tap-dance: Support user_data for the callbacks

Refactored the code a little, so all callbacks now receive a `user_data`
pointer, which can be anything. As an example, the key pairs from
`ACTION_TAP_DANCE_DOUBLE` now use this, and custom, built-in functions.

This makes it easier to extend the tap dance functionality, and also
simplifies the code a little.

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>

2 files changed, 38 insertions, 64 deletions

diff --git a/quantum/process_keycode/process_tap_dance.c b/quantum/process_keycode/process_tap_dance.c
index 097440405..94b6af130 100644
--- a/quantum/process_keycode/process_tap_dance.c
+++ b/quantum/process_keycode/process_tap_dance.c
@@ -2,28 +2,32 @@
 
 static qk_tap_dance_state_t qk_tap_dance_state;
 
-static void _process_tap_dance_action_pair (qk_tap_dance_state_t *state,
-                                            uint16_t kc1, uint16_t kc2) {
-  uint16_t kc;
+void qk_tap_dance_pair_finished (qk_tap_dance_state_t *state, void *user_data) {
+  qk_tap_dance_pair_t *pair = (qk_tap_dance_pair_t *)user_data;
 
-  if (state->count == 0)
-    return;
-
-  kc = (state->count == 1) ? kc1 : kc2;
+  if (state->count == 1) {
+    register_code (pair->kc1);
+  } else if (state->count == 2) {
+    register_code (pair->kc2);
+  }
+}
 
-  register_code (kc);
-  unregister_code (kc);
+void qk_tap_dance_pair_reset (qk_tap_dance_state_t *state, void *user_data) {
+  qk_tap_dance_pair_t *pair = (qk_tap_dance_pair_t *)user_data;
 
-  if (state->count >= 2) {
-    reset_tap_dance (state);
+  if (state->count == 1) {
+    unregister_code (pair->kc1);
+  } else if (state->count == 2) {
+    unregister_code (pair->kc2);
   }
 }
 
 static void _process_tap_dance_action_fn (qk_tap_dance_state_t *state,
+                                          void *user_data,
                                           qk_tap_dance_user_fn_t fn)
 {
   if (fn) {
-    fn(state);
+    fn(state, user_data);
   }
 }
 
@@ -34,14 +38,7 @@ void process_tap_dance_action_on_each_tap (uint16_t keycode)
 
   action = tap_dance_actions[idx];
 
-  switch (action.type) {
-  case QK_TAP_DANCE_TYPE_FN:
-    _process_tap_dance_action_fn (&qk_tap_dance_state, action.fn.on_each_tap);
-    break;
-
-  default:
-    break;
-  }
+  _process_tap_dance_action_fn (&qk_tap_dance_state, action.user_data, action.fn.on_each_tap);
 }
 
 void process_tap_dance_action_on_dance_finished (uint16_t keycode)
@@ -51,18 +48,7 @@ void process_tap_dance_action_on_dance_finished (uint16_t keycode)
 
   action = tap_dance_actions[idx];
 
-  switch (action.type) {
-  case QK_TAP_DANCE_TYPE_PAIR:
-    _process_tap_dance_action_pair (&qk_tap_dance_state,
-                                    action.pair.kc1, action.pair.kc2);
-    break;
-  case QK_TAP_DANCE_TYPE_FN:
-    _process_tap_dance_action_fn (&qk_tap_dance_state, action.fn.on_dance_finished);
-    break;
-
-  default:
-    break;
-  }
+  _process_tap_dance_action_fn (&qk_tap_dance_state, action.user_data, action.fn.on_dance_finished);
 }
 
 bool process_tap_dance(uint16_t keycode, keyrecord_t *record) {
@@ -118,15 +104,8 @@ void reset_tap_dance (qk_tap_dance_state_t *state) {
     return;
 
   action = tap_dance_actions[idx];
-  switch (action.type) {
-  case QK_TAP_DANCE_TYPE_FN:
-    if (action.fn.on_reset) {
-      action.fn.on_reset(state);
-    }
-    break;
-
-  default:
-    break;
+  if (action.fn.on_reset) {
+    action.fn.on_reset(state, action.user_data);
   }
 
   state->keycode = 0;
diff --git a/quantum/process_keycode/process_tap_dance.h b/quantum/process_keycode/process_tap_dance.h
index d457db9b3..e2c74efe9 100644
--- a/quantum/process_keycode/process_tap_dance.h
+++ b/quantum/process_keycode/process_tap_dance.h
@@ -17,42 +17,34 @@ typedef struct
 
 #define TD(n) (QK_TAP_DANCE + n)
 
-typedef enum
-{
-  QK_TAP_DANCE_TYPE_PAIR,
-  QK_TAP_DANCE_TYPE_FN,
-} qk_tap_dance_type_t;
-
-typedef void (*qk_tap_dance_user_fn_t) (qk_tap_dance_state_t *state);
+typedef void (*qk_tap_dance_user_fn_t) (qk_tap_dance_state_t *state, void *user_data);
 
 typedef struct
 {
-  qk_tap_dance_type_t type;
-  union {
-    struct {
-      uint16_t kc1;
-      uint16_t kc2;
-    } pair;
-    struct {
-      qk_tap_dance_user_fn_t on_each_tap;
-      qk_tap_dance_user_fn_t on_dance_finished;
-      qk_tap_dance_user_fn_t on_reset;
-    } fn;
-  };
+  struct {
+    qk_tap_dance_user_fn_t on_each_tap;
+    qk_tap_dance_user_fn_t on_dance_finished;
+    qk_tap_dance_user_fn_t on_reset;
+  } fn;
+  void *user_data;
 } qk_tap_dance_action_t;
 
+typedef struct
+{
+  uint16_t kc1;
+  uint16_t kc2;
+} qk_tap_dance_pair_t;
+
 #define ACTION_TAP_DANCE_DOUBLE(kc1, kc2) { \
-    .type = QK_TAP_DANCE_TYPE_PAIR, \
-    .pair = { kc1, kc2 }            \
+    .fn = { NULL, qk_tap_dance_pair_finished, qk_tap_dance_pair_reset }, \
+    .user_data = (void *)&((qk_tap_dance_pair_t) { kc1, kc2 })  \
   }
 
 #define ACTION_TAP_DANCE_FN(user_fn) {  \
-    .type = QK_TAP_DANCE_TYPE_FN, \
     .fn = { NULL, user_fn, NULL } \
   }
 
 #define ACTION_TAP_DANCE_FN_ADVANCED(user_fn_on_each_tap, user_fn_on_dance_finished, user_fn_on_reset) { \
-    .type = QK_TAP_DANCE_TYPE_FN,                                              \
     .fn = { user_fn_on_each_tap, user_fn_on_dance_finished, user_fn_on_reset } \
   }
 
@@ -64,6 +56,9 @@ bool process_tap_dance(uint16_t keycode, keyrecord_t *record);
 void matrix_scan_tap_dance (void);
 void reset_tap_dance (qk_tap_dance_state_t *state);
 
+void qk_tap_dance_pair_finished (qk_tap_dance_state_t *state, void *user_data);
+void qk_tap_dance_pair_reset (qk_tap_dance_state_t *state, void *user_data);
+
 #else
 
 #define TD(n) KC_NO