diff -r 2e431fb98c6b -r 0e8b0b9a7acc mercurial/pure/mpatch.py
--- a/mercurial/pure/mpatch.py	Sun May 28 15:45:52 2017 +0900
+++ b/mercurial/pure/mpatch.py	Tue May 02 21:15:31 2017 +0900
@@ -9,10 +9,8 @@
 
 import struct
 
-from .. import policy, pycompat
+from .. import pycompat
 stringio = pycompat.stringio
-modulepolicy = policy.policy
-policynocffi = policy.policynocffi
 
 class mpatchError(Exception):
     """error raised when a delta cannot be decoded
@@ -127,43 +125,3 @@
 
     outlen += orig - last
     return outlen
-
-if modulepolicy not in policynocffi:
-    try:
-        from ..cffi._mpatch import ffi, lib
-    except ImportError:
-        if modulepolicy == 'cffi': # strict cffi import
-            raise
-    else:
-        @ffi.def_extern()
-        def cffi_get_next_item(arg, pos):
-            all, bins = ffi.from_handle(arg)
-            container = ffi.new("struct mpatch_flist*[1]")
-            to_pass = ffi.new("char[]", str(bins[pos]))
-            all.append(to_pass)
-            r = lib.mpatch_decode(to_pass, len(to_pass) - 1, container)
-            if r < 0:
-                return ffi.NULL
-            return container[0]
-
-        def patches(text, bins):
-            lgt = len(bins)
-            all = []
-            if not lgt:
-                return text
-            arg = (all, bins)
-            patch = lib.mpatch_fold(ffi.new_handle(arg),
-                                    lib.cffi_get_next_item, 0, lgt)
-            if not patch:
-                raise mpatchError("cannot decode chunk")
-            outlen = lib.mpatch_calcsize(len(text), patch)
-            if outlen < 0:
-                lib.mpatch_lfree(patch)
-                raise mpatchError("inconsistency detected")
-            buf = ffi.new("char[]", outlen)
-            if lib.mpatch_apply(buf, text, len(text), patch) < 0:
-                lib.mpatch_lfree(patch)
-                raise mpatchError("error applying patches")
-            res = ffi.buffer(buf, outlen)[:]
-            lib.mpatch_lfree(patch)
-            return res