[PULL 13/14] rust: declare self as qemu_api for proc-macros

[Paolo Bonzini <pbonzini@redhat.com>]

From: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>

Fix an outstanding TODO.

Declaring `extern crate self as qemu_api` allows use of `qemu_api`
within the qemu_api crate; this allows the Wrapper derive macro and
future proc macros to be used interchangeably in the qemu_api crate and
other crates. This is not required currently and is only for
future-proofing.

Signed-off-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
Link: https://lore.kernel.org/r/20250728-self-as-qemu_api-v1-1-001c339cccc8@linaro.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 rust/qemu-api-macros/src/lib.rs | 14 ++++++--------
 rust/qemu-api/src/lib.rs        |  4 ++++
 2 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/rust/qemu-api-macros/src/lib.rs b/rust/qemu-api-macros/src/lib.rs
index a6147418891..959726efe6d 100644
--- a/rust/qemu-api-macros/src/lib.rs
+++ b/rust/qemu-api-macros/src/lib.rs
@@ -123,23 +123,21 @@ fn derive_opaque_or_error(input: DeriveInput) -> Result<proc_macro2::TokenStream
     let field = &get_unnamed_field(&input, "#[derive(Wrapper)]")?;
     let typ = &field.ty;
 
-    // TODO: how to add "::qemu_api"?  For now, this is only used in the
-    // qemu_api crate so it's not a problem.
     Ok(quote! {
-        unsafe impl crate::cell::Wrapper for #name {
-            type Wrapped = <#typ as crate::cell::Wrapper>::Wrapped;
+        unsafe impl ::qemu_api::cell::Wrapper for #name {
+            type Wrapped = <#typ as ::qemu_api::cell::Wrapper>::Wrapped;
         }
         impl #name {
-            pub unsafe fn from_raw<'a>(ptr: *mut <Self as crate::cell::Wrapper>::Wrapped) -> &'a Self {
+            pub unsafe fn from_raw<'a>(ptr: *mut <Self as ::qemu_api::cell::Wrapper>::Wrapped) -> &'a Self {
                 let ptr = ::std::ptr::NonNull::new(ptr).unwrap().cast::<Self>();
                 unsafe { ptr.as_ref() }
             }
 
-            pub const fn as_mut_ptr(&self) -> *mut <Self as crate::cell::Wrapper>::Wrapped {
+            pub const fn as_mut_ptr(&self) -> *mut <Self as ::qemu_api::cell::Wrapper>::Wrapped {
                 self.0.as_mut_ptr()
             }
 
-            pub const fn as_ptr(&self) -> *const <Self as crate::cell::Wrapper>::Wrapped {
+            pub const fn as_ptr(&self) -> *const <Self as ::qemu_api::cell::Wrapper>::Wrapped {
                 self.0.as_ptr()
             }
 
@@ -147,7 +145,7 @@ pub const fn as_void_ptr(&self) -> *mut ::core::ffi::c_void {
                 self.0.as_void_ptr()
             }
 
-            pub const fn raw_get(slot: *mut Self) -> *mut <Self as crate::cell::Wrapper>::Wrapped {
+            pub const fn raw_get(slot: *mut Self) -> *mut <Self as ::qemu_api::cell::Wrapper>::Wrapped {
                 slot.cast()
             }
         }
diff --git a/rust/qemu-api/src/lib.rs b/rust/qemu-api/src/lib.rs
index 86dcd8ef17a..bcb51c7986a 100644
--- a/rust/qemu-api/src/lib.rs
+++ b/rust/qemu-api/src/lib.rs
@@ -32,6 +32,10 @@
 pub mod vmstate;
 pub mod zeroable;
 
+// Allow proc-macros to refer to `::qemu_api` inside the `qemu_api` crate (this
+// crate).
+extern crate self as qemu_api;
+
 use std::{
     alloc::{GlobalAlloc, Layout},
     ffi::c_void,
-- 
2.51.0