libobs: Add obs_source_duplicate function

Allows full duplication of sources (with exception of sources that are
marked with the OBS_SOURCE_DO_NOT_DUPLICATE output capability flag)

libobs/obs-source.c

@@ -344,6 +344,68 @@ obs_source_t *obs_source_create_private(const char *id, const char *name,
 	return obs_source_create_internal(id, name, settings, NULL, true);
 }
 
+static void duplicate_filters(obs_source_t *dst, obs_source_t *src,
+		bool private)
+{
+	DARRAY(obs_source_t*) filters;
+
+	da_init(filters);
+
+	pthread_mutex_lock(&src->filter_mutex);
+	for (size_t i = 0; i < src->filters.num; i++)
+		obs_source_addref(src->filters.array[i]);
+	da_copy(filters, src->filters);
+	pthread_mutex_unlock(&src->filter_mutex);
+
+	for (size_t i = filters.num; i > 0; i--) {
+		obs_source_t *src_filter = filters.array[i - 1];
+		obs_source_t *dst_filter = obs_source_duplicate(src_filter,
+				src_filter->context.name, private);
+
+		obs_source_filter_add(dst, dst_filter);
+		obs_source_release(dst_filter);
+		obs_source_release(src_filter);
+	}
+
+	da_free(filters);
+}
+
+obs_source_t *obs_source_duplicate(obs_source_t *source,
+		const char *new_name, bool create_private)
+{
+	obs_source_t *new_source;
+	obs_data_t *settings;
+
+	if (!obs_source_valid(source, "obs_source_duplicate"))
+		return NULL;
+
+	if ((source->info.output_flags & OBS_SOURCE_DO_NOT_DUPLICATE) != 0) {
+		obs_source_addref(source);
+		return source;
+	}
+
+	settings = obs_data_create();
+	obs_data_apply(settings, source->context.settings);
+
+	new_source = create_private ?
+		obs_source_create_private(source->info.id, new_name, settings) :
+		obs_source_create(source->info.id, new_name, settings, NULL);
+
+	new_source->audio_mixers = source->audio_mixers;
+	new_source->sync_offset = source->sync_offset;
+	new_source->user_volume = source->user_volume;
+	new_source->user_muted = source->user_muted;
+	new_source->volume = source->volume;
+	new_source->muted = source->muted;
+	new_source->flags = source->flags;
+
+	if (source->info.type != OBS_SOURCE_TYPE_FILTER)
+		duplicate_filters(new_source, source, create_private);
+
+	obs_data_release(settings);
+	return new_source;
+}
+
 void obs_source_frame_init(struct obs_source_frame *frame,
 		enum video_format format, uint32_t width, uint32_t height)
 {

libobs/obs.h

@@ -650,6 +650,11 @@ EXPORT obs_source_t *obs_source_create(const char *id, const char *name,
 
 EXPORT obs_source_t *obs_source_create_private(const char *id,
 		const char *name, obs_data_t *settings);
+
+/* if source has OBS_SOURCE_DO_NOT_DUPLICATE output flag set, only returns a
+ * reference */
+EXPORT obs_source_t *obs_source_duplicate(obs_source_t *source,
+		const char *desired_name, bool create_private);
 /**
  * Adds/releases a reference to a source.  When the last reference is
  * released, the source is destroyed.