libobs: Add function to remove properties

Allows removing a property from a properties list in get_properties or
modified callback to enable dynamic property generation. The behavior
is undefined if the UI properties list is not refreshed by returning
true from the modified callback.

libobs/obs-properties.c

@@ -271,6 +271,31 @@ obs_property_t *obs_properties_get(obs_properties_t *props, const char *name)
 	return NULL;
 }
 
+void obs_properties_remove_by_name(obs_properties_t *props, const char *name)
+{
+	if (!props)
+		return;
+
+	/* obs_properties_t is a forward-linked-list, so we need to keep both
+	 * previous and current pointers around. That way we can fix up the
+	 * pointers for the previous element if we find a match.
+	 */
+	struct obs_property *cur = props->first_property;
+	struct obs_property *prev = props->first_property;
+
+	while (cur) {
+		if (strcmp(cur->name, name) == 0) {
+			prev->next = cur->next;
+			cur->next = 0;
+			obs_property_destroy(cur);
+			break;
+		}
+
+		prev = cur;
+		cur = cur->next;
+	}
+}
+
 void obs_properties_apply_settings(obs_properties_t *props, obs_data_t *settings)
 {
 	struct obs_property *p;

libobs/obs-properties.h

@@ -122,6 +122,19 @@ EXPORT obs_property_t *obs_properties_first(obs_properties_t *props);
 EXPORT obs_property_t *obs_properties_get(obs_properties_t *props,
 		const char *property);
 
+/** Remove a property from a properties list.
+ *
+ * Removes a property from a properties list. Only valid in either
+ * get_properties or modified_callback(2). modified_callback(2) must return
+ * true so that all UI properties are rebuilt and returning false is undefined
+ * behavior.
+ *
+ * @param props Properties to remove from.
+ * @param property Name of the property to remove.
+ */
+EXPORT void obs_properties_remove_by_name(obs_properties_t *props,
+		const char *property);
+
 /**
  * Applies settings to the properties by calling all the necessary
  * modification callbacks