From f721f1104b8cce5c1642cb9f9b7aea45332b4b83 Mon Sep 17 00:00:00 2001
From: Raheman Vaiya <r.vaiya@gmail.com>
Date: Thu, 22 Sep 2022 00:47:16 -0400
Subject: [PATCH] refactor: Consolidate timeout/overload logic

---
 Makefile             |   4 +-
 src/keyboard.c       | 279 ++++++++++++++++++++-----------------------
 src/keyboard.h       |  38 +++---
 t/overload-nested2.t |   2 -
 t/overload.t         |   2 -
 t/overload3.t        |   4 +-
 t/overload5.t        |   4 -
 t/overload_2.t       |   4 +-
 t/overload_3.t       |   2 +-
 t/timeout2.t         |   2 -
 10 files changed, 155 insertions(+), 186 deletions(-)

diff --git a/Makefile b/Makefile
index 828338d..16f367d 100644
--- a/Makefile
+++ b/Makefile
@@ -96,7 +96,9 @@ test:
 	done
 test-io:
 	-mkdir bin
-	$(CC) -o bin/test-io \
+	$(CC) \
+	-DDATA_DIR= \
+	-o bin/test-io \
 		t/test-io.c \
 		src/keyboard.c \
 		src/string.c \
diff --git a/src/keyboard.c b/src/keyboard.c
index 43ccbb5..3ca8c35 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -340,9 +340,33 @@ static void setlayout(struct keyboard *kbd, uint8_t idx)
 }
 
 
+static void schedule_timeout(struct keyboard *kbd, long timeout)
+{
+	assert(kbd->nr_timeouts < ARRAY_SIZE(kbd->timeouts));
+	kbd->timeouts[kbd->nr_timeouts++] = timeout;
+}
+
+static long calculate_main_loop_timeout(struct keyboard *kbd, long time) 
+{
+	size_t i;
+	long timeout = 0;
+	size_t n = 0;
+
+	for (i = 0; i < kbd->nr_timeouts; i++)
+		if (kbd->timeouts[i] > time) {
+			if (!timeout || kbd->timeouts[i] < timeout)
+				timeout = kbd->timeouts[i];
+
+			kbd->timeouts[n++] = kbd->timeouts[i];
+		}
+
+	kbd->nr_timeouts = n;
+	return timeout ? timeout - time : 0;
+}
+
 static long process_descriptor(struct keyboard *kbd, uint8_t code,
 			       struct descriptor *d, int dl,
-			       int pressed)
+			       int pressed, long time)
 {
 	int timeout = 0;
 
@@ -395,20 +419,20 @@ static long process_descriptor(struct keyboard *kbd, uint8_t code,
 		if (pressed) {
 			uint8_t layer = d->args[0].idx;
 			struct descriptor *action = &kbd->config.descriptors[d->args[1].idx];
-			timeout = d->args[2].idx;
-
-			kbd->overload2.active = 1;
-			kbd->overload2.resolve_on_tap = d->op == OP_OVERLOAD_TIMEOUT_TAP ? 1 : 0;
-			kbd->overload2.code = code;
-			kbd->overload2.layer = layer;
-			kbd->overload2.action = action;
-			kbd->overload2.dl = dl;
-			kbd->overload2.n = 0;
-		} else {
-			deactivate_layer(kbd, d->args[0].idx);
-			update_mods(kbd, -1, 0);
-		}
 
+			kbd->pending_key.code = code;
+			kbd->pending_key.behaviour = 
+				d->op == OP_OVERLOAD_TIMEOUT_TAP ?
+					PK_UNINTERRUPTIBLE_TAP_ACTION2 :
+					PK_UNINTERRUPTIBLE;
+
+			kbd->pending_key.action1 = *action;
+			kbd->pending_key.action2.op = OP_LAYER;
+			kbd->pending_key.action2.args[0].idx = layer;
+			kbd->pending_key.expire = time+d->args[2].timeout;
+
+			schedule_timeout(kbd, kbd->pending_key.expire);
+		}
 
 		break;
 	case OP_LAYOUT:
@@ -451,19 +475,14 @@ static long process_descriptor(struct keyboard *kbd, uint8_t code,
 		action = &kbd->config.descriptors[d->args[1].idx];
 
 		if (pressed) {
-			activate_layer(kbd, code, idx);
-			update_mods(kbd, -1, 0);
-		} else {
-			deactivate_layer(kbd, idx);
-
-			if (kbd->last_pressed_code == code) {
-				clear_oneshot(kbd);
-
-				process_descriptor(kbd, code, action, dl, 1);
-				process_descriptor(kbd, code, action, dl, 0);
-			}
-
-			update_mods(kbd, -1, 0);
+			kbd->pending_key.action1 = *action;
+			kbd->pending_key.action2.op = OP_LAYER;
+			kbd->pending_key.action2.args[0].idx = idx;
+
+			kbd->pending_key.expire = time+1E6;
+			kbd->pending_key.code = code;
+			kbd->pending_key.dl = dl;
+			kbd->pending_key.behaviour = PK_INTERRUPT_ACTION2;
 		}
 
 		break;
@@ -533,16 +552,17 @@ static long process_descriptor(struct keyboard *kbd, uint8_t code,
 		break;
 	case OP_TIMEOUT:
 		if (pressed) {
-			kbd->pending_timeout.d1 = kbd->config.descriptors[d->args[0].idx];
-			kbd->pending_timeout.d2 = kbd->config.descriptors[d->args[2].idx];
-
-			kbd->pending_timeout.code = code;
-			kbd->pending_timeout.dl = dl;
+			kbd->pending_key.action1 = kbd->config.descriptors[d->args[0].idx];
+			kbd->pending_key.action2 = kbd->config.descriptors[d->args[2].idx];
 
-			kbd->pending_timeout.active = 1;
+			kbd->pending_key.code = code;
+			kbd->pending_key.dl = dl;
+			kbd->pending_key.expire = time + d->args[1].timeout;
+			kbd->pending_key.behaviour = PK_INTERRUPT_ACTION1;
 
-			timeout = d->args[1].timeout;
+			schedule_timeout(kbd, kbd->pending_key.expire);
 		}
+
 		break;
 	case OP_COMMAND:
 		if (pressed)
@@ -633,152 +653,115 @@ struct keyboard *new_keyboard(struct config *config,
 	return kbd;
 }
 
-static int resolve_overload2(struct keyboard *kbd, int time, int hold)
-{
-	int timeout = 0;
-	int timeout_ts;
-
-	struct key_event queue[ARRAY_SIZE(kbd->overload2.queued)];
-	int n = kbd->overload2.n;
-
-	kbd->overload2.active = 0;
-
-	memcpy(queue, kbd->overload2.queued, sizeof(struct key_event)*n);
-
-	if (hold) {
-		activate_layer(kbd, kbd->overload2.code, kbd->overload2.layer);
-		update_mods(kbd, -1, 0);
-	} else {
-		process_descriptor(kbd,
-				   kbd->overload2.code,
-				   kbd->overload2.action,
-				   kbd->overload2.dl, 1);
-
-		process_descriptor(kbd,
-				   kbd->overload2.code,
-				   kbd->overload2.action,
-				   kbd->overload2.dl, 0);
-
-		cache_set(kbd, kbd->overload2.code, NULL, -1);
-	}
-
-	if (!n)
-		return 0;
-
-	timeout = kbd_process_events(kbd, queue, n);
-	timeout_ts = queue[n-1].timestamp + timeout;
-
-	if (timeout_ts <= time) {
-		struct key_event ev = {.code = 0, .timestamp = timeout_ts};
-		return kbd_process_events(kbd, &ev, 1);
-	}
-
-	return timeout_ts - time;
-}
-
 /*
  * `code` may be 0 in the event of a timeout.
  *
  * The return value corresponds to a timeout before which the next invocation
- * of kbd_process_key_event must take place. A return value of 0 permits the
+ * of process_event must take place. A return value of 0 permits the
  * main loop to call at liberty.
  */
-static long process_event(struct keyboard *kbd, uint8_t code, int pressed, int time)
+static long process_event(struct keyboard *kbd, uint8_t code, int pressed, long time)
 {
 	int dl = -1;
 	struct descriptor d;
 
-	int timeleft = kbd->timeout - (time - kbd->last_event_ts);
-	kbd->last_event_ts = time;
+	if (kbd->pending_key.code) {
+		struct descriptor action = {0};
 
-	/* timeout */
-	if (!code) {
-		if (kbd->overload2.active)
-			return resolve_overload2(kbd, time, 1);
+		if (code) {
+			struct key_event *ev;
 
-		if (kbd->active_macro) {
-			execute_macro(kbd, kbd->active_macro_layer, kbd->active_macro);
-			return kbd->macro_repeat_timeout;
-		}
+			assert(kbd->pending_key.queue_sz < ARRAY_SIZE(kbd->pending_key.queue));
 
-		if (kbd->pending_timeout.active) {
-			int dl = kbd->pending_timeout.dl;
-			uint8_t code = kbd->pending_timeout.code;
-			struct descriptor *d = &kbd->pending_timeout.d2;
+			ev = &kbd->pending_key.queue[kbd->pending_key.queue_sz];
+			ev->code = code;
+			ev->pressed = pressed;
+			ev->timestamp = time;
 
-			cache_set(kbd, code, d, dl);
-
-			kbd->pending_timeout.active = 0;
-			return process_descriptor(kbd, code, d, dl, 1);
+			kbd->pending_key.queue_sz++;
 		}
-	} else {
-		if (kbd->overload2.active) {
-			if (kbd->overload2.code == code) {
-				return resolve_overload2(kbd, time, 0);
-			} else {
-				assert(kbd->overload2.n < ARRAY_SIZE(kbd->overload2.queued));
-				struct key_event *ev = &kbd->overload2.queued[kbd->overload2.n++];
-
-				ev->code = code;
-				ev->pressed = pressed;
-				ev->timestamp = time;
-
-				//TODO: make this optional (overload3)
-				if (kbd->overload2.resolve_on_tap && !pressed) {
-					size_t i;
-					for (i = 0; i < kbd->overload2.n; i++)
-						if (kbd->overload2.queued[i].code == code &&
-						    kbd->overload2.queued[i].pressed) {
-							return resolve_overload2(kbd, time, 1);
-						}
-				}
 
-				return timeleft;
-			}
 
+		if (time >= kbd->pending_key.expire)
+			action = kbd->pending_key.action2;
+		else if (code == kbd->pending_key.code)
+			action = kbd->pending_key.action1;
+		else if (code && pressed && kbd->pending_key.behaviour == PK_INTERRUPT_ACTION1)
+			action = kbd->pending_key.action1;
+		else if (code && pressed && kbd->pending_key.behaviour == PK_INTERRUPT_ACTION2)
+			action = kbd->pending_key.action2;
+		else if (kbd->pending_key.behaviour == PK_UNINTERRUPTIBLE_TAP_ACTION2 && !pressed) {
+			size_t i;
+
+			for (i = 0; i < kbd->pending_key.queue_sz; i++)
+				if (kbd->pending_key.queue[i].code == code) {
+					action = kbd->pending_key.action2;
+					break;
+				}
 		}
 
-		if (kbd->pending_timeout.active) {
-			int dl = kbd->pending_timeout.dl;
-			uint8_t code = kbd->pending_timeout.code;
-			struct descriptor *d = &kbd->pending_timeout.d1;
+		if (action.op) {
+			/* Create a copy of the queue on the stack to
+			   allow for recursive pending key processing. */
+			struct key_event queue[ARRAY_SIZE(kbd->pending_key.queue)];
+			size_t queue_sz = kbd->pending_key.queue_sz;
+
+			uint8_t code = kbd->pending_key.code;
+			int dl = kbd->pending_key.dl;
+
+			memcpy(queue, kbd->pending_key.queue, sizeof kbd->pending_key.queue);
+
+			kbd->pending_key.code = 0;
+			kbd->pending_key.queue_sz = 0;
 
-			cache_set(kbd, code, d, dl);
-			process_descriptor(kbd, code, d, dl, 1);
+			process_descriptor(kbd, code, &action, dl, 1, time);
+			cache_set(kbd, code, &action, dl);
+
+			/* Flush queued events */
+			kbd_process_events(kbd, queue, queue_sz);
 		}
 
-		if (kbd->active_macro) {
+		goto exit;
+	}
+
+	if (kbd->active_macro) {
+		if (code) {
 			kbd->active_macro = NULL;
 			update_mods(kbd, -1, 0);
+		} else {
+			execute_macro(kbd, kbd->active_macro_layer, kbd->active_macro);
+			schedule_timeout(kbd, time+kbd->macro_repeat_timeout);
 		}
+	} 
 
-		kbd->pending_timeout.active = 0;
-	}
-
+	if (code) {
+		if (pressed) {
+			/*
+			 * Guard against successive key down events
+			 * of the same key code. This can be caused
+			 * by unorthodox hardware or by different
+			 * devices mapped to the same config.
+			 */
+			if (cache_get(kbd, code, &d, &dl) == 0)
+				goto exit;
 
-	if (pressed) {
-		/*
-		 * Guard against successive key down events
-		 * of the same key code. This can be caused
-		 * by unorthodox hardware or by different
-		 * devices mapped to the same config.
-		 */
-		if (cache_get(kbd, code, &d, &dl) == 0)
-			return 0;
+			lookup_descriptor(kbd, code, &d, &dl);
 
-		lookup_descriptor(kbd, code, &d, &dl);
+			if (cache_set(kbd, code, &d, dl) < 0)
+				goto exit;
+		} else {
+			if (cache_get(kbd, code, &d, &dl) < 0)
+				goto exit;
 
-		if (cache_set(kbd, code, &d, dl) < 0)
-			return 0;
-	} else {
-		if (cache_get(kbd, code, &d, &dl) < 0)
-			return 0;
+			cache_set(kbd, code, NULL, -1);
+		}
 
-		cache_set(kbd, code, NULL, -1);
+		process_descriptor(kbd, code, &d, dl, pressed, time);
 	}
 
-	kbd->timeout = process_descriptor(kbd, code, &d, dl, pressed);
-	return kbd->timeout;
+
+exit:
+	return calculate_main_loop_timeout(kbd, time);
 }
 
 
diff --git a/src/keyboard.h b/src/keyboard.h
index 27df75e..633b86b 100644
--- a/src/keyboard.h
+++ b/src/keyboard.h
@@ -49,21 +49,28 @@ struct keyboard {
 	int active_macro_layer;
 
 	long macro_repeat_timeout;
-	int timeout;
-	int last_event_ts;
+
+	long timeouts[32];
+	size_t nr_timeouts; 
 
 	struct {
-		uint8_t active;
 		uint8_t code;
-
-		uint8_t layer;
-		struct descriptor *action;
 		uint8_t dl;
+		long expire;
 
-		struct key_event queued[32];
-		uint8_t n;
-		uint8_t resolve_on_tap;
-	} overload2;
+		enum {
+			PK_INTERRUPT_ACTION1,
+			PK_INTERRUPT_ACTION2,
+			PK_UNINTERRUPTIBLE,
+			PK_UNINTERRUPTIBLE_TAP_ACTION2,
+		} behaviour;
+
+		struct key_event queue[32];
+		size_t queue_sz;
+
+		struct descriptor action1;
+		struct descriptor action2;
+	} pending_key;
 
 	struct {
 		long activation_time;
@@ -73,17 +80,6 @@ struct keyboard {
 		uint8_t oneshot;
 	} layer_state[MAX_LAYERS];
 
-	struct {
-		uint8_t active;
-
-		uint8_t code;
-
-		struct descriptor d1;
-		struct descriptor d2;
-
-		int dl;
-	} pending_timeout;
-
 	uint8_t keystate[256];
 	void (*output) (uint8_t code, uint8_t state);
 	void (*layer_observer) (struct keyboard *kbd, const char *layer, int state);
diff --git a/t/overload-nested2.t b/t/overload-nested2.t
index 436b2dc..798ff05 100644
--- a/t/overload-nested2.t
+++ b/t/overload-nested2.t
@@ -4,8 +4,6 @@ o up
 6 up
 
 control down
-meta down
-meta up
 control up
 \ down
 \ up
diff --git a/t/overload.t b/t/overload.t
index 695e729..12a4608 100644
--- a/t/overload.t
+++ b/t/overload.t
@@ -1,7 +1,5 @@
 6 down
 6 up
 
-control down
-control up
 esc down
 esc up
diff --git a/t/overload3.t b/t/overload3.t
index 1c971bb..7c2b36d 100644
--- a/t/overload3.t
+++ b/t/overload3.t
@@ -4,8 +4,6 @@ j up
 6 up
 
 j down
-control down
-j up
-control up
 esc down
+j up
 esc up
diff --git a/t/overload5.t b/t/overload5.t
index 84f2418..0818853 100644
--- a/t/overload5.t
+++ b/t/overload5.t
@@ -7,10 +7,6 @@ x down
 x up
 7 up
 
-meta down
-control down
-meta up
-control up
 control down
 x down
 x up
diff --git a/t/overload_2.t b/t/overload_2.t
index c9cc5ef..39e56a6 100644
--- a/t/overload_2.t
+++ b/t/overload_2.t
@@ -22,10 +22,10 @@ a up
 control down
 control up
 a down
-a up
 x down
 x up
-a down
 a up
+a down
 x down
+a up
 x up
diff --git a/t/overload_3.t b/t/overload_3.t
index af195ad..5bf6fbb 100644
--- a/t/overload_3.t
+++ b/t/overload_3.t
@@ -17,8 +17,8 @@ x down
 x up
 control up
 ' down
-' up
 x down
+' up
 x up
 control down
 x down
diff --git a/t/timeout2.t b/t/timeout2.t
index cb41267..6372721 100644
--- a/t/timeout2.t
+++ b/t/timeout2.t
@@ -12,8 +12,6 @@ control down
 x down
 x up
 control up
-control down
-control up
 a down
 a up
 b down