process_key_lock.c (6605B)
1 /* Copyright 2017 Fredric Silberberg 2 * 3 * This program is free software: you can redistribute it and/or modify 4 * it under the terms of the GNU General Public License as published by 5 * the Free Software Foundation, either version 2 of the License, or 6 * (at your option) any later version. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 * GNU General Public License for more details. 12 * 13 * You should have received a copy of the GNU General Public License 14 * along with this program. If not, see <http://www.gnu.org/licenses/>. 15 */ 16 17 #include <inttypes.h> 18 #include <stdint.h> 19 #include "process_key_lock.h" 20 21 #define BV_64(shift) (((uint64_t)1) << (shift)) 22 #define GET_KEY_ARRAY(code) (((code) < 0x40) ? key_state[0] : ((code) < 0x80) ? key_state[1] : ((code) < 0xC0) ? key_state[2] : key_state[3]) 23 #define GET_CODE_INDEX(code) (((code) < 0x40) ? (code) : ((code) < 0x80) ? (code) - 0x40 : ((code) < 0xC0) ? (code) - 0x80 : (code) - 0xC0) 24 #define KEY_STATE(code) (GET_KEY_ARRAY(code) & BV_64(GET_CODE_INDEX(code))) == BV_64(GET_CODE_INDEX(code)) 25 #define SET_KEY_ARRAY_STATE(code, val) \ 26 do { \ 27 switch (code) { \ 28 case 0x00 ... 0x3F: \ 29 key_state[0] = (val); \ 30 break; \ 31 case 0x40 ... 0x7F: \ 32 key_state[1] = (val); \ 33 break; \ 34 case 0x80 ... 0xBF: \ 35 key_state[2] = (val); \ 36 break; \ 37 case 0xC0 ... 0xFF: \ 38 key_state[3] = (val); \ 39 break; \ 40 } \ 41 } while (0) 42 #define SET_KEY_STATE(code) SET_KEY_ARRAY_STATE(code, (GET_KEY_ARRAY(code) | BV_64(GET_CODE_INDEX(code)))) 43 #define UNSET_KEY_STATE(code) SET_KEY_ARRAY_STATE(code, (GET_KEY_ARRAY(code)) & ~(BV_64(GET_CODE_INDEX(code)))) 44 #define IS_STANDARD_KEYCODE(code) ((code) <= 0xFF) 45 46 // Locked key state. This is an array of 256 bits, one for each of the standard keys supported qmk. 47 uint64_t key_state[4] = {0x0, 0x0, 0x0, 0x0}; 48 bool watching = false; 49 50 // Translate any OSM keycodes back to their unmasked versions. 51 static inline uint16_t translate_keycode(uint16_t keycode) { 52 if (keycode > QK_ONE_SHOT_MOD && keycode <= QK_ONE_SHOT_MOD_MAX) { 53 return keycode ^ QK_ONE_SHOT_MOD; 54 } else { 55 return keycode; 56 } 57 } 58 59 void cancel_key_lock(void) { 60 watching = false; 61 UNSET_KEY_STATE(0x0); 62 } 63 64 bool process_key_lock(uint16_t *keycode, keyrecord_t *record) { 65 // We start by categorizing the keypress event. In the event of a down 66 // event, there are several possibilities: 67 // 1. The key is not being locked, and we are not watching for new keys. 68 // In this case, we bail immediately. This is the common case for down events. 69 // 2. The key was locked, and we need to unlock it. In this case, we will 70 // reset the state in our map and return false. When the user releases the 71 // key, the up event will no longer be masked and the OS will observe the 72 // released key. 73 // 3. QK_LOCK was just pressed. In this case, we set up the state machine 74 // to watch for the next key down event, and finish processing 75 // 4. The keycode is below 0xFF, and we are watching for new keys. In this case, 76 // we will send the key down event to the os, and set the key_state for that 77 // key to mask the up event. 78 // 5. The keycode is above 0xFF, and we're wathing for new keys. In this case, 79 // the user pressed a key that we cannot "lock", as it's a series of keys, 80 // or a macro invocation, or a layer transition, or a custom-defined key, or 81 // or some other arbitrary code. In this case, we bail immediately, reset 82 // our watch state, and return true. 83 // 84 // In the event of an up event, there are these possibilities: 85 // 1. The key is not being locked. In this case, we return true and bail 86 // immediately. This is the common case. 87 // 2. The key is being locked. In this case, we will mask the up event 88 // by returning false, so the OS never sees that the key was released 89 // until the user pressed the key again. 90 91 // We translate any OSM keycodes back to their original keycodes, so that if the key being 92 // one-shot modded is a standard keycode, we can handle it. This is the only set of special 93 // keys that we handle 94 uint16_t translated_keycode = translate_keycode(*keycode); 95 96 if (record->event.pressed) { 97 // Non-standard keycode, reset and return 98 if (!(IS_STANDARD_KEYCODE(translated_keycode) || translated_keycode == QK_LOCK)) { 99 watching = false; 100 return true; 101 } 102 103 // If we're already watching, turn off the watch. 104 if (translated_keycode == QK_LOCK) { 105 watching = !watching; 106 return false; 107 } 108 109 if (IS_STANDARD_KEYCODE(translated_keycode)) { 110 // We check watching first. This is so that in the following scenario, we continue to 111 // hold the key: QK_LOCK, KC_F, QK_LOCK, KC_F 112 // If we checked in reverse order, we'd end up holding the key pressed after the second 113 // KC_F press is registered, when the user likely meant to hold F 114 if (watching) { 115 watching = false; 116 SET_KEY_STATE(translated_keycode); 117 // We need to set the keycode passed in to be the translated keycode, in case we 118 // translated a OSM back to the original keycode. 119 *keycode = translated_keycode; 120 // Let the standard keymap send the keycode down event. The up event will be masked. 121 return true; 122 } 123 124 if (KEY_STATE(translated_keycode)) { 125 UNSET_KEY_STATE(translated_keycode); 126 // The key is already held, stop this process. The up event will be sent when the user 127 // releases the key. 128 return false; 129 } 130 } 131 132 // Either the key isn't a standard key, or we need to send the down event. Continue standard 133 // processing 134 return true; 135 } else { 136 // Stop processing if it's a standard key and we're masking up. 137 return !(IS_STANDARD_KEYCODE(translated_keycode) && KEY_STATE(translated_keycode)); 138 } 139 }