ryanmce created this revision.
Herald added a subscriber: mercurial-devel.
Herald added a reviewer: hg-reviewers.
REVISION SUMMARY
Implement a `mercurial.cext.xdiff` module that exposes the xdiff algorithm.
`xdiff.blocks` should be a drop-in replacement for `bdiff.blocks`.
In theory we can change the pure C version of `bdiff.c` directly. However
that means we lose bdiff entirely. It seems more flexible to have both at
the same time so they can be easily switched via Python code. Hence the
Python module approach.
TEST PLAN
`make local`. And test from `hg debugshell`:
In [1]: from mercurial.cext import bdiff, xdiff
In [2]: bdiff.blocks('b\nc\nd\n', 'a\nb\nc\ne\nf\n')
Out[2]: [(0, 2, 1, 3), (3, 3, 5, 5)]
In [3]: xdiff.blocks('b\nc\nd\n', 'a\nb\nc\ne\nf\n')
Out[3]: [(0, 2, 1, 3), (3, 3, 5, 5)]
In [4]: bdiff.blocks('a\nb', '')
Out[4]: [(2, 2, 0, 0)]
In [5]: xdiff.blocks('a\nb', '')
Out[5]: [(2, 2, 0, 0)]
In [6]: bdiff.blocks('a\nb', 'a\nb\n')
Out[6]: [(0, 1, 0, 1), (2, 2, 2, 2)]
In [7]: xdiff.blocks('a\nb', 'a\nb\n')
Out[7]: [(0, 1, 0, 1), (2, 2, 2, 2)]
In [8]: xdiff.blocks('', '')
Out[8]: [(0, 0, 0, 0)]
In [9]: bdiff.blocks('', '')
Out[9]: [(0, 0, 0, 0)]
In [10]: xdiff.blocks('', '\n')
Out[10]: [(0, 0, 1, 1)]
REPOSITORY
rHG Mercurial
REVISION DETAIL
https://phab.mercurial-scm.org/D2576
AFFECTED FILES
contrib/check-code.py
mercurial/thirdparty/xdiff.c
setup.py
CHANGE DETAILS
diff --git a/setup.py b/setup.py
--- a/setup.py
+++ b/setup.py
@@ -220,7 +220,7 @@
py2exe.Distribution # silence unused import warning
py2exeloaded = True
# import py2exe's patched Distribution class
-from distutils.core import Distribution
+from distutils.core import Distribution # noqa: F811
except ImportError:
py2exeloaded = False
@@ -874,6 +874,28 @@
extra_compile_args=osutil_cflags,
extra_link_args=osutil_ldflags,
depends=common_depends),
+Extension('mercurial.cext.xdiff',
+ sources=[
+ 'mercurial/thirdparty/xdiff/xdiffi.c',
+ 'mercurial/thirdparty/xdiff/xemit.c',
+ 'mercurial/thirdparty/xdiff/xmerge.c',
+ 'mercurial/thirdparty/xdiff/xprepare.c',
+ 'mercurial/thirdparty/xdiff/xutils.c',
+ 'mercurial/thirdparty/xdiff.c',
+ ],
+ include_dirs=common_include_dirs + [
+ 'mercurial/thirdparty/xdiff',
+ ],
+ depends=common_depends + [
+ 'mercurial/thirdparty/xdiff/xdiff.h',
+ 'mercurial/thirdparty/xdiff/xdiffi.h',
+ 'mercurial/thirdparty/xdiff/xemit.h',
+ 'mercurial/thirdparty/xdiff/xinclude.h',
+ 'mercurial/thirdparty/xdiff/xmacros.h',
+ 'mercurial/thirdparty/xdiff/xprepare.h',
+ 'mercurial/thirdparty/xdiff/xtypes.h',
+ 'mercurial/thirdparty/xdiff/xutils.h',
+ ]),
Extension('hgext.fsmonitor.pywatchman.bser',
['hgext/fsmonitor/pywatchman/bser.c']),
]
diff --git a/mercurial/thirdparty/xdiff.c b/mercurial/thirdparty/xdiff.c
new file mode 100644
--- /dev/null
+++ b/mercurial/thirdparty/xdiff.c
@@ -0,0 +1,96 @@
+/*
+ xdiff.c: simple Python wrapper for xdiff library
+
+ Copyright (c) 2018 Facebook, Inc.
+
+ This software may be used and distributed according to the terms of the
+ GNU General Public License version 2 or any later version.
+*/
+
+#include "xdiff.h"
+#include "Python.h"
+
+static int hunk_consumer(long a1, long a2, long b1, long b2, void *priv)
+{
+ PyObject *rl = (PyObject *)priv;
+ PyObject *m = Py_BuildValue("", a1, a2, b1, b2);
+ if (!m)
+ return -1;
+ if (PyList_Append(rl, m) != 0) {
+ Py_DECREF(m);
+ return -1;
+ }
+ return 0;
+}
+
+static PyObject *blocks(PyObject *self, PyObject *args)
+{
+ char *sa, *sb;
+ int na, nb;
+
+ if (!PyArg_ParseTuple(args, "s#s#", , , , ))
+ return NULL;
+
+ mmfile_t a = {sa, na}, b = {sb, nb};
+
+ PyObject *rl = PyList_New(0);
+ if (!rl)
+ return PyErr_NoMemory();
+
+ xpparam_t xpp = {
+ 0,/* flags */
+ NULL, /* anchors */
+ 0,/* anchors_nr */
+ };
+ xdemitconf_t xecfg = {
+ 0, /* ctxlen */
+ 0, /* interhunkctxlen */
+ XDL_EMIT_BDIFFHUNK, /* flags */
+ NULL, /* find_func */
+ NULL, /* find_func_priv */
+ hunk_consumer, /* hunk_consume_func */
+ };
+ xdemitcb_t ecb = {
+ rl, /* priv */
+ NULL, /* outf */
+ };
+
+ if (xdl_diff(, , , , ) != 0)
