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

[Eric Blake]

Fairly straightforward, as the code in plugins.c already takes
care of necessary .pwrite fallbacks.

Signed-off-by: Eric Blake <eblake at redhat.com>
---
 plugins/python/nbdkit-python-plugin.pod | 8 +++++++-
 plugins/python/python.c                 | 7 +++++++
 tests/test.py                           | 4 ++++
 3 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/plugins/python/nbdkit-python-plugin.pod b/plugins/python/nbdkit-python-plugin.pod
index f504cf7a..ec126f5a 100644
--- a/plugins/python/nbdkit-python-plugin.pod
+++ b/plugins/python/nbdkit-python-plugin.pod
@@ -208,6 +208,13 @@ 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)
@@ -317,7 +324,6 @@ C<config_help>,
 C<magic_config_key>,
 C<can_fua>,
 C<can_cache>,
-C<can_zero>,
 C<can_fast_zero>,
 C<can_extents>,
 C<can_multi_conn>,
diff --git a/plugins/python/python.c b/plugins/python/python.c
index d18bcb5e..aa09dce7 100644
--- a/plugins/python/python.c
+++ b/plugins/python/python.c
@@ -718,6 +718,12 @@ py_can_trim (void *handle)
   return boolean_callback (handle, "can_trim", "trim");
 }

+static int
+py_can_zero (void *handle)
+{
+  return boolean_callback (handle, "can_zero", "zero");
+}
+
 #define py_config_help \
   "script=<FILENAME>     (required) The Python plugin to run.\n" \
   "[other arguments may be used by the plugin that you load]"
@@ -744,6 +750,7 @@ static struct nbdkit_plugin plugin = {
   .can_write         = py_can_write,
   .can_flush         = py_can_flush,
   .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 a83f1181..1b7d3e0e 100644
--- a/tests/test.py
+++ b/tests/test.py
@@ -32,6 +32,10 @@ def can_trim(h):
     return True


+def can_zero(h):
+    return True
+
+
 def pread(h, count, offset):
     global disk
     return disk[offset:offset+count]
-- 
2.21.0