~bzr-pqm/bzr/bzr.dev

# Copyright (C) 2006 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.

    """

    f = open(path, 'rb')

    try:

        text_file(f)

    finally:

        f.close()