Merge pull request #35 from algernon/f/event-handler/keycode-chain-restart

A way to restart the event handler with a different code

src/Model01.cpp

@@ -107,12 +107,12 @@ void Model01::act_on_matrix_scan() {
 
             uint8_t keynum = (row*8)+(col);
 
-            handle_key_event(row, 7-col,
+            handle_key_event(Key_NoKey, row, 7-col,
                              bitRead(leftHandState.all, keynum),
                              bitRead(previousLeftHandState.all, keynum)
                             );
 
-            handle_key_event(row, (15- col),
+            handle_key_event(Key_NoKey, row, (15- col),
                              bitRead(rightHandState.all, keynum),
                              bitRead(previousRightHandState.all, keynum)
                             );

src/TestMode.cpp

@@ -61,7 +61,7 @@ void TestMode_::TestMatrix () {
 void TestMode_::setup() {
     eventHandlers[0] = handle_key_event_test;
 }
-bool handle_key_event_test(byte row, byte col, uint8_t currentState, uint8_t previousState) {
+bool handle_key_event_test(Key mappedKey, byte row, byte col, uint8_t currentState, uint8_t previousState) {
     Serial.write(row);
 }
 

src/TestMode.h

@@ -15,4 +15,4 @@ class TestMode_ {
 
 extern TestMode_ TestMode;
 
-bool handle_key_event_test(byte row, byte col, uint8_t currentState, uint8_t previousState);
+bool handle_key_event_test(Key mappedKey, byte row, byte col, uint8_t currentState, uint8_t previousState);

src/hooks.h

@@ -1,10 +1,11 @@
 #pragma once
 
 #include <Arduino.h>
+#include "key_defs.h"
 
 #define HOOK_MAX 64
 
-typedef bool (*custom_handler_t)(byte row, byte col, uint8_t currentState, uint8_t previousState);
+typedef bool (*custom_handler_t)(Key mappedKey, byte row, byte col, uint8_t currentState, uint8_t previousState);
 extern custom_handler_t eventHandlers[HOOK_MAX];
 
 void event_handler_hook_add (custom_handler_t hook);

src/key_events.cpp

@@ -49,19 +49,21 @@ Key lookup_key(byte keymap, byte row, byte col) {
     return mappedKey;
 }
 
-void handle_key_event(byte row, byte col, uint8_t currentState, uint8_t previousState) {
+void handle_key_event(Key mappedKey, byte row, byte col, uint8_t currentState, uint8_t previousState) {
     for (byte i = 0; eventHandlers[i] != NULL && i < HOOK_MAX; i++) {
         custom_handler_t handler = eventHandlers[i];
-        if ((*handler)(row, col, currentState, previousState))
+        if ((*handler)(mappedKey, row, col, currentState, previousState))
             return;
     }
 }
 
-bool handle_key_event_default(byte row, byte col, uint8_t currentState, uint8_t previousState) {
+bool handle_key_event_default(Key mappedKey, byte row, byte col, uint8_t currentState, uint8_t previousState) {
     //for every newly pressed button, figure out what logical key it is and send a key down event
     // for every newly released button, figure out what logical key it is and send a key up event
 
-    Key mappedKey = lookup_key(temporary_keymap, row, col);
+    if (mappedKey.raw == Key_NoKey.raw) {
+      mappedKey = lookup_key(temporary_keymap, row, col);
+    }
     Key baseKey   = lookup_key(primary_keymap, row, col);
 
     if ((baseKey.flags & SWITCH_TO_KEYMAP

src/key_events.h

@@ -15,11 +15,39 @@ extern uint8_t temporary_keymap;
 extern const Key keymaps[][ROWS][COLS];
 
 // sending events to the computer
+/* The event handling starts with the Scanner calling handle_key_event() for
+ * every key in the matrix, and it is the task of this method to figure out what
+ * to do, it is the main entry point.
+ *
+ * This function will iterate through an array of handler functions, and stop as
+ * soon as one of them signals that the event has been handled. To make it
+ * possible to inject synthetic events, one can call handle_key_event from
+ * within a custom handler (making the event handling recursive), with a
+ * different keycode.
+ *
+ * This is useful for example for one-shot modifiers, where we would like to
+ * temporarily disable the one-shot functionality, and have them work as a
+ * normal modifier instead. In this case, the keymap would contain a key with
+ * OSM flags set, and the event handler would remove the OSM flags, and let the
+ * system handle the key as it would have, without the OSM flags. So we simply
+ * clear the flags, and call handle_key_event again, with the modifier keycode
+ * as the first argument. This way, we could insert an event, and have the whole
+ * chain re-process it, instead of registering the keycode ourselves with HID
+ * ourselves. Injecting allows any and all custom handlers to have a chance,
+ * too.
+ *
+ * For this reason, the handle_key_event receives four arguments: the mapped key
+ * (or Key_NoKey if we do not want to override what is in the keymap), the row
+ * and column of the key, so we can look up the code for it, and the current and
+ * previous state of the key, so we can determine what the event is.
+ */
+void handle_key_event(Key mappedKey, byte row, byte col, uint8_t currentState, uint8_t previousState);
+
+// Internal use
 void handle_synthetic_key_event( Key mappedKey, uint8_t currentState, uint8_t previousState);
-void handle_key_event(byte row, byte col, uint8_t currentState, uint8_t previousState);
 void press_key(Key mappedKey);
 void handle_keymap_key_event(Key keymapEntry, uint8_t currentState, uint8_t previousState);
 void handle_mouse_key_event(Key mappedKey, uint8_t currentState, uint8_t previousState);
-bool handle_key_event_default(byte row, byte col, uint8_t currentState, uint8_t previousState);
+bool handle_key_event_default(Key mappedKey, byte row, byte col, uint8_t currentState, uint8_t previousState);
 
 Key lookup_key(byte keymap, byte row, byte col);