~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 'v' and the version, then 'i' and the included

previous versions.  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...

FORMAT_1 = '# bzr weave file v1\n'

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

    if format == None or format == 1:

        return write_weave_v1(weave, f)

    else:

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

def write_weave_v1(weave, f):

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

    print >>f, FORMAT_1,

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

        print >>f, 'v', version

        if included:

            # find a minimal expression of it; bias towards using

            # later revisions

            li = list(included)

            li.sort()

            li.reverse()

            mininc = []

            gotit = set()

            for pv in li:

                if pv not in gotit:

                    mininc.append(pv)

                    gotit.update(weave._v[pv])

            assert mininc[0] >= 0

            assert mininc[-1] < version

            print >>f, 'i',

            for i in mininc:

                print >>f, i,

            print >>f

        else:

            print >>f, 'i'

        print >>f

    print >>f, 'w'

    for l in weave._l:

        if isinstance(l, tuple):

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

            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_v1(f)

def read_weave_v1(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)

    v_cnt = 0

    while True:

        l = f.readline()

        if l.startswith('v '):

            ver = int(l[2:])

            if ver != v_cnt:

                raise WeaveFormatError('version %d!=%d out of order'

                                       % (ver, v_cnt))

            v_cnt += 1

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

            if l[0] != 'i':

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

            if len(l) > 2:

                included = map(int, l[2:].split(' '))

                full = set()

                for pv in included:

                    full.add(pv)

                    full.update(w._v[pv])

                w._addversion(full)

            else:

                w._addversion(None)

            assert f.readline() == '\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._l.append(l[2:])           # include newline

        elif l.startswith(', '):

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

        else:

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

            assert l[1] == ' ', l

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

    return w