vtable: Don't automatically add extern C

Cargo.toml

@@ -131,7 +131,7 @@ slint-cpp = { version = "=1.12.0", path = "api/cpp", default-features = false }
 slint-interpreter = { version = "=1.12.0", path = "internal/interpreter", default-features = false }
 slint-macros = { version = "=1.12.0", path = "api/rs/macros", default-features = false }
 
-vtable = { version = "0.2.1", path = "helper_crates/vtable", default-features = false }
+vtable = { version = "0.3", path = "helper_crates/vtable" }
 
 by_address = { version = "1.0.4" }
 bytemuck = { version = "1.13.1" }

helper_crates/vtable/CHANGELOG.md

@@ -3,6 +3,10 @@
 # Changelog
 All notable changes to this crate will be documented in this file.
 
+## [0.3.0]
+
+ - Don't automatically add "extern C" to the function that do not have it.
+
 ## [0.2.1] - 2024-12-18
 
  - Fixed Warnings

helper_crates/vtable/Cargo.toml

@@ -3,7 +3,7 @@
 
 [package]
 name = "vtable"
-version = "0.2.1"
+version = "0.3.0"
 authors = ["Slint Developers <info@slint.dev>"]
 edition = "2021"
 license = "MIT OR Apache-2.0"
@@ -14,7 +14,7 @@ homepage = "https://slint.dev"
 [lib]
 
 [dependencies]
-vtable-macro = { version = "=0.2.1", path = "./macro" }
+vtable-macro = { version = "=0.3.0", path = "./macro" }
 const-field-offset = { version = "0.1", path = "../const-field-offset" }
 stable_deref_trait = { version = "1.2.0", default-features = false }
 portable-atomic = "1"

helper_crates/vtable/macro/Cargo.toml

@@ -3,7 +3,7 @@
 
 [package]
 name = "vtable-macro"
-version = "0.2.1"
+version = "0.3.0"
 authors = ["Slint Developers <info@slint.dev>"]
 edition = "2021"
 license = "MIT OR Apache-2.0"

helper_crates/vtable/macro/macro.rs

@@ -68,7 +68,6 @@ allowing to access methods from the trait directly from VRef.
 This macro does the following transformation:
 
 For function type fields:
- - If the function has no ABI, it is changed to `extern "C"` (unless `no_extern` is passed as `#[vtable(no_extern)]`)
  - `unsafe` is added to the signature, since it is unsafe to call these functions directly from
    the vtable without having a valid pointer to the actual object. But if the original function was
    marked unsafe, the unsafety is forwarded to the trait.
@@ -112,7 +111,7 @@ use vtable::*;
 #[repr(C)]
 struct AnimalVTable {
     /// Pointer to a function that make noise.
-    /// `unsafe` and `extern "C"` will automatically be added
+    /// `unsafe` will automatically be added
     make_noise: fn(VRef<AnimalVTable>, i32) -> i32,
 
     /// if there is a 'drop' member, it is considered as the destructor
@@ -165,9 +164,7 @@ assert_eq!(dog.is_hungry, true);
 
 */
 #[proc_macro_attribute]
-pub fn vtable(attr: TokenStream, item: TokenStream) -> TokenStream {
-    let no_extern = attr.to_string().trim() == "no_extern";
-
+pub fn vtable(_attr: TokenStream, item: TokenStream) -> TokenStream {
     let mut input = parse_macro_input!(item as ItemStruct);
 
     let fields = if let Fields::Named(fields) = &mut input.fields {
@@ -386,19 +383,6 @@ pub fn vtable(attr: TokenStream, item: TokenStream) -> TokenStream {
             // Add unsafe: The function are not safe to call unless the self parameter is of the correct type
             f.unsafety = Some(Default::default());
 
-            // Add extern "C" if it isn't there
-            if let Some(a) = &f.abi {
-                if !a
-                    .name
-                    .as_ref()
-                    .map(|s| matches!(s.value().as_str(), "C" | "C-unwind"))
-                    .unwrap_or(false)
-                {
-                    return Error::new(a.span(), "invalid ABI").to_compile_error().into();
-                }
-            } else if !no_extern {
-                f.abi = Some(parse_str("extern \"C\"").unwrap());
-            }
             sig_extern.abi.clone_from(&f.abi);
 
             let mut wrap_trait_call = None;

helper_crates/vtable/src/lib.rs

@@ -24,9 +24,6 @@ use vtable::*;
 struct AnimalVTable {
     /// pointer to a function that makes a noise.  The `VRef<AnimalVTable>` is the type of
     /// the self object.
-    ///
-    /// Note: the #[vtable] macro will automatically add `extern "C"` if that is missing.
-    /// (unless `no_extern` is specified)
     make_noise: fn(VRef<AnimalVTable>, i32) -> i32,
 
     /// if there is a 'drop' member, it is considered as the destructor.

internal/core/graphics/image.rs

@@ -21,7 +21,7 @@ mod svg;
 
 #[allow(missing_docs)]
 #[cfg_attr(not(feature = "ffi"), i_slint_core_macros::remove_extern)]
-#[vtable::vtable(no_extern)]
+#[vtable::vtable]
 #[repr(C)]
 pub struct OpaqueImageVTable {
     drop_in_place: extern "C-unwind" fn(VRefMut<OpaqueImageVTable>) -> Layout,

internal/core/item_tree.rs

@@ -42,7 +42,7 @@ impl From<IndexRange> for core::ops::Range<usize> {
 
 /// A ItemTree is representing an unit that is allocated together
 #[cfg_attr(not(feature = "ffi"), i_slint_core_macros::remove_extern)]
-#[vtable(no_extern)]
+#[vtable]
 #[repr(C)]
 pub struct ItemTreeVTable {
     /// Visit the children of the item at index `index`.
@@ -1049,7 +1049,7 @@ impl<'a> From<&'a [ItemTreeNode]> for ItemTreeNodeArray<'a> {
 }
 
 #[cfg_attr(not(feature = "ffi"), i_slint_core_macros::remove_extern)]
-#[vtable(no_extern)]
+#[vtable]
 #[repr(C)]
 /// Object to be passed in visit_item_children method of the ItemTree.
 pub struct ItemVisitorVTable {

internal/core/items.rs

@@ -113,7 +113,7 @@ pub enum RenderingResult {
 
 /// Items are the nodes in the render tree.
 #[cfg_attr(not(feature = "ffi"), i_slint_core_macros::remove_extern)]
-#[vtable(no_extern)]
+#[vtable]
 #[repr(C)]
 pub struct ItemVTable {
     /// This function is called by the run-time after the memory for the item

internal/core/menus.rs

@@ -22,15 +22,17 @@ use i_slint_core_macros::SlintElement;
 use vtable::{VRef, VRefMut};
 
 /// Interface for native menu and menubar
+#[cfg_attr(not(feature = "ffi"), i_slint_core_macros::remove_extern)]
 #[vtable::vtable]
 #[repr(C)]
 pub struct MenuVTable {
     /// destructor
-    drop: fn(VRefMut<MenuVTable>),
+    drop: extern "C-unwind" fn(VRefMut<MenuVTable>),
     /// Return the list of items for the sub menu (or the main menu of parent is None)
-    sub_menu: fn(VRef<MenuVTable>, Option<&MenuEntry>, &mut SharedVector<MenuEntry>),
+    sub_menu:
+        extern "C-unwind" fn(VRef<MenuVTable>, Option<&MenuEntry>, &mut SharedVector<MenuEntry>),
     /// Handler when the menu entry is activated
-    activate: fn(VRef<MenuVTable>, &MenuEntry),
+    activate: extern "C-unwind" fn(VRef<MenuVTable>, &MenuEntry),
 }
 
 struct ShadowTreeNode {