Fix SIGBUS crash on macOS arm64 for any \setmainfont{} call (#1345) (#1346)

Author: CraftSpider

crates/mac_core/src/array.rs

@@ -1,6 +1,5 @@
 use super::{sys, CoreType};
 use std::marker::PhantomData;
-use std::ops::Index;
 use std::ptr;
 use std::ptr::NonNull;
 
@@ -53,20 +52,22 @@ impl<T: CoreType> CFArray<T> {
     pub fn is_empty(&self) -> bool {
         self.len() == 0
     }
-}
-
-impl<T: CoreType> Index<usize> for CFArray<T> {
-    type Output = T;
 
-    fn index(&self, index: usize) -> &Self::Output {
+    /// Get a borrowed value at the given index. The returned value has its reference count
+    /// incremented and will be released when dropped.
+    ///
+    /// `CFArrayGetValueAtIndex` returns the stored `CFTypeRef` value directly (not a pointer
+    /// to it), so we must construct a new borrowed `T` from it rather than casting to `&T`.
+    pub fn get(&self, index: usize) -> T {
         if index >= self.len() {
             panic!("Index {index} out of bounds for CFArray");
         }
         // SAFETY: Internal pointer is guaranteed valid. Index has been verified in-bounds.
-        let ptr =
-            unsafe { sys::CFArrayGetValueAtIndex(self.0.cast().as_ptr(), index as sys::CFIndex) }
-                .cast::<T>();
-        // SAFETY: API contracts ensure all values are of the correct type and live for our lifetime.
-        unsafe { &*ptr }
+        let value =
+            unsafe { sys::CFArrayGetValueAtIndex(self.0.cast().as_ptr(), index as sys::CFIndex) };
+        // SAFETY: The returned value is a valid CFTypeRef for type T.
+        //         new_borrowed calls CFRetain, giving us ownership of a new reference.
+        let ptr = NonNull::new(value.cast_mut()).unwrap();
+        unsafe { T::new_borrowed(ptr.cast()) }
     }
 }

crates/xetex_layout/src/font.rs

@@ -274,7 +274,7 @@ impl Font {
                     let sz = engine.input_get_size(afm_handle);
                     let mut backing_data2 = vec![0; sz];
                     engine
-                        .input_read(handle, &mut backing_data2)
+                        .input_read(afm_handle, &mut backing_data2)
                         .expect("failed to read AFM file");
 
                     self.ft_face().attach_stream_mem(backing_data2).unwrap();

crates/xetex_layout/src/manager/mac.rs

@@ -21,11 +21,11 @@ fn find_fonts_with_name(name: CFString, key: FontAttribute) -> CFArray<CTFontDes
 fn find_font_with_name(name: CFString, key: FontAttribute) -> Option<CTFontDescriptor> {
     let matches = find_fonts_with_name(name, key);
 
-    let mut matched = None;
     if !matches.is_empty() {
-        matched = Some(matches[0].clone());
+        Some(matches.get(0))
+    } else {
+        None
     }
-    matched
 }
 
 fn append_name_to_list(font: &CTFont, name_list: &mut Vec<CString>, name_key: FontNameKey) {
@@ -48,9 +48,9 @@ impl MacBackend {
 
     fn add_fonts_to_caches(&self, maps: &mut FontMaps, members: CFArray<CTFontDescriptor>) {
         for i in 0..members.len() {
-            let font = &members[i];
+            let font = members.get(i);
             let names = self.read_names(font.clone());
-            maps.add_to_maps(self, font.clone(), &names)
+            maps.add_to_maps(self, font, &names)
         }
     }