comparison mercurial/revlog.py @ 16423:a150923b49ba

revlog: avoid an expensive string copy

This showed up in a statprof profile of "hg svn rebuildmeta", which
is read-intensive on the changelog.  This two-line patch improved
the performance of that command by 10%.

16422:c0b5bab3fb11

        df.seek(offset)
        d = df.read(readahead)
        df.close()
        self._addchunk(offset, d)
        if readahead > length:
            return d[:length]
        return d

    def _getchunk(self, offset, length):
        o, d = self._chunkcache
        l = len(d)

        cachestart = offset - o
        cacheend = cachestart + length
        if cachestart >= 0 and cacheend <= l:
            if cachestart == 0 and cacheend == l:
                return d # avoid a copy
            return d[cachestart:cacheend]

        return self._loadchunk(offset, length)

    def _chunkraw(self, startrev, endrev):
        start = self.start(startrev)

            return rev - 1

    def revdiff(self, rev1, rev2):
        """return or calculate a delta between two revisions"""
        if rev1 != nullrev and self.deltaparent(rev2) == rev1:
            return self._chunk(rev2)

        return mdiff.textdiff(self.revision(self.node(rev1)),
                              self.revision(self.node(rev2)))

    def revision(self, nodeorrev):

        # drop cache to save memory
        self._cache = None

        self._chunkraw(base, rev)
        if text is None:
            text = self._chunkbase(base)

        bins = [self._chunk(r) for r in chain]
        text = mdiff.patches(text, bins)

        text = self._checkhash(text, node, rev)

16423:a150923b49ba

        df.seek(offset)
        d = df.read(readahead)
        df.close()
        self._addchunk(offset, d)
        if readahead > length:
            return util.buffer(d, 0, length)
        return d

    def _getchunk(self, offset, length):
        o, d = self._chunkcache
        l = len(d)

        cachestart = offset - o
        cacheend = cachestart + length
        if cachestart >= 0 and cacheend <= l:
            if cachestart == 0 and cacheend == l:
                return d # avoid a copy
            return util.buffer(d, cachestart, cacheend - cachestart)

        return self._loadchunk(offset, length)

    def _chunkraw(self, startrev, endrev):
        start = self.start(startrev)

            return rev - 1

    def revdiff(self, rev1, rev2):
        """return or calculate a delta between two revisions"""
        if rev1 != nullrev and self.deltaparent(rev2) == rev1:
            return str(self._chunk(rev2))

        return mdiff.textdiff(self.revision(self.node(rev1)),
                              self.revision(self.node(rev2)))

    def revision(self, nodeorrev):

        # drop cache to save memory
        self._cache = None

        self._chunkraw(base, rev)
        if text is None:
            text = str(self._chunkbase(base))

        bins = [self._chunk(r) for r in chain]
        text = mdiff.patches(text, bins)

        text = self._checkhash(text, node, rev)