Implement Deref for FnPtr

Author: lucic71

cpp2rust/converter/converter.cpp

@@ -131,7 +131,6 @@ bool Converter::VisitRecordType(clang::RecordType *type) {
   if (auto lambda = clang::dyn_cast<clang::CXXRecordDecl>(decl)) {
     if (lambda->isLambda()) {
       if (in_function_formals_) {
-        // Function parameters can't use `_`. Emit `impl Fn(args) -> ret`.
         auto call_op = lambda->getLambdaCallOperator();
         StrCat("impl Fn(");
         for (auto p : call_op->parameters()) {

cpp2rust/converter/models/converter_refcount.cpp

@@ -180,10 +180,8 @@ std::string ConverterRefCount::BuildFnAdapter(
   // Build adapter signature: |a0: T0, a1: T1, ...| -> Tr
   std::string closure = "(|";
   for (unsigned i = 0; i < target_proto->getNumParams(); ++i) {
-    if (i > 0)
-      closure += ", ";
     closure +=
-        std::format("a{}: {}", i, ToString(target_proto->getParamType(i)));
+        std::format("a{}: {},", i, ToString(target_proto->getParamType(i)));
   }
   closure += "|";
   if (!target_proto->getReturnType()->isVoidType()) {
@@ -1025,8 +1023,9 @@ bool ConverterRefCount::VisitImplicitCastExpr(clang::ImplicitCastExpr *expr) {
 }
 
 void ConverterRefCount::EmitFnPtrCall(clang::Expr *callee) {
+  StrCat("(*");
   Convert(callee);
-  StrCat(".call()");
+  StrCat(")");
 }
 
 void ConverterRefCount::EmitFnAsValue(const clang::FunctionDecl *fn_decl) {

libcc2rs/src/fn_ptr.rs

@@ -3,6 +3,7 @@
 
 use std::any::{Any, TypeId};
 use std::marker::PhantomData;
+use std::ops::Deref;
 use std::rc::Rc;
 
 use crate::rc::{AnyPtr, ErasedPtr};
@@ -75,17 +76,18 @@ impl<T: 'static> FnPtr<T> {
         }
     }
 
-    pub fn call(&self) -> T
-    where
-        T: Copy,
-    {
+}
+
+impl<T: 'static> Deref for FnPtr<T> {
+    type Target = T;
+    fn deref(&self) -> &T {
         let state = self.state.as_ref().expect("ub: null fn pointer call");
         let entry = state
             .cast_history
             .last()
             .expect("empty fn pointer cast_history");
         match entry {
-            Some(rc) => *rc
+            Some(rc) => rc
                 .downcast_ref::<T>()
                 .expect("ub: fn pointer type mismatch"),
             None => panic!("ub: calling through incompatible fn pointer type"),

tests/unit/out/refcount/fn_ptr.rs

@@ -16,7 +16,7 @@ pub fn foo_1(fn_: FnPtr<fn(AnyPtr) -> i32>, pi: Ptr<i32>) -> i32 {
     let pi: Value<Ptr<i32>> = Rc::new(RefCell::new(pi));
     return ({
         let _arg0: AnyPtr = ((*pi.borrow()).clone() as Ptr<i32>).to_any();
-        (*fn_.borrow()).call()(_arg0)
+        (*(*fn_.borrow()))(_arg0)
     });
 }
 pub fn main() {

tests/unit/out/refcount/fn_ptr_array.rs

@@ -35,21 +35,21 @@ fn main_0() -> i32 {
         (({
             let _arg0: i32 = 2;
             let _arg1: i32 = 3;
-            (*ops.borrow())[(0) as usize].call()(_arg0, _arg1)
+            (*(*ops.borrow())[(0) as usize])(_arg0, _arg1)
         }) == 5)
     );
     assert!(
         (({
             let _arg0: i32 = 7;
             let _arg1: i32 = 4;
-            (*ops.borrow())[(1) as usize].call()(_arg0, _arg1)
+            (*(*ops.borrow())[(1) as usize])(_arg0, _arg1)
         }) == 3)
     );
     assert!(
         (({
             let _arg0: i32 = 6;
             let _arg1: i32 = 5;
-            (*ops.borrow())[(2) as usize].call()(_arg0, _arg1)
+            (*(*ops.borrow())[(2) as usize])(_arg0, _arg1)
         }) == 30)
     );
     assert!(!(((*ops.borrow())[(0) as usize]).is_null()));

tests/unit/out/refcount/fn_ptr_as_condition.rs

@@ -21,7 +21,7 @@ pub fn maybe_call_1(cb: FnPtr<fn(Ptr<i32>)>, x: Ptr<i32>) {
     if !(*cb.borrow()).is_null() {
         ({
             let _arg0: Ptr<i32> = (*x.borrow()).clone();
-            (*cb.borrow()).call()(_arg0)
+            (*(*cb.borrow()))(_arg0)
         });
     }
 }
@@ -51,7 +51,7 @@ fn main_0() -> i32 {
     if !(*fn_.borrow()).is_null() {
         ({
             let _arg0: Ptr<i32> = (c.as_pointer());
-            (*fn_.borrow()).call()(_arg0)
+            (*(*fn_.borrow()))(_arg0)
         });
     }
     assert!(((*c.borrow()) == 6));

tests/unit/out/refcount/fn_ptr_cast.rs

@@ -17,7 +17,7 @@ pub fn test_roundtrip_1() {
     assert!(
         (({
             let _arg0: i32 = 5;
-            (*fn_.borrow()).call()(_arg0)
+            (*(*fn_.borrow()))(_arg0)
         }) == 10)
     );
     let gfn: Value<FnPtr<fn()>> =
@@ -29,7 +29,7 @@ pub fn test_roundtrip_1() {
     assert!(
         (({
             let _arg0: i32 = 5;
-            (*fn2.borrow()).call()(_arg0)
+            (*(*fn2.borrow()))(_arg0)
         }) == 10)
     );
     assert!({
@@ -49,7 +49,7 @@ pub fn test_double_cast_2() {
     assert!(
         (({
             let _arg0: i32 = 5;
-            (*fn2.borrow()).call()(_arg0)
+            (*(*fn2.borrow()))(_arg0)
         }) == 10)
     );
     assert!({
@@ -82,7 +82,7 @@ pub fn test_void_ptr_to_fn_3() {
     assert!(
         (({
             let _arg0: i32 = 5;
-            (*fn_.borrow()).call()(_arg0)
+            (*(*fn_.borrow()))(_arg0)
         }) == 10)
     );
 }
@@ -106,7 +106,7 @@ pub fn test_call_through_cast_5() {
         ({
             let _arg0: AnyPtr = ((val.as_pointer()) as Ptr<i32>).to_any();
             let _arg1: i32 = 42;
-            (*gfn.borrow()).call()(_arg0, _arg1)
+            (*(*gfn.borrow()))(_arg0, _arg1)
         }),
     ));
     assert!(((*result.borrow()) == 142));

tests/unit/out/refcount/fn_ptr_conditional.rs

@@ -42,7 +42,7 @@ pub fn apply_4(fn_: FnPtr<fn(i32) -> i32>, x: i32) -> i32 {
         }));
     return ({
         let _arg0: i32 = (*x.borrow());
-        (*actual.borrow()).call()(_arg0)
+        (*(*actual.borrow()))(_arg0)
     });
 }
 pub fn main() {
@@ -52,31 +52,28 @@ fn main_0() -> i32 {
     assert!(
         (({
             let _arg0: i32 = 10;
-            ({
+            (*({
                 let _mode: i32 = 1;
                 pick_3(_mode)
-            })
-            .call()(_arg0)
+            }))(_arg0)
         }) == 11)
     );
     assert!(
         (({
             let _arg0: i32 = 10;
-            ({
+            (*({
                 let _mode: i32 = -1_i32;
                 pick_3(_mode)
-            })
-            .call()(_arg0)
+            }))(_arg0)
         }) == 9)
     );
     assert!(
         (({
             let _arg0: i32 = 10;
-            ({
+            (*({
                 let _mode: i32 = 0;
                 pick_3(_mode)
-            })
-            .call()(_arg0)
+            }))(_arg0)
         }) == 10)
     );
     assert!(

tests/unit/out/refcount/fn_ptr_default_arg.rs

@@ -17,7 +17,7 @@ pub fn apply_1(x: i32, fn_: Option<FnPtr<fn(i32) -> i32>>) -> i32 {
     if !(*fn_.borrow()).is_null() {
         return ({
             let _arg0: i32 = (*x.borrow());
-            (*fn_.borrow()).call()(_arg0)
+            (*(*fn_.borrow()))(_arg0)
         });
     }
     return (*x.borrow());

tests/unit/out/refcount/fn_ptr_global.rs

@@ -27,7 +27,7 @@ pub fn call_op_3(x: i32) -> i32 {
     if !(*g_op.with(Value::clone).borrow()).is_null() {
         return ({
             let _arg0: i32 = (*x.borrow());
-            (*g_op.with(Value::clone).borrow()).call()(_arg0)
+            (*(*g_op.with(Value::clone).borrow()))(_arg0)
         });
     }
     return (*x.borrow());