Fix memory leak for battery tooltips

Instead of returning a const string, that is fed into strdup, tooltip
functions are now supposed to return allocated strings. This fixes a
memory leak in the battery tooltip.

This is used instead of simply freeing the memory in the battery
tooltip function, since it also avoids a uselesss strdup().

src/battery/battery.c

@@ -220,7 +220,7 @@ void init_battery()
 		battery_timeout = add_timeout(10, 30000, update_battery_tick, 0, &battery_timeout);
 }
 
-const char* battery_get_tooltip(void* obj) {
+char* battery_get_tooltip(void* obj) {
 #if defined(__linux)
 	return linux_batteries_get_tooltip();
 #else

src/battery/battery.h

@@ -97,7 +97,7 @@ void battery_action(int button);
 gboolean init_linux_batteries();
 void free_linux_batteries();
 void update_linux_batteries(enum chargestate *state, gint64 *energy_now, gint64 *energy_full, int *seconds);
-const char* linux_batteries_get_tooltip();
+char* linux_batteries_get_tooltip();
 #endif
 
 #endif

src/battery/linux.c

@@ -319,7 +319,7 @@ static gchar* power_human_readable(struct psy_battery *bat) {
 	}
 }
 
-const char* linux_batteries_get_tooltip() {
+char* linux_batteries_get_tooltip() {
 	GList *l;
 	GString *tooltip = g_string_new("");
 	gchar *result;

src/clock/clock.c

@@ -144,10 +144,10 @@ struct tm* clock_gettime_for_tz(const char* timezone) {
 	else return localtime(&time_clock.tv_sec);
 }
 
-const char* clock_get_tooltip(void* obj)
+char* clock_get_tooltip(void* obj)
 {
 	strftime(buf_tooltip, sizeof(buf_tooltip), time_tooltip_format, clock_gettime_for_tz(time_tooltip_timezone));
-	return buf_tooltip;
+	return strdup(buf_tooltip);
 }
 
 int time_format_needs_sec_ticks(char *time_format)

src/launcher/launcher.c

@@ -347,10 +347,10 @@ void launcher_icon_on_change_layout(void *obj)
 	launcherIcon->area.height = launcherIcon->icon_size;
 }
 
-const char* launcher_icon_get_tooltip_text(void *obj)
+char* launcher_icon_get_tooltip_text(void *obj)
 {
 	LauncherIcon *launcherIcon = (LauncherIcon*)obj;
-	return launcherIcon->icon_tooltip;
+	return strdup(launcherIcon->icon_tooltip);
 }
 
 void draw_launcher_icon(void *obj, cairo_t *c)

src/taskbar/task.c

@@ -38,10 +38,10 @@
 timeout* urgent_timeout;
 GSList* urgent_list;
 
-const char* task_get_tooltip(void* obj)
+char* task_get_tooltip(void* obj)
 {
 	Task* t = obj;
-	return t->title;
+	return strdup(t->title);
 }
 
 

src/tooltip/tooltip.c

@@ -304,7 +304,7 @@ void tooltip_copy_text(Area* area)
 {
 	free(g_tooltip.tooltip_text);
 	if (area && area->_get_tooltip_text)
-		g_tooltip.tooltip_text = strdup(area->_get_tooltip_text(area));
+		g_tooltip.tooltip_text = area->_get_tooltip_text(area);
 	else
 		g_tooltip.tooltip_text = NULL;
 	g_tooltip.area = area;

src/util/area.h

@@ -91,7 +91,8 @@ typedef struct {
 	// after pos/size changed, the rendering engine will call _on_change_layout(Area*)
 	int on_changed;
 	void (*_on_change_layout)(void *obj);
-	const char* (*_get_tooltip_text)(void *obj);
+	// returns allocated string, that must be free'd after usage
+	char* (*_get_tooltip_text)(void *obj);
 } Area;
 
 // on startup, initialize fixed pos/size