~bzr-pqm/bzr/bzr.dev

#! /usr/bin/python

# Copyright (C) 2005 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

# Author: Martin Pool <mbp@canonical.com>

"""Store and retrieve weaves in files.

There is one format marker followed by a blank line, followed by a

series of version headers, followed by the weave itself.

Each version marker has 'i' and the included previous versions, then

'1' and the SHA-1 of the text, if known.  The inclusions do not need

to list versions included by a parent.

The weave is bracketed by 'w' and 'W' lines, and includes the '{}[]'

processing instructions.  Lines of text are prefixed by '.' if the

line contains a newline, or ',' if not.

"""

# TODO: When extracting a single version it'd be enough to just pass

# an iterator returning the weave lines...  We don't really need to

# deserialize it into memory.

FORMAT_1 = '# bzr weave file v4\n'

def write_weave(weave, f, format=None):

    if format == None or format == 1:

        return write_weave_v4(weave, f)

    else:

        raise ValueError("unknown weave format %r" % format)

def write_weave_v4(weave, f):

    """Write weave to file f."""

    print >>f, FORMAT_1,

    for version, included in enumerate(weave._parents):

        if included:

            # mininc = weave.minimal_parents(version)

            mininc = included

            print >>f, 'i',

            for i in mininc:

                print >>f, i,

            print >>f

        else:

            print >>f, 'i'

        print >>f, '1', weave._sha1s[version]

        print >>f

    print >>f, 'w'

    for l in weave._weave:

        if isinstance(l, tuple):

            assert l[0] in '{}[]'

            if l[0] == '}':

                print >>f, '}'

            else:

                print >>f, '%s %d' % l

        else: # text line

            if not l:

                print >>f, ', '

            elif l[-1] == '\n':

                assert l.find('\n', 0, -1) == -1

                print >>f, '.', l,

            else:

                assert l.find('\n') == -1

                print >>f, ',', l

    print >>f, 'W'

def read_weave(f):

    return read_weave_v4(f)

def read_weave_v4(f):

    from weave import Weave, WeaveFormatError

    w = Weave()

    wfe = WeaveFormatError

    l = f.readline()

    if l != FORMAT_1:

        raise WeaveFormatError('invalid weave file header: %r' % l)

    ver = 0

    while True:

        l = f.readline()

        if l[0] == 'i':

            ver += 1

            if len(l) > 2:

                w._parents.append(map(int, l[2:].split(' ')))

            else:

                w._parents.append([])

            l = f.readline()[:-1]

            assert l.startswith('1 ')

            w._sha1s.append(l[2:])

            l = f.readline()

            assert l == '\n'

        elif l == 'w\n':

            break

        else:

            raise WeaveFormatError('unexpected line %r' % l)

    while True:

        l = f.readline()

        if l == 'W\n':

            break

        elif l.startswith('. '):

            w._weave.append(l[2:])  # include newline

        elif l.startswith(', '):

            w._weave.append(l[2:-1])        # exclude newline

        elif l == '}\n':

            w._weave.append(('}', None))

        else:

            assert l[0] in '{[]', l

            assert l[1] == ' ', l

            w._weave.append((intern(l[0]), int(l[2:])))

    return w