/brz/remove-bazaar

# Copyright (C) 2007 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

"""Container format for Bazaar data.

"Containers" and "records" are described in doc/developers/container-format.txt.

"""

import re

from bzrlib import errors

FORMAT_ONE = "Bazaar pack format 1"

_whitespace_re = re.compile('[\t\n\x0b\x0c\r ]')

def _check_name(name):

    """Do some basic checking of 'name'.

    At the moment, this just checks that there are no whitespace characters in a

    name.

    :raises InvalidRecordError: if name is not valid.

    """

    # XXX: consider checking that name is a str of valid UTF-8 too?

    if _whitespace_re.search(name) is not None:

        raise errors.InvalidRecordError("%r is not a valid name." % (name,))

class ContainerWriter(object):

    """A class for writing containers."""

    def __init__(self, write_func):

        """Constructor.

        :param write_func: a callable that will be called when this

            ContainerWriter needs to write some bytes.

        """

        self.write_func = write_func

    def begin(self):

        """Begin writing a container."""

        self.write_func(FORMAT_ONE + "\n")

    def end(self):

        """Finish writing a container."""

        self.write_func("E")

    def add_bytes_record(self, bytes, names):

        """Add a Bytes record with the given names."""

        # Kind marker

        self.write_func("B")

        # Length

        self.write_func(str(len(bytes)) + "\n")

        # Names

        for name in names:

            # Make sure we're writing valid names.  Note that we will leave a

            # half-written record if a name is bad!

            _check_name(name)

            self.write_func(name + "\n")

        # End of headers

        self.write_func("\n")

        # Finally, the contents.

        self.write_func(bytes)

class BaseReader(object):

    def __init__(self, reader_func):

        """Constructor.

        :param reader_func: a callable that takes one optional argument,

            ``size``, and returns at most that many bytes.  When the callable

            returns less than the requested number of bytes, then the end of the

            file/stream has been reached.

        """

        self.reader_func = reader_func

    def _read_line(self):

        """Read a line from the input stream.

        This is a simple but inefficient implementation that just reads one byte

        at a time.  Lines should not be very long, so this is probably

        tolerable.

        :returns: a line, without the trailing newline

        """

        # XXX: Have a maximum line length, to prevent malicious input from

        # consuming an unreasonable amount of resources?

        #   -- Andrew Bennetts, 2007-05-07.

        line = ''

        while not line.endswith('\n'):

            byte = self.reader_func(1)

            if byte == '':

                raise errors.UnexpectedEndOfContainerError()

            line += byte

        return line[:-1]

class ContainerReader(BaseReader):

    """A class for reading Bazaar's container format."""

    def iter_records(self):

        """Iterate over the container, yielding each record as it is read.

        Each yielded record will be a 2-tuple of (names, bytes), where names is

        a ``list`` and bytes is a ``str``.

        :raises UnknownContainerFormatError: if the format of the container is

            unrecognised.

        """

        format = self._read_line()

        if format != FORMAT_ONE:

            raise errors.UnknownContainerFormatError(format)

        return self._iter_records()

    def _iter_records(self):

        while True:

            record_kind = self.reader_func(1)

            if record_kind == 'B':

                # Bytes record.

                reader = BytesRecordReader(self.reader_func)

                yield reader.read()

            elif record_kind == 'E':

                # End marker.  There are no more records.

                return

            elif record_kind == '':

                # End of stream encountered, but no End Marker record seen, so

                # this container is incomplete.

                raise errors.UnexpectedEndOfContainerError()

            else:

                # Unknown record type.

                raise errors.UnknownRecordTypeError(record_kind)

class BytesRecordReader(BaseReader):

    def read(self):

        # Read the content length.

        length_line = self._read_line()

        try:

            length = int(length_line)

        except ValueError:

            raise errors.InvalidRecordError(

                "%r is not a valid length." % (length_line,))

        # Read the list of names.

        names = []

        while True:

            name = self._read_line()

            if name == '':

                break

            _check_name(name)

            names.append(name)

        bytes = self.reader_func(length)

        if len(bytes) != length:

            raise errors.UnexpectedEndOfContainerError()

        return names, bytes