Add a `State` struct

The plan is to use this as an opaque pointer to be passed between the
Objective-C code and Rust code. It will contain the current mode (if in
a mode) and the parsed `MapGroup` definitions.

For now just some code inspired by the Rust FFI Omnibus
(http://jakegoulding.com/rust-ffi-omnibus/objects/) to create and free a
`State`.

1 files changed, 16 insertions, 0 deletions

diff --git a/src/cocoa_bridge.rs b/src/cocoa_bridge.rs
index e860d24..a864e13 100644
--- a/src/cocoa_bridge.rs
+++ b/src/cocoa_bridge.rs
@@ -92,6 +92,22 @@ pub struct CKeyActionResult {
     pub in_mode: *const Trigger,
 }
 
+#[derive(Default)]
+pub struct State {
+    in_mode: Option<Vec<HeadphoneButton>>,
+}
+
+#[no_mangle]
+pub extern "C" fn state_new() -> *mut State {
+    Box::into_raw(Box::new(State::default()))
+}
+
+#[no_mangle]
+pub extern "C" fn state_free(ptr: *mut State) {
+    if ptr.is_null() { return }
+    unsafe { Box::from_raw(ptr); }
+}
+
 #[no_mangle]
 pub extern "C" fn c_run_key_action(
     trigger: Trigger,