Handle all OpenFX errors

A *real* `#[must_use]` annotation should stop any unhandled errors from
slipping through. *This* fixes the Nuke crash--we were dereferencing a
null pointer returned by a function call that errored.

Author: valadaptive

crates/openfx-plugin/build.rs

@@ -19,7 +19,9 @@ fn main() {
         .header("wrapper.h")
         .blocklist_function("OfxGetNumberOfPlugins")
         .blocklist_function("OfxGetPlugin")
-        .must_use_type("OfxStatus")
+        // We wrap the OfxStatus enum in a newtype struct so we can annotate it with #[must_use].
+        .blocklist_type("OfxStatus")
+        .blocklist_var("kOfxStat.+")
         // Tell cargo to invalidate the built crate whenever any of the
         // included header files changed.
         .parse_callbacks(Box::new(bindgen::CargoCallbacks::new()))

crates/openfx-plugin/src/bindings.rs

@@ -4,4 +4,60 @@
 #![allow(unused)]
 #![allow(clippy::all)]
 
+#[must_use]
+#[repr(transparent)]
+#[derive(Clone, Copy, PartialEq, Eq)]
+pub struct OfxStatus(pub std::ffi::c_int);
+
+impl std::fmt::Debug for OfxStatus {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self.0 {
+            0 => f.write_str("kOfxStatOK"),
+            1 => f.write_str("kOfxStatFailed"),
+            2 => f.write_str("kOfxStatErrFatal"),
+            3 => f.write_str("kOfxStatErrUnknown"),
+            4 => f.write_str("kOfxStatErrMissingHostFeature"),
+            5 => f.write_str("kOfxStatErrUnsupported"),
+            6 => f.write_str("kOfxStatErrExists"),
+            7 => f.write_str("kOfxStatErrFormat"),
+            8 => f.write_str("kOfxStatErrMemory"),
+            9 => f.write_str("kOfxStatErrBadHandle"),
+            10 => f.write_str("kOfxStatErrBadIndex"),
+            11 => f.write_str("kOfxStatErrValue"),
+            12 => f.write_str("kOfxStatReplyYes"),
+            13 => f.write_str("kOfxStatReplyNo"),
+            14 => f.write_str("kOfxStatReplyDefault"),
+            _ => f.debug_tuple("OfxStatus").field(&self.0).finish(),
+        }
+    }
+}
+
+impl From<std::ffi::c_int> for OfxStatus {
+    fn from(value: std::ffi::c_int) -> Self {
+        Self(value)
+    }
+}
+
+// bindgen can't import these
+#[allow(dead_code)]
+pub mod OfxStat {
+    use crate::bindings::OfxStatus;
+
+    pub const kOfxStatOK: OfxStatus = OfxStatus(0);
+    pub const kOfxStatFailed: OfxStatus = OfxStatus(1);
+    pub const kOfxStatErrFatal: OfxStatus = OfxStatus(2);
+    pub const kOfxStatErrUnknown: OfxStatus = OfxStatus(3);
+    pub const kOfxStatErrMissingHostFeature: OfxStatus = OfxStatus(4);
+    pub const kOfxStatErrUnsupported: OfxStatus = OfxStatus(5);
+    pub const kOfxStatErrExists: OfxStatus = OfxStatus(6);
+    pub const kOfxStatErrFormat: OfxStatus = OfxStatus(7);
+    pub const kOfxStatErrMemory: OfxStatus = OfxStatus(8);
+    pub const kOfxStatErrBadHandle: OfxStatus = OfxStatus(9);
+    pub const kOfxStatErrBadIndex: OfxStatus = OfxStatus(10);
+    pub const kOfxStatErrValue: OfxStatus = OfxStatus(11);
+    pub const kOfxStatReplyYes: OfxStatus = OfxStatus(12);
+    pub const kOfxStatReplyNo: OfxStatus = OfxStatus(13);
+    pub const kOfxStatReplyDefault: OfxStatus = OfxStatus(14);
+}
+
 include!(concat!(env!("OUT_DIR"), "/bindings.rs"));