Patchwork [v2] mpatch: write a cffi version of mpatch.patches

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Submitter Maciej Fijalkowski
Date Aug. 20, 2016, 9:07 p.m.
Message ID <7fa693de90d23c034e36.1471727279@brick.arcode.com>
Download mbox | patch
Permalink /patch/16367/
State Accepted
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Maciej Fijalkowski - Aug. 20, 2016, 9:07 p.m.
# HG changeset patch
# User Maciej Fijalkowski <fijall@gmail.com>
# Date 1469452252 -7200
#      Mon Jul 25 15:10:52 2016 +0200
# Node ID 7fa693de90d23c034e36e0fe1b9552feb4eca839
# Parent  8e2d1b2d5248620ff4ccfcb61e1b383cf0e4e204
mpatch: write a cffi version of mpatch.patches
Yuya Nishihara - Aug. 21, 2016, 3:20 p.m.
On Sat, 20 Aug 2016 23:07:59 +0200, Maciej Fijalkowski wrote:
> # HG changeset patch
> # User Maciej Fijalkowski <fijall@gmail.com>
> # Date 1469452252 -7200
> #      Mon Jul 25 15:10:52 2016 +0200
> # Node ID 7fa693de90d23c034e36e0fe1b9552feb4eca839
> # Parent  8e2d1b2d5248620ff4ccfcb61e1b383cf0e4e204
> mpatch: write a cffi version of mpatch.patches

Oops, V1 was landed as f2846d546645. Can you resend a patch which only
adds missing setup_mpatch_cffi.py?

Patch

diff --git a/mercurial/pure/mpatch.py b/mercurial/pure/mpatch.py
--- a/mercurial/pure/mpatch.py
+++ b/mercurial/pure/mpatch.py
@@ -9,8 +9,10 @@ 
 
 import struct
 
-from . import pycompat
+from . import policy, pycompat
 stringio = pycompat.stringio
+modulepolicy = policy.policy
+policynocffi = policy.policynocffi
 
 class mpatchError(Exception):
     """error raised when a delta cannot be decoded
@@ -125,3 +127,44 @@ 
 
     outlen += orig - last
     return outlen
+
+if modulepolicy not in policynocffi:
+    try:
+        from _mpatch_cffi 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
+
diff --git a/setup.py b/setup.py
--- a/setup.py
+++ b/setup.py
@@ -318,7 +318,8 @@ 
         if self.distribution.pure:
             self.distribution.ext_modules = []
         elif self.distribution.cffi:
-            exts = []
+            import setup_mpatch_cffi
+            exts = [setup_mpatch_cffi.ffi.distutils_extension()]
             # cffi modules go here
             if sys.platform == 'darwin':
                 import setup_osutil_cffi
diff --git a/setup_mpatch_cffi.py b/setup_mpatch_cffi.py
new file mode 100644
--- /dev/null
+++ b/setup_mpatch_cffi.py
@@ -0,0 +1,36 @@ 
+
+from __future__ import absolute_import
+
+import os
+import cffi
+
+ffi = cffi.FFI()
+mpatch_c = os.path.join(os.path.join(os.path.dirname(__file__), 'mercurial',
+                                     'mpatch.c'))
+ffi.set_source("_mpatch_cffi", open(mpatch_c).read(),
+               include_dirs=["mercurial"])
+ffi.cdef("""
+
+struct mpatch_frag {
+       int start, end, len;
+       const char *data;
+};
+
+struct mpatch_flist {
+       struct mpatch_frag *base, *head, *tail;
+};
+
+extern "Python" struct mpatch_flist* cffi_get_next_item(void*, ssize_t);
+
+int mpatch_decode(const char *bin, ssize_t len, struct mpatch_flist** res);
+ssize_t mpatch_calcsize(size_t len, struct mpatch_flist *l);
+void mpatch_lfree(struct mpatch_flist *a);
+static int mpatch_apply(char *buf, const char *orig, size_t len,
+                        struct mpatch_flist *l);
+struct mpatch_flist *mpatch_fold(void *bins,
+                       struct mpatch_flist* (*get_next_item)(void*, ssize_t),
+                       ssize_t start, ssize_t end);
+""")
+
+if __name__ == '__main__':
+    ffi.compile()