[Libguestfs] [nbdkit PATCH 08/10] plugins: Wire up rust plugin support for NBD_INFO_INIT_STATE

[Eric Blake]

The NBD protocol is adding an extension to let servers advertise
initialization state to the client: whether the image contains holes,
and whether it is known to read as all zeroes.  For Rust, the changes
are just copy-and-paste, but I wasn't sure how to test them beyond a
successful build.

Signed-off-by: Eric Blake <eblake at redhat.com>
---
 plugins/rust/nbdkit-rust-plugin.pod | 2 +-
 plugins/rust/src/lib.rs             | 9 +++++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/plugins/rust/nbdkit-rust-plugin.pod b/plugins/rust/nbdkit-rust-plugin.pod
index 77eb0c4..5fcd7ff 100644
--- a/plugins/rust/nbdkit-rust-plugin.pod
+++ b/plugins/rust/nbdkit-rust-plugin.pod
@@ -103,7 +103,7 @@ C<nbdkit::ThreadModel::Parallel>.

 =over 4

-=item Missing: C<can_extents> and C<extents>
+=item Missing: C<can_extents>, C<extents>, C<preconnect>.

 These are not yet supported.

diff --git a/plugins/rust/src/lib.rs b/plugins/rust/src/lib.rs
index 2d691e7..58bbc62 100644
--- a/plugins/rust/src/lib.rs
+++ b/plugins/rust/src/lib.rs
@@ -107,6 +107,12 @@ pub struct Plugin {
     pub thread_model: Option<extern fn () -> ThreadModel>,

     pub can_fast_zero: Option<extern fn (h: *mut c_void) -> c_int>,
+
+    // Slot for preconnect function, which needs more integration.
+    _preconnect: Option<extern fn ()>,
+
+    pub init_sparse: Option<extern fn (h: *mut c_void) -> c_int>,
+    pub init_zero: Option<extern fn (h: *mut c_void) -> c_int>,
 }

 #[repr(C)]
@@ -166,6 +172,9 @@ impl Plugin {
             cache: None,
             thread_model: None,
             can_fast_zero: None,
+	    _preconnect: None,
+	    init_sparse: None,
+	    init_zero: None,
         }
     }
 }
-- 
2.24.1