Rework the way that argument types and names are found from function …

…signatures.

This fixes the issue seen in #1500 where function
pointers as a return type have their parameters incorrectly generated.

This also fixes a broken test case, objc_property_fnptr, as its types
are now generated correctly.

src/clang.rs

@@ -550,33 +550,27 @@ impl Cursor {
 
     /// Given that this cursor's referent is a function, return cursors to its
     /// parameters.
+    ///
+    /// Returns None if the cursor's referent is not a function/method call or
+    /// declaration.
     pub fn args(&self) -> Option<Vec<Cursor>> {
-        // XXX: We might want to use and keep num_args
         // match self.kind() {
         // CXCursor_FunctionDecl |
         // CXCursor_CXXMethod => {
-        unsafe {
-            let w = clang_Cursor_getNumArguments(self.x);
-            if w == -1 {
-                None
-            } else {
-                let num = w as u32;
-
-                let mut args = vec![];
-                for i in 0..num {
-                    args.push(Cursor {
-                        x: clang_Cursor_getArgument(self.x, i as c_uint),
-                    });
+        self.num_args().ok().map(|num| {
+            (0..num).map(|i| {
+                Cursor {
+                    x: unsafe { clang_Cursor_getArgument(self.x, i as c_uint) },
                 }
-                Some(args)
-            }
-        }
+            })
+            .collect()
+        })
     }
 
     /// Given that this cursor's referent is a function/method call or
     /// declaration, return the number of arguments it takes.
     ///
-    /// Returns -1 if the cursor's referent is not a function/method call or
+    /// Returns Err if the cursor's referent is not a function/method call or
     /// declaration.
     pub fn num_args(&self) -> Result<u32, ()> {
         unsafe {
@@ -1017,6 +1011,31 @@ impl Type {
         })
     }
 
+    /// Given that this type is a function prototype, return the types of its parameters.
+    ///
+    /// Returns None if the type is not a function prototype.
+    pub fn args(&self) -> Option<Vec<Type>> {
+        self.num_args().ok().map(|num| {
+            (0..num).map(|i| {
+                Type {
+                    x: unsafe { clang_getArgType(self.x, i as c_uint) },
+                }
+            })
+            .collect()
+        })
+    }
+
+    /// Given that this type is a function prototype, return the number of arguments it takes.
+    ///
+    /// Returns Err if the type is not a function prototype.
+    pub fn num_args(&self) -> Result<u32, ()> {
+        unsafe {
+            let w = clang_getNumArgTypes(self.x);
+            if w == -1 { Err(()) } else { Ok(w as u32) }
+        }
+    }
+
+
     /// Given that this type is a pointer type, return the type that it points
     /// to.
     pub fn pointee_type(&self) -> Option<Type> {

src/ir/function.rs

@@ -309,6 +309,31 @@ pub fn cursor_mangling(
     Some(mangling)
 }
 
+fn args_from_ty_and_cursor(
+    ty: &clang::Type,
+    cursor: &clang::Cursor,
+    ctx: &mut BindgenContext,
+) -> Vec<(Option<String>, TypeId)> {
+    match (cursor.args(), ty.args()) {
+        (Some(cursor_args), Some(ty_args)) => {
+            ty_args.iter().enumerate().map(|(i, ty)| {
+                let name = cursor_args.get(i)
+                    .map(|c| c.spelling())
+                    .and_then(|name| if name.is_empty() { None } else { Some(name) });
+                (name, Item::from_ty_or_ref(*ty, *cursor, None, ctx))
+            }).collect()
+        }
+        (Some(cursor_args), None) => {
+            cursor_args.iter().map(|cursor| {
+                let name = cursor.spelling();
+                let name = if name.is_empty() { None } else { Some(name) };
+                (name, Item::from_ty_or_ref(cursor.cur_type(), *cursor, None, ctx))
+            }).collect()
+        }
+        _ => panic!()
+    }
+}
+
 impl FunctionSig {
     /// Construct a new function signature.
     pub fn new(
@@ -363,28 +388,14 @@ impl FunctionSig {
             ty.declaration()
         };
 
-        let mut args: Vec<_> = match kind {
+        let mut args = match kind {
             CXCursor_FunctionDecl |
             CXCursor_Constructor |
             CXCursor_CXXMethod |
             CXCursor_ObjCInstanceMethodDecl |
             CXCursor_ObjCClassMethodDecl => {
-                // For CXCursor_FunctionDecl, cursor.args() is the reliable way
-                // to get parameter names and types.
-                cursor
-                    .args()
-                    .unwrap()
-                    .iter()
-                    .map(|arg| {
-                        let arg_ty = arg.cur_type();
-                        let name = arg.spelling();
-                        let name =
-                            if name.is_empty() { None } else { Some(name) };
-                        let ty = Item::from_ty_or_ref(arg_ty, *arg, None, ctx);
-                        (name, ty)
-                    })
-                    .collect()
-            }
+                args_from_ty_and_cursor(&ty, &cursor, ctx)
+            },
             _ => {
                 // For non-CXCursor_FunctionDecl, visiting the cursor's children
                 // is the only reliable way to get parameter names.

src/ir/item.rs

@@ -1449,6 +1449,7 @@ impl ClangItemParser for Item {
         let is_const = ty.is_const();
         let kind = TypeKind::UnresolvedTypeRef(ty, location, parent_id);
         let current_module = ctx.current_module();
+
         ctx.add_item(
             Item::new(
                 potential_id,

tests/expectations/tests/block_return_type.rs

@@ -0,0 +1,16 @@
+/* automatically generated by rust-bindgen */
+
+#![allow(
+    dead_code,
+    non_snake_case,
+    non_camel_case_types,
+    non_upper_case_globals
+)]
+#![cfg(target_os = "macos")]
+
+extern crate block;
+extern "C" {
+    pub fn func() -> _bindgen_ty_id_4;
+}
+pub type _bindgen_ty_id_4 =
+    *const ::block::Block<(::std::os::raw::c_int, ::std::os::raw::c_int), ::std::os::raw::c_int>;

tests/expectations/tests/func_ptr_return_type.rs

@@ -0,0 +1,18 @@
+/* automatically generated by rust-bindgen */
+
+#![allow(
+    dead_code,
+    non_snake_case,
+    non_camel_case_types,
+    non_upper_case_globals
+)]
+
+extern "C" {
+    pub fn func() -> ::std::option::Option<
+        unsafe extern "C" fn(
+            arg1: ::std::os::raw::c_int,
+            arg2: ::std::os::raw::c_int,
+        ) -> ::std::os::raw::c_int,
+    >;
+}
+

tests/expectations/tests/objc_property_fnptr.rs

@@ -1,22 +1,42 @@
 /* automatically generated by rust-bindgen */
 
-
-#![allow(dead_code, non_snake_case, non_camel_case_types, non_upper_case_globals)]
+#![allow(
+    dead_code,
+    non_snake_case,
+    non_camel_case_types,
+    non_upper_case_globals
+)]
 #![cfg(target_os = "macos")]
 
 #[macro_use]
 extern crate objc;
 #[allow(non_camel_case_types)]
 pub type id = *mut objc::runtime::Object;
 pub trait Foo {
-    unsafe fn func(self) -> ::std::option::Option<unsafe extern "C" fn() -> ::std::os::raw::c_int>;
+    unsafe fn func(
+        self,
+    ) -> ::std::option::Option<
+        unsafe extern "C" fn(
+            arg1: ::std::os::raw::c_char,
+            arg2: ::std::os::raw::c_short,
+            arg3: f32,
+        ) -> ::std::os::raw::c_int,
+    >;
     unsafe fn setFunc_(
         self,
         func: ::std::option::Option<unsafe extern "C" fn() -> ::std::os::raw::c_int>,
     );
 }
 impl Foo for id {
-    unsafe fn func(self) -> ::std::option::Option<unsafe extern "C" fn() -> ::std::os::raw::c_int> {
+    unsafe fn func(
+        self,
+    ) -> ::std::option::Option<
+        unsafe extern "C" fn(
+            arg1: ::std::os::raw::c_char,
+            arg2: ::std::os::raw::c_short,
+            arg3: f32,
+        ) -> ::std::os::raw::c_int,
+    > {
         msg_send!(self, func)
     }
     unsafe fn setFunc_(

tests/headers/block_return_type.h

@@ -0,0 +1,4 @@
+// bindgen-flags: --generate-block --block-extern-crate -- -fblocks
+// bindgen-osx-only
+
+int (^func(void))(int, int);

tests/headers/func_ptr_return_type.h

@@ -0,0 +1 @@
+int (*func(void))(int, int);

tests/headers/objc_property_fnptr.h

@@ -2,7 +2,5 @@
 // bindgen-osx-only
 
 @interface Foo
-// FIXME: We are not generating valid code for this
-//        but at least we should not die
 @property int (*func)(char, short, float);
 @end