[PATCH 6 of 7] pathencode: use Py_SIZE directly

Gregory Szorc gregory.szorc at gmail.com
Sat Oct 8 16:48:12 EDT 2016


# HG changeset patch
# User Gregory Szorc <gregory.szorc at gmail.com>
# Date 1475958082 -7200
#      Sat Oct 08 22:21:22 2016 +0200
# Node ID 40775aad0c78f6c1fd07e7160d50426efbe032ed
# Parent  a33e93c20bc1290af106a0f077fece735ea05245
pathencode: use Py_SIZE directly

On Python 2, PyBytes_GET_SIZE is the same as PyString_GET_SIZE which
is the same as Py_SIZE which resolves to a struct member.

On Python 3, PyBytes_GET_SIZE is
"(assert(PyBytes_Check(op)),Py_SIZE(op))". The compiler barfs when
assigning to this version.

This patch simply changes PyBytes_GET_SIZE to Py_SIZE. On Python 2,
there is no effective change in behavior. On Python 3, we drop the
PyBytes_Check(). However, in all cases we have explicitly created
a PyBytesObject in the same function, so the PyBytes_Check() is
guaranteed to be true. Despite this, code changes over time, so
I've added added assert() in all callers so we can catch this in
debug builds.

With this patch, all mercurial.* C extensions now compile on Python 3
on my OS X machine. There are several compiler warnings and I'm sure
there are incompatibilities with Python 3, including possibly
segfaults. But it is a milestone.

diff --git a/mercurial/pathencode.c b/mercurial/pathencode.c
--- a/mercurial/pathencode.c
+++ b/mercurial/pathencode.c
@@ -170,9 +170,10 @@ PyObject *encodedir(PyObject *self, PyOb
 
 	newobj = PyBytes_FromStringAndSize(NULL, newlen);
 
 	if (newobj) {
-		PyBytes_GET_SIZE(newobj)--;
+		assert(PyBytes_Check(newobj));
+		Py_SIZE(newobj)--;
 		_encodedir(PyBytes_AS_STRING(newobj), newlen, path,
 			   len + 1);
 	}
 
@@ -637,9 +638,10 @@ static PyObject *hashmangle(const char *
 	if (lastdot >= 0)
 		memcopy(dest, &destlen, destsize, &src[lastdot],
 			len - lastdot - 1);
 
-	PyBytes_GET_SIZE(ret) = destlen;
+	PyBytes_Check(ret);
+	Py_SIZE(ret) = destlen;
 
 	return ret;
 }
 
@@ -749,9 +751,10 @@ PyObject *pathencode(PyObject *self, PyO
 
 		newobj = PyBytes_FromStringAndSize(NULL, newlen);
 
 		if (newobj) {
-			PyBytes_GET_SIZE(newobj)--;
+			PyBytes_Check(newobj);
+			Py_SIZE(newobj)--;
 			basicencode(PyBytes_AS_STRING(newobj), newlen, path,
 				    len + 1);
 		}
 	}


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