Check and update target of the source periodically

Fix #1

src/async-source-duplication-source.c

@@ -1,4 +1,5 @@
 #include <obs-module.h>
+#include <util/threading.h>
 #include "plugin-macros.generated.h"
 
 struct source_s
@@ -8,7 +9,9 @@ struct source_s
 	// properties
 	char *target_source_name;
 
+	pthread_mutex_t target_update_mutex;
 	obs_weak_source_t *target_weak;
+	float target_check;
 };
 
 static const char *get_name(void *type_data)
@@ -66,6 +69,7 @@ static void set_weak_target(struct source_s *s, obs_source_t *target)
 	if (s->target_weak)
 		release_weak_target(s);
 	s->target_weak = obs_source_get_weak_source(target);
+	s->target_check = 3.0f;
 
 	signal_handler_t *sh = obs_source_get_signal_handler(target);
 	signal_handler_connect(sh, "output_video", output_video, s);
@@ -96,36 +100,64 @@ static inline obs_source_t *source_to_filter(obs_source_t *src)
 	return target;
 }
 
-static inline void set_weak_target_by_name(struct source_s *s, const char *target_source_name)
+static obs_source_t *get_filter_by_target_source_name(const char *target_source_name)
 {
 	obs_source_t *src = obs_get_source_by_name(target_source_name);
 	if (!src)
-		return;
+		return NULL;
 	obs_source_t *target = source_to_filter(src);
+	obs_source_release(src);
+	return target;
+}
+
+static inline void set_weak_target_by_name(struct source_s *s, const char *target_source_name)
+{
+	obs_source_t *target = get_filter_by_target_source_name(target_source_name);
 	if (target) {
 		set_weak_target(s, target);
 		obs_source_release(target);
 	}
-	obs_source_release(src);
 }
 
 static void update(void *data, obs_data_t *settings)
 {
 	struct source_s *s = data;
 
 	const char *target_source_name = obs_data_get_string(settings, "target_source_name");
+	pthread_mutex_lock(&s->target_update_mutex);
 	if (target_source_name && (!s->target_source_name || strcmp(target_source_name, s->target_source_name))) {
 		bfree(s->target_source_name);
 		s->target_source_name = bstrdup(target_source_name);
 		release_weak_target(s);
 		set_weak_target_by_name(s, target_source_name);
 	}
+	pthread_mutex_unlock(&s->target_update_mutex);
+}
+
+static void tick(void *data, float seconds)
+{
+	struct source_s *s = data;
+
+	pthread_mutex_lock(&s->target_update_mutex);
+	if ((s->target_check -= seconds) < 0.0f) {
+		obs_source_t *target_by_name = get_filter_by_target_source_name(s->target_source_name);
+		obs_source_t *target_by_weak = obs_weak_source_get_source(s->target_weak);
+		if (target_by_name != target_by_weak) {
+			blog(LOG_INFO, "updating target from %p to %p", target_by_weak, target_by_name);
+			set_weak_target(s, target_by_name);
+		}
+		obs_source_release(target_by_weak);
+		obs_source_release(target_by_name);
+		s->target_check = 3.0f;
+	}
+	pthread_mutex_unlock(&s->target_update_mutex);
 }
 
 static void *create(obs_data_t *settings, obs_source_t *source)
 {
 	struct source_s *s = bzalloc(sizeof(struct source_s));
 	s->context = source;
+	pthread_mutex_init(&s->target_update_mutex, NULL);
 
 	update(s, settings);
 
@@ -137,6 +169,7 @@ static void destroy(void *data)
 	struct source_s *s = data;
 
 	release_weak_target(s);
+	pthread_mutex_destroy(&s->target_update_mutex);
 	bfree(s->target_source_name);
 
 	bfree(s);
@@ -150,5 +183,6 @@ const struct obs_source_info async_srcdup_source = {
 	.create = create,
 	.destroy = destroy,
 	.update = update,
+	.video_tick = tick,
 	.get_properties = get_properties,
 };