view mercurial/manifest.py @ 5042:f191bc3916f7

merge: do early copy to deal with issue636

Without copies/renames, merges source names are 1:1 with their
targets. Copies and renames introduce the possibility that there will
be two merges with the same input but different output. By doing the
copy to the destination name before the merge, the actual merge
becomes 1:1 again, and no source is the input to two different merges.

- add a preliminary scan to applyupdates to do copies
- for the merge action, pass the old name (for finding ancestors) and
  the new name (for input to the merge) to filemerge
- eliminate the old post-merge copy
- lookup file contents from new name in filemerge
- pass new name to external merge helper
- report merge failure at new name
- add a test

# manifest.py - manifest revision class for mercurial
#
# Copyright 2005-2007 Matt Mackall <[e-mail]>
#
# This software may be used and distributed according to the terms
# of the GNU General Public License, incorporated herein by reference.

from revlog import *
from i18n import _
import array, bisect, struct, mdiff

class manifestdict(dict):
    def __init__(self, mapping=None, flags=None):
        if mapping is None: mapping = {}
        if flags is None: flags = {}
        dict.__init__(self, mapping)
        self._flags = flags
    def flags(self, f):
        return self._flags.get(f, "")
    def execf(self, f):
        "test for executable in manifest flags"
        return "x" in self.flags(f)
    def linkf(self, f):
        "test for symlink in manifest flags"
        return "l" in self.flags(f)
    def rawset(self, f, entry):
        self[f] = bin(entry[:40])
        fl = entry[40:-1]
        if fl: self._flags[f] = fl
    def set(self, f, execf=False, linkf=False):
        if linkf: self._flags[f] = "l"
        elif execf: self._flags[f] = "x"
        else: self._flags[f] = ""
    def copy(self):
        return manifestdict(dict.copy(self), dict.copy(self._flags))

class manifest(revlog):
    def __init__(self, opener):
        self.mapcache = None
        self.listcache = None
        revlog.__init__(self, opener, "00manifest.i")

    def parselines(self, lines):
        for l in lines.splitlines(1):
            yield l.split('\0')

    def readdelta(self, node):
        delta = mdiff.patchtext(self.delta(node))
        deltamap = manifestdict()
        for f, n in self.parselines(delta):
            deltamap.rawset(f, n)
        return deltamap

    def read(self, node):
        if node == nullid: return manifestdict() # don't upset local cache
        if self.mapcache and self.mapcache[0] == node:
            return self.mapcache[1]
        text = self.revision(node)
        self.listcache = array.array('c', text)
        mapping = manifestdict()
        for f, n in self.parselines(text):
            mapping.rawset(f, n)
        self.mapcache = (node, mapping)
        return mapping

    def _search(self, m, s, lo=0, hi=None):
        '''return a tuple (start, end) that says where to find s within m.

        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 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)

    def find(self, node, f):
        '''look up entry for a single file efficiently.
        return (node, flags) pair if found, (None, None) if not.'''
        if self.mapcache and node == self.mapcache[0]:
            return self.mapcache[1].get(f), self.mapcache[1].flags(f)
        text = self.revision(node)
        start, end = self._search(text, f)
        if start == end:
            return None, None
        l = text[start:end]
        f, n = l.split('\0')
        return bin(n[:40]), n[40:-1]

    def add(self, map, transaction, link, p1=None, p2=None,
            changed=None):
        # 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 ])

        def checkforbidden(f):
            if '\n' in f or '\r' in f:
                raise RevlogError(_("'\\n' and '\\r' disallowed in filenames"))

        # if we're using the listcache, make sure it is valid and
        # parented by the same node we're diffing against
        if not (changed and self.listcache and p1 and self.mapcache[0] == p1):
            files = map.keys()
            files.sort()

            for f in files:
                checkforbidden(f)

            # if this is changed to support newlines in filenames,
            # be sure to check the templates/ dir again (especially *-raw.tmpl)
            text = ["%s\000%s%s\n" % (f, hex(map[f]), map.flags(f))
                    for f in files]
            self.listcache = array.array('c', "".join(text))
            cachedelta = None
        else:
            addlist = self.listcache

            for f in changed[0]:
                checkforbidden(f)
            # 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 = self._search(addbuf, f, start)
                if w[1] == 0:
                    l = "%s\000%s%s\n" % (f, hex(map[f]), map.flags(f))
                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") % 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)

        return n