820         return self._getchunk(start, length)

   820         return self._getchunk(start, length)

   821 

   821 

   822     def _chunk(self, rev):

   822     def _chunk(self, rev):

   823         return decompress(self._chunkraw(rev, rev))

   823         return decompress(self._chunkraw(rev, rev))

   824 

   824 

   825     def _chunkclear(self):

   828     def _chunkclear(self):

   826         self._chunkcache = (0, '')

   829         self._chunkcache = (0, '')

   827 

   830 

   828     def deltaparent(self, rev):

   831     def deltaparent(self, rev):

   829         """return previous revision or parentrev according to flags"""

   832         """return previous revision or parentrev according to flags"""

   882         # drop cache to save memory

   885         # drop cache to save memory

   883         self._cache = None

   886         self._cache = None

   884 

   887 

   885         self._chunkraw(base, rev)

   888         self._chunkraw(base, rev)

   886         if text is None:

   889         if text is None:

   888 

   891 

   889         bins = [self._chunk(r) for r in chain]

   892         bins = [self._chunk(r) for r in chain]

   890         text = mdiff.patches(text, bins)

   893         text = mdiff.patches(text, bins)

   891 

   894 

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

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