~bzr-pqm/bzr/bzr.dev

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
# Copyright (C) 2006 by Canonical Ltd
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

"""Utilities for distinguishing binary files from text files"""

from itertools import chain 

from bzrlib.errors import BinaryFile
from bzrlib.iterablefile import IterableFile
from bzrlib.osutils import file_iterator


def text_file(input):
    """Produce a file iterator that is guaranteed to be text, without seeking.
    BinaryFile is raised if the file contains a NUL in the first 1024 bytes.
    """
    first_chunk = input.read(1024)
    if '\x00' in first_chunk:
        raise BinaryFile()
    return IterableFile(chain((first_chunk,), file_iterator(input)))


def check_text_lines(lines):
    """Raise BinaryFile if the supplied lines contain NULs.
    Only the first 1024 characters are checked.
    """
    f = IterableFile(lines)
    if '\x00' in f.read(1024):
        raise BinaryFile()


def check_text_path(path):
    """Check whether the supplied path is a text, not binary file.
    Raise BinaryFile if a NUL occurs in the first 1024 bytes.
    """
    text_file(open(path, 'rb'))