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From: Wei Liu <wei.liu2@citrix.com>
To: xen-devel@lists.xenproject.org
Cc: George Dunlap <george.dunlap@eu.citrix.com>,
	Anthony PERARD <anthony.perard@citrix.com>,
	Wei Liu <wei.liu2@citrix.com>,
	Ian Jackson <ian.jackson@eu.citrix.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>
Subject: [PATCH for-next v2 v2 4/5] pygrub: make it build with python 3
Date: Wed, 6 Mar 2019 17:52:09 +0000	[thread overview]
Message-ID: <20190306175210.28145-5-wei.liu2@citrix.com> (raw)
In-Reply-To: <20190306175210.28145-1-wei.liu2@citrix.com>

With the help of two porting guides and cpython source code:

1. Use PyBytes to replace PyString counterparts.
2. Use PyVarObject_HEAD_INIT and provide compatibility for 2.5 and
   earlier.
3. Remove usage of Py_FindMethod.
4. Use new module initialisation routine.

For #3, Py_FindMethod was removed, yet an alternative wasn't
documented.  The code is the result of reverse-engineering cpython
commit 6116d4a1d1

https://docs.python.org/3/howto/cporting.html
http://python3porting.com/cextensions.html

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
---
v2: use PyBytes.
---
 tools/pygrub/src/fsimage/fsimage.c | 96 ++++++++++++++++++++++++++++++++++----
 1 file changed, 88 insertions(+), 8 deletions(-)

diff --git a/tools/pygrub/src/fsimage/fsimage.c b/tools/pygrub/src/fsimage/fsimage.c
index 743a3fb7b8..7e124f7bb3 100644
--- a/tools/pygrub/src/fsimage/fsimage.c
+++ b/tools/pygrub/src/fsimage/fsimage.c
@@ -26,11 +26,15 @@
 #include <xenfsimage.h>
 #include <stdlib.h>
 
+#if PY_MAJOR_VERSION < 3
 #if (PYTHON_API_VERSION >= 1011)
 #define PY_PAD 0L,0L,0L,0L,0L,0L,0L,0L,0L,0L,0L,0L,0L,0L,0L,0L,0L,0L,0L,0L,0L,0L,0L,0L
 #else
 #define PY_PAD 0L,0L,0L,0L
 #endif
+#else
+#define PY_PAD 0L,0L,0L,0L,0L,0L,0L,0L,0L,0L,0L,0L,0L,0L,0L,0L,0L
+#endif
 
 typedef struct fsimage_fs {
 	PyObject_HEAD
@@ -66,12 +70,24 @@ fsimage_file_read(fsimage_file_t *file, PyObject *args, PyObject *kwargs)
 
 	bufsize = size ? size : 4096;
 
-	if ((buffer = PyString_FromStringAndSize(NULL, bufsize)) == NULL)
+	buffer =
+#if PY_MAJOR_VERSION < 3
+		PyString_FromStringAndSize(NULL, bufsize);
+#else
+		PyBytes_FromStringAndSize(NULL, bufsize);
+#endif
+
+	if (buffer == NULL)
 		return (NULL);
  
 	while (1) {
 		int err;
-		void *buf = PyString_AS_STRING(buffer) + bytesread;
+		void *buf =
+#if PY_MAJOR_VERSION < 3
+			PyString_AS_STRING(buffer) + bytesread;
+#else
+			PyBytes_AS_STRING(buffer) + bytesread;
+#endif
 
 		err = fsi_pread_file(file->file, buf, bufsize,
 		    bytesread + offset);
@@ -91,12 +107,20 @@ fsimage_file_read(fsimage_file_t *file, PyObject *args, PyObject *kwargs)
 			if (bufsize == 0)
 				break;
 		} else {
+#if PY_MAJOR_VERSION < 3
 			if (_PyString_Resize(&buffer, bytesread + bufsize) < 0)
+#else
+			if (_PyBytes_Resize(&buffer, bytesread + bufsize) < 0)
+#endif
 				return (NULL);
 		}
 	}
 
+#if PY_MAJOR_VERSION < 3
 	_PyString_Resize(&buffer, bytesread);
+#else
+	_PyBytes_Resize(&buffer, bytesread);
+#endif
 	return (buffer);
 }
 
@@ -113,11 +137,13 @@ static struct PyMethodDef fsimage_file_methods[] = {
 	{ NULL, NULL, 0, NULL }	
 };
 
+#if PY_MAJOR_VERSION < 3
 static PyObject *
 fsimage_file_getattr(fsimage_file_t *file, char *name)
 {
 	return (Py_FindMethod(fsimage_file_methods, (PyObject *)file, name));
 }
+#endif
 
 static void
 fsimage_file_dealloc(fsimage_file_t *file)
@@ -128,16 +154,25 @@ fsimage_file_dealloc(fsimage_file_t *file)
 	PyObject_DEL(file);
 }
 
+/* Compatibility for 2.5 and earlier */
+#ifndef PyVarObject_HEAD_INIT
+#define PyVarObject_HEAD_INIT(type, size) \
+	PyObject_HEAD_INIT(type) size,
+#endif
+
 static char fsimage_file_type__doc__[] = "Filesystem image file";
 PyTypeObject fsimage_file_type = {
-	PyObject_HEAD_INIT(&PyType_Type)
-	0,					/* ob_size */
+	PyVarObject_HEAD_INIT(&PyType_Type, 0)
 	"xenfsimage.file",			/* tp_name */
 	sizeof(fsimage_file_t),			/* tp_size */
 	0,					/* tp_itemsize */
 	(destructor) fsimage_file_dealloc, 	/* tp_dealloc */
 	0,					/* tp_print */
+#if PY_MAJOR_VERSION < 3
 	(getattrfunc) fsimage_file_getattr, 	/* tp_getattr */
+#else
+	0,					/* tp_getattr */
+#endif
 	0,					/* tp_setattr */
 	0,					/* tp_compare */
 	0,					/* tp_repr */
@@ -151,7 +186,16 @@ PyTypeObject fsimage_file_type = {
 	0,					/* tp_setattro */
 	0,					/* tp_as_buffer */
 	Py_TPFLAGS_DEFAULT,			/* tp_flags */
-	fsimage_file_type__doc__,
+	fsimage_file_type__doc__,		/* tp_doc */
+#if PY_MAJOR_VERSION >= 3
+	0,					/* tp_traverse */
+	0,					/* tp_clear */
+	0,					/* tp_richcompare */
+	0,					/* tp_weaklistoffset */
+	0,					/* tp_iter */
+	0,					/* tp_iternext */
+	fsimage_file_methods,			/* tp_methods */
+#endif
 	PY_PAD
 };
 
@@ -215,11 +259,13 @@ static struct PyMethodDef fsimage_fs_methods[] = {
 	{ NULL, NULL, 0, NULL }	
 };
 
+#if PY_MAJOR_VERSION < 3
 static PyObject *
 fsimage_fs_getattr(fsimage_fs_t *fs, char *name)
 {
 	return (Py_FindMethod(fsimage_fs_methods, (PyObject *)fs, name));
 }
+#endif
 
 static void
 fsimage_fs_dealloc (fsimage_fs_t *fs)
@@ -232,14 +278,17 @@ fsimage_fs_dealloc (fsimage_fs_t *fs)
 PyDoc_STRVAR(fsimage_fs_type__doc__, "Filesystem image");
 
 PyTypeObject fsimage_fs_type = {
-	PyObject_HEAD_INIT(&PyType_Type)
-	0,					/* ob_size */
+	PyVarObject_HEAD_INIT(&PyType_Type, 0)
 	"xenfsimage.fs",			/* tp_name */
 	sizeof(fsimage_fs_t),			/* tp_size */
 	0,					/* tp_itemsize */
 	(destructor) fsimage_fs_dealloc, 	/* tp_dealloc */
 	0,					/* tp_print */
+#if PY_MAJOR_VERSION < 3
 	(getattrfunc) fsimage_fs_getattr, 	/* tp_getattr */
+#else
+	0,					/* tp_getattr */
+#endif
 	0,					/* tp_setattr */
 	0,					/* tp_compare */
 	0,					/* tp_repr */
@@ -253,7 +302,16 @@ PyTypeObject fsimage_fs_type = {
 	0,					/* tp_setattro */
 	0,					/* tp_as_buffer */
 	Py_TPFLAGS_DEFAULT,			/* tp_flags */
-	fsimage_fs_type__doc__,
+	fsimage_fs_type__doc__,			/* tp_doc */
+#if PY_MAJOR_VERSION >= 3
+	0,					/* tp_traverse */
+	0,					/* tp_clear */
+	0,					/* tp_richcompare */
+	0,					/* tp_weaklistoffset */
+	0,					/* tp_iter */
+	0,					/* tp_iternext */
+	fsimage_fs_methods,			/* tp_methods */
+#endif
 	PY_PAD
 };
 
@@ -316,8 +374,30 @@ static struct PyMethodDef fsimage_module_methods[] = {
 	{ NULL, NULL, 0, NULL }
 };
 
+#if PY_MAJOR_VERSION >= 3
+static struct PyModuleDef fsimage_module_def = {
+	PyModuleDef_HEAD_INIT,
+	"xenfsimage",		/* m_name */
+	"",			/* m_doc */
+	-1,			/* m_size */
+	fsimage_module_methods,	/* m_methods */
+	NULL,			/* m_reload */
+	NULL,			/* m_traverse */
+	NULL,			/* m_clear */
+	NULL			/* m_free */
+};
+#endif
+
 PyMODINIT_FUNC
+#if PY_MAJOR_VERSION >= 3
+PyInit_xenfsimage(void)
+#else
 initxenfsimage(void)
+#endif
 {
+#if PY_MAJOR_VERSION < 3
 	Py_InitModule("xenfsimage", fsimage_module_methods);
+#else
+	return PyModule_Create(&fsimage_module_def);
+#endif
 }
-- 
2.11.0


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  parent reply	other threads:[~2019-03-06 17:52 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-06 17:52 [PATCH for-next v2 v2 0/5] tools: Python 3 compatibility Wei Liu
2019-03-06 17:52 ` [PATCH for-next v2 v2 1/5] build/m4: make python_devel.m4 work with both python 2 and 3 Wei Liu
2019-03-07 11:14   ` Anthony PERARD
2019-03-06 17:52 ` [PATCH for-next v2 v2 2/5] libxl: make python scripts work with python 2.6 and up Wei Liu
2019-03-06 18:20   ` Andrew Cooper
2019-03-06 20:58   ` Hans van Kranenburg
2019-03-07 10:37     ` Wei Liu
2019-03-07 11:30       ` Wei Liu
2019-03-06 17:52 ` [PATCH for-next v2 v2 3/5] pygrub: convert python scripts to work with " Wei Liu
2019-03-06 18:23   ` Andrew Cooper
2019-03-06 17:52 ` Wei Liu [this message]
2019-03-06 18:46   ` [PATCH for-next v2 v2 4/5] pygrub: make it build with python 3 Andrew Cooper
2019-03-06 17:52 ` [PATCH for-next v2 v2 5/5] Update python requirement Wei Liu
2019-03-07 11:21   ` Anthony PERARD
2019-03-07 11:24     ` Wei Liu
2019-03-06 18:17 ` [PATCH for-next v2 v2 0/5] tools: Python 3 compatibility Wei Liu

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