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`.

2 files changed, 22 insertions, 0 deletions

diff --git a/dome_key_map.h b/dome_key_map.h
index 7bd77ca..633e9b3 100644
--- a/dome_key_map.h
+++ b/dome_key_map.h
@@ -23,6 +23,8 @@ typedef enum {
   MapKind_Command,
 } MapKind;
 
+typedef struct State State;
+
 typedef struct {
   const HeadphoneButton *buttons;
   size_t length;
@@ -35,3 +37,7 @@ typedef struct {
 } CKeyActionResult;
 
 const CKeyActionResult *c_run_key_action(Trigger trigger, const Trigger *mode);
+
+void state_free(State *ptr);
+
+State *state_new(void);
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,