python-nwdiag 1.0.0-1 / usr / share / pyshared / packetdiag / parser.py

# -*- coding: utf-8 -*-

# Copyright (c) 2008/2009 Andrey Vlasovskikh
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
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# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be included
# in all copies or substantial portions of the Software.
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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r'''A DOT language parser using funcparserlib.

The parser is based on [the DOT grammar][1]. It is pretty complete with a few
not supported things:

* Ports and compass points
* XML identifiers

At the moment, the parser builds only a parse tree, not an abstract syntax tree
(AST) or an API for dealing with DOT.

  [1]: http://www.graphviz.org/doc/info/lang.html
'''

import re
import io
from re import MULTILINE, DOTALL
from collections import namedtuple
from funcparserlib.lexer import make_tokenizer, Token, LexerError
from funcparserlib.parser import (some, a, maybe, many, finished, skip)
from blockdiag.utils.compat import u

ENCODING = 'utf-8'

Graph = namedtuple('Graph', 'type id stmts')
FieldItem = namedtuple('FieldItem', 'number label attrs')
Attr = namedtuple('Attr', 'name value')
DefAttrs = namedtuple('DefAttrs', 'object attrs')
AttrPlugin = namedtuple('AttrPlugin', 'name attrs')


class ParseException(Exception):
    pass


def tokenize(string):
    """str -> Sequence(Token)"""
    specs = [
        ('Comment', (r'/\*(.|[\r\n])*?\*/', MULTILINE)),
        ('Comment', (r'(//|#).*',)),
        ('NL',      (r'[\r\n]+',)),
        ('Space',   (r'[ \t\r\n]+',)),
        ('DefLabel', (r':[^\r\n\[]+',)),
        ('Range',  (r'[0-9]+-[0-9]+',)),
        ('Number',  (r'[0-9]+',)),
        ('FieldListItem', (r'[\*\-]\s*[^\r\n\[]+',)),
        ('Name',    (u('[A-Za-z_0-9\u0080-\uffff]') +
                     u('[A-Za-z_\\-.0-9\u0080-\uffff]*'),)),
        ('Op',      (r'[{}:;,=\[\]]',)),
        ('String',  (r'(?P<quote>"|\').*?(?<!\\)(?P=quote)', DOTALL)),
    ]
    useless = ['Comment', 'NL', 'Space']
    t = make_tokenizer(specs)
    return [x for x in t(string) if x.type not in useless]


def parse(seq):
    """Sequence(Token) -> object"""
    unarg = lambda f: lambda args: f(*args)
    tokval = lambda x: x.value
    flatten = lambda list: sum(list, [])
    n = lambda s: a(Token('Name', s)) >> tokval
    op = lambda s: a(Token('Op', s)) >> tokval
    op_ = lambda s: skip(op(s))
    _id = some(lambda t: t.type in ['Name', 'Number', 'String', 'Units']
               ).named('id') >> tokval
    number = some(lambda t: t.type == 'Number').named('number') >> tokval
    _range = some(lambda t: t.type == 'Range').named('range') >> tokval
    field_list_item = some(lambda t: t.type == 'FieldListItem'
                           ).named('itemize') >> tokval
    deflabel = some(lambda t: t.type == 'DefLabel').named('deflabel') >> tokval

    field_label = lambda text: re.sub("^:\s*(.*?)\s*;?$", "\\1", text)
    make_field_item = (lambda no, text, attr:
                       FieldItem(no, field_label(text), attr))
    make_field_list_item = (lambda text, attr:
                            FieldItem(None, re.sub("^.\s*", "", text), attr))

    a_list = (
        _id +
        maybe(op_('=') + _id) +
        skip(maybe(op(',')))
        >> unarg(Attr))
    attr_list = (
        many(op_('[') + many(a_list) + op_(']'))
        >> flatten)
    numbered_field_item_stmt = (
        (number | _range) +
        deflabel +
        attr_list
        >> unarg(make_field_item))
    nonnumbered_field_item_stmt = (
        field_list_item +
        attr_list
        >> unarg(make_field_list_item))
    field_item_stmt = (
        numbered_field_item_stmt
        | nonnumbered_field_item_stmt
    )

    # plugin definition
    plugin_stmt = (
        skip(n('plugin')) +
        _id +
        attr_list
        >> unarg(AttrPlugin))

    stmt = (
        field_item_stmt
        | plugin_stmt
        | a_list
    )
    stmt_list = many(stmt + skip(maybe(op(';'))))
    graph = (
        maybe(n('diagram') | n('pktdiag')) +
        maybe(_id) +
        op_('{') +
        stmt_list +
        op_('}')
        >> unarg(Graph))
    dotfile = graph + skip(finished)

    return dotfile.parse(seq)


def sort_tree(tree):
    def weight(node):
        if isinstance(node, (Attr, DefAttrs, AttrPlugin)):
            return 1
        else:
            return 2

    if hasattr(tree, 'stmts'):
        tree.stmts.sort(key=lambda x: weight(x))
        for stmt in tree.stmts:
            sort_tree(stmt)

    return tree


def parse_string(string):
    try:
        tree = parse(tokenize(string))
        return sort_tree(tree)
    except LexerError as e:
        message = "Got unexpected token at line %d column %d" % e.place
        raise ParseException(message)
    except Exception as e:
        raise ParseException(str(e))


def parse_file(path):
    code = io.open(path, 'r', encoding='utf-8-sig').read()
    return parse_string(code)