~bzr-pqm/bzr/bzr.dev

# Copyright (C) 2005-2010 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 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'   parent version indexes

 '1'   SHA-1 of text

 'n'   name

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.

"""

from __future__ import absolute_import

# 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 v5\n'

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

    if format is None or format == 1:

        return write_weave_v5(weave, f)

    else:

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

def write_weave_v5(weave, f):

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

    f.write(FORMAT_1)

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

        if included:

            # mininc = weave.minimal_parents(version)

            mininc = included

            f.write('i ')

            f.write(' '.join(str(i) for i in mininc))

            f.write('\n')

        else:

            f.write('i\n')

        f.write('1 ' + weave._sha1s[version] + '\n')

        f.write('n ' + weave._names[version] + '\n')

        f.write('\n')

    f.write('w\n')

    for l in weave._weave:

        if isinstance(l, tuple):

            if l[0] == '}':

                f.write('}\n')

            else:

                f.write('%s %d\n' % l)

        else: # text line

            if not l:

                f.write(', \n')

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

                f.write('. ' + l)

            else:

                f.write(', ' + l + '\n')

    f.write('W\n')

def read_weave(f):

    # FIXME: detect the weave type and dispatch

    from bzrlib.weave import Weave

    w = Weave(getattr(f, 'name', None))

    _read_weave_v5(f, w)

    return w

def _read_weave_v5(f, w):

    """Private helper routine to read a weave format 5 file into memory.

    This is only to be used by read_weave and WeaveFile.__init__.

    """

    #  200   0   2075.5080   1084.0360   bzrlib.weavefile:104(_read_weave_v5)

    # +60412 0    366.5900    366.5900   +<method 'readline' of 'file' objects>

    # +59982 0    320.5280    320.5280   +<method 'startswith' of 'str' objects>

    # +59363 0    297.8080    297.8080   +<method 'append' of 'list' objects>

    # replace readline call with iter over all lines ->

    # safe because we already suck on memory.

    #  200   0   1492.7170    802.6220   bzrlib.weavefile:104(_read_weave_v5)

    # +59982 0    329.9100    329.9100   +<method 'startswith' of 'str' objects>

    # +59363 0    320.2980    320.2980   +<method 'append' of 'list' objects>

    # replaced startswith with slice lookups:

    #  200   0    851.7250    501.1120   bzrlib.weavefile:104(_read_weave_v5)

    # +59363 0    311.8780    311.8780   +<method 'append' of 'list' objects>

    # +200   0     30.2500     30.2500   +<method 'readlines' of 'file' objects>

    from bzrlib.weave import WeaveFormatError

    try:

        lines = iter(f.readlines())

    finally:

        f.close()

    try:

        l = lines.next()

    except StopIteration:

        raise WeaveFormatError('invalid weave file: no header')

    if l != FORMAT_1:

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

    ver = 0

    # read weave header.

    while True:

        l = lines.next()

        if l[0] == 'i':

            if len(l) > 2:

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

            else:

                w._parents.append([])

            l = lines.next()[:-1]

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

            l = lines.next()

            name = l[2:-1]

            w._names.append(name)

            w._name_map[name] = ver

            l = lines.next()

            ver += 1

        elif l == 'w\n':

            break

        else:

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

    # read weave body

    while True:

        l = lines.next()

        if l == 'W\n':

            break

        elif '. ' == l[0:2]:

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

        elif ', ' == l[0:2]:

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

        elif l == '}\n':

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

        else:

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

    return w