Send IPC modifier event on bar_modifier up/down

Detects when a bar modifier key is pressed/released and sends a modifier
IPC event to any listeners (usually swaybars).

This way a swaybar can listen on the modifier event and hide/show the
bar accordingly (not implemented yet)

The modifier event looks like this:

    {
      "change": "pressed", // or released
      "modifier": "Mod4"
    }

include/ipc-server.h

@@ -15,6 +15,12 @@ void ipc_event_barconfig_update(struct bar_config *bar);
  * Send IPC mode event to all listening clients
  */
 void ipc_event_mode(const char *mode);
+/**
+ * Sends an IPC modifier event to all listening clients.  The modifier event
+ * includes a key 'change' with the value of state and a key 'modifier' with
+ * the name of that modifier.
+ */
+void ipc_event_modifier(uint32_t modifier, const char *state);
 const char *swayc_type_string(enum swayc_types type);
 
 #endif

include/ipc.h

@@ -17,6 +17,7 @@ enum ipc_command_type {
 	IPC_EVENT_WINDOW = (1 << 31 | 3),
 	IPC_EVENT_BARCONFIG_UPDATE = (1 << 31 | 4),
 	IPC_EVENT_BINDING = (1 << 31 | 5),
+	IPC_EVENT_MODIFIER = (1 << 31 | 6),
 	IPC_SWAY_GET_PIXELS = 0x81
 };
 

sway/commands.c

@@ -1897,7 +1897,7 @@ static struct cmd_results *bar_cmd_modifier(int argc, char **argv) {
 		bool is_mod = false;
 		for (j = 0; j < (int)(sizeof(modifiers) / sizeof(struct modifier_key)); ++j) {
 			if (strcasecmp(modifiers[j].name, split->items[i]) == 0) {
-				mod |= modifiers[j].mod;
+				mod = modifiers[j].mod;
 				is_mod = true;
 				break;
 			}

sway/handlers.c

@@ -20,6 +20,7 @@
 #include "resize.h"
 #include "extensions.h"
 #include "criteria.h"
+#include "ipc-server.h"
 
 // Event should be sent to client
 #define EVENT_PASSTHROUGH false
@@ -392,13 +393,15 @@ static bool handle_key(wlc_handle view, uint32_t time, const struct wlc_modifier
 	struct bar_config *bar;
 	for (i = 0; i < config->bars->length; ++i) {
 		bar = config->bars->items[i];
-		switch (modifier_state_changed(modifiers->mods, bar->modifier)) {
+		if (strcmp(bar->mode, "hide") == 0 && strcmp(bar->hidden_state, "hide") == 0) {
-		case MOD_STATE_PRESSED:
+			switch (modifier_state_changed(modifiers->mods, bar->modifier)) {
-			sway_log(L_INFO, "pressed!!!");
+			case MOD_STATE_PRESSED:
-			break;
+				ipc_event_modifier(bar->modifier, "pressed");
-		case MOD_STATE_RELEASED:
+				break;
-			sway_log(L_INFO, "released!!!");
+			case MOD_STATE_RELEASED:
-			break;
+				ipc_event_modifier(bar->modifier, "released");
+				break;
+			}
 		}
 	}
 	// update modifiers state

sway/ipc-server.c

@@ -35,6 +35,22 @@ struct ipc_client {
 	enum ipc_command_type subscribed_events;
 };
 
+static struct modifier_key {
+	char *name;
+	uint32_t mod;
+} modifiers[] = {
+	{ XKB_MOD_NAME_SHIFT, WLC_BIT_MOD_SHIFT },
+	{ XKB_MOD_NAME_CAPS, WLC_BIT_MOD_CAPS },
+	{ XKB_MOD_NAME_CTRL, WLC_BIT_MOD_CTRL },
+	{ "Ctrl", WLC_BIT_MOD_CTRL },
+	{ XKB_MOD_NAME_ALT, WLC_BIT_MOD_ALT },
+	{ "Alt", WLC_BIT_MOD_ALT },
+	{ XKB_MOD_NAME_NUM, WLC_BIT_MOD_MOD2 },
+	{ "Mod3", WLC_BIT_MOD_MOD3 },
+	{ XKB_MOD_NAME_LOGO, WLC_BIT_MOD_LOGO },
+	{ "Mod5", WLC_BIT_MOD_MOD5 },
+};
+
 struct sockaddr_un *ipc_user_sockaddr(void);
 int ipc_handle_connection(int fd, uint32_t mask, void *data);
 int ipc_client_handle_readable(int client_fd, uint32_t mask, void *data);
@@ -295,6 +311,8 @@ void ipc_client_handle_command(struct ipc_client *client) {
 				client->subscribed_events |= IPC_EVENT_BARCONFIG_UPDATE;
 			} else if (strcmp(event_type, "mode") == 0) {
 				client->subscribed_events |= IPC_EVENT_MODE;
+			} else if (strcmp(event_type, "modifier") == 0) {
+				client->subscribed_events |= IPC_EVENT_MODIFIER;
 			} else {
 				ipc_send_reply(client, "{\"success\": false}", 18);
 				ipc_client_disconnect(client);
@@ -617,3 +635,24 @@ void ipc_event_mode(const char *mode) {
 
 	json_object_put(obj); // free
 }
+
+void ipc_event_modifier(uint32_t modifier, const char *state) {
+	json_object *obj = json_object_new_object();
+	json_object_object_add(obj, "change", json_object_new_string(state));
+
+	const char *modifier_name = NULL;
+	int i;
+	for (i = 0; i < (int)(sizeof(modifiers) / sizeof(struct modifier_key)); ++i) {
+		if (modifiers[i].mod == modifier) {
+			modifier_name = modifiers[i].name;
+			break;
+		}
+	}
+
+	json_object_object_add(obj, "modifier", json_object_new_string(modifier_name));
+
+	const char *json_string = json_object_to_json_string(obj);
+	ipc_send_event(json_string, IPC_EVENT_MODIFIER);
+
+	json_object_put(obj); // free
+}