Add One Shot Key callbacks (#4697)

* Added callbacks to one shot modifier changes

* Altered signature of callback functions

* Reordered the callback methods, shortened brief documentation

* Added One Shot Modifier callback documentation

* First attempt at unit tests

* Revert "First attempt at unit tests"

This reverts commit 5ec21a782202c0d74cf21cb852bd319f0c8b4842.

* Simplified oneshot function implementations

* Made clear_oneshot_locked_mods to be conform action_util.h, adhering to the (void) signature

* Made used datatypes for oneshot mods consistently unsigned integers

* Corrected callback to call clear callback when clear_oneshot_locked_mods is invoked

* Simplified oneshot equals statements

* Corrected return type and signature of get and set oneshot locked mods

* Consolidated one shot callbacks, added initial layer callback version

* Fixed non-updating one shot layer variable after timeout or other clear, added code comments

* Added better one shot key docs

1 files changed, 9 insertions, 2 deletions

diff --git a/tmk_core/common/action_util.h b/tmk_core/common/action_util.h
index 345893151..d03f5682a 100644
--- a/tmk_core/common/action_util.h
+++ b/tmk_core/common/action_util.h
@@ -71,8 +71,8 @@ void oneshot_enable(void);
 void oneshot_disable(void);
 bool has_oneshot_mods_timed_out(void);
 
-int8_t get_oneshot_locked_mods(void);
-void set_oneshot_locked_mods(int8_t mods);
+uint8_t get_oneshot_locked_mods(void);
+void set_oneshot_locked_mods(uint8_t mods);
 void clear_oneshot_locked_mods(void);
 
 typedef enum {
@@ -89,6 +89,13 @@ bool is_oneshot_layer_active(void);
 uint8_t get_oneshot_layer_state(void);
 bool has_oneshot_layer_timed_out(void);
 
+void oneshot_locked_mods_changed_user(uint8_t mods);
+void oneshot_locked_mods_changed_kb(uint8_t mods);
+void oneshot_mods_changed_user(uint8_t mods);
+void oneshot_mods_changed_kb(uint8_t mods);
+void oneshot_layer_changed_user(uint8_t layer);
+void oneshot_layer_changed_kb(uint8_t layer);
+
 /* inspect */
 uint8_t has_anymod(void);