gui: Constify list title text

Use const char* pointers for list titles. Only one debug menu
actually modifies the title, and in that case it's legal to
cast away const because the title points to a known mutable
buffer on the stack.

Change-Id: Idb8ab307b9a6ec23a93d8420c5e19fafd9f59c30

apps/debug_menu.c

@@ -1247,7 +1247,8 @@ static int disk_callback(int btn, struct gui_synclist *lists)
     int *cardnum = (int*)lists->data;
     unsigned char card_name[6];
     unsigned char pbuf[32];
-    char *title = lists->title;
+    /* Casting away const is safe; the buffer is defined as non-const. */
+    char *title = (char *)lists->title;
     static const unsigned char i_vmin[] = { 0, 1, 5, 10, 25, 35, 60, 100 };
     static const unsigned char i_vmax[] = { 1, 5, 10, 25, 35, 45, 80, 200 };
     static const unsigned char * const kbit_units[] = { "kBit/s", "MBit/s", "GBit/s" };

apps/gui/bitmap/list.c

@@ -103,7 +103,7 @@ static void _default_listdraw_fn(struct list_putlineinfo_t *list_info)
     bool show_cursor = list_info->show_cursor;
     bool have_icons = list_info->have_icons;
     struct line_desc *linedes = list_info->linedes;
-    char *dsp_text = list_info->dsp_text;
+    const char *dsp_text = list_info->dsp_text;
 
     if (is_title)
     {

apps/gui/list.c

@@ -490,7 +490,7 @@ void gui_list_screen_scroll_out_of_view(bool enable)
  * both the title and icon. Use NOICON if there is no icon.
  */
 void gui_synclist_set_title(struct gui_synclist * gui_list,
-                            char * title, enum themable_icons icon)
+                            const char * title, enum themable_icons icon)
 {
     gui_list->title = title;
     gui_list->title_icon = icon;

apps/gui/list.h

@@ -96,7 +96,7 @@ struct list_putlineinfo_t {
     struct viewport *vp;
     struct line_desc *linedes;
     struct gui_synclist * list;
-    char *dsp_text;
+    const char *dsp_text;
 
     bool is_selected;
     bool is_title;
@@ -185,7 +185,7 @@ struct gui_synclist
     /* The data that will be passed to the callback function YOU implement */
     void * data;
     /* The optional title, set to NULL for none */
-    char * title;
+    const char * title;
     /* Optional title icon */
     enum themable_icons title_icon;
 
@@ -233,7 +233,7 @@ extern void gui_synclist_select_item(struct gui_synclist * lists,
 extern void gui_synclist_add_item(struct gui_synclist * lists);
 extern void gui_synclist_del_item(struct gui_synclist * lists);
 extern void gui_synclist_limit_scroll(struct gui_synclist * lists, bool scroll);
-extern void gui_synclist_set_title(struct gui_synclist * lists, char * title,
+extern void gui_synclist_set_title(struct gui_synclist * lists, const char * title,
                                    enum themable_icons icon);
 extern void gui_synclist_hide_selection_marker(struct gui_synclist *lists,
                                                 bool hide);
@@ -301,7 +301,7 @@ extern bool list_do_action(int context, int timeout,
  **/
 
 struct simplelist_info {
-    char *title; /* title to show on the list */
+    const char *title; /* title to show on the list */
     int  count; /* number of items in the list, each item is selection_size high */
     int selection_size; /* list selection size, usually 1 */
     bool hide_selection;

apps/gui/statusbar-skinned.c

@@ -49,11 +49,11 @@
 static int update_delay = DEFAULT_UPDATE_DELAY;
 
 static bool sbs_has_title[NB_SCREENS];
-static char* sbs_title[NB_SCREENS];
+static const char* sbs_title[NB_SCREENS];
 static enum themable_icons sbs_icon[NB_SCREENS];
 static bool sbs_loaded[NB_SCREENS] = { false };
 
-bool sb_set_title_text(char* title, enum themable_icons icon, enum screen_type screen)
+bool sb_set_title_text(const char* title, enum themable_icons icon, enum screen_type screen)
 {
     sbs_title[screen] = title;
     /* Icon_NOICON == -1 which the skin engine wants at position 1, so + 2 */

apps/gui/statusbar-skinned.h

@@ -39,7 +39,7 @@ struct viewport *sb_skin_get_info_vp(enum screen_type screen);
 void sb_skin_update(enum screen_type screen, bool force);
 
 void sb_skin_set_update_delay(int delay);
-bool sb_set_title_text(char* title, enum themable_icons icon, enum screen_type screen);
+bool sb_set_title_text(const char* title, enum themable_icons icon, enum screen_type screen);
 void sb_skin_has_title(enum screen_type screen);
 const char* sb_get_title(enum screen_type screen);
 enum themable_icons sb_get_icon(enum screen_type screen);

apps/plugin.h

@@ -387,7 +387,7 @@ struct plugin_api {
     void (*gui_synclist_limit_scroll)(struct gui_synclist * lists, bool scroll);
     bool (*gui_synclist_do_button)(struct gui_synclist * lists,
                                    int *action, enum list_wrap wrap);
-    void (*gui_synclist_set_title)(struct gui_synclist *lists, char* title,
+    void (*gui_synclist_set_title)(struct gui_synclist *lists, const char* title,
                                    enum themable_icons icon);
     enum yesno_res (*gui_syncyesno_run)(const struct text_message * main_message,
                                         const struct text_message * yes_message,

apps/plugins/lib/printcell_helper.c

@@ -234,7 +234,7 @@ static void printcell_listdraw_fn(struct list_putlineinfo_t *list_info)
     bool show_cursor = list_info->show_cursor;
     bool have_icons = list_info->have_icons;
     struct line_desc *linedes = list_info->linedes;
-    char *dsp_text = list_info->dsp_text;
+    const char *dsp_text = list_info->dsp_text;
     struct viewport *vp = list_info->vp;
     int line = list_info->line;