# 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 __future__ import absolute_import

import struct

import zlib

from ..node import nullid

from .. import pycompat

stringio = pycompat.bytesio

_pack = struct.pack

_unpack = struct.unpack

_compress = zlib.compress

_decompress = zlib.decompress

# 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

indexformatng = ">Qiiiiii20s12x"

indexfirst = struct.calcsize('Q')

sizeint = struct.calcsize('i')

indexsize = struct.calcsize(indexformatng)

def gettype(q):

    return int(q & 0xFFFF)

def offset_type(offset, type):

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

class BaseIndexObject(object):

    def __len__(self):

    def append(self, tup):

        self._extra.append(tup)

    def _fix_index(self, i):

        if not isinstance(i, int):

            raise TypeError("expecting int indexes")

            raise IndexError

        return i

    def __getitem__(self, i):

            return (0, 0, 0, -1, -1, -1, -1, nullid)

        i = self._fix_index(i)

        if i >= self._lgt:

            return self._extra[i - self._lgt]

        index = self._calculate_index(i)

        r = struct.unpack(indexformatng, self._data[index:index + indexsize])

        if i == 0:

            e = list(r)

            type = gettype(e[0])

            e[0] = offset_type(0, type)

            return tuple(e)

        return r

class IndexObject(BaseIndexObject):

    def __init__(self, data):

        assert len(data) % indexsize == 0

        self._data = data

        self._lgt = len(data) // indexsize

        self._extra = []

    def _calculate_index(self, i):

        return i * indexsize

    def __delitem__(self, i):

        if not isinstance(i, slice) or not i.stop == -1 or i.step is not None:

            raise ValueError("deleting slices only supports a:-1 with step 1")

        i = self._fix_index(i.start)

        if i < self._lgt:

            self._data = self._data[:i * indexsize]

            self._lgt = i

            self._extra = []

        else:

            self._extra = self._extra[:i - self._lgt]

class InlinedIndexObject(BaseIndexObject):

    def __init__(self, data, inline=0):

        self._data = data

        self._lgt = self._inline_scan(None)

        self._inline_scan(self._lgt)

        self._extra = []

    def _inline_scan(self, lgt):

        off = 0

        if lgt is not None:

            self._offsets = [0] * lgt

        count = 0

        while off <= len(self._data) - indexsize:

            s, = struct.unpack('>i',

                self._data[off + indexfirst:off + sizeint + indexfirst])

            if lgt is not None:

                self._offsets[count] = off

            count += 1

            off += indexsize + s

        if off != len(self._data):

            raise ValueError("corrupted data")

        return count

    def __delitem__(self, i):

        if not isinstance(i, slice) or not i.stop == -1 or i.step is not None:

            raise ValueError("deleting slices only supports a:-1 with step 1")

        i = self._fix_index(i.start)

        if i < self._lgt:

            self._offsets = self._offsets[:i]

            self._lgt = i

            self._extra = []

        else:

            self._extra = self._extra[:i - self._lgt]

    def _calculate_index(self, i):

        return self._offsets[i]

def parse_index2(data, inline):

    if not inline:

        return IndexObject(data), None

    return InlinedIndexObject(data, inline), (0, data)

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 = 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()