[Libguestfs] [PATCH libnbd 1/5] python: Change aio_buffer into nbd.Buffer class.
Richard W.M. Jones
rjones at redhat.com
Sat Aug 10 17:02:56 UTC 2019
Create a class for AIO buffers. This is a mostly neutral code
refactoring, but we add a convenient function for getting the size of
the buffer (same as previous commit for OCaml).
---
generator/generator | 111 +++++++++++++++++------------
python/handle.c | 26 +++++--
python/t/500-aio-pread.py | 4 +-
python/t/505-aio-pread-callback.py | 10 +--
python/t/510-aio-pwrite.py | 6 +-
5 files changed, 96 insertions(+), 61 deletions(-)
diff --git a/generator/generator b/generator/generator
index 26ab365..0107724 100755
--- a/generator/generator
+++ b/generator/generator
@@ -3981,8 +3981,10 @@ raise_exception ()
pr "extern PyObject *nbd_internal_py_%s (PyObject *self, PyObject *args);\n"
name;
) ([ "create"; "close";
- "alloc_aio_buffer"; "aio_buffer_from_bytearray";
- "aio_buffer_to_bytearray" ] @ List.map fst handle_calls);
+ "alloc_aio_buffer";
+ "aio_buffer_from_bytearray";
+ "aio_buffer_to_bytearray";
+ "aio_buffer_size" ] @ List.map fst handle_calls);
pr "\n";
pr "#endif /* LIBNBD_METHODS_H */\n"
@@ -4009,8 +4011,10 @@ let generate_python_libnbdmod_c () =
pr " { (char *) \"%s\", nbd_internal_py_%s, METH_VARARGS, NULL },\n"
name name;
) ([ "create"; "close";
- "alloc_aio_buffer"; "aio_buffer_from_bytearray";
- "aio_buffer_to_bytearray" ] @ List.map fst handle_calls);
+ "alloc_aio_buffer";
+ "aio_buffer_from_bytearray";
+ "aio_buffer_to_bytearray";
+ "aio_buffer_size" ] @ List.map fst handle_calls);
pr " { NULL, NULL, 0, NULL }\n";
pr "};\n";
pr "\n";
@@ -4502,17 +4506,28 @@ Error.__str__ = _str
pr "\
-# AIO buffer functions.
-def aio_buffer (len):
- '''allocate an AIO buffer used for nbd.aio_pread and nbd.aio_pwrite'''
- return libnbdmod.alloc_aio_buffer (len)
-
-def aio_buffer_from_bytearray (ba):
- '''create an AIO buffer from a bytearray'''
- return libnbdmod.aio_buffer_from_bytearray (ba)
-def aio_buffer_to_bytearray (buf):
- '''copy an AIO buffer into a bytearray'''
- return libnbdmod.aio_buffer_to_bytearray (buf)
+class Buffer (object):
+ '''Asynchronous I/O persistent buffer'''
+
+ def __init__ (self, len):
+ '''allocate an uninitialized AIO buffer used for nbd.aio_pread'''
+ self._o = libnbdmod.alloc_aio_buffer (len)
+
+ @classmethod
+ def from_bytearray (cls, ba):
+ '''create an AIO buffer from a bytearray'''
+ o = libnbdmod.aio_buffer_from_bytearray (ba)
+ self = cls (0)
+ self._o = o
+ return self
+
+ def to_bytearray (self):
+ '''copy an AIO buffer into a bytearray'''
+ return libnbdmod.aio_buffer_to_bytearray (self._o)
+
+ def size (self):
+ '''return the size of an AIO buffer'''
+ return libnbdmod.aio_buffer_size (self._o)
class NBD (object):
'''NBD handle'''
@@ -4532,42 +4547,46 @@ class NBD (object):
let args =
List.map (
function
- | Bool n -> n
- | BytesIn (n, _) | BytesPersistIn (n, _) -> n
- | BytesPersistOut (n, _) -> n
- | BytesOut (_, count) -> count
- | Closure { cbname } -> cbname
- | Int n -> n
- | Int64 n -> n
- | Path n -> n
- | SockAddrAndLen (n, _) -> n
- | String n -> n
- | StringList n -> n
- | UInt n -> n
- | UInt32 n -> n
- | UInt64 n -> n
+ | Bool n -> n, None, None
+ | BytesIn (n, _) -> n, None, None
+ | BytesOut (_, count) -> count, None, None
+ | BytesPersistIn (n, _) -> n, None, Some (sprintf "%s._o" n)
+ | BytesPersistOut (n, _) -> n, None, Some (sprintf "%s._o" n)
+ | Closure { cbname } -> cbname, None, None
+ | Int n -> n, None, None
+ | Int64 n -> n, None, None
+ | Path n -> n, None, None
+ | SockAddrAndLen (n, _) -> n, None, None
+ | String n -> n, None, None
+ | StringList n -> n, None, None
+ | UInt n -> n, None, None
+ | UInt32 n -> n, None, None
+ | UInt64 n -> n, None, None
) args in
let optargs =
List.map (
function
- | OFlags n -> n, "0"
+ | OFlags n -> n, Some "0", None
) optargs in
- let () =
- let params = args @ List.map (fun (n, def) -> n ^ "=" ^ def) optargs in
- let params = List.map ((^) ", ") params in
- let params = String.concat "" params in
- pr " def %s (self%s):\n" name params in
- let () =
- let longdesc = Str.global_replace py_fn_rex "C<nbd." longdesc in
- let longdesc = Str.global_replace py_const_rex "C<" longdesc in
- let longdesc = pod2text longdesc in
- pr " '''▶ %s\n\n%s'''\n"
- shortdesc (String.concat "\n" longdesc) in
- let () =
- let vars = args @ List.map fst optargs in
- let vars = List.map ((^) ", ") vars in
- let vars = String.concat "" vars in
- pr " return libnbdmod.%s (self._o%s)\n" name vars in
+ let args = args @ optargs in
+ pr " def %s (self" name;
+ List.iter (
+ function
+ | n, None, _ -> pr ", %s" n
+ | n, Some default, _ -> pr ", %s=%s" n default
+ ) args;
+ pr "):\n";
+ let longdesc = Str.global_replace py_fn_rex "C<nbd." longdesc in
+ let longdesc = Str.global_replace py_const_rex "C<" longdesc in
+ let longdesc = pod2text longdesc in
+ pr " '''▶ %s\n\n%s'''\n" shortdesc (String.concat "\n" longdesc);
+ pr " return libnbdmod.%s (self._o" name;
+ List.iter (
+ function
+ | _, _, Some getter -> pr ", %s" getter
+ | n, _, None -> pr ", %s" n
+ ) args;
+ pr ")\n";
pr "\n"
) handle_calls;
diff --git a/python/handle.c b/python/handle.c
index 7cff41a..4b510ad 100644
--- a/python/handle.c
+++ b/python/handle.c
@@ -72,7 +72,7 @@ nbd_internal_py_close (PyObject *self, PyObject *args)
return Py_None;
}
-static char aio_buffer_name[] = "struct py_aio_buffer";
+static const char aio_buffer_name[] = "nbd.Buffer";
struct py_aio_buffer *
nbd_internal_py_get_aio_buffer (PyObject *capsule)
@@ -89,9 +89,7 @@ free_aio_buffer (PyObject *capsule)
free (buf);
}
-/* Allocate a persistent buffer used for nbd_aio_pread and
- * nbd_aio_pwrite.
- */
+/* Allocate a persistent buffer used for nbd_aio_pread. */
PyObject *
nbd_internal_py_alloc_aio_buffer (PyObject *self, PyObject *args)
{
@@ -115,7 +113,7 @@ nbd_internal_py_alloc_aio_buffer (PyObject *self, PyObject *args)
free (buf);
return NULL;
}
- buf->data = calloc (1, buf->len);
+ buf->data = malloc (buf->len);
if (buf->data == NULL) {
PyErr_NoMemory ();
free (buf);
@@ -193,3 +191,21 @@ nbd_internal_py_aio_buffer_to_bytearray (PyObject *self, PyObject *args)
return PyByteArray_FromStringAndSize (buf->data, buf->len);
}
+
+PyObject *
+nbd_internal_py_aio_buffer_size (PyObject *self, PyObject *args)
+{
+ PyObject *obj;
+ struct py_aio_buffer *buf;
+
+ if (!PyArg_ParseTuple (args,
+ (char *) "O:nbd_internal_py_aio_buffer_size",
+ &obj))
+ return NULL;
+
+ buf = nbd_internal_py_get_aio_buffer (obj);
+ if (buf == NULL)
+ return NULL;
+
+ return PyLong_FromSsize_t (buf->len);
+}
diff --git a/python/t/500-aio-pread.py b/python/t/500-aio-pread.py
index 6ff06fd..0c5a07a 100644
--- a/python/t/500-aio-pread.py
+++ b/python/t/500-aio-pread.py
@@ -20,12 +20,12 @@ import nbd
h = nbd.NBD ()
h.connect_command (["nbdkit", "-s", "--exit-with-parent", "-v",
"pattern", "size=512"])
-buf = nbd.aio_buffer (512)
+buf = nbd.Buffer (512)
cookie = h.aio_pread (buf, 0)
while not (h.aio_command_completed (cookie)):
h.poll (-1)
-buf = nbd.aio_buffer_to_bytearray (buf)
+buf = buf.to_bytearray ()
print ("%r" % buf)
diff --git a/python/t/505-aio-pread-callback.py b/python/t/505-aio-pread-callback.py
index 9246616..e552db8 100644
--- a/python/t/505-aio-pread-callback.py
+++ b/python/t/505-aio-pread-callback.py
@@ -43,21 +43,21 @@ def callback (user_data, err):
assert user_data == 42
# First try: succeed in both callbacks
-buf = nbd.aio_buffer (512)
+buf = nbd.Buffer (512)
cookie = h.aio_pread_structured_callback (buf, 0,
lambda *args: chunk (42, *args),
lambda *args: callback (42, *args))
while not (h.aio_command_completed (cookie)):
h.poll (-1)
-buf = nbd.aio_buffer_to_bytearray (buf)
+buf = buf.to_bytearray ()
print ("%r" % buf)
assert buf == expected
# Second try: fail only during callback
-buf = nbd.aio_buffer (512)
+buf = nbd.Buffer (512)
cookie = h.aio_pread_structured_callback (buf, 0,
lambda *args: chunk (42, *args),
lambda *args: callback (43, *args))
@@ -69,7 +69,7 @@ except nbd.Error as ex:
assert ex.errnum == errno.ENOMEM
# Third try: fail during both
-buf = nbd.aio_buffer (512)
+buf = nbd.Buffer (512)
cookie = h.aio_pread_structured_callback (buf, 0,
lambda *args: chunk (43, *args),
lambda *args: callback (44, *args))
@@ -81,7 +81,7 @@ except nbd.Error as ex:
assert ex.errnum == errno.ENOMEM
# Fourth try: fail only during chunk
-buf = nbd.aio_buffer (512)
+buf = nbd.Buffer (512)
cookie = h.aio_pread_structured_callback (buf, 0,
lambda *args: chunk (43, *args),
lambda *args: callback (42, *args))
diff --git a/python/t/510-aio-pwrite.py b/python/t/510-aio-pwrite.py
index 4bbc494..71aa9ba 100644
--- a/python/t/510-aio-pwrite.py
+++ b/python/t/510-aio-pwrite.py
@@ -33,17 +33,17 @@ h = nbd.NBD ()
h.connect_command (["nbdkit", "-s", "--exit-with-parent", "-v",
"file", datafile])
-buf1 = nbd.aio_buffer_from_bytearray (buf)
+buf1 = nbd.Buffer.from_bytearray (buf)
cookie = h.aio_pwrite (buf1, 0, nbd.CMD_FLAG_FUA)
while not (h.aio_command_completed (cookie)):
h.poll (-1)
-buf2 = nbd.aio_buffer (512)
+buf2 = nbd.Buffer (512)
cookie = h.aio_pread (buf2, 0)
while not (h.aio_command_completed (cookie)):
h.poll (-1)
-assert buf == nbd.aio_buffer_to_bytearray (buf2)
+assert buf == buf2.to_bytearray ()
with open (datafile, "rb") as f:
content = f.read ()
--
2.22.0
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