libobs: Add button support to properties

This adds button support to properties, which will allow a properties
pane to let the user click a button to activate something with a
particular obs context.  When pressed, the button will execute the
callback given, with the context's private data as a parameter.

libobs/obs-properties.c

@@ -17,6 +17,7 @@
 
 #include "util/bmem.h"
 #include "util/darray.h"
+#include "obs-internal.h"
 #include "obs-properties.h"
 
 static inline void *get_property_data(struct obs_property *prop);
@@ -51,6 +52,10 @@ struct list_data {
 	enum obs_combo_format    format;
 };
 
+struct button_data {
+	obs_property_clicked_t callback;
+};
+
 static inline void list_item_free(struct list_data *data,
 		struct list_item *item)
 {
@@ -214,6 +219,7 @@ static inline size_t get_property_size(enum obs_property_type type)
 	case OBS_PROPERTY_PATH:      return 0;
 	case OBS_PROPERTY_LIST:      return sizeof(struct list_data);
 	case OBS_PROPERTY_COLOR:     return 0;
+	case OBS_PROPERTY_BUTTON:    return sizeof(struct button_data);
 	}
 
 	return 0;
@@ -350,6 +356,18 @@ obs_property_t obs_properties_add_color(obs_properties_t props,
 	return new_prop(props, name, desc, OBS_PROPERTY_COLOR);
 }
 
+obs_property_t obs_properties_add_button(obs_properties_t props,
+		const char *name, const char *text,
+		obs_property_clicked_t callback)
+{
+	if (!props || has_prop(props, name)) return NULL;
+
+	struct obs_property *p = new_prop(props, name, text,
+			OBS_PROPERTY_BUTTON);
+	struct button_data *data = get_property_data(p);
+	data->callback = callback;
+	return p;
+}
 
 static inline bool is_combo(struct obs_property *p)
 {
@@ -395,6 +413,19 @@ bool obs_property_modified(obs_property_t p, obs_data_t settings)
 	return false;
 }
 
+bool obs_property_button_clicked(obs_property_t p, void *obj)
+{
+	struct obs_context_data *context = obj;
+	if (p) {
+		struct button_data *data = get_type_data(p,
+				OBS_PROPERTY_BUTTON);
+		if (data && data->callback)
+			return data->callback(p->parent, p, context->data);
+	}
+
+	return false;
+}
+
 void obs_property_set_visible(obs_property_t p, bool visible)
 {
 	if (p) p->visible = visible;

libobs/obs-properties.h

@@ -33,6 +33,7 @@ enum obs_property_type {
 	OBS_PROPERTY_PATH,
 	OBS_PROPERTY_LIST,
 	OBS_PROPERTY_COLOR,
+	OBS_PROPERTY_BUTTON,
 };
 
 enum obs_combo_format {
@@ -82,6 +83,14 @@ extern void obs_properties_apply_settings(obs_properties_t props,
 
 /* ------------------------------------------------------------------------- */
 
+/**
+ * Callback for when a button property is clicked.  If the properties
+ * need to be refreshed due to changes to the property layout, return true,
+ * otherwise return false.
+ */
+typedef bool (*obs_property_clicked_t)(obs_properties_t props,
+		obs_property_t property, void *data);
+
 EXPORT obs_property_t obs_properties_add_bool(obs_properties_t props,
 		const char *name, const char *description);
 
@@ -107,6 +116,10 @@ EXPORT obs_property_t obs_properties_add_list(obs_properties_t props,
 EXPORT obs_property_t obs_properties_add_color(obs_properties_t props,
 		const char *name, const char *description);
 
+EXPORT obs_property_t obs_properties_add_button(obs_properties_t props,
+		const char *name, const char *text,
+		obs_property_clicked_t callback);
+
 /* ------------------------------------------------------------------------- */
 
 /**
@@ -121,6 +134,7 @@ EXPORT void obs_property_set_modified_callback(obs_property_t p,
 		obs_property_modified_t modified);
 
 EXPORT bool obs_property_modified(obs_property_t p, obs_data_t settings);
+EXPORT bool obs_property_button_clicked(obs_property_t p, void *obj);
 
 EXPORT void obs_property_set_visible(obs_property_t p, bool visible);
 EXPORT void obs_property_set_enabled(obs_property_t p, bool enabled);