Improves argument name parsing in function pointers.

Previously, all function pointer types always had their arguments bound
as arg1, arg2, etc.  This change preserves the argument names, when they
are available.

parser.rs
- Uses the type cursor to visit children and gather argument names and
  types.

tests/func_ptr.rs
- Binds tests/headers/func_ptr.h and tests/headers/func_ptr_in_struct.h
  and ensures that argument names are correctly bound.

4 files changed, 29 insertions, 3 deletions

diff --git a/src/parser.rs b/src/parser.rs
index 5b06b0e9..e26ce4f5 100644
--- a/src/parser.rs
+++ b/src/parser.rs
@@ -167,9 +167,14 @@ fn conv_ptr_ty(ctx: &mut ClangParserCtx, ty: &cx::Type, cursor: &Cursor, layout:
             let ret_ty = ty.ret_type();
             let decl = ty.declaration();
             return if ret_ty.kind() != CXType_Invalid {
-                let args_lst = ty.arg_types().iter().map(|arg| {
-                    ("".to_string(), conv_ty(ctx, arg, cursor))
-                }).collect();
+                let mut args_lst = vec!();
+                cursor.visit(|c, _| {
+                    if c.kind() == CXCursor_ParmDecl {
+                        args_lst.push((c.spelling(), conv_ty(ctx, &c.cur_type(), c)));
+                    }
+                    CXChildVisit_Continue
+                });
+
                 let ret_ty = box conv_ty(ctx, &ret_ty, cursor);
                 let abi = get_abi(ty.call_conv());
 
diff --git a/tests/func_ptr.rs b/tests/func_ptr.rs
new file mode 100644
index 00000000..7851c4ff
--- /dev/null
+++ b/tests/func_ptr.rs
@@ -0,0 +1,17 @@
+extern crate bindgen;
+extern crate regex;
+extern crate syntax;
+
+mod util;
+
+#[test]
+fn test_func_ptr() {
+    let output = util::generate_unpretty_output("tests/headers/func_ptr.h");
+    assert_eq!(output, r##"extern "C" { pub static mut foo: ::std::option::Option<extern "C" fn(x: ::libc::c_int, y: ::libc::c_int) -> ::libc::c_int>; }"##);
+}
+
+#[test]
+fn test_func_ptr_in_struct() {
+    let output = util::generate_unpretty_output("tests/headers/func_ptr_in_struct.h");
+    assert_eq!(output, r##"#[repr(C)] #[deriving(Copy)] pub struct Struct_Foo { pub bar: ::std::option::Option<extern "C" fn(x: ::libc::c_int, y: ::libc::c_int) -> Enum_baz>, } extern "C" { }"##);
+}
diff --git a/tests/headers/func_ptr.h b/tests/headers/func_ptr.h
new file mode 100644
index 00000000..a4662f3d
--- /dev/null
+++ b/tests/headers/func_ptr.h
@@ -0,0 +1 @@
+int (*foo) (int x, int y);
diff --git a/tests/headers/func_ptr_in_struct.h b/tests/headers/func_ptr_in_struct.h
new file mode 100644
index 00000000..8e9bf60c
--- /dev/null
+++ b/tests/headers/func_ptr_in_struct.h
@@ -0,0 +1,3 @@
+struct Foo {
+    enum baz (*bar) (int x, int y);
+};