src/tools/vppapigen/vppapigen.py

#!/usr/bin/env python3

import ply.lex as lex
import ply.yacc as yacc
import sys
import argparse
import keyword
import logging
import binascii
import os
import sys
from subprocess import Popen, PIPE

assert sys.version_info >= (3, 6), \
    "Not supported Python version: {}".format(sys.version)
log = logging.getLogger('vppapigen')

# Ensure we don't leave temporary files around
sys.dont_write_bytecode = True

#
# VPP API language
#

# Global dictionary of new types (including enums)
global_types = {}

seen_imports = {}


def global_type_add(name, obj):
    '''Add new type to the dictionary of types '''
    type_name = 'vl_api_' + name + '_t'
    if type_name in global_types:
        raise KeyError("Attempted redefinition of {!r} with {!r}.".format(
            name, obj))
    global_types[type_name] = obj


# All your trace are belong to us!
def exception_handler(exception_type, exception, traceback):
    print("%s: %s" % (exception_type.__name__, exception))


#
# Lexer
#
class VPPAPILexer(object):
    def __init__(self, filename):
        self.filename = filename

    reserved = {
        'service': 'SERVICE',
        'rpc': 'RPC',
        'returns': 'RETURNS',
        'null': 'NULL',
        'stream': 'STREAM',
        'events': 'EVENTS',
        'define': 'DEFINE',
        'typedef': 'TYPEDEF',
        'enum': 'ENUM',
        'typeonly': 'TYPEONLY',
        'manual_print': 'MANUAL_PRINT',
        'manual_endian': 'MANUAL_ENDIAN',
        'dont_trace': 'DONT_TRACE',
        'autoreply': 'AUTOREPLY',
        'option': 'OPTION',
        'u8': 'U8',
        'u16': 'U16',
        'u32': 'U32',
        'u64': 'U64',
        'i8': 'I8',
        'i16': 'I16',
        'i32': 'I32',
        'i64': 'I64',
        'f64': 'F64',
        'bool': 'BOOL',
        'string': 'STRING',
        'import': 'IMPORT',
        'true': 'TRUE',
        'false': 'FALSE',
        'union': 'UNION',
    }

    tokens = ['STRING_LITERAL',
              'ID', 'NUM'] + list(reserved.values())

    t_ignore_LINE_COMMENT = '//.*'

    def t_FALSE(self, t):
        r'false'
        t.value = False
        return t

    def t_TRUE(self, t):
        r'false'
        t.value = True
        return t

    def t_NUM(self, t):
        r'0[xX][0-9a-fA-F]+|-?\d+\.?\d*'
        base = 16 if t.value.startswith('0x') else 10
        if '.' in t.value:
            t.value = float(t.value)
        else:
            t.value = int(t.value, base)
        return t

    def t_ID(self, t):
        r'[a-zA-Z_][a-zA-Z_0-9]*'
        # Check for reserved words
        t.type = VPPAPILexer.reserved.get(t.value, 'ID')
        return t

    # C string
    def t_STRING_LITERAL(self, t):
        r'\"([^\\\n]|(\\.))*?\"'
        t.value = str(t.value).replace("\"", "")
        return t

    # C or C++ comment (ignore)
    def t_comment(self, t):
        r'(/\*(.|\n)*?\*/)|(//.*)'
        t.lexer.lineno += t.value.count('\n')

    # Error handling rule
    def t_error(self, t):
        raise ParseError("Illegal character '{}' ({})"
                         "in {}: line {}".format(t.value[0],
                                                 hex(ord(t.value[0])),
                                                 self.filename,
                                                 t.lexer.lineno))
        t.lexer.skip(1)

    # Define a rule so we can track line numbers
    def t_newline(self, t):
        r'\n+'
        t.lexer.lineno += len(t.value)

    literals = ":{}[];=.,"

    # A string containing ignored characters (spaces and tabs)
    t_ignore = ' \t'


def crc_block_combine(block, crc):
    s = str(block).encode()
    return binascii.crc32(s, crc) & 0xffffffff


def vla_is_last_check(name, block):
    vla = False
    for i, b in enumerate(block):
        if isinstance(b, Array) and b.vla:
            vla = True
            if i + 1 < len(block):
                raise ValueError(
                    'VLA field "{}" must be the last field in message "{}"'
                    .format(b.fieldname, name))
        elif b.fieldtype.startswith('vl_api_'):
            if global_types[b.fieldtype].vla:
                vla = True
                if i + 1 < len(block):
                    raise ValueError(
                        'VLA field "{}" must be the last '
                        'field in message "{}"'
                        .format(b.fieldname, name))
        elif b.fieldtype == 'string' and b.length == 0:
            vla = True
            if i + 1 < len(block):
                raise ValueError(
                    'VLA field "{}" must be the last '
                    'field in message "{}"'
                    .format(b.fieldname, name))
    return vla


class Service():
    def __init__(self, caller, reply, events=None, stream=False):
        self.caller = caller
        self.reply = reply
        self.stream = stream
        self.events = [] if events is None else events


class Typedef():
    def __init__(self, name, flags, block):
        self.name = name
        self.flags = flags
        self.block = block
        self.crc = str(block).encode()
        self.manual_print = False
        self.manual_endian = False
        for f in flags:
            if f == 'manual_print':
                self.manual_print = True
            elif f == 'manual_endian':
                self.manual_endian = True

        global_type_add(name, self)

        self.vla = vla_is_last_check(name, block)

    def __repr__(self):
        return self.name + str(self.flags) + str(self.block)


class Using():
    def __init__(self, name, flags, alias):
        self.name = name
        self.vla = False
        self.block = []
        self.manual_print = True
        self.manual_endian = True

        self.manual_print = False
        self.manual_endian = False
        for f in flags:
            if f == 'manual_print':
                self.manual_print = True
            elif f == 'manual_endian':
                self.manual_endian = True

        if isinstance(alias, Array):
            a = {'type': alias.fieldtype,
                 'length': alias.length}
        else:
            a = {'type': alias.fieldtype}
        self.alias = a
        self.crc = str(alias).encode()
        global_type_add(name, self)

    def __repr__(self):
        return self.name + str(self.alias)


class Union():
    def __init__(self, name, flags, block):
        self.type = 'Union'
        self.manual_print = False
        self.manual_endian = False
        self.name = name

        for f in flags:
            if f == 'manual_print':
                self.manual_print = True
            elif f == 'manual_endian':
                self.manual_endian = True

        self.block = block
        self.crc = str(block).encode()
        self.vla = vla_is_last_check(name, block)

        global_type_add(name, self)

    def __repr__(self):
        return str(self.block)


class Define():
    def __init__(self, name, flags, block):
        self.name = name
        self.flags = flags
        self.block = block
        self.dont_trace = False
        self.manual_print = False
        self.manual_endian = False
        self.autoreply = False
        self.singular = False
        self.options = {}
        for f in flags:
            if f == 'dont_trace':
                self.dont_trace = True
            elif f == 'manual_print':
                self.manual_print = True
            elif f == 'manual_endian':
                self.manual_endian = True
            elif f == 'autoreply':
                self.autoreply = True

        remove = []
        for b in block:
            if isinstance(b, Option):
                if b[1] == 'singular' and b[2] == 'true':
                    self.singular = True
                else:
                    self.options[b.option] = b.value
                remove.append(b)

        block = [x for x in block if x not in remove]
        self.block = block
        self.vla = vla_is_last_check(name, block)
        self.crc = str(block).encode()

    def __repr__(self):
        return self.name + str(self.flags) + str(self.block)


class Enum():
    def __init__(self, name, block, enumtype='u32'):
        self.name = name
        self.enumtype = enumtype
        self.vla = False

        count = 0
        for i, b in enumerate(block):
            if type(b) is list:
                count = b[1]
            else:
                count += 1
                block[i] = [b, count]

        self.block = block
        self.crc = str(block).encode()
        global_type_add(name, self)

    def __repr__(self):
        return self.name + str(self.block)


class Import():

    def __new__(cls, *args, **kwargs):
        if args[0] not in seen_imports:
            instance = super().__new__(cls)
            instance._initialized = False
            seen_imports[args[0]] = instance

        return seen_imports[args[0]]

    def __init__(self, filename, revision):
        if self._initialized:
            return
        else:
            self.filename = filename
            # Deal with imports
            parser = VPPAPI(filename=filename, revision=revision)
            dirlist = dirlist_get()
            f = filename
            for dir in dirlist:
                f = os.path.join(dir, filename)
                if os.path.exists(f):
                    break
            self.result = parser.parse_filename(f, None)
            self._initialized = True

    def __repr__(self):
        return self.filename


class Option():
    def __init__(self, option, value):
        self.type = 'Option'
        self.option = option
        self.value = value
        self.crc = str(option).encode()

    def __repr__(self):
        return str(self.option)

    def __getitem__(self, index):
        return self.option[index]


class Array():
    def __init__(self, fieldtype, name, length, modern_vla=False):
        self.type = 'Array'
        self.fieldtype = fieldtype
        self.fieldname = name
        self.modern_vla = modern_vla
        if type(length) is str:
            self.lengthfield = length
            self.length = 0
            self.vla = True
        else:
            self.length = length
            self.lengthfield = None
            self.vla = False

    def __repr__(self):
        return str([self.fieldtype, self.fieldname, self.length,
                    self.lengthfield])


class Field():
    def __init__(self, fieldtype, name, limit=None):
        self.type = 'Field'
        self.fieldtype = fieldtype

        if self.fieldtype == 'string':
            raise ValueError("The string type {!r} is an "
                             "array type ".format(name))

        if name in keyword.kwlist:
            raise ValueError("Fieldname {!r} is a python keyword and is not "
                             "accessible via the python API. ".format(name))
        self.fieldname = name
        self.limit = limit

    def __repr__(self):
        return str([self.fieldtype, self.fieldname])


class Coord(object):
    """ Coordinates of a syntactic element. Consists of:
            - File name
            - Line number
            - (optional) column number, for the Lexer
    """
    __slots__ = ('file', 'line', 'column', '__weakref__')

    def __init__(self, file, line, column=None):
        self.file = file
        self.line = line
        self.column = column

    def __str__(self):
        str = "%s:%s" % (self.file, self.line)
        if self.column:
            str += ":%s" % self.column
        return str


class ParseError(Exception):
    pass


#
# Grammar rules
#
class VPPAPIParser(object):
    tokens = VPPAPILexer.tokens

    def __init__(self, filename, logger, revision=None):
        self.filename = filename
        self.logger = logger
        self.fields = []
        self.revision = revision

    def _parse_error(self, msg, coord):
        raise ParseError("%s: %s" % (coord, msg))

    def _parse_warning(self, msg, coord):
        if self.logger:
            self.logger.warning("%s: %s" % (coord, msg))

    def _coord(self, lineno, column=None):
        return Coord(
                file=self.filename,
                line=lineno, column=column)

    def _token_coord(self, p, token_idx):
        """ Returns the coordinates for the YaccProduction object 'p' indexed
            with 'token_idx'. The coordinate includes the 'lineno' and
            'column'. Both follow the lex semantic, starting from 1.
        """
        last_cr = p.lexer.lexdata.rfind('\n', 0, p.lexpos(token_idx))
        if last_cr < 0:
            last_cr = -1
        column = (p.lexpos(token_idx) - (last_cr))
        return self._coord(p.lineno(token_idx), column)

    def p_slist(self, p):
        '''slist : stmt
                 | slist stmt'''
        if len(p) == 2:
            p[0] = [p[1]]
        else:
            p[0] = p[1] + [p[2]]

    def p_stmt(self, p):
        '''stmt : define
                | typedef
                | option
                | import
                | enum
                | union
                | service'''
        p[0] = p[1]

    def p_import(self, p):
        '''import : IMPORT STRING_LITERAL ';' '''
        p[0] = Import(p[2], revision=self.revision)

    def p_service(self, p):
        '''service : SERVICE '{' service_statements '}' ';' '''
        p[0] = p[3]

    def p_service_statements(self, p):
        '''service_statements : service_statement
                        | service_statements service_statement'''
        if len(p) == 2:
            p[0] = [p[1]]
        else:
            p[0] = p[1] + [p[2]]

    def p_service_statement(self, p):
        '''service_statement : RPC ID RETURNS NULL ';'
                             | RPC ID RETURNS ID ';'
                             | RPC ID RETURNS STREAM ID ';'
                             | RPC ID RETURNS ID EVENTS event_list ';' '''
        if p[2] == p[4]:
            # Verify that caller and reply differ
            self._parse_error(
                'Reply ID ({}) should not be equal to Caller ID'.format(p[2]),
                self._token_coord(p, 1))
        if len(p) == 8:
            p[0] = Service(p[2], p[4], p[6])
        elif len(p) == 7:
            p[0] = Service(p[2], p[5], stream=True)
        else:
            p[0] = Service(p[2], p[4])

    def p_event_list(self, p):
        '''event_list : events
                      | event_list events '''
        if len(p) == 2:
            p[0] = [p[1]]
        else:
            p[0] = p[1] + [p[2]]

    def p_event(self, p):
        '''events : ID
                  | ID ',' '''
        p[0] = p[1]

    def p_enum(self, p):
        '''enum : ENUM ID '{' enum_statements '}' ';' '''
        p[0] = Enum(p[2], p[4])

    def p_enum_type(self, p):
        ''' enum : ENUM ID ':' enum_size '{' enum_statements '}' ';' '''
        if len(p) == 9:
            p[0] = Enum(p[2], p[6], enumtype=p[4])
        else:
            p[0] = Enum(p[2], p[4])

    def p_enum_size(self, p):
        ''' enum_size : U8
                      | U16
                      | U32 '''
        p[0] = p[1]

    def p_define(self, p):
        '''define : DEFINE ID '{' block_statements_opt '}' ';' '''
        self.fields = []
        p[0] = Define(p[2], [], p[4])

    def p_define_flist(self, p):
        '''define : flist DEFINE ID '{' block_statements_opt '}' ';' '''
        # Legacy typedef
        if 'typeonly' in p[1]:
            self._parse_error('legacy typedef. use typedef: {} {}[{}];'
                              .format(p[1], p[2], p[4]),
                              self._token_coord(p, 1))
        else:
            p[0] = Define(p[3], p[1], p[5])

    def p_flist(self, p):
        '''flist : flag
                 | flist flag'''
        if len(p) == 2:
            p[0] = [p[1]]
        else:
            p[0] = p[1] + [p[2]]

    def p_flag(self, p):
        '''flag : MANUAL_PRINT
                | MANUAL_ENDIAN
                | DONT_TRACE
                | TYPEONLY
                | AUTOREPLY'''
        if len(p) == 1:
            return
        p[0] = p[1]

    def p_typedef(self, p):
        '''typedef : TYPEDEF ID '{' block_statements_opt '}' ';' '''
        p[0] = Typedef(p[2], [], p[4])

    def p_typedef_flist(self, p):
        '''typedef : flist TYPEDEF ID '{' block_statements_opt '}' ';' '''
        p[0] = Typedef(p[3], p[1], p[5])

    def p_typedef_alias(self, p):
        '''typedef : TYPEDEF declaration '''
        p[0] = Using(p[2].fieldname, [], p[2])

    def p_typedef_alias_flist(self, p):
        '''typedef : flist TYPEDEF declaration '''
        p[0] = Using(p[3].fieldname, p[1], p[3])

    def p_block_statements_opt(self, p):
        '''block_statements_opt : block_statements '''
        p[0] = p[1]

    def p_block_statements(self, p):
        '''block_statements : block_statement
                            | block_statements block_statement'''
        if len(p) == 2:
            p[0] = [p[1]]
        else:
            p[0] = p[1] + [p[2]]

    def p_block_statement(self, p):
        '''block_statement : declaration
                           | option '''
        p[0] = p[1]

    def p_enum_statements(self, p):
        '''enum_statements : enum_statement
                           | enum_statements enum_statement'''
        if len(p) == 2:
            p[0] = [p[1]]
        else:
            p[0] = p[1] + [p[2]]

    def p_enum_statement(self, p):
        '''enum_statement : ID '=' NUM ','
                          | ID ',' '''
        if len(p) == 5:
            p[0] = [p[1], p[3]]
        else:
            p[0] = p[1]

    def p_field_options(self, p):
        '''field_options : field_option
                           | field_options field_option'''
        if len(p) == 2:
            p[0] = p[1]
        else:
            p[0] = {**p[1], **p[2]}

    def p_field_option(self, p):
        '''field_option : ID
                        | ID '=' assignee ','
                        | ID '=' assignee

        '''
        if len(p) == 2:
            p[0] = {p[1]: None}
        else:
            p[0] = {p[1]: p[3]}

    def p_declaration(self, p):
        '''declaration : type_specifier ID ';'
                       | type_specifier ID '[' field_options ']' ';' '''
        if len(p) == 7:
            p[0] = Field(p[1], p[2], p[4])
        elif len(p) == 4:
            p[0] = Field(p[1], p[2])
        else:
            self._parse_error('ERROR', self._token_coord(p, 1))
        self.fields.append(p[2])

    def p_declaration_array_vla(self, p):
        '''declaration : type_specifier ID '[' ']' ';' '''
        p[0] = Array(p[1], p[2], 0, modern_vla=True)

    def p_declaration_array(self, p):
        '''declaration : type_specifier ID '[' NUM ']' ';'
                       | type_specifier ID '[' ID ']' ';' '''

        if len(p) != 7:
            return self._parse_error(
                'array: %s' % p.value,
                self._coord(lineno=p.lineno))

        # Make this error later
        if type(p[4]) is int and p[4] == 0:
            # XXX: Line number is wrong
            self._parse_warning('Old Style VLA: {} {}[{}];'
                                .format(p[1], p[2], p[4]),
                                self._token_coord(p, 1))

        if type(p[4]) is str and p[4] not in self.fields:
            # Verify that length field exists
            self._parse_error('Missing length field: {} {}[{}];'
                              .format(p[1], p[2], p[4]),
                              self._token_coord(p, 1))
        p[0] = Array(p[1], p[2], p[4])

    def p_option(self, p):
        '''option : OPTION ID '=' assignee ';' '''
        p[0] = Option(p[2], p[4])

    def p_assignee(self, p):
        '''assignee : NUM
                    | TRUE
                    | FALSE
                    | STRING_LITERAL '''
        p[0] = p[1]

    def p_type_specifier(self, p):
        '''type_specifier : U8
                          | U16
                          | U32
                          | U64
                          | I8
                          | I16
                          | I32
                          | I64
                          | F64
                          | BOOL
                          | STRING'''
        p[0] = p[1]

    # Do a second pass later to verify that user defined types are defined
    def p_typedef_specifier(self, p):
        '''type_specifier : ID '''
        if p[1] not in global_types:
            self._parse_error('Undefined type: {}'.format(p[1]),
                              self._token_coord(p, 1))
        p[0] = p[1]

    def p_union(self, p):
        '''union : UNION ID '{' block_statements_opt '}' ';' '''
        p[0] = Union(p[2], [], p[4])

    def p_union_flist(self, p):
        '''union : flist UNION ID '{' block_statements_opt '}' ';' '''
        p[0] = Union(p[3], p[1], p[5])

    # Error rule for syntax errors
    def p_error(self, p):
        if p:
            self._parse_error(
                'before: %s' % p.value,
                self._coord(lineno=p.lineno))
        else:
            self._parse_error('At end of input', self.filename)


class VPPAPI(object):

    def __init__(self, debug=False, filename='', logger=None, revision=None):
        self.lexer = lex.lex(module=VPPAPILexer(filename), debug=debug)
        self.parser = yacc.yacc(module=VPPAPIParser(filename, logger,
                                                    revision=revision),
                                write_tables=False, debug=debug)
        self.logger = logger
        self.revision = revision
        self.filename = filename

    def parse_string(self, code, debug=0, lineno=1):
        self.lexer.lineno = lineno
        return self.parser.parse(code, lexer=self.lexer, debug=debug)

    def parse_fd(self, fd, debug=0):
        data = fd.read()
        return self.parse_string(data, debug=debug)

    def parse_filename(self, filename, debug=0):
        if self.revision:
            git_show = f'git show  {self.revision}:{filename}'
            proc = Popen(git_show.split(), stdout=PIPE, encoding='utf-8')
            try:
                data, errs = proc.communicate()
                if proc.returncode != 0:
                    print(f'File not found: {self.revision}:{filename}', file=sys.stderr)
                    sys.exit(2)
                return self.parse_string(data, debug=debug)
            except Exception as e:
                sys.exit(3)
        else:
            try:
                with open(filename, encoding='utf-8') as fd:
                    return self.parse_fd(fd, None)
            except FileNotFoundError:
                print(f'File not found: {filename}', file=sys.stderr)
                sys.exit(2)

    def autoreply_block(self, name, parent):
        block = [Field('u32', 'context'),
                 Field('i32', 'retval')]
        # inherhit the parent's options
        for k, v in parent.options.items():
            block.append(Option(k, v))
        return Define(name + '_reply', [], block)

    def process(self, objs):
        s = {}
        s['Option'] = {}
        s['Define'] = []
        s['Service'] = []
        s['types'] = []
        s['Import'] = []
        crc = 0
        for o in objs:
            tname = o.__class__.__name__
            try:
                crc = binascii.crc32(o.crc, crc) & 0xffffffff
            except AttributeError:
                pass
            if isinstance(o, Define):
                s[tname].append(o)
                if o.autoreply:
                    s[tname].append(self.autoreply_block(o.name, o))
            elif isinstance(o, Option):
                s[tname][o.option] = o.value
            elif type(o) is list:
                for o2 in o:
                    if isinstance(o2, Service):
                        s['Service'].append(o2)
            elif (isinstance(o, Enum) or
                  isinstance(o, Typedef) or
                  isinstance(o, Using) or
                  isinstance(o, Union)):
                s['types'].append(o)
            else:
                if tname not in s:
                    raise ValueError('Unknown class type: {} {}'
                                     .format(tname, o))
                s[tname].append(o)

        msgs = {d.name: d for d in s['Define']}
        svcs = {s.caller: s for s in s['Service']}
        replies = {s.reply: s for s in s['Service']}
        seen_services = {}

        s['file_crc'] = crc

        for service in svcs:
            if service not in msgs:
                raise ValueError(
                    'Service definition refers to unknown message'
                    ' definition: {}'.format(service))
            if svcs[service].reply != 'null' and \
               svcs[service].reply not in msgs:
                raise ValueError('Service definition refers to unknown message'
                                 ' definition in reply: {}'
                                 .format(svcs[service].reply))
            if service in replies:
                raise ValueError('Service definition refers to message'
                                 ' marked as reply: {}'.format(service))
            for event in svcs[service].events:
                if event not in msgs:
                    raise ValueError('Service definition refers to unknown '
                                     'event: {} in message: {}'
                                     .format(event, service))
                seen_services[event] = True

        # Create services implicitly
        for d in msgs:
            if d in seen_services:
                continue
            if msgs[d].singular is True:
                continue
            if d.endswith('_reply'):
                if d[:-6] in svcs:
                    continue
                if d[:-6] not in msgs:
                    raise ValueError('{} missing calling message'
                                     .format(d))
                continue
            if d.endswith('_dump'):
                if d in svcs:
                    continue
                if d[:-5]+'_details' in msgs:
                    s['Service'].append(Service(d, d[:-5]+'_details',
                                                stream=True))
                else:
                    raise ValueError('{} missing details message'
                                     .format(d))
                continue

            if d.endswith('_details'):
                if d[:-8]+'_dump' not in msgs:
                    raise ValueError('{} missing dump message'
                                     .format(d))
                continue

            if d in svcs:
                continue
            if d+'_reply' in msgs:
                s['Service'].append(Service(d, d+'_reply'))
            else:
                raise ValueError(
                    '{} missing reply message ({}) or service definition'
                    .format(d, d+'_reply'))

        return s

    def process_imports(self, objs, in_import, result):
        imported_objs = []
        for o in objs:
            # Only allow the following object types from imported file
            if in_import and not (isinstance(o, Enum) or
                                  isinstance(o, Union) or
                                  isinstance(o, Typedef) or
                                  isinstance(o, Import) or
                                  isinstance(o, Using)):
                continue
            if isinstance(o, Import):
                result.append(o)
                result = self.process_imports(o.result, True, result)
            else:
                result.append(o)
        return result


# Add message ids to each message.
def add_msg_id(s):
    for o in s:
        o.block.insert(0, Field('u16', '_vl_msg_id'))
    return s


dirlist = []


def dirlist_add(dirs):
    global dirlist
    if dirs:
        dirlist = dirlist + dirs


def dirlist_get():
    return dirlist


def foldup_blocks(block, crc):
    for b in block:
        # Look up CRC in user defined types
        if b.fieldtype.startswith('vl_api_'):
            # Recursively
            t = global_types[b.fieldtype]
            try:
                crc = crc_block_combine(t.block, crc)
                return foldup_blocks(t.block, crc)
            except AttributeError:
                pass
    return crc


def foldup_crcs(s):
    for f in s:
        f.crc = foldup_blocks(f.block,
                              binascii.crc32(f.crc) & 0xffffffff)


#
# Main
#
def main():
    if sys.version_info < (3, 5,):
        log.exception('vppapigen requires a supported version of python. '
                      'Please use version 3.5 or greater. '
                      'Using {}'.format(sys.version))
        return 1

    cliparser = argparse.ArgumentParser(description='VPP API generator')
    cliparser.add_argument('--pluginpath', default=""),
    cliparser.add_argument('--includedir', action='append'),
    cliparser.add_argument('--outputdir', action='store'),
    cliparser.add_argument('--input')
    cliparser.add_argument('--output', nargs='?',
                           type=argparse.FileType('w', encoding='UTF-8'),
                           default=sys.stdout)

    cliparser.add_argument('output_module', nargs='?', default='C')
    cliparser.add_argument('--debug', action='store_true')
    cliparser.add_argument('--show-name', nargs=1)
    cliparser.add_argument('--git-revision',
                           help="Git revision to use for opening files")
    args = cliparser.parse_args()

    dirlist_add(args.includedir)
    if not args.debug:
        sys.excepthook = exception_handler

    # Filename
    if args.show_name:
        filename = args.show_name[0]
    elif args.input:
        filename = args.input
    else:
        filename = ''

    if args.debug:
        logging.basicConfig(stream=sys.stdout, level=logging.WARNING)
    else:
        logging.basicConfig()

    parser = VPPAPI(debug=args.debug, filename=filename, logger=log,
                    revision=args.git_revision)

    try:
        if not args.input:
            parsed_objects = parser.parse_fd(sys.stdin, log)
        else:
            parsed_objects = parser.parse_filename(args.input, log)
    except ParseError as e:
        print('Parse error: ', e, file=sys.stderr)
        sys.exit(1)

    # Build a list of objects. Hash of lists.
    result = []

    if args.output_module == 'C':
        s = parser.process(parsed_objects)
    else:
        result = parser.process_imports(parsed_objects, False, result)
        s = parser.process(result)

    # Add msg_id field
    s['Define'] = add_msg_id(s['Define'])

    # Fold up CRCs
    foldup_crcs(s['Define'])

    #
    # Debug
    if args.debug:
        import pprint
        pp = pprint.PrettyPrinter(indent=4, stream=sys.stderr)
        for t in s['Define']:
            pp.pprint([t.name, t.flags, t.block])
        for t in s['types']:
            pp.pprint([t.name, t.block])

    #
    # Generate representation
    #
    from importlib.machinery import SourceFileLoader

    # Default path
    pluginpath = ''
    if not args.pluginpath:
        cand = []
        cand.append(os.path.dirname(os.path.realpath(__file__)))
        cand.append(os.path.dirname(os.path.realpath(__file__)) +
                    '/../share/vpp/')
        for c in cand:
            c += '/'
            if os.path.isfile('{}vppapigen_{}.py'
                              .format(c, args.output_module.lower())):
                pluginpath = c
                break
    else:
        pluginpath = args.pluginpath + '/'
    if pluginpath == '':
        log.exception('Output plugin not found')
        return 1
    module_path = '{}vppapigen_{}.py'.format(pluginpath,
                                             args.output_module.lower())

    try:
        plugin = SourceFileLoader(args.output_module,
                                  module_path).load_module()
    except Exception as err:
        log.exception('Error importing output plugin: {}, {}'
                      .format(module_path, err))
        return 1

    result = plugin.run(args, filename, s)
    if result:
        print(result, file=args.output)
    else:
        log.exception('Running plugin failed: {} {}'
                      .format(filename, result))
        return 1
    return 0


if __name__ == '__main__':
    sys.exit(main())