[Libguestfs] [nbdkit PATCH v2 2/5] python: Expose can_zero callback

Fairly straightforward, as the code in plugins.c already takes care of necessary .pwrite fallbacks. Simplify similar can_FOO callbacks that were copy-and-pasted while implementing py_can_zero. Signed-off-by: Eric Blake <eblake(a)redhat.com&gt; --- plugins/python/nbdkit-python-plugin.pod | 7 +++++ plugins/python/python.c | 51 +++++++++++++++++++-------------- tests/test.py | 4 +++ 3 files changed, 41 insertions(+), 21 deletions(-) diff --git a/plugins/python/nbdkit-python-plugin.pod b/plugins/python/nbdkit-python-plugin.pod index 19f9eff..29250ce 100644 --- a/plugins/python/nbdkit-python-plugin.pod +++ b/plugins/python/nbdkit-python-plugin.pod @@ -183,6 +183,13 @@ contents will be garbage collected. def can_trim(h): # return a boolean +=item C<can_zero> + +(Optional) + + def can_zero(h): + # return a boolean + =item C<pread> (Required) diff --git a/plugins/python/python.c b/plugins/python/python.c index 07559a5..d75b36a 100644 --- a/plugins/python/python.c +++ b/plugins/python/python.c @@ -629,13 +629,8 @@ py_can_write (void *handle) Py_DECREF (r); return ret; } - /* No Python can_write callback, but there's a Python pwrite callback - * defined, so return 1. (In C modules, nbdkit would do this). - */ - else if (callback_defined ("pwrite", NULL)) - return 1; - else - return 0; + /* No Python can_write callback, so check for Python pwrite callback. */ + return callback_defined ("pwrite", NULL); } static int @@ -657,13 +652,8 @@ py_can_flush (void *handle) Py_DECREF (r); return ret; } - /* No Python can_flush callback, but there's a Python flush callback - * defined, so return 1. (In C modules, nbdkit would do this). - */ - else if (callback_defined ("flush", NULL)) - return 1; - else - return 0; + /* No Python can_flush callback, so check for Python flush callback. */ + return callback_defined ("flush", NULL); } static int @@ -708,13 +698,31 @@ py_can_trim (void *handle) Py_DECREF (r); return ret; } - /* No Python can_trim callback, but there's a Python trim callback - * defined, so return 1. (In C modules, nbdkit would do this). - */ - else if (callback_defined ("trim", NULL)) - return 1; - else - return 0; + /* No Python can_trim callback, so check for Python trim callback. */ + return callback_defined ("trim", NULL); +} + +static int +py_can_zero (void *handle) +{ + PyObject *obj = handle; + PyObject *fn; + PyObject *r; + int ret; + + if (callback_defined ("can_zero", &fn)) { + PyErr_Clear (); + + r = PyObject_CallFunctionObjArgs (fn, obj, NULL); + Py_DECREF (fn); + if (check_python_failure ("can_zero") == -1) + return -1; + ret = r == Py_True; + Py_DECREF (r); + return ret; + } + /* No Python can_zero callback, so check for Python zero callback. */ + return callback_defined ("zero", NULL); } #define py_config_help \ @@ -743,6 +751,7 @@ static struct nbdkit_plugin plugin = { .can_flush = py_can_flush, .is_rotational = py_is_rotational, .can_trim = py_can_trim, + .can_zero = py_can_zero, .pread = py_pread, .pwrite = py_pwrite, diff --git a/tests/test.py b/tests/test.py index 518cdd4..852af55 100644 --- a/tests/test.py +++ b/tests/test.py @@ -30,6 +30,10 @@ def can_trim(h): return True +def can_zero(h): + return True + + def pread(h, count, offset): global disk return disk[offset:offset+count] -- 2.14.3