keymap: Add option "unlockOnPress" for LockMods action

This is an extensions to XKB. It intends to allow to deactivate CapsLock on press
rather than on release, as in other platforms such as Windows.

Author: wismill

src/keymap.h

@@ -152,6 +152,7 @@ enum xkb_action_flags {
     ACTION_ACCEL = (1 << 8),
     ACTION_SAME_SCREEN = (1 << 9),
     ACTION_LOCK_ON_RELEASE = (1 << 10),
+    ACTION_UNLOCK_ON_PRESS = (1 << 11),
 };
 
 enum xkb_action_controls {

src/state.c

@@ -395,9 +395,17 @@ xkb_filter_mod_lock_new(struct xkb_state *state, struct xkb_filter *filter)
 {
     filter->priv = (state->components.locked_mods &
                     filter->action.mods.mods.mask);
-    state->set_mods |= filter->action.mods.mods.mask;
-    if (!(filter->action.mods.flags & ACTION_LOCK_NO_LOCK))
-        state->components.locked_mods |= filter->action.mods.mods.mask;
+    if (filter->priv && (filter->action.mods.flags & ACTION_UNLOCK_ON_PRESS)) {
+        /* XKB extension: Unlock on second press */
+        state->clear_mods |= filter->action.mods.mods.mask;
+        if (!(filter->action.mods.flags & ACTION_LOCK_NO_UNLOCK))
+            state->components.locked_mods &= ~filter->priv;
+        filter->priv = 0;
+    } else {
+        state->set_mods |= filter->action.mods.mods.mask;
+        if (!(filter->action.mods.flags & ACTION_LOCK_NO_LOCK))
+            state->components.locked_mods |= filter->action.mods.mods.mask;
+    }
 }
 
 static bool

src/xkbcomp/action.c

@@ -101,6 +101,7 @@ enum action_field {
     ACTION_FIELD_KEYCODE,
     ACTION_FIELD_MODS_TO_CLEAR,
     ACTION_FIELD_LOCK_ON_RELEASE,
+    ACTION_FIELD_UNLOCK_ON_PRESS,
 };
 
 ActionsInfo *
@@ -168,6 +169,7 @@ static const LookupEntry fieldStrings[] = {
     { "clearmods",        ACTION_FIELD_MODS_TO_CLEAR   },
     { "clearmodifiers",   ACTION_FIELD_MODS_TO_CLEAR   },
     { "lockOnRelease",    ACTION_FIELD_LOCK_ON_RELEASE },
+    { "unlockOnPress",    ACTION_FIELD_UNLOCK_ON_PRESS },
     { NULL,               0                            }
 };
 
@@ -334,10 +336,15 @@ HandleSetLatchLockMods(struct xkb_context *ctx, const struct xkb_mod_set *mods,
         return CheckBooleanFlag(ctx, action->type, field,
                                 ACTION_LATCH_TO_LOCK, array_ndx, value,
                                 &act->flags);
-    if (type == ACTION_TYPE_MOD_LOCK &&
-        field == ACTION_FIELD_AFFECT)
-        return CheckAffectField(ctx, action->type, array_ndx, value,
-                                &act->flags);
+    if (type == ACTION_TYPE_MOD_LOCK) {
+        if (field == ACTION_FIELD_AFFECT)
+            return CheckAffectField(ctx, action->type, array_ndx, value,
+                                    &act->flags);
+        if (field == ACTION_FIELD_UNLOCK_ON_PRESS)
+            return CheckBooleanFlag(ctx, action->type, field,
+                                    ACTION_UNLOCK_ON_PRESS, array_ndx, value,
+                                    &act->flags);
+    }
 
     return ReportIllegal(ctx, action->type, field);
 }

src/xkbcomp/keymap-dump.c

@@ -316,10 +316,11 @@ write_action(struct xkb_keymap *keymap, struct buf *buf,
         else
             args = ModMaskText(keymap->ctx, &keymap->mods,
                                action->mods.mods.mods);
-        write_buf(buf, "%s%s(modifiers=%s%s%s%s)%s", prefix, type, args,
+        write_buf(buf, "%s%s(modifiers=%s%s%s%s%s)%s", prefix, type, args,
                   (action->type != ACTION_TYPE_MOD_LOCK && (action->mods.flags & ACTION_LOCK_CLEAR)) ? ",clearLocks" : "",
                   (action->type != ACTION_TYPE_MOD_LOCK && (action->mods.flags & ACTION_LATCH_TO_LOCK)) ? ",latchToLock" : "",
                   (action->type == ACTION_TYPE_MOD_LOCK) ? affect_lock_text(action->mods.flags, false) : "",
+                  (action->type == ACTION_TYPE_MOD_LOCK && (action->mods.flags & ACTION_UNLOCK_ON_PRESS)) ? ",unlockOnPress" : "",
                   suffix);
         break;
 

test/data/compat/caps

@@ -9,3 +9,9 @@ partial xkb_compatibility "caps_lock" {
         action = LockMods(modifiers = Lock);
     };
 };
+
+partial xkb_compatibility "caps_lock_unlock_on_press" {
+    interpret Caps_Lock {
+        action = LockMods(modifiers = Lock, unlockOnPress);
+    };
+};

test/data/rules/evdev

@@ -1160,6 +1160,7 @@
   mod_led:compose	=	+ledcompose(compose)
   japan:kana_lock	=	+japan(kana_lock)
   caps:shiftlock	=	+ledcaps(shift_lock)
+  caps:unlock_on_press  = +caps(caps_lock_unlock_on_press)
   grab:break_actions    =       +xfree86(grab_break)