# manifest.py - manifest revision class for mercurial

#

# Copyright 2005 Matt Mackall <mpm@selenic.com>

#

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

# of the GNU General Public License, incorporated herein by reference.

import sys, struct

from revlog import *

from i18n import gettext as _

from demandload import *

demandload(globals(), "bisect array")

class manifest(revlog):

    def __init__(self, opener):

        self.mapcache = None

        self.listcache = None

        revlog.__init__(self, opener, "00manifest.i", "00manifest.d")

    def read(self, node):

        if node == nullid: return {} # don't upset local cache

        if self.mapcache and self.mapcache[0] == node:

            return self.mapcache[1]

        text = self.revision(node)

        map = {}

        flag = {}

        self.listcache = array.array('c', text)

        lines = text.splitlines(1)

        for l in lines:

            (f, n) = l.split('\0')

            map[f] = bin(n[:40])

            flag[f] = (n[40:-1] == "x")

        self.mapcache = (node, map, flag)

        return map

    def readflags(self, node):

        if node == nullid: return {} # don't upset local cache

        if not self.mapcache or self.mapcache[0] != node:

            self.read(node)

        return self.mapcache[2]

    def diff(self, a, b):

        return mdiff.textdiff(str(a), str(b))

    def add(self, map, flags, transaction, link, p1=None, p2=None,

            changed=None):

        # returns a tuple (start, end).  If the string is found

        # m[start:end] are the line containing that string.  If start == end

        # the string was not found and they indicate the proper sorted 

        # insertion point.  This was taken from bisect_left, and modified

        # to find line start/end as it goes along.

        #

        # m should be a buffer or a string

        # s is a string

        #

        def manifestsearch(m, s, lo=0, hi=None):

            def advance(i, c):

                while i < lenm and m[i] != c:

                    i += 1

                return i

            lenm = len(m)

            if not hi:

                hi = lenm

            while lo < hi:

                mid = (lo + hi) // 2

                start = mid

                while start > 0 and m[start-1] != '\n':

                    start -= 1

                end = advance(start, '\0')

                if m[start:end] < s:

                    # we know that after the null there are 40 bytes of sha1

                    # this translates to the bisect lo = mid + 1

                    lo = advance(end + 40, '\n') + 1

                else:

                    # this translates to the bisect hi = mid

                    hi = start

            end = advance(lo, '\0')

            found = m[lo:end]

            if cmp(s, found) == 0: 

                # we know that after the null there are 40 bytes of sha1

                end = advance(end + 40, '\n')

                return (lo, end+1)

            else:

                return (lo, lo)

        # apply the changes collected during the bisect loop to our addlist

        # return a delta suitable for addrevision

        def addlistdelta(addlist, x):

            # start from the bottom up

            # so changes to the offsets don't mess things up.

            i = len(x)

            while i > 0:

                i -= 1

                start = x[i][0]

                end = x[i][1]

                if x[i][2]:

                    addlist[start:end] = array.array('c', x[i][2])

                else:

                    del addlist[start:end]

            return "".join([struct.pack(">lll", d[0], d[1], len(d[2])) + d[2] \

                            for d in x ])

        # if we're using the listcache, make sure it is valid and

        # parented by the same node we're diffing against

        if not changed or not self.listcache or not p1 or \

               self.mapcache[0] != p1:

            files = map.keys()

            files.sort()

            text = ["%s\000%s%s\n" %

                            (f, hex(map[f]), flags[f] and "x" or '')

                            for f in files]

            self.listcache = array.array('c', "".join(text))

            cachedelta = None

        else:

            addlist = self.listcache

            # combine the changed lists into one list for sorting

            work = [[x, 0] for x in changed[0]]

            work[len(work):] = [[x, 1] for x in changed[1]]

            work.sort()

            delta = []

            dstart = None

            dend = None

            dline = [""]

            start = 0

            # zero copy representation of addlist as a buffer

            addbuf = buffer(addlist)

            # start with a readonly loop that finds the offset of

            # each line and creates the deltas

            for w in work:

                f = w[0]

                # bs will either be the index of the item or the insert point

                start, end = manifestsearch(addbuf, f, start)

                if w[1] == 0:

                    l = "%s\000%s%s\n" % (f, hex(map[f]),

                                          flags[f] and "x" or '')

                else:

                    l = ""

                if start == end and w[1] == 1:

                    # item we want to delete was not found, error out

                    raise AssertionError(

                            _("failed to remove %s from manifest\n") % f)

                if dstart != None and dstart <= start and dend >= start:

                    if dend < end:

                        dend = end

                    if l:

                        dline.append(l)

                else:

                    if dstart != None:

                        delta.append([dstart, dend, "".join(dline)])

                    dstart = start

                    dend = end

                    dline = [l]

            if dstart != None:

                delta.append([dstart, dend, "".join(dline)])

            # apply the delta to the addlist, and get a delta for addrevision

            cachedelta = addlistdelta(addlist, delta)

            # the delta is only valid if we've been processing the tip revision

            if self.mapcache[0] != self.tip():

                cachedelta = None

            self.listcache = addlist

        n = self.addrevision(buffer(self.listcache), transaction, link, p1,  \

                             p2, cachedelta)

        self.mapcache = (n, map, flags)

        return n