rust: split "bql" crate

Unfortunately, an example had to be compile-time disabled, since it
relies on higher level crates (qdev, irq etc). The alternative is
probably to move that code to an example in qemu-api or elsewere and
make a link to it, or include_str.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Link: https://lore.kernel.org/r/20250827104147.717203-12-marcandre.lureau@redhat.com
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 8 insertions, 9 deletions

diff --git a/rust/qemu-api/src/chardev.rs b/rust/qemu-api/src/chardev.rs
index 5a351dcecb..2ec90cc0b2 100644
--- a/rust/qemu-api/src/chardev.rs
+++ b/rust/qemu-api/src/chardev.rs
@@ -18,13 +18,10 @@ use std::{
     slice,
 };
 
+use bql::{BqlRefCell, BqlRefMut};
 use common::{callbacks::FnCall, errno, Opaque};
 
-use crate::{
-    bindings,
-    cell::{BqlRefCell, BqlRefMut},
-    prelude::*,
-};
+use crate::{bindings, prelude::*};
 
 /// A safe wrapper around [`bindings::Chardev`].
 #[repr(transparent)]
@@ -44,13 +41,15 @@ pub struct CharBackend {
     _pin: PhantomPinned,
 }
 
-impl Write for BqlRefMut<'_, bindings::CharBackend> {
+pub struct CharBackendMut<'a>(BqlRefMut<'a, bindings::CharBackend>);
+
+impl Write for CharBackendMut<'_> {
     fn flush(&mut self) -> io::Result<()> {
         Ok(())
     }
 
     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
-        let chr: &mut bindings::CharBackend = self;
+        let chr: &mut bindings::CharBackend = &mut self.0;
 
         let len = buf.len().try_into().unwrap();
         let r = unsafe { bindings::qemu_chr_fe_write(addr_of_mut!(*chr), buf.as_ptr(), len) };
@@ -58,7 +57,7 @@ impl Write for BqlRefMut<'_, bindings::CharBackend> {
     }
 
     fn write_all(&mut self, buf: &[u8]) -> io::Result<()> {
-        let chr: &mut bindings::CharBackend = self;
+        let chr: &mut bindings::CharBackend = &mut self.0;
 
         let len = buf.len().try_into().unwrap();
         let r = unsafe { bindings::qemu_chr_fe_write_all(addr_of_mut!(*chr), buf.as_ptr(), len) };
@@ -198,7 +197,7 @@ impl CharBackend {
     /// the big QEMU lock while the character device is borrowed, as
     /// that might cause C code to write to the character device.
     pub fn borrow_mut(&self) -> impl Write + '_ {
-        self.inner.borrow_mut()
+        CharBackendMut(self.inner.borrow_mut())
     }
 
     /// Send a continuous stream of zero bits on the line if `enabled` is