# parsers.py - Python implementation of parsers.c

#

# Copyright 2009 Matt Mackall <mpm@selenic.com> and others

#

# This software may be used and distributed according to the terms of the

# GNU General Public License version 2 or any later version.

from mercurial import util

import struct, zlib, cStringIO

_pack = struct.pack

_unpack = struct.unpack

_compress = zlib.compress

_decompress = zlib.decompress

_sha = util.sha1

# Some code below makes tuples directly because it's more convenient. However,

# code outside this module should always use dirstatetuple.

def dirstatetuple(*x):

    # x is a tuple

    return x

def parse_index2(data, inline):

    def gettype(q):

        return int(q & 0xFFFF)

    def offset_type(offset, type):

        return long(long(offset) << 16 | type)

    indexformatng = ">Qiiiiii20s12x"

    s = struct.calcsize(indexformatng)

    index = []

    cache = None

    off = 0

    l = len(data) - s

    append = index.append

    if inline:

        cache = (0, data)

        while off <= l:

            e = _unpack(indexformatng, data[off:off + s])

            append(e)

            if e[1] < 0:

                break

            off += e[1] + s

    else:

        while off <= l:

            e = _unpack(indexformatng, data[off:off + s])

            append(e)

            off += s

    if off != len(data):

        raise ValueError('corrupt index file')

    if index:

        e = list(index[0])

        type = gettype(e[0])

        e[0] = offset_type(0, type)

        index[0] = tuple(e)

    # add the magic null revision at -1

    index.append((0, 0, 0, -1, -1, -1, -1, nullid))

    return index, cache

def parse_dirstate(dmap, copymap, st):

    parents = [st[:20], st[20: 40]]

    # dereference fields so they will be local in loop

    format = ">cllll"

    e_size = struct.calcsize(format)

    pos1 = 40

    l = len(st)

    # the inner loop

    while pos1 < l:

        pos2 = pos1 + e_size

        e = _unpack(">cllll", st[pos1:pos2]) # a literal here is faster

        pos1 = pos2 + e[4]

        f = st[pos2:pos1]

        if '\0' in f:

            f, c = f.split('\0')

            copymap[f] = c

        dmap[f] = e[:4]

    return parents

def pack_dirstate(dmap, copymap, pl, now):

    now = int(now)

    cs = cStringIO.StringIO()

    write = cs.write

    write("".join(pl))

    for f, e in dmap.iteritems():

        if e[0] == 'n' and e[3] == now:

            # The file was last modified "simultaneously" with the current

            # write to dirstate (i.e. within the same second for file-

            # systems with a granularity of 1 sec). This commonly happens

            # for at least a couple of files on 'update'.

            # The user could change the file without changing its size

            # within the same second. Invalidate the file's mtime in

            # dirstate, forcing future 'status' calls to compare the

            # contents of the file if the size is the same. This prevents

            # mistakenly treating such files as clean.

            e = dirstatetuple(e[0], e[1], e[2], -1)

            dmap[f] = e

        if f in copymap:

            f = "%s\0%s" % (f, copymap[f])

        e = _pack(">cllll", e[0], e[1], e[2], e[3], len(f))

        write(e)

        write(f)

    return cs.getvalue()