Add memoryview support to c-api (#8240)

crates/capi/src/lib.rs

@@ -22,6 +22,7 @@ pub mod genericaliasobject;
 pub mod import;
 pub mod listobject;
 pub mod longobject;
+pub mod memoryobject;
 pub mod methodobject;
 pub mod moduleobject;
 pub mod object;

crates/capi/src/memoryobject.rs

@@ -0,0 +1,37 @@
+use crate::object::define_py_check;
+use crate::{PyObject, pystate::with_vm};
+use rustpython_vm::PyPayload;
+use rustpython_vm::builtins::PyMemoryView;
+
+define_py_check!(fn PyMemoryView_Check, types.memoryview_type);
+
+#[unsafe(no_mangle)]
+pub unsafe extern "C" fn PyMemoryView_FromObject(obj: *mut PyObject) -> *mut PyObject {
+    with_vm(|vm| {
+        let obj = unsafe { &*obj };
+        Ok(PyMemoryView::from_object(obj, vm)?.into_ref(&vm.ctx))
+    })
+}
+
+#[cfg(test)]
+mod tests {
+    use pyo3::prelude::*;
+    use pyo3::types::{PyBytes, PyMemoryView};
+
+    #[test]
+    fn memoryview_from_bytes() {
+        Python::attach(|py| {
+            let bytes = PyBytes::new(py, b"hello");
+            let view = PyMemoryView::from(&bytes).unwrap();
+
+            assert!(view.is_instance_of::<PyMemoryView>());
+
+            let copied = view
+                .call_method1("tobytes", ())
+                .unwrap()
+                .cast_into::<PyBytes>()
+                .unwrap();
+            assert_eq!(copied.as_bytes(), b"hello");
+        })
+    }
+}