# 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 demandload import *

demandload(globals(), "bisect")

class manifest(revlog):

    def __init__(self, opener):

        self.mapcache = None

        self.listcache = None

        self.addlist = 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 = (text, text.splitlines(1))

        for l in self.listcache[1]:

            (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):

        # this is sneaky, as we're not actually using a and b

        if self.listcache and self.addlist and self.listcache[0] == a:

            d = mdiff.diff(self.listcache[1], self.addlist, 1)

            if mdiff.patch(a, d) != b:

                raise AssertionError("sortdiff failed!")

            return d

        else:

            return mdiff.textdiff(a, b)

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

            changed=None):

        # directly generate the mdiff delta from the data collected during

        # the bisect loop below

        def gendelta(delta):

            i = 0

            result = []

            while i < len(delta):

                start = delta[i][2]

                end = delta[i][3]

                l = delta[i][4]

                if l == None:

                    l = ""

                while i < len(delta) - 1 and start <= delta[i+1][2] \

                          and end >= delta[i+1][2]:

                    if delta[i+1][3] > end:

                        end = delta[i+1][3]

                    if delta[i+1][4]:

                        l += delta[i+1][4]

                    i += 1

                result.append(struct.pack(">lll", start, end, len(l)) +  l)

                i += 1

            return result

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

        def addlistdelta(addlist, delta):

            # apply the deltas to the addlist.  start from the bottom up

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

            i = len(delta)

            while i > 0:

                i -= 1

                start = delta[i][0]

                end = delta[i][1]

                if delta[i][4]:

                    addlist[start:end] = [delta[i][4]]

                else:

                    del addlist[start:end]

            return addlist

        # calculate the byte offset of the start of each line in the

        # manifest

        def calcoffsets(addlist):

            offsets = [0] * (len(addlist) + 1)

            offset = 0

            i = 0

            while i < len(addlist):

                offsets[i] = offset

                offset += len(addlist[i])

                i += 1

            offsets[i] = offset

            return offsets

        # 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()

            self.addlist = ["%s\000%s%s\n" %

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

                            for f in files]

            cachedelta = None

        else:

            addlist = self.listcache[1]

            # find the starting offset for each line in the add list

            offsets = calcoffsets(addlist)

            # 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 = []

            bs = 0

            for w in work:

                f = w[0]

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

                bs = bisect.bisect(addlist, f, bs)

                if bs < len(addlist):

                    fn = addlist[bs][:addlist[bs].index('\0')]

                else:

                    fn = None

                if w[1] == 0:

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

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

                else:

                    l = None

                start = bs

                if fn != f:

                    # item not found, insert a new one

                    end = bs

                    if w[1] == 1:

                        raise AssertionError(

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

                else:

                    # item is found, replace/delete the existing line

                    end = bs + 1

                delta.append([start, end, offsets[start], offsets[end], l])

            self.addlist = addlistdelta(addlist, delta)

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

                cachedelta = "".join(gendelta(delta))

            else:

                cachedelta = None

        text = "".join(self.addlist)

        if cachedelta and mdiff.patch(self.listcache[0], cachedelta) != text:

            raise AssertionError("manifest delta failure\n")

        n = self.addrevision(text, transaction, link, p1, p2, cachedelta)

        self.mapcache = (n, map, flags)

        self.listcache = (text, self.addlist)

        self.addlist = None

        return n