add support for nested functions

Author: gnzlbg

ctest/Cargo.toml

@@ -14,7 +14,6 @@ Automated tests of FFI bindings.
 [dependencies]
 syntex_syntax = "0.59.1"
 cc = "1.0.1"
-syn = { version = "0.15", features = ["full"] }
 
 [workspace]
 members = ["testcrate"]

ctest/src/lib.rs

@@ -13,7 +13,6 @@
 
 extern crate cc;
 extern crate syntex_syntax as syntax;
-extern crate syn;
 
 use std::cell::RefCell;
 use std::collections::{HashMap, HashSet};
@@ -1208,7 +1207,7 @@ impl<'a> Generator<'a> {
         let cname = cname.unwrap_or_else(|| name.to_string());
 
         if rust_ty.contains("extern fn") {
-            let c_ty = c_ty.replace("(*)", &format!("(* __test_static_{}(void))", name));
+            let c_ty = c_ty.replacen("(*)", &format!("(* __test_static_{}(void))", name), 1);
             t!(writeln!(self.c, r#"
             {ty} {{
                 return {cname};
@@ -1318,7 +1317,13 @@ impl<'a> Generator<'a> {
                     if args.len() == 0 {
                         args.push("void".to_string());
                     }
-                    format!("{}(*)({})", ret, args.join(", "))
+
+                    let s = if ret.contains("(*)") {
+                        ret.replace("(*)", &format!("(*(*)({}))", args.join(", ")))
+                    } else {
+                        format!("{}(*)({})", ret, args.join(", "))
+                    };
+                    s
                 }
             }
             ast::TyKind::Array(ref t, ref e) => {

ctest/testcrate/src/t1.c

@@ -21,6 +21,13 @@ uint8_t foo(uint8_t a, uint8_t b) { return a + b; }
 void bar(uint8_t a) { return; }
 void baz(void) { return; }
 
+uint32_t (*nested(uint8_t arg))(uint16_t) {
+  return NULL;
+}
+
+uint32_t (*nested2(uint8_t(*arg0)(uint8_t), uint16_t(*arg1)(uint16_t)))(uint16_t) {
+  return NULL;
+}
 
 uint8_t (*T1_static_mut_fn_ptr)(uint8_t, uint8_t) = foo;
 uint8_t (*const T1_static_const_fn_ptr_unsafe)(uint8_t, uint8_t) = foo;
@@ -29,3 +36,6 @@ void (*const T1_static_const_fn_ptr_unsafe3)(void) = baz;
 
 const uint8_t T1_static_right = 7;
 uint8_t (*T1_static_right2)(uint8_t, uint8_t) = foo;
+
+uint32_t (*(*T1_fn_ptr_s)(uint8_t))(uint16_t) = nested;
+uint32_t (*(*T1_fn_ptr_s2)(uint8_t(*arg0)(uint8_t), uint16_t(*arg1)(uint16_t)))(uint16_t) = nested2;

ctest/testcrate/src/t1.h

@@ -56,3 +56,13 @@ void (*const T1_static_const_fn_ptr_unsafe3)(void);
 
 const uint8_t T1_static_right;
 uint8_t (*T1_static_right2)(uint8_t, uint8_t);
+
+// T1_fn_ptr_nested: function pointer to a function, taking a uint8_t, and
+// returning a function pointer to a function taking a uint16_t and returning a
+// uint32_t
+uint32_t (*(*T1_fn_ptr_s)(uint8_t))(uint16_t);
+
+// T1_fn_ptr_nested: function pointer to a function, taking a function pointer
+// uint8_t -> uint8_t, and returning a function pointer to a function taking a
+// uint16_t and returning a uint32_t
+uint32_t (*(*T1_fn_ptr_s2)(uint8_t(*)(uint8_t), uint16_t(*)(uint16_t)))(uint16_t);

ctest/testcrate/src/t1.rs

@@ -84,4 +84,8 @@ extern "C" {
     pub static T1_static_wrong: u8;
     #[link_name = "T1_static_right2"]
     pub static mut T1_static_wrong2: extern "C" fn(u8, u8) -> u8;
+
+    pub static T1_fn_ptr_s: unsafe extern "C" fn(u8) -> extern fn(u16)->u32;
+    pub static T1_fn_ptr_s2: unsafe extern "C" fn(extern fn(u8)->u8,
+                                                  extern fn(u16)->u16) -> extern fn(u16)->u32;
 }