keyboard: Assign state to keys rather than symbols

The keys are pressed and released, not the symbols. This fixes tracking
of the state of a key through modifier changes. E.g. A capital 'A' may
be received from the client while the shift key is pressed, but if the
shift key is released before the 'a' key, the 'a' symbol is generated.

include/keyboard.h

@@ -20,6 +20,8 @@
 #include <xkbcommon/xkbcommon.h>
 #include <stdbool.h>
 
+#include "intset.h"
+
 struct zwp_virtual_keyboard_v1;
 struct table_entry;
 
@@ -33,6 +35,8 @@ struct keyboard {
 	size_t lookup_table_size;
 	size_t lookup_table_length;
 	struct table_entry* lookup_table;
+
+	struct intset key_state;
 };
 
 int keyboard_init(struct keyboard* self, const char* layout);

src/keyboard.c

@@ -31,12 +31,12 @@
 #include "keyboard.h"
 #include "shm.h"
 #include "logging.h"
+#include "intset.h"
 
 struct table_entry {
 	xkb_keysym_t symbol;
 	xkb_keycode_t code;
 	int level;
-	bool is_pressed;
 };
 
 static void append_entry(struct keyboard* self, xkb_keysym_t symbol,
@@ -59,7 +59,6 @@ static void append_entry(struct keyboard* self, xkb_keysym_t symbol,
 	entry->symbol = symbol;
 	entry->code = code;
 	entry->level = level;
-	entry->is_pressed = false;
 }
 
 static void key_iter(struct xkb_keymap* map, xkb_keycode_t code, void* userdata)
@@ -125,8 +124,10 @@ static void keyboard__dump_entry(const struct keyboard* self,
 	const char* code_name =
 		xkb_keymap_key_get_name(self->keymap, entry->code);
 
+	bool is_pressed = intset_is_set(&self->key_state, entry->code);
+
 	log_debug("symbol=%s level=%d code=%s %s\n", sym_name, entry->level,
-	          code_name, entry->is_pressed ? "pressed" : "released");
+	          code_name, is_pressed ? "pressed" : "released");
 }
 
 void keyboard_dump_lookup_table(const struct keyboard* self)
@@ -141,6 +142,9 @@ int keyboard_init(struct keyboard* self, const char* layout)
 	if (!self->context)
 		return -1;
 
+	if (intset_init(&self->key_state, 0) < 0)
+		goto key_state_failure;
+
 	struct xkb_rule_names rule_names = {
 		.layout = layout,
 		.model = "pc105",
@@ -193,6 +197,8 @@ table_failure:
 state_failure:
 	xkb_keymap_unref(self->keymap);
 keymap_failure:
+	intset_destroy(&self->key_state);
+key_state_failure:
 	xkb_context_unref(self->context);
 	return -1;
 }
@@ -202,6 +208,7 @@ void keyboard_destroy(struct keyboard* self)
 	free(self->lookup_table);
 	xkb_state_unref(self->state);
 	xkb_keymap_unref(self->keymap);
+	intset_destroy(&self->key_state);
 	xkb_context_unref(self->context);
 }
 
@@ -294,10 +301,14 @@ void keyboard_feed(struct keyboard* self, xkb_keysym_t symbol, bool is_pressed)
 			return; // TODO: Notify the user about this
 	}
 
-	if (entry->is_pressed == is_pressed)
+	bool was_pressed = intset_is_set(&self->key_state, entry->code);
+	if (was_pressed == is_pressed)
 		return;
 
-	entry->is_pressed = is_pressed;
+	if (is_pressed)
+		intset_set(&self->key_state, entry->code);
+	else
+		intset_clear(&self->key_state, entry->code);
 
 #ifndef NDEBUG
 	keyboard__dump_entry(self, entry);