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-rw-r--r--README.md21
-rw-r--r--tmk_core/common/action.c18
-rw-r--r--tmk_core/common/action.h4
-rw-r--r--tmk_core/common/action_layer.c77
-rw-r--r--tmk_core/common/action_layer.h11
5 files changed, 124 insertions, 7 deletions
diff --git a/README.md b/README.md
index 9857330679..ab7373023a 100644
--- a/README.md
+++ b/README.md
@@ -98,6 +98,27 @@ We've added shortcuts to make common modifier/tap (mod-tap) mappings more compac
`DF(layer)` - sets default layer to *layer*. The default layer is the one at the "bottom" of the layer stack - the ultimate fallback layer. This currently does not persist over power loss. When you plug the keyboard back in, layer 0 will always be the default. It is theoretically possible to work around that, but that's not what `DF` does.
+### Prevent stuck modifiers
+
+Consider the following scenario:
+
+1. Layer 0 has a key defined as Shift.
+2. The same key is defined on layer 1 as the letter A.
+3. User presses Shift.
+4. User switches to layer 1 for whatever reason.
+5. User releases Shift, or rather the letter A.
+6. User switches back to layer 0.
+
+Shift was actually never released and is still considered pressed.
+
+If such situation bothers you add this to your `config.h`:
+
+ #define PREVENT_STUCK_MODIFIERS
+
+This option uses 5 bytes of memory per every 8 keys on the keyboard
+rounded up (5 bits per key). For example on Planck (48 keys) it uses
+(48/8)\*5 = 30 bytes.
+
### Remember: These are just aliases
These functions work the same way that their `ACTION_*` functions do - they're just quick aliases. To dig into all of the tmk ACTION_* functions, please see the [TMK documentation](https://github.com/jackhumbert/qmk_firmware/blob/master/tmk_core/doc/keymap.md#2-action).
diff --git a/tmk_core/common/action.c b/tmk_core/common/action.c
index 9010896343..f9e6c17dc3 100644
--- a/tmk_core/common/action.c
+++ b/tmk_core/common/action.c
@@ -53,6 +53,22 @@ void action_exec(keyevent_t event)
#endif
}
+#if !defined(NO_ACTION_LAYER) && defined(PREVENT_STUCK_MODIFIERS)
+bool disable_action_cache = false;
+
+void process_action_nocache(keyrecord_t *record)
+{
+ disable_action_cache = true;
+ process_action(record);
+ disable_action_cache = false;
+}
+#else
+void process_action_nocache(keyrecord_t *record)
+{
+ process_action(record);
+}
+#endif
+
__attribute__ ((weak))
void process_action_kb(keyrecord_t *record) {}
@@ -67,7 +83,7 @@ void process_action(keyrecord_t *record)
process_action_kb(record);
- action_t action = layer_switch_get_action(event.key);
+ action_t action = store_or_get_action(event.pressed, event.key);
dprint("ACTION: "); debug_action(action);
#ifndef NO_ACTION_LAYER
dprint(" layer_state: "); layer_debug();
diff --git a/tmk_core/common/action.h b/tmk_core/common/action.h
index 9f528af4b9..44ec3047ba 100644
--- a/tmk_core/common/action.h
+++ b/tmk_core/common/action.h
@@ -62,6 +62,10 @@ void action_function(keyrecord_t *record, uint8_t id, uint8_t opt);
void process_action_kb(keyrecord_t *record);
/* Utilities for actions. */
+#if !defined(NO_ACTION_LAYER) && defined(PREVENT_STUCK_MODIFIERS)
+extern bool disable_action_cache;
+#endif
+void process_action_nocache(keyrecord_t *record);
void process_action(keyrecord_t *record);
void register_code(uint8_t code);
void unregister_code(uint8_t code);
diff --git a/tmk_core/common/action_layer.c b/tmk_core/common/action_layer.c
index c535615f44..fc721a7323 100644
--- a/tmk_core/common/action_layer.c
+++ b/tmk_core/common/action_layer.c
@@ -110,9 +110,71 @@ void layer_debug(void)
}
#endif
+#if !defined(NO_ACTION_LAYER) && defined(PREVENT_STUCK_MODIFIERS)
+uint8_t source_layers_cache[MAX_LAYER_BITS][(MATRIX_ROWS * MATRIX_COLS + 7) / 8] = {0};
+void update_source_layers_cache(keypos_t key, uint8_t layer)
+{
+ const uint8_t key_number = key.col + (key.row * MATRIX_COLS);
+ const uint8_t storage_row = key_number / 8;
+ const uint8_t storage_bit = key_number % 8;
-action_t layer_switch_get_action(keypos_t key)
+ for (uint8_t bit_number = 0; bit_number < MAX_LAYER_BITS; bit_number++) {
+ source_layers_cache[bit_number][storage_row] ^=
+ (-((layer & (1U << bit_number)) != 0)
+ ^ source_layers_cache[bit_number][storage_row])
+ & (1U << storage_bit);
+ }
+}
+
+uint8_t read_source_layers_cache(keypos_t key)
+{
+ const uint8_t key_number = key.col + (key.row * MATRIX_COLS);
+ const uint8_t storage_row = key_number / 8;
+ const uint8_t storage_bit = key_number % 8;
+ uint8_t layer = 0;
+
+ for (uint8_t bit_number = 0; bit_number < MAX_LAYER_BITS; bit_number++) {
+ layer |=
+ ((source_layers_cache[bit_number][storage_row]
+ & (1U << storage_bit)) != 0)
+ << bit_number;
+ }
+
+ return layer;
+}
+#endif
+
+/*
+ * Make sure the action triggered when the key is released is the same
+ * one as the one triggered on press. It's important for the mod keys
+ * when the layer is switched after the down event but before the up
+ * event as they may get stuck otherwise.
+ */
+action_t store_or_get_action(bool pressed, keypos_t key)
+{
+#if !defined(NO_ACTION_LAYER) && defined(PREVENT_STUCK_MODIFIERS)
+ if (disable_action_cache) {
+ return layer_switch_get_action(key);
+ }
+
+ uint8_t layer;
+
+ if (pressed) {
+ layer = layer_switch_get_layer(key);
+ update_source_layers_cache(key, layer);
+ }
+ else {
+ layer = read_source_layers_cache(key);
+ }
+ return action_for_key(layer, key);
+#else
+ return layer_switch_get_action(key);
+#endif
+}
+
+
+int8_t layer_switch_get_layer(keypos_t key)
{
action_t action;
action.code = ACTION_TRANSPARENT;
@@ -124,15 +186,18 @@ action_t layer_switch_get_action(keypos_t key)
if (layers & (1UL<<i)) {
action = action_for_key(i, key);
if (action.code != ACTION_TRANSPARENT) {
- return action;
+ return i;
}
}
}
/* fall back to layer 0 */
- action = action_for_key(0, key);
- return action;
+ return 0;
#else
- action = action_for_key(biton32(default_layer_state), key);
- return action;
+ return biton32(default_layer_state);
#endif
}
+
+action_t layer_switch_get_action(keypos_t key)
+{
+ return action_for_key(layer_switch_get_layer(key), key);
+}
diff --git a/tmk_core/common/action_layer.h b/tmk_core/common/action_layer.h
index b6da353cfd..3a4b1e3349 100644
--- a/tmk_core/common/action_layer.h
+++ b/tmk_core/common/action_layer.h
@@ -70,6 +70,17 @@ void layer_xor(uint32_t state);
#define layer_debug()
#endif
+/* pressed actions cache */
+#if !defined(NO_ACTION_LAYER) && defined(PREVENT_STUCK_MODIFIERS)
+/* The number of bits needed to represent the layer number: log2(32). */
+#define MAX_LAYER_BITS 5
+void update_source_layers_cache(keypos_t key, uint8_t layer);
+uint8_t read_source_layers_cache(keypos_t key);
+#endif
+action_t store_or_get_action(bool pressed, keypos_t key);
+
+/* return the topmost non-transparent layer currently associated with key */
+int8_t layer_switch_get_layer(keypos_t key);
/* return action depending on current layer status */
action_t layer_switch_get_action(keypos_t key);