comparison mercurial/revlog.py @ 14252:19067884c5f5

revlog: calculate base revisions iteratively

This is in preparation for generaldelta, where the revlog entry base field is
reinterpreted as the deltaparent. For that reason we also rename the base
function to chainbase.

Without generaldelta, performance is unaffected, but generaldelta will suffer
from this in _addrevision, since delta chains will be walked repeatedly.
A cache has been added to eliminate this problem completely.

14251:258fbccf22f5

        """
        self.indexfile = indexfile
        self.datafile = indexfile[:-2] + ".d"
        self.opener = opener
        self._cache = None
        self._chunkcache = (0, '')
        self.index = []
        self._pcache = {}
        self._nodecache = {nullid: nullrev}
        self._nodepos = None

        return int(self.index[rev][0] >> 16)
    def end(self, rev):
        return self.start(rev) + self.length(rev)
    def length(self, rev):
        return self.index[rev][1]
    def base(self, rev):
        return self.index[rev][3]
    def flags(self, rev):
        return self.index[rev][0] & 0xFFFF
    def rawsize(self, rev):
        """return the length of the uncompressed text for a given revision"""
        l = self.index[rev][2]

            cachedrev = self._cache[1]

        # look up what we need to read
        text = None
        rev = self.rev(node)
        base = self.base(rev)

        # check rev flags
        if self.flags(rev) & ~REVIDX_KNOWN_FLAGS:
            raise RevlogError(_('incompatible revision flag %x') %
                              (self.flags(rev) & ~REVIDX_KNOWN_FLAGS))

        # build delta chain
        chain = []
        iterrev = rev
        while iterrev != base and iterrev != cachedrev:
            chain.append(iterrev)
            iterrev -= 1
        chain.reverse()
        base = iterrev

        if iterrev == cachedrev:
            # cache hit

                t = buildtext()
                ptext = self.revision(self.node(rev))
                delta = mdiff.textdiff(ptext, t)
            data = compress(delta)
            l = len(data[1]) + len(data[0])
            base = self.base(rev)
            dist = l + offset - self.start(base)
            return dist, l, data, base

        curr = len(self)
        prev = curr - 1

            ifh.write(data[1])
            self.checkinlinesize(transaction, ifh)

        if type(text) == str: # only accept immutable objects
            self._cache = (node, curr, text)
        return node

    def group(self, nodelist, bundler):
        """Calculate a delta group, yielding a sequence of changegroup chunks
        (strings).

14252:19067884c5f5

        """
        self.indexfile = indexfile
        self.datafile = indexfile[:-2] + ".d"
        self.opener = opener
        self._cache = None
        self._basecache = None
        self._chunkcache = (0, '')
        self.index = []
        self._pcache = {}
        self._nodecache = {nullid: nullrev}
        self._nodepos = None

        return int(self.index[rev][0] >> 16)
    def end(self, rev):
        return self.start(rev) + self.length(rev)
    def length(self, rev):
        return self.index[rev][1]
    def chainbase(self, rev):
        index = self.index
        base = index[rev][3]
        while base != rev:
            rev = base
            base = index[rev][3]
        return base
    def flags(self, rev):
        return self.index[rev][0] & 0xFFFF
    def rawsize(self, rev):
        """return the length of the uncompressed text for a given revision"""
        l = self.index[rev][2]

            cachedrev = self._cache[1]

        # look up what we need to read
        text = None
        rev = self.rev(node)

        # check rev flags
        if self.flags(rev) & ~REVIDX_KNOWN_FLAGS:
            raise RevlogError(_('incompatible revision flag %x') %
                              (self.flags(rev) & ~REVIDX_KNOWN_FLAGS))

        # build delta chain
        chain = []
        index = self.index # for performance
        iterrev = rev
        e = index[iterrev]
        while iterrev != e[3] and iterrev != cachedrev:
            chain.append(iterrev)
            iterrev -= 1
            e = index[iterrev]
        chain.reverse()
        base = iterrev

        if iterrev == cachedrev:
            # cache hit

                t = buildtext()
                ptext = self.revision(self.node(rev))
                delta = mdiff.textdiff(ptext, t)
            data = compress(delta)
            l = len(data[1]) + len(data[0])
            basecache = self._basecache
            if basecache and basecache[0] == rev:
                base = basecache[1]
            else:
                base = self.chainbase(rev)
            dist = l + offset - self.start(base)
            return dist, l, data, base

        curr = len(self)
        prev = curr - 1

            ifh.write(data[1])
            self.checkinlinesize(transaction, ifh)

        if type(text) == str: # only accept immutable objects
            self._cache = (node, curr, text)
        self._basecache = (curr, base)
        return node

    def group(self, nodelist, bundler):
        """Calculate a delta group, yielding a sequence of changegroup chunks
        (strings).