ui/ncurses: Separate menu item creation & initialisation from insertion

Currently, the menu item creation is has two main functions:
pmenu_item_alloc and pmenu_item_setup. The latter does initialisation
(it sets item->name), and inserts the item into the menu. We have
pmenu_item_init to combine this into one, but that means we need to do
further initialisation (eg, to set on_execute) after the item has been
added to the menu.

Instead, this change use a more direct _create and _insert interface.
Create does the allocation and initialisation, while _insert does the
actual insertion.

This means new_item failures will be detected at creation time, rather
than during pmenu_insert. Also, we're now insert a completely-populated
item into the menu, rather than populating on_edit, on_execute and data
after insertion.

Because we can detect errors from creation (ie, from new_item failing),
we add handling code to cui_boot_option_add and cui_boot_editor_on_exit.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>

4 files changed, 67 insertions, 70 deletions

diff --git a/ui/ncurses/generic-main.c b/ui/ncurses/generic-main.c
index 67b0b61..0d0a38a 100644
--- a/ui/ncurses/generic-main.c
+++ b/ui/ncurses/generic-main.c
@@ -201,16 +201,25 @@ static struct pmenu *pb_mm_init(struct pb_cui *pb_cui)
 		"Enter=accept, e=edit, n=new, x=exit, h=help");
 	m->scr.frame.status = talloc_strdup(m, "Welcome to Petitboot");
 
-	i = pmenu_item_init(m, 0, " ");
+	i = pmenu_item_create(m, " ");
 	item_opts_off(i->nci, O_SELECTABLE);
-	i = pmenu_item_init(m, 1, "System information");
+	pmenu_item_insert(m, i, 0);
+
+	i = pmenu_item_create(m, "System information");
 	i->on_execute = pmenu_sysinfo;
-	i = pmenu_item_init(m, 2, "System configuration");
+	pmenu_item_insert(m, i, 1);
+
+	i = pmenu_item_create(m, "System configuration");
 	i->on_execute = pmenu_config;
-	i = pmenu_item_init(m, 3, "Rescan devices");
+	pmenu_item_insert(m, i, 2);
+
+	i = pmenu_item_create(m, "Rescan devices");
 	i->on_execute = pmenu_reinit;
-	i = pmenu_item_init(m, 4, "Exit to shell");
+	pmenu_item_insert(m, i, 3);
+
+	i = pmenu_item_create(m, "Exit to shell");
 	i->on_execute = pmenu_exit_cb;
+	pmenu_item_insert(m, i, 4);
 
 	result = pmenu_setup(m);
 
diff --git a/ui/ncurses/nc-cui.c b/ui/ncurses/nc-cui.c
index e8aaf9a..3a89869 100644
--- a/ui/ncurses/nc-cui.c
+++ b/ui/ncurses/nc-cui.c
@@ -175,22 +175,27 @@ static void cui_boot_editor_on_exit(struct cui *cui,
 	if (!item) {
 		int insert_pt;
 
+		cod = talloc_zero(NULL, struct cui_opt_data);
+		cod->name = talloc_asprintf(cod, "User item %u", ++user_idx);
+
+		item = pmenu_item_create(menu, cod->name);
+		if (!item) {
+			talloc_free(cod);
+			goto out;
+		}
+
+		item->on_edit = cui_item_edit;
+		item->on_execute = cui_boot;
+		item->data = cod;
+
+		talloc_steal(item, cod);
+
 		/* Detach the items array. */
 		set_menu_items(menu->ncm, NULL);
 
 		/* Insert new item at insert_pt. */
 		insert_pt = pmenu_grow(menu, 1);
-		item = pmenu_item_alloc(menu);
-		item->on_edit = cui_item_edit;
-		item->on_execute = cui_boot;
-		item->data = cod = talloc_zero(item, struct cui_opt_data);
-
-		cod->name = talloc_asprintf(cod, "User item %u:", ++user_idx);
-		if (pmenu_item_setup(menu, item, insert_pt,
-				talloc_strdup(item, cod->name)) == NULL) {
-			talloc_free(item);
-			item = NULL;
-		}
+		pmenu_item_insert(menu, item, insert_pt);
 
 		/* Re-attach the items array. */
 		set_menu_items(menu->ncm, menu->items);
@@ -201,8 +206,8 @@ static void cui_boot_editor_on_exit(struct cui *cui,
 
 	cod->bd = talloc_steal(cod, bd);
 
-	if (item)
-		set_current_item(item->pmenu->ncm, item->nci);
+	set_current_item(item->pmenu->ncm, item->nci);
+out:
 	cui_set_current(cui, &cui->main->scr);
 	talloc_free(cui->boot_editor);
 	cui->boot_editor = NULL;
@@ -407,19 +412,11 @@ static int cui_boot_option_add(struct device *dev, struct boot_option *opt,
 	if (cui->current == &cui->main->scr)
 		nc_scr_unpost(cui->current);
 
-	/* This disconnects items array from menu. */
-
-	result = set_menu_items(cui->main->ncm, NULL);
-
-	if (result)
-		pb_log("%s: set_menu_items failed: %d\n", __func__, result);
-
-	/* Insert new items at insert_pt. */
-	insert_pt = pmenu_grow(cui->main, 1);
-
 	/* Save the item in opt->ui_info for cui_device_remove() */
 
-	opt->ui_info = i = pmenu_item_alloc(cui->main);
+	opt->ui_info = i = pmenu_item_create(cui->main, opt->name);
+	if (!i)
+		return -1;
 
 	i->on_edit = cui_item_edit;
 	i->on_execute = cui_boot;
@@ -436,7 +433,15 @@ static int cui_boot_option_add(struct device *dev, struct boot_option *opt,
 	cod->bd->dtb = talloc_strdup(cod->bd, opt->dtb_file);
 	cod->bd->args = talloc_strdup(cod->bd, opt->boot_args);
 
-	pmenu_item_setup(cui->main, i, insert_pt, cod->name);
+	/* This disconnects items array from menu. */
+	result = set_menu_items(cui->main->ncm, NULL);
+
+	if (result)
+		pb_log("%s: set_menu_items failed: %d\n", __func__, result);
+
+	/* Insert new items at insert_pt. */
+	insert_pt = pmenu_grow(cui->main, 1);
+	pmenu_item_insert(cui->main, i, insert_pt);
 
 	pb_log("%s: adding opt '%s'\n", __func__, cod->name);
 	pb_log("   image  '%s'\n", cod->bd->image);
diff --git a/ui/ncurses/nc-menu.c b/ui/ncurses/nc-menu.c
index ef00ff2..5691f42 100644
--- a/ui/ncurses/nc-menu.c
+++ b/ui/ncurses/nc-menu.c
@@ -77,43 +77,39 @@ static void pmenu_resize(struct nc_scr *scr)
 }
 
 /**
- * pmenu_item_init - Allocate and initialize a new pmenu_item instance.
+ * pmenu_item_create - Allocate and initialize a new pmenu_item instance.
  *
  * Returns a pointer the the initialized struct pmenu_item instance or NULL
  * on error. The caller is responsible for calling talloc_free() for the
  * returned instance.
  */
-
-struct pmenu_item *pmenu_item_alloc(struct pmenu *menu)
+struct pmenu_item *pmenu_item_create(struct pmenu *menu, const char *name)
 {
-	/* Items go with the menu, not the pointer array. */
-
-	struct pmenu_item *i = talloc_zero(menu, struct pmenu_item);
+	struct pmenu_item *item = talloc_zero(menu, struct pmenu_item);
 
-	return i;
-}
-
-struct pmenu_item *pmenu_item_setup(struct pmenu *menu, struct pmenu_item *i,
-	unsigned int index, const char *name)
-{
-	assert(i);
-	assert(name);
+	item->i_sig = pb_item_sig;
+	item->pmenu = menu;
+	item->nci = new_item(name, NULL);
 
-	if (!i)
+	if (!item->nci) {
+		talloc_free(item);
 		return NULL;
+	}
 
-	i->i_sig = pb_item_sig;
-	i->pmenu = menu;
-	i->nci = new_item(name, NULL);
-
-	if (!i->nci)
-		return NULL;
+	set_item_userptr(item->nci, item);
 
-	set_item_userptr(i->nci, i);
+	return item;
+}
 
-	menu->items[index] = i->nci;
+void pmenu_item_insert(struct pmenu *menu, struct pmenu_item *item,
+	unsigned int index)
+{
+	assert(item);
+	assert(index < menu->item_count);
+	assert(menu->items[index] == NULL);
+	assert(menu_items(menu->ncm) == NULL);
 
-	return i;
+	menu->items[index] = item->nci;
 }
 
 static int pmenu_item_get_index(const struct pmenu_item *item)
diff --git a/ui/ncurses/nc-menu.h b/ui/ncurses/nc-menu.h
index 63da2e5..8e9c56b 100644
--- a/ui/ncurses/nc-menu.h
+++ b/ui/ncurses/nc-menu.h
@@ -53,9 +53,9 @@ struct pmenu_item {
 	int (*on_execute)(struct pmenu_item *item);
 };
 
-struct pmenu_item *pmenu_item_alloc(struct pmenu *menu);
-struct pmenu_item *pmenu_item_setup(struct pmenu *menu, struct pmenu_item *i,
-	unsigned int index, const char *name);
+struct pmenu_item *pmenu_item_create(struct pmenu *menu, const char *name);
+void pmenu_item_insert(struct pmenu *menu, struct pmenu_item *item,
+	unsigned int index);
 void pmenu_item_delete(struct pmenu_item *item);
 
 static inline struct pmenu_item *pmenu_item_from_arg(void *arg)
@@ -71,19 +71,6 @@ static inline struct cui_opt_data *cod_from_item(struct pmenu_item *item)
 	return item->data;
 }
 
-static inline struct pmenu_item *pmenu_item_init(struct pmenu *menu,
-	unsigned int index, const char *name)
-{
-	struct pmenu_item *item = pmenu_item_alloc(menu);
-
-	if (pmenu_item_setup(menu, item, index, name)) {
-		talloc_free(item);
-		item = NULL;
-	}
-
-	return item;
-}
-
 /**
  * struct pmenu - Data structure defining complete menu.
  * @insert_pt: Index in nc item array.