From a685618480bf1de529db58bb188b7c32d8dddd12 Mon Sep 17 00:00:00 2001
From: xs5871 <xs5871@altlast.tk>
Date: Sat, 29 Jan 2022 21:11:57 +0000
Subject: [PATCH] implement hold-tap interrupt on other key tap (i.e. release)

---
 kmk/key_validators.py  | 18 ++++++++++++++----
 kmk/modules/holdtap.py | 42 ++++++++++++++++++++++++++++++++++--------
 kmk/types.py           | 25 +++++++++++++++----------
 3 files changed, 63 insertions(+), 22 deletions(-)

diff --git a/kmk/key_validators.py b/kmk/key_validators.py
index e819275..e3faa28 100644
--- a/kmk/key_validators.py
+++ b/kmk/key_validators.py
@@ -11,7 +11,7 @@ def key_seq_sleep_validator(ms):
     return KeySeqSleepMeta(ms)
 
 
-def layer_key_validator(layer, kc=None):
+def layer_key_validator(layer, kc=None, tap_time=None):
     '''
     Validates the syntax (but not semantics) of a layer key call.  We won't
     have access to the keymap here, so we can't verify much of anything useful
@@ -19,14 +19,24 @@ def layer_key_validator(layer, kc=None):
     existing is mostly that Python will catch extraneous args/kwargs and error
     out.
     '''
-    return LayerKeyMeta(layer=layer, kc=kc)
+    return LayerKeyMeta(
+        layer=layer, kc=kc, prefer_hold=False, tap_interrupted=False, tap_time=tap_time
+    )
 
 
-def mod_tap_validator(kc, mods=None, prefer_hold=True, tap_time=None):
+def mod_tap_validator(
+    kc, mods=None, prefer_hold=True, tap_interrupted=False, tap_time=None
+):
     '''
     Validates that mod tap keys are correctly used
     '''
-    return ModTapKeyMeta(kc=kc, mods=mods, prefer_hold=prefer_hold, tap_time=tap_time)
+    return ModTapKeyMeta(
+        kc=kc,
+        mods=mods,
+        prefer_hold=prefer_hold,
+        tap_interrupted=tap_interrupted,
+        tap_time=tap_time,
+    )
 
 
 def tap_dance_key_validator(*codes):
diff --git a/kmk/modules/holdtap.py b/kmk/modules/holdtap.py
index a1aa152..d2a7a6b 100644
--- a/kmk/modules/holdtap.py
+++ b/kmk/modules/holdtap.py
@@ -21,6 +21,7 @@ class HoldTap(Module):
     tap_time = 300
 
     def __init__(self):
+        self.key_buffer = set()
         self.key_states = {}
 
     def during_bootup(self, keyboard):
@@ -33,19 +34,36 @@ class HoldTap(Module):
         return
 
     def process_key(self, keyboard, key, is_pressed):
-        '''Before other key down decide to send tap kc down.'''
+        '''Handle holdtap being interrupted by another key press/release.'''
         current_key = key
         for key, state in self.key_states.items():
             if key == current_key:
                 continue
-            if is_pressed:
-                if state.activated == ActivationType.NOT_ACTIVATED:
-                    # press tap because interrupted by other key
-                    self.key_states[key].activated = ActivationType.INTERRUPTED
-                    self.ht_activate_on_interrupt(
-                        key, keyboard, *state.args, **state.kwargs
-                    )
+            if state.activated != ActivationType.NOT_ACTIVATED:
+                continue
+
+            # holdtap is interrupted by another key event.
+            if (is_pressed and not key.meta.tap_interrupted) or (
+                not is_pressed and key.meta.tap_interrupted and self.key_buffer
+            ):
+
+                keyboard.cancel_timeout(state.timeout_key)
+                self.key_states[key].activated = ActivationType.INTERRUPTED
+                self.ht_activate_on_interrupt(
+                    key, keyboard, *state.args, **state.kwargs
+                )
+
                     keyboard._send_hid()
+
+                self.send_key_buffer(keyboard)
+
+            # if interrupt on release: store interrupting keys until one of them
+            # is released.
+            if key.meta.tap_interrupted:
+                if is_pressed:
+                    self.key_buffer.add(current_key)
+                    current_key = None
+
         return current_key
 
     def before_hid_send(self, keyboard):
@@ -91,6 +109,7 @@ class HoldTap(Module):
                     False,
                     lambda: self.ht_deactivate_tap(key, keyboard, *args, **kwargs),
                 )
+                self.send_key_buffer(keyboard)
             del self.key_states[key]
         return keyboard
 
@@ -103,6 +122,13 @@ class HoldTap(Module):
             # press hold because timer expired after tap time
             self.key_states[key].activated = ActivationType.HOLD_TIMEOUT
             self.ht_activate_hold(key, keyboard, *args, **kwargs)
+            self.send_key_buffer(keyboard)
+
+    def send_key_buffer(self, keyboard):
+        for key in self.key_buffer:
+            key.on_press(keyboard)
+            keyboard._send_hid()
+        self.key_buffer.clear()
 
     def ht_activate_hold(self, key, keyboard, *args, **kwargs):
         pass
diff --git a/kmk/types.py b/kmk/types.py
index 10d5802..d64fece 100644
--- a/kmk/types.py
+++ b/kmk/types.py
@@ -11,21 +11,26 @@ class AttrDict(dict):
         return self[key]
 
 
-class LayerKeyMeta:
-    def __init__(self, layer, kc=None, tap_time=None):
-        self.layer = layer
+class HoldTapKeyMeta:
+    def __init__(self, kc=None, prefer_hold=True, tap_interrupted=False, tap_time=None):
         self.kc = kc
-        self.tap_time = tap_time
-
-
-class ModTapKeyMeta:
-    def __init__(self, kc=None, mods=None, prefer_hold=True, tap_time=None):
         self.prefer_hold = prefer_hold
-        self.kc = kc
-        self.mods = mods
+        self.tap_interrupted = tap_interrupted
         self.tap_time = tap_time
 
 
+class LayerKeyMeta(HoldTapKeyMeta):
+    def __init__(self, layer, **kwargs):
+        super().__init__(**kwargs)
+        self.layer = layer
+
+
+class ModTapKeyMeta(HoldTapKeyMeta):
+    def __init__(self, kc=None, mods=None, **kwargs):
+        super().__init__(kc=kc, **kwargs)
+        self.mods = mods
+
+
 class KeySequenceMeta:
     def __init__(self, seq):
         self.seq = seq