Auto merge of #207 - Natim:130-cursor-args-return-vector, r=emilio

clang::Cursor::args should return an Option<Vec<Cursor>>

Attempt to fix #130

Author: bors-servo

libbindgen/src/clang.rs

@@ -420,16 +420,26 @@ impl Cursor {
 
     /// Given that this cursor's referent is a function, return cursors to its
     /// parameters.
-    pub fn args(&self) -> Vec<Cursor> {
+    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 num = self.num_args().expect("expected value, got none") as u32;
-            let mut args = vec![];
-            for i in 0..num {
-                args.push(Cursor {
-                    x: clang_Cursor_getArgument(self.x, i as c_uint),
-                });
+            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),
+                    });
+                }
+                Some(args)
             }
-            args
         }
     }
 

libbindgen/src/ir/function.rs

@@ -150,7 +150,7 @@ impl FunctionSig {
             CXCursor_CXXMethod => {
                 // For CXCursor_FunctionDecl, cursor.args() is the reliable way
                 // to get parameter names and types.
-                cursor.args()
+                cursor.args().expect("It cannot be None because we are in a method/function")
                     .iter()
                     .map(|arg| {
                         let arg_ty = arg.cur_type();

libbindgen/tests/expectations/tests/variadic_template_function.rs

@@ -0,0 +1,12 @@
+/* automatically generated by rust-bindgen */
+
+
+#![allow(non_snake_case)]
+
+
+#[repr(C)]
+#[derive(Debug, Copy, Clone)]
+pub struct VariadicFunctionObject<T> {
+    pub _address: u8,
+    pub _phantom_0: ::std::marker::PhantomData<T>,
+}

libbindgen/tests/headers/variadic_template_function.hpp

@@ -0,0 +1,6 @@
+
+template <typename T>
+class VariadicFunctionObject {
+public:
+	int add_em_up(T count,...);
+};