From 27a63e34145ea023e8b0a0fb08117c38ba137af7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C5=99emysl=20Eric=20Janouch?= <p@janouch.name>
Date: Fri, 25 Sep 2020 06:45:27 +0200
Subject: [PATCH] Collect events in the main thread

---
 wdmtg.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 55 insertions(+), 13 deletions(-)

diff --git a/wdmtg.c b/wdmtg.c
index 1b8e7ec..c5a1f71 100644
--- a/wdmtg.c
+++ b/wdmtg.c
@@ -243,6 +243,41 @@ x_text_property(xcb_window_t window, xcb_atom_t property)
 	return NULL;
 }
 
+// --- Async Queue Source ------------------------------------------------------
+
+static gboolean
+async_queue_source_prepare(G_GNUC_UNUSED GSource *source,
+	G_GNUC_UNUSED gint *timeout_)
+{
+	return g_async_queue_length(g.queue) > 0;
+}
+
+static gboolean
+async_queue_source_dispatch(G_GNUC_UNUSED GSource *source,
+	GSourceFunc callback, gpointer user_data)
+{
+	// I don't want to call it once per message, prefer batch processing
+	if (callback)
+		return callback(user_data);
+
+	return G_SOURCE_CONTINUE;
+}
+
+static GSource *
+async_queue_source_new(void)
+{
+	static GSourceFuncs funcs = {
+		.prepare  = async_queue_source_prepare,
+		.check    = NULL,
+		.dispatch = async_queue_source_dispatch,
+		.finalize = NULL,
+	};
+
+	GSource *source = g_source_new(&funcs, sizeof *source);
+	g_source_set_name(source, "AsyncQueueSource");
+	return source;
+}
+
 // --- Generator ---------------------------------------------------------------
 
 static void
@@ -252,6 +287,9 @@ push_event(void) {
 	event->title = g_strdup(gen.current_title);
 	event->idle = gen.current_idle;
 	g_async_queue_push(g.queue, event);
+
+	// This is the best thing GLib exposes (GWakeUp is internal)
+	g_main_context_wakeup(g_main_context_default());
 }
 
 static char *
@@ -309,11 +347,8 @@ update_current_window(void)
 	}
 
 	free(gpr);
-	if (update_window_title(new_title)) {
-		printf("Window changed: %s\n",
-			gen.current_title ? gen.current_title : "(none)");
+	if (update_window_title(new_title))
 		push_event();
-	}
 }
 
 static void
@@ -324,10 +359,8 @@ on_x_property_notify(const xcb_property_notify_event_t *ev)
 		update_current_window();
 	} else if (ev->window == gen.current_window &&
 		ev->atom == gen.atom_net_wm_name) {
-		if (update_window_title(x_window_title(ev->window))) {
-			printf("Title changed: %s\n", gen.current_title);
+		if (update_window_title(x_window_title(ev->window)))
 			push_event();
-		}
 	}
 }
 
@@ -357,7 +390,6 @@ static void
 on_x_alarm_notify(const xcb_sync_alarm_notify_event_t *ev)
 {
 	if (ev->alarm == gen.idle_alarm_inactive) {
-		printf("User is inactive\n");
 		gen.current_idle = true;
 		push_event();
 
@@ -369,7 +401,6 @@ on_x_alarm_notify(const xcb_sync_alarm_notify_event_t *ev)
 		set_idle_alarm(&gen.idle_alarm_active,
 			XCB_SYNC_TESTTYPE_NEGATIVE_COMPARISON, minus_one);
 	} else if (ev->alarm == gen.idle_alarm_active) {
-		printf("User is active\n");
 		gen.current_idle = false;
 		push_event();
 
@@ -508,6 +539,18 @@ generator_cleanup(void)
 
 // --- Main --------------------------------------------------------------------
 
+static gboolean
+on_queue_incoming(G_GNUC_UNUSED gpointer user_data)
+{
+	struct event *event = NULL;
+	while ((event = g_async_queue_try_pop(g.queue))) {
+		printf("Event: ts: %ld, title: %s, idle: %d\n",
+			event->timestamp, event->title ?: "(none)", event->idle);
+		event_free(event);
+	}
+	return G_SOURCE_CONTINUE;
+}
+
 static sqlite3 *
 database_init(const gchar *db_path)
 {
@@ -642,10 +685,9 @@ main(int argc, char *argv[])
 	g.db = database_init(db_path);
 	g_free(db_path);
 
-	// TODO: somehow read events from the async queue
-	// TODO: how in the name of fuck would our custom source wake up a sleeping
-	// main loop?  There is g_main_context_wakeup() but...
-	//  - GWakeUp is internal, apparently
+	GSource *queue_source = async_queue_source_new();
+	g_source_set_callback(queue_source, on_queue_incoming, NULL, NULL);
+	g_source_attach(queue_source, g_main_context_default());
 
 	// TODO: listen for connections on the control socket