s>" % (self.get_c_name())

    def get_reply_type_alias(self):
        return "using %s = %s;" % (
            self.get_cpp_name(), self.get_reply_template_name())

    def get_msg_class_instantiation(self):
        return "template class Msg<%s>;" % self.get_c_name()

    def get_get_msg_id_t_instantiation(self):
        return "\n".join([
            ("template <> inline vapi_msg_id_t vapi_get_msg_id_t<%s>()"
                % self.get_c_name()),
            "{",
            "  return ::%s; " % self.get_msg_id_name(),
            "}",
            "",
            ("template <> inline vapi_msg_id_t "
             "vapi_get_msg_id_t<Msg<%s>>()" % self.get_c_name()),
            "{",
            "  return ::%s; " % self.get_msg_id_name(),
            "}",
        ])

    def get_cpp_constructor(self):
        return '\n'.join([
            ('static void __attribute__((constructor)) '
             '__vapi_cpp_constructor_%s()'
             % self.name),
            '{',
            ('  vapi::vapi_msg_set_msg_id<%s>(%s);' % (
                self.get_c_name(), self.get_msg_id_name())),
            '}',
        ])


def gen_json_header(parser, logger, j, io, gen_h_prefix, add_debug_comments):
    logger.info("Generating header `%s'" % io.name)
    orig_stdout = sys.stdout
    sys.stdout = io
    include_guard = "__included_hpp_%s" % (
        j.replace(".", "_").replace("/", "_").replace("-", "_"))
    print("#ifndef %s" % include_guard)
    print("#define %s" % include_guard)
    print("")
    print("#include <vapi/vapi.hpp>")
    print("#include <%s%s>" % (gen_h_prefix, json_to_c_header_name(j)))
    print("")
    print("namespace vapi {")
    print("")
    for m in parser.messages_by_json[j].values():
        # utility functions need to go first, otherwise internal instantiation
        # causes headaches ...
        if add_debug_comments:
            print("/* m.get_swap_to_be_template_instantiation() */")
        print("%s" % m.get_swap_to_be_template_instantiation())
        print("")
        if add_debug_comments:
            print("/* m.get_swap_to_host_template_instantiation() */")
        print("%s" % m.get_swap_to_host_template_instantiation())
        print("")
        if add_debug_comments:
            print("/* m.get_get_msg_id_t_instantiation() */")
        print("%s" % m.get_get_msg_id_t_instantiation())
        print("")
        if add_debug_comments:
            print("/* m.get_cpp_constructor() */")
        print("%s" % m.get_cpp_constructor())
        print("")
        if not m.is_reply():
            if add_debug_comments:
                print("/* m.get_alloc_template_instantiation() */")
            print("%s" % m.get_alloc_template_instantiation())
            print("")
        if add_debug_comments:
            print("/* m.get_msg_class_instantiation() */")
        print("%s" % m.get_msg_class_instantiation())
        print("")
        if m.is_reply():
            if add_debug_comments:
                print("/* m.get_reply_type_alias() */")
            print("%s" % m.get_reply_type_alias())
            continue
        if add_debug_comments:
            print("/* m.get_req_template_instantiation() */")
        print("%s" % m.get_req_template_instantiation())
        print("")
        if add_debug_comments:
            print("/* m.get_type_alias() */")
        print("%s" % m.get_type_alias())
        print("")
    print("}")  # namespace vapi

    print("#endif")
    sys.stdout = orig_stdout


def json_to_cpp_header_name(json_name):
    if json_name.endswith(".json"):
        return "%s.vapi.hpp" % os.path.splitext(json_name)[0]
    raise Exception("Unexpected json name `%s'!" % json_name)


def gen_cpp_headers(parser, logger, prefix, gen_h_prefix,
                    add_debug_comments=False):
    if prefix == "" or prefix is None:
        prefix = ""
    else:
        prefix = "%s/" % prefix
    if gen_h_prefix is None:
        gen_h_prefix = ""
    else:
        gen_h_prefix = "%s/" % gen_h_prefix
    for j in parser.json_files:
        with open('%s%s' % (prefix, json_to_cpp_header_name(j)), "w") as io:
            gen_json_header(parser, logger, j, io,
                            gen_h_prefix, add_debug_comments)


if __name__ == '__main__':
    try:
        verbose = int(os.getenv("V", 0))
    except:
        verbose = 0

    if verbose >= 2:
        log_level = 10
    elif verbose == 1:
        log_level = 20
    else:
        log_level = 40

    logging.basicConfig(stream=sys.stdout, level=log_level)
    logger = logging.getLogger("VAPI CPP GEN")
    logger.setLevel(log_level)

    argparser = argparse.ArgumentParser(description="VPP C++ API generator")
    argparser.add_argument('files', metavar='api-file', action='append',
                           type=str, help='json api file'
                           '(may be specified multiple times)')
    argparser.add_argument('--prefix', action='store', default=None,
                           help='path prefix')
    argparser.add_argument('--gen-h-prefix', action='store', default=None,
                           help='generated C header prefix')
    args = argparser.parse_args()

    jsonparser = JsonParser(logger, args.files,
                            simple_type_class=CppSimpleType,
                            struct_type_class=CppStructType,
                            field_class=CppField,
                            message_class=CppMessage)

    gen_cpp_headers(jsonparser, logger, args.prefix, args.gen_h_prefix)

    for e in jsonparser.exceptions:
        logger.error(e)