capi: better clarify story around panic safety

- catches panics for all functions now except frame for performance reasons

librashader-capi/src/ffi.rs

@@ -1,6 +1,31 @@
 macro_rules! ffi_body {
+    (nopanic $body:block) => {
+        {
+            let result: Result<(), $crate::error::LibrashaderError> = try {
+                $body
+            };
+
+            let Err(e) = result else {
+                return $crate::error::LibrashaderError::ok()
+            };
+            e.export()
+        }
+    };
     ($body:block) => {
         {
+            let result = ::std::panic::catch_unwind(::std::panic::AssertUnwindSafe(|| {
+                $crate::ffi::ffi_body!(nopanic $body)
+            }));
+
+            result.unwrap_or_else(|e| $crate::error::LibrashaderError::UnknownError(e).export())
+        }
+    };
+    (nopanic |$($ref_capture:ident),*|; mut |$($mut_capture:ident),*| $body:block) => {
+        {
+            $($crate::error::assert_non_null!($ref_capture);)*
+            $(let $ref_capture = unsafe { &*$ref_capture };)*
+            $($crate::error::assert_non_null!($mut_capture);)*
+            $(let $mut_capture = unsafe { &mut *$mut_capture };)*
             let result: Result<(), $crate::error::LibrashaderError> = try {
                 $body
             };
@@ -13,8 +38,15 @@ macro_rules! ffi_body {
     };
     (|$($ref_capture:ident),*|; mut |$($mut_capture:ident),*| $body:block) => {
         {
-            $($crate::error::assert_non_null!($ref_capture);)*
-            $(let $ref_capture = unsafe { &*$ref_capture };)*
+            let result = ::std::panic::catch_unwind(::std::panic::AssertUnwindSafe(|| {
+                $crate::ffi::ffi_body!(nopanic |$($ref_capture),*|; mut |$($mut_capture),*| $body)
+            }));
+
+            result.unwrap_or_else(|e| $crate::error::LibrashaderError::UnknownError(e).export())
+        }
+    };
+    (nopanic mut |$($mut_capture:ident),*| $body:block) => {
+        {
             $($crate::error::assert_non_null!($mut_capture);)*
             $(let $mut_capture = unsafe { &mut *$mut_capture };)*
             let result: Result<(), $crate::error::LibrashaderError> = try {
@@ -29,19 +61,14 @@ macro_rules! ffi_body {
     };
     (mut |$($mut_capture:ident),*| $body:block) => {
          {
-            $($crate::error::assert_non_null!($mut_capture);)*
-            $(let $mut_capture = unsafe { &mut *$mut_capture };)*
-            let result: Result<(), $crate::error::LibrashaderError> = try {
-                $body
-            };
+            let result = ::std::panic::catch_unwind(::std::panic::AssertUnwindSafe(|| {
+                $crate::ffi::ffi_body!(nopanic mut |$($mut_capture),*| $body)
+            }));
 
-            let Err(e) = result else {
-                return $crate::error::LibrashaderError::ok()
-            };
-            e.export()
+            result.unwrap_or_else(|e| $crate::error::LibrashaderError::UnknownError(e).export())
         }
     };
-    (|$($ref_capture:ident),*| $body:block) => {
+    (nopanic |$($ref_capture:ident),*| $body:block) => {
         {
             $($crate::error::assert_non_null!($ref_capture);)*
             $(let $ref_capture = unsafe { &*$ref_capture };)*
@@ -54,24 +81,20 @@ macro_rules! ffi_body {
             };
             e.export()
         }
+    };
+    (|$($ref_capture:ident),*| $body:block) => {
+        {
+            let result = ::std::panic::catch_unwind(::std::panic::AssertUnwindSafe(|| {
+                $crate::ffi::ffi_body!(nopanic |$($ref_capture),*| $body)
+            }));
+
+            result.unwrap_or_else(|e| $crate::error::LibrashaderError::UnknownError(e).export())
         }
+    };
 }
 
 macro_rules! extern_fn {
-    ($(#[$($attrss:tt)*])* fn $func_name:ident ($($arg_name:ident : $arg_ty:ty),* $(,)?) $body:block) => {
-        ::paste::paste! {
-            /// Function pointer definition for
-            #[doc = ::std::stringify!($func_name)]
-            pub type [<PFN_ $func_name>] = unsafe extern "C" fn($($arg_name: $arg_ty,)*) -> $crate::ctypes::libra_error_t;
-        }
-
-        #[no_mangle]
-        $(#[$($attrss)*])*
-        pub unsafe extern "C" fn $func_name($($arg_name: $arg_ty,)*) -> $crate::ctypes::libra_error_t {
-            $crate::ffi::ffi_body!($body)
-        }
-    };
-
+    // raw doesn't wrap in ffi_body
     ($(#[$($attrss:tt)*])* raw fn $func_name:ident ($($arg_name:ident : $arg_ty:ty),* $(,)?) $body:block) => {
         ::paste::paste! {
             /// Function pointer definition for
@@ -86,6 +109,21 @@ macro_rules! extern_fn {
         }
     };
 
+    // ffi_body but panic-safe
+    ($(#[$($attrss:tt)*])* fn $func_name:ident ($($arg_name:ident : $arg_ty:ty),* $(,)?) $body:block) => {
+        ::paste::paste! {
+            /// Function pointer definition for
+            #[doc = ::std::stringify!($func_name)]
+            pub type [<PFN_ $func_name>] = unsafe extern "C" fn($($arg_name: $arg_ty,)*) -> $crate::ctypes::libra_error_t;
+        }
+
+        #[no_mangle]
+        $(#[$($attrss)*])*
+        pub unsafe extern "C" fn $func_name($($arg_name: $arg_ty,)*) -> $crate::ctypes::libra_error_t {
+            $crate::ffi::ffi_body!($body)
+        }
+    };
+
     ($(#[$($attrss:tt)*])* fn $func_name:ident ($($arg_name:ident : $arg_ty:ty),* $(,)?) |$($ref_capture:ident),*|; mut |$($mut_capture:ident),*| $body:block) => {
         ::paste::paste! {
             /// Function pointer definition for
@@ -126,6 +164,62 @@ macro_rules! extern_fn {
             $crate::ffi::ffi_body!(|$($ref_capture),*| $body)
         }
     };
+
+    // nopanic variants that are UB if panics
+    ($(#[$($attrss:tt)*])* nopanic fn $func_name:ident ($($arg_name:ident : $arg_ty:ty),* $(,)?) $body:block) => {
+        ::paste::paste! {
+            /// Function pointer definition for
+            #[doc = ::std::stringify!($func_name)]
+            pub type [<PFN_ $func_name>] = unsafe extern "C" fn($($arg_name: $arg_ty,)*) -> $crate::ctypes::libra_error_t;
+        }
+
+        #[no_mangle]
+        $(#[$($attrss)*])*
+        pub unsafe extern "C" fn $func_name($($arg_name: $arg_ty,)*) -> $crate::ctypes::libra_error_t {
+            $crate::ffi::ffi_body!(nopanic $body)
+        }
+    };
+
+    ($(#[$($attrss:tt)*])* nopanic fn $func_name:ident ($($arg_name:ident : $arg_ty:ty),* $(,)?) |$($ref_capture:ident),*|; mut |$($mut_capture:ident),*| $body:block) => {
+        ::paste::paste! {
+            /// Function pointer definition for
+            #[doc = ::std::stringify!($func_name)]
+            pub type [<PFN_ $func_name>] = unsafe extern "C" fn($($arg_name: $arg_ty,)*) -> $crate::ctypes::libra_error_t;
+        }
+
+        #[no_mangle]
+        $(#[$($attrss)*])*
+        pub unsafe extern "C" fn $func_name($($arg_name: $arg_ty,)*) -> $crate::ctypes::libra_error_t {
+            $crate::ffi::ffi_body!(nopanic |$($ref_capture),*|; mut |$($mut_capture),*| $body)
+        }
+    };
+
+    ($(#[$($attrss:tt)*])* nopanic fn $func_name:ident ($($arg_name:ident : $arg_ty:ty),* $(,)?) mut |$($mut_capture:ident),*| $body:block) => {
+        ::paste::paste! {
+            /// Function pointer definition for
+            #[doc = ::std::stringify!($func_name)]
+            pub type [<PFN_ $func_name>] = unsafe extern "C" fn($($arg_name: $arg_ty,)*) -> $crate::ctypes::libra_error_t;
+        }
+
+        #[no_mangle]
+        $(#[$($attrss)*])*
+        pub unsafe extern "C" fn $func_name($($arg_name: $arg_ty,)*) -> $crate::ctypes::libra_error_t {
+            $crate::ffi::ffi_body!(nopanic mut |$($mut_capture),*| $body)
+        }
+    };
+    ($(#[$($attrss:tt)*])* nopanic fn $func_name:ident ($($arg_name:ident : $arg_ty:ty),* $(,)?) |$($ref_capture:ident),*| $body:block) => {
+        ::paste::paste! {
+            /// Function pointer definition for
+             #[doc = ::std::stringify!($func_name)]
+             pub type [<PFN_ $func_name>] = unsafe extern "C" fn($($arg_name: $arg_ty,)*) -> $crate::ctypes::libra_error_t;
+        }
+
+        #[no_mangle]
+        $(#[$($attrss)*])*
+        pub unsafe extern "C" fn $func_name($($arg_name: $arg_ty,)*) -> $crate::ctypes::libra_error_t {
+            $crate::ffi::ffi_body!(nopanic |$($ref_capture),*| $body)
+        }
+    };
 }
 
 pub(crate) use extern_fn;

librashader-capi/src/runtime/d3d11/filter_chain.rs

@@ -216,7 +216,7 @@ extern_fn! {
     ///   the filter chain was created with.
     /// - You must ensure that only one thread has access to `chain` before you call this function. Only one
     ///   thread at a time may call this function.
-    fn libra_d3d11_filter_chain_frame(
+    nopanic fn libra_d3d11_filter_chain_frame(
         chain: *mut libra_d3d11_filter_chain_t,
         // cbindgen can't discover that ID3D11DeviceContext has the niche optimization
         // so ManuallyDrop<Option<ID3D11DeviceContext>> doesn't generate correct bindings.

librashader-capi/src/runtime/d3d12/filter_chain.rs

@@ -226,7 +226,7 @@ extern_fn! {
     ///    and must be associated with the `ID3D12Device` this filter chain was created with.
     /// - You must ensure that only one thread has access to `chain` before you call this function. Only one
     ///   thread at a time may call this function.
-    fn libra_d3d12_filter_chain_frame(
+    nopanic fn libra_d3d12_filter_chain_frame(
         chain: *mut libra_d3d12_filter_chain_t,
         command_list: ManuallyDrop<ID3D12GraphicsCommandList>,
         frame_count: usize,

librashader-capi/src/runtime/gl/filter_chain.rs

@@ -172,7 +172,7 @@ extern_fn! {
     ///   thread at a time may call this function. The thread `libra_gl_filter_chain_frame` is called from
     ///   must have its thread-local OpenGL context initialized with the same context used to create
     ///   the filter chain.
-    fn libra_gl_filter_chain_frame(
+    nopanic fn libra_gl_filter_chain_frame(
         chain: *mut libra_gl_filter_chain_t,
         frame_count: usize,
         image: libra_source_image_gl_t,

librashader-capi/src/runtime/vk/filter_chain.rs

@@ -246,7 +246,7 @@ extern_fn! {
     ///    struct.
     /// - You must ensure that only one thread has access to `chain` before you call this function. Only one
     ///   thread at a time may call this function.
-    fn libra_vk_filter_chain_frame(
+    nopanic fn libra_vk_filter_chain_frame(
         chain: *mut libra_vk_filter_chain_t,
         command_buffer: vk::CommandBuffer,
         frame_count: usize,