common/menu.c

   1 /*
   2  * Copyright 2010-2011 Calxeda, Inc.
   3  *
   4  * SPDX-License-Identifier:     GPL-2.0+
   5  */
   6
   7 #include <common.h>
   8 #include <cli.h>
   9 #include <malloc.h>
  10 #include <errno.h>
  11 #include <linux/list.h>
  12
  13 #include "menu.h"
  14
  15 /*
  16  * Internally, each item in a menu is represented by a struct menu_item.
  17  *
  18  * These items will be alloc'd and initialized by menu_item_add and destroyed
  19  * by menu_item_destroy, and the consumer of the interface never sees that
  20  * this struct is used at all.
  21  */
  22 struct menu_item {
  23         char *key;
  24         void *data;
  25         struct list_head list;
  26 };
  27
  28 /*
  29  * The menu is composed of a list of items along with settings and callbacks
  30  * provided by the user. An incomplete definition of this struct is available
  31  * in menu.h, but the full definition is here to prevent consumers from
  32  * relying on its contents.
  33  */
  34 struct menu {
  35         struct menu_item *default_item;
  36         int timeout;
  37         char *title;
  38         int prompt;
  39         void (*item_data_print)(void *);
  40         char *(*item_choice)(void *);
  41         void *item_choice_data;
  42         struct list_head items;
  43 };
  44
  45 /*
  46  * An iterator function for menu items. callback will be called for each item
  47  * in m, with m, a pointer to the item, and extra being passed to callback. If
  48  * callback returns a value other than NULL, iteration stops and the value
  49  * return by callback is returned from menu_items_iter.  This allows it to be
  50  * used for search type operations. It is also safe for callback to remove the
  51  * item from the list of items.
  52  */
  53 static inline void *menu_items_iter(struct menu *m,
  54                 void *(*callback)(struct menu *, struct menu_item *, void *),
  55                 void *extra)
  56 {
  57         struct list_head *pos, *n;
  58         struct menu_item *item;
  59         void *ret;
  60
  61         list_for_each_safe(pos, n, &m->items) {
  62                 item = list_entry(pos, struct menu_item, list);
  63
  64                 ret = callback(m, item, extra);
  65
  66                 if (ret)
  67                         return ret;
  68         }
  69
  70         return NULL;
  71 }
  72
  73 /*
  74  * Print a menu_item. If the consumer provided an item_data_print function
  75  * when creating the menu, call it with a pointer to the item's private data.
  76  * Otherwise, print the key of the item.
  77  */
  78 static inline void *menu_item_print(struct menu *m,
  79                                 struct menu_item *item,
  80                                 void *extra)
  81 {
  82         if (!m->item_data_print) {
  83                 puts(item->key);
  84                 putc('\n');
  85         } else {
  86                 m->item_data_print(item->data);
  87         }
  88
  89         return NULL;
  90 }
  91
  92 /*
  93  * Free the memory used by a menu item. This includes the memory used by its
  94  * key.
  95  */
  96 static inline void *menu_item_destroy(struct menu *m,
  97                                 struct menu_item *item,
  98                                 void *extra)
  99 {
 100         if (item->key)
 101                 free(item->key);
 102
 103         free(item);
 104
 105         return NULL;
 106 }
 107
 108 __weak void menu_display_statusline(struct menu *m)
 109 {
 110 }
 111
 112 /*
 113  * Display a menu so the user can make a choice of an item. First display its
 114  * title, if any, and then each item in the menu.
 115  */
 116 static inline void menu_display(struct menu *m)
 117 {
 118         if (m->title) {
 119                 puts(m->title);
 120                 putc('\n');
 121         }
 122         menu_display_statusline(m);
 123
 124         menu_items_iter(m, menu_item_print, NULL);
 125 }
 126
 127 /*
 128  * Check if an item's key matches a provided string, pointed to by extra. If
 129  * extra is NULL, an item with a NULL key will match. Otherwise, the item's
 130  * key has to match according to strcmp.
 131  *
 132  * This is called via menu_items_iter, so it returns a pointer to the item if
 133  * the key matches, and returns NULL otherwise.
 134  */
 135 static inline void *menu_item_key_match(struct menu *m,
 136                         struct menu_item *item, void *extra)
 137 {
 138         char *item_key = extra;
 139
 140         if (!item_key || !item->key) {
 141                 if (item_key == item->key)
 142                         return item;
 143
 144                 return NULL;
 145         }
 146
 147         if (strcmp(item->key, item_key) == 0)
 148                 return item;
 149
 150         return NULL;
 151 }
 152
 153 /*
 154  * Find the first item with a key matching item_key, if any exists.
 155  */
 156 static inline struct menu_item *menu_item_by_key(struct menu *m,
 157                                                         char *item_key)
 158 {
 159         return menu_items_iter(m, menu_item_key_match, item_key);
 160 }
 161
 162 /*
 163  * Set *choice to point to the default item's data, if any default item was
 164  * set, and returns 1. If no default item was set, returns -ENOENT.
 165  */
 166 int menu_default_choice(struct menu *m, void **choice)
 167 {
 168         if (m->default_item) {
 169                 *choice = m->default_item->data;
 170                 return 1;
 171         }
 172
 173         return -ENOENT;
 174 }
 175
 176 /*
 177  * Displays the menu and asks the user to choose an item. *choice will point
 178  * to the private data of the item the user chooses. The user makes a choice
 179  * by inputting a string matching the key of an item. Invalid choices will
 180  * cause the user to be prompted again, repeatedly, until the user makes a
 181  * valid choice. The user can exit the menu without making a choice via ^c.
 182  *
 183  * Returns 1 if the user made a choice, or -EINTR if they bail via ^c.
 184  */
 185 static inline int menu_interactive_choice(struct menu *m, void **choice)
 186 {
 187         char cbuf[CONFIG_SYS_CBSIZE];
 188         struct menu_item *choice_item = NULL;
 189         int readret;
 190
 191         while (!choice_item) {
 192                 cbuf[0] = '\0';
 193
 194                 menu_display(m);
 195
 196                 if (!m->item_choice) {
 197                         readret = cli_readline_into_buffer("Enter choice: ",
 198                                                            cbuf,
 199                                                            m->timeout / 10);
 200
 201                         if (readret >= 0) {
 202                                 choice_item = menu_item_by_key(m, cbuf);
 203                                 if (!choice_item)
 204                                         printf("%s not found\n", cbuf);
 205                         } else {
 206                                 return menu_default_choice(m, choice);
 207                         }
 208                 } else {
 209                         char *key = m->item_choice(m->item_choice_data);
 210
 211                         if (key)
 212                                 choice_item = menu_item_by_key(m, key);
 213                 }
 214
 215                 if (!choice_item)
 216                         m->timeout = 0;
 217         }
 218
 219         *choice = choice_item->data;
 220
 221         return 1;
 222 }
 223
 224 /*
 225  * menu_default_set() - Sets the default choice for the menu. This is safe to
 226  * call more than once on a menu.
 227  *
 228  * m - Points to a menu created by menu_create().
 229  *
 230  * item_key - Points to a string that, when compared using strcmp, matches the
 231  * key for an existing item in the menu.
 232  *
 233  * Returns 1 if successful, -EINVAL if m is NULL, or -ENOENT if no item with a
 234  * key matching item_key is found.
 235  */
 236 int menu_default_set(struct menu *m, char *item_key)
 237 {
 238         struct menu_item *item;
 239
 240         if (!m)
 241                 return -EINVAL;
 242
 243         item = menu_item_by_key(m, item_key);
 244
 245         if (!item)
 246                 return -ENOENT;
 247
 248         m->default_item = item;
 249
 250         return 1;
 251 }
 252
 253 /*
 254  * menu_get_choice() - Returns the user's selected menu entry, or the default
 255  * if the menu is set to not prompt or the timeout expires. This is safe to
 256  * call more than once.
 257  *
 258  * m - Points to a menu created by menu_create().
 259  *
 260  * choice - Points to a location that will store a pointer to the selected
 261  * menu item. If no item is selected or there is an error, no value will be
 262  * written at the location it points to.
 263  *
 264  * Returns 1 if successful, -EINVAL if m or choice is NULL, -ENOENT if no
 265  * default has been set and the menu is set to not prompt or the timeout
 266  * expires, or -EINTR if the user exits the menu via ^c.
 267  */
 268 int menu_get_choice(struct menu *m, void **choice)
 269 {
 270         if (!m || !choice)
 271                 return -EINVAL;
 272
 273         if (!m->prompt)
 274                 return menu_default_choice(m, choice);
 275
 276         return menu_interactive_choice(m, choice);
 277 }
 278
 279 /*
 280  * menu_item_add() - Adds or replaces a menu item. Note that this replaces the
 281  * data of an item if it already exists, but doesn't change the order of the
 282  * item.
 283  *
 284  * m - Points to a menu created by menu_create().
 285  *
 286  * item_key - Points to a string that will uniquely identify the item.  The
 287  * string will be copied to internal storage, and is safe to discard after
 288  * passing to menu_item_add.
 289  *
 290  * item_data - An opaque pointer associated with an item. It is never
 291  * dereferenced internally, but will be passed to the item_data_print, and
 292  * will be returned from menu_get_choice if the menu item is selected.
 293  *
 294  * Returns 1 if successful, -EINVAL if m is NULL, or -ENOMEM if there is
 295  * insufficient memory to add the menu item.
 296  */
 297 int menu_item_add(struct menu *m, char *item_key, void *item_data)
 298 {
 299         struct menu_item *item;
 300
 301         if (!m)
 302                 return -EINVAL;
 303
 304         item = menu_item_by_key(m, item_key);
 305
 306         if (item) {
 307                 item->data = item_data;
 308                 return 1;
 309         }
 310
 311         item = malloc(sizeof *item);
 312         if (!item)
 313                 return -ENOMEM;
 314
 315         item->key = strdup(item_key);
 316
 317         if (!item->key) {
 318                 free(item);
 319                 return -ENOMEM;
 320         }
 321
 322         item->data = item_data;
 323
 324         list_add_tail(&item->list, &m->items);
 325
 326         return 1;
 327 }
 328
 329 /*
 330  * menu_create() - Creates a menu handle with default settings
 331  *
 332  * title - If not NULL, points to a string that will be displayed before the
 333  * list of menu items. It will be copied to internal storage, and is safe to
 334  * discard after passing to menu_create().
 335  *
 336  * timeout - A delay in seconds to wait for user input. If 0, timeout is
 337  * disabled, and the default choice will be returned unless prompt is 1.
 338  *
 339  * prompt - If 0, don't ask for user input unless there is an interrupted
 340  * timeout. If 1, the user will be prompted for input regardless of the value
 341  * of timeout.
 342  *
 343  * item_data_print - If not NULL, will be called for each item when the menu
 344  * is displayed, with the pointer to the item's data passed as the argument.
 345  * If NULL, each item's key will be printed instead.  Since an item's key is
 346  * what must be entered to select an item, the item_data_print function should
 347  * make it obvious what the key for each entry is.
 348  *
 349  * item_choice - If not NULL, will be called when asking the user to choose an
 350  * item. Returns a key string corresponding to the choosen item or NULL if
 351  * no item has been selected.
 352  *
 353  * item_choice_data - Will be passed as the argument to the item_choice function
 354  *
 355  * Returns a pointer to the menu if successful, or NULL if there is
 356  * insufficient memory available to create the menu.
 357  */
 358 struct menu *menu_create(char *title, int timeout, int prompt,
 359                                 void (*item_data_print)(void *),
 360                                 char *(*item_choice)(void *),
 361                                 void *item_choice_data)
 362 {
 363         struct menu *m;
 364
 365         m = malloc(sizeof *m);
 366
 367         if (!m)
 368                 return NULL;
 369
 370         m->default_item = NULL;
 371         m->prompt = prompt;
 372         m->timeout = timeout;
 373         m->item_data_print = item_data_print;
 374         m->item_choice = item_choice;
 375         m->item_choice_data = item_choice_data;
 376
 377         if (title) {
 378                 m->title = strdup(title);
 379                 if (!m->title) {
 380                         free(m);
 381                         return NULL;
 382                 }
 383         } else
 384                 m->title = NULL;
 385
 386
 387         INIT_LIST_HEAD(&m->items);
 388
 389         return m;
 390 }
 391
 392 /*
 393  * menu_destroy() - frees the memory used by a menu and its items.
 394  *
 395  * m - Points to a menu created by menu_create().
 396  *
 397  * Returns 1 if successful, or -EINVAL if m is NULL.
 398  */
 399 int menu_destroy(struct menu *m)
 400 {
 401         if (!m)
 402                 return -EINVAL;
 403
 404         menu_items_iter(m, menu_item_destroy, NULL);
 405
 406         if (m->title)
 407                 free(m->title);
 408
 409         free(m);
 410
 411         return 1;
 412 }