~bzr-pqm/bzr/bzr.dev

# Copyright (C) 2007, 2008 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

"""Python implementations of Dirstate Helper functions."""

from __future__ import absolute_import

import binascii

import os

import struct

# We cannot import the dirstate module, because it loads this module

# All we really need is the IN_MEMORY_MODIFIED constant

from bzrlib import errors

from bzrlib.dirstate import DirState

def pack_stat(st, _b64=binascii.b2a_base64, _pack=struct.Struct('>6L').pack):

    """Convert stat values into a packed representation

    Not all of the fields from the stat included are strictly needed, and by

    just encoding the mtime and mode a slight speed increase could be gained.

    However, using the pyrex version instead is a bigger win.

    """

    # base64 encoding always adds a final newline, so strip it off

    return _b64(_pack(st.st_size & 0xFFFFFFFF, int(st.st_mtime) & 0xFFFFFFFF,

        int(st.st_ctime) & 0xFFFFFFFF, st.st_dev & 0xFFFFFFFF,

        st.st_ino & 0xFFFFFFFF, st.st_mode))[:-1]

def _unpack_stat(packed_stat):

    """Turn a packed_stat back into the stat fields.

    This is meant as a debugging tool, should not be used in real code.

    """

    (st_size, st_mtime, st_ctime, st_dev, st_ino,

     st_mode) = struct.unpack('>6L', binascii.a2b_base64(packed_stat))

    return dict(st_size=st_size, st_mtime=st_mtime, st_ctime=st_ctime,

                st_dev=st_dev, st_ino=st_ino, st_mode=st_mode)

def _bisect_path_left(paths, path):

    """Return the index where to insert path into paths.

    This uses the dirblock sorting. So all children in a directory come before

    the children of children. For example::

        a/

          b/

            c

          d/

            e

          b-c

          d-e

        a-a

        a=c

    Will be sorted as::

        a

        a-a

        a=c

        a/b

        a/b-c

        a/d

        a/d-e

        a/b/c

        a/d/e

    :param paths: A list of paths to search through

    :param path: A single path to insert

    :return: An offset where 'path' can be inserted.

    :seealso: bisect.bisect_left

    """

    hi = len(paths)

    lo = 0

    while lo < hi:

        mid = (lo + hi) // 2

        # Grab the dirname for the current dirblock

        cur = paths[mid]

        if _cmp_path_by_dirblock(cur, path) < 0:

            lo = mid + 1

        else:

            hi = mid

    return lo

def _bisect_path_right(paths, path):

    """Return the index where to insert path into paths.

    This uses a path-wise comparison so we get::

        a

        a-b

        a=b

        a/b

    Rather than::

        a

        a-b

        a/b

        a=b

    :param paths: A list of paths to search through

    :param path: A single path to insert

    :return: An offset where 'path' can be inserted.

    :seealso: bisect.bisect_right

    """

    hi = len(paths)

    lo = 0

    while lo < hi:

        mid = (lo+hi)//2

        # Grab the dirname for the current dirblock

        cur = paths[mid]

        if _cmp_path_by_dirblock(path, cur) < 0:

            hi = mid

        else:

            lo = mid + 1

    return lo

def bisect_dirblock(dirblocks, dirname, lo=0, hi=None, cache={}):

    """Return the index where to insert dirname into the dirblocks.

    The return value idx is such that all directories blocks in dirblock[:idx]

    have names < dirname, and all blocks in dirblock[idx:] have names >=

    dirname.

    Optional args lo (default 0) and hi (default len(dirblocks)) bound the

    slice of a to be searched.

    """

    if hi is None:

        hi = len(dirblocks)

    try:

        dirname_split = cache[dirname]

    except KeyError:

        dirname_split = dirname.split('/')

        cache[dirname] = dirname_split

    while lo < hi:

        mid = (lo + hi) // 2

        # Grab the dirname for the current dirblock

        cur = dirblocks[mid][0]

        try:

            cur_split = cache[cur]

        except KeyError:

            cur_split = cur.split('/')

            cache[cur] = cur_split

        if cur_split < dirname_split: lo = mid + 1

        else: hi = mid

    return lo

def cmp_by_dirs(path1, path2):

    """Compare two paths directory by directory.

    This is equivalent to doing::

       cmp(path1.split('/'), path2.split('/'))

    The idea is that you should compare path components separately. This

    differs from plain ``cmp(path1, path2)`` for paths like ``'a-b'`` and

    ``a/b``. "a-b" comes after "a" but would come before "a/b" lexically.

    :param path1: first path

    :param path2: second path

    :return: negative number if ``path1`` comes first,

        0 if paths are equal,

        and positive number if ``path2`` sorts first

    """

    if not isinstance(path1, str):

        raise TypeError("'path1' must be a plain string, not %s: %r"

                        % (type(path1), path1))

    if not isinstance(path2, str):

        raise TypeError("'path2' must be a plain string, not %s: %r"

                        % (type(path2), path2))

    return cmp(path1.split('/'), path2.split('/'))

def _cmp_path_by_dirblock(path1, path2):

    """Compare two paths based on what directory they are in.

    This generates a sort order, such that all children of a directory are

    sorted together, and grandchildren are in the same order as the

    children appear. But all grandchildren come after all children.

    :param path1: first path

    :param path2: the second path

    :return: negative number if ``path1`` comes first,

        0 if paths are equal

        and a positive number if ``path2`` sorts first

    """

    if not isinstance(path1, str):

        raise TypeError("'path1' must be a plain string, not %s: %r"

                        % (type(path1), path1))

    if not isinstance(path2, str):

        raise TypeError("'path2' must be a plain string, not %s: %r"

                        % (type(path2), path2))

    dirname1, basename1 = os.path.split(path1)

    key1 = (dirname1.split('/'), basename1)

    dirname2, basename2 = os.path.split(path2)

    key2 = (dirname2.split('/'), basename2)

    return cmp(key1, key2)

def _read_dirblocks(state):

    """Read in the dirblocks for the given DirState object.

    This is tightly bound to the DirState internal representation. It should be

    thought of as a member function, which is only separated out so that we can

    re-write it in pyrex.

    :param state: A DirState object.

    :return: None

    """

    state._state_file.seek(state._end_of_header)

    text = state._state_file.read()

    # TODO: check the crc checksums. crc_measured = zlib.crc32(text)

    fields = text.split('\0')

    # Remove the last blank entry

    trailing = fields.pop()

    if trailing != '':

        raise errors.DirstateCorrupt(state,

            'trailing garbage: %r' % (trailing,))

    # consider turning fields into a tuple.

    # skip the first field which is the trailing null from the header.

    cur = 1

    # Each line now has an extra '\n' field which is not used

    # so we just skip over it

    # entry size:

    #  3 fields for the key

    #  + number of fields per tree_data (5) * tree count

    #  + newline

    num_present_parents = state._num_present_parents()

    tree_count = 1 + num_present_parents

    entry_size = state._fields_per_entry()

    expected_field_count = entry_size * state._num_entries

    field_count = len(fields)

    # this checks our adjustment, and also catches file too short.

    if field_count - cur != expected_field_count:

        raise errors.DirstateCorrupt(state,

            'field count incorrect %s != %s, entry_size=%s, '\

            'num_entries=%s fields=%r' % (

            field_count - cur, expected_field_count, entry_size,

            state._num_entries, fields))

    if num_present_parents == 1:

        # Bind external functions to local names

        _int = int

        # We access all fields in order, so we can just iterate over

        # them. Grab an straight iterator over the fields. (We use an

        # iterator because we don't want to do a lot of additions, nor

        # do we want to do a lot of slicing)

        next = iter(fields).next

        # Move the iterator to the current position

        for x in xrange(cur):

            next()

        # The two blocks here are deliberate: the root block and the

        # contents-of-root block.

        state._dirblocks = [('', []), ('', [])]

        current_block = state._dirblocks[0][1]

        current_dirname = ''

        append_entry = current_block.append

        for count in xrange(state._num_entries):

            dirname = next()

            name = next()

            file_id = next()

            if dirname != current_dirname:

                # new block - different dirname

                current_block = []

                current_dirname = dirname

                state._dirblocks.append((current_dirname, current_block))

                append_entry = current_block.append

            # we know current_dirname == dirname, so re-use it to avoid

            # creating new strings

            entry = ((current_dirname, name, file_id),

                     [(# Current Tree

                         next(),                # minikind

                         next(),                # fingerprint

                         _int(next()),          # size

                         next() == 'y',         # executable

                         next(),                # packed_stat or revision_id

                     ),

                     ( # Parent 1

                         next(),                # minikind

                         next(),                # fingerprint

                         _int(next()),          # size

                         next() == 'y',         # executable

                         next(),                # packed_stat or revision_id

                     ),

                     ])

            trailing = next()

            if trailing != '\n':

                raise ValueError("trailing garbage in dirstate: %r" % trailing)

            # append the entry to the current block

            append_entry(entry)

        state._split_root_dirblock_into_contents()

    else:

        fields_to_entry = state._get_fields_to_entry()

        entries = [fields_to_entry(fields[pos:pos+entry_size])

                   for pos in xrange(cur, field_count, entry_size)]

        state._entries_to_current_state(entries)

    # To convert from format 2  => format 3

    # state._dirblocks = sorted(state._dirblocks,

    #                          key=lambda blk:blk[0].split('/'))

    # To convert from format 3 => format 2

    # state._dirblocks = sorted(state._dirblocks)

    state._dirblock_state = DirState.IN_MEMORY_UNMODIFIED