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 if (readret == -1)  {
 206                                 printf("<INTERRUPT>\n");
 207                                 return -EINTR;
 208                         } else {
 209                                 return menu_default_choice(m, choice);
 210                         }
 211                 } else {
 212                         char *key = m->item_choice(m->item_choice_data);
 213
 214                         if (key)
 215                                 choice_item = menu_item_by_key(m, key);
 216                 }
 217
 218                 if (!choice_item)
 219                         m->timeout = 0;
 220         }
 221
 222         *choice = choice_item->data;
 223
 224         return 1;
 225 }
 226
 227 /*
 228  * menu_default_set() - Sets the default choice for the menu. This is safe to
 229  * call more than once on a menu.
 230  *
 231  * m - Points to a menu created by menu_create().
 232  *
 233  * item_key - Points to a string that, when compared using strcmp, matches the
 234  * key for an existing item in the menu.
 235  *
 236  * Returns 1 if successful, -EINVAL if m is NULL, or -ENOENT if no item with a
 237  * key matching item_key is found.
 238  */
 239 int menu_default_set(struct menu *m, char *item_key)
 240 {
 241         struct menu_item *item;
 242
 243         if (!m)
 244                 return -EINVAL;
 245
 246         item = menu_item_by_key(m, item_key);
 247
 248         if (!item)
 249                 return -ENOENT;
 250
 251         m->default_item = item;
 252
 253         return 1;
 254 }
 255
 256 /*
 257  * menu_get_choice() - Returns the user's selected menu entry, or the default
 258  * if the menu is set to not prompt or the timeout expires. This is safe to
 259  * call more than once.
 260  *
 261  * m - Points to a menu created by menu_create().
 262  *
 263  * choice - Points to a location that will store a pointer to the selected
 264  * menu item. If no item is selected or there is an error, no value will be
 265  * written at the location it points to.
 266  *
 267  * Returns 1 if successful, -EINVAL if m or choice is NULL, -ENOENT if no
 268  * default has been set and the menu is set to not prompt or the timeout
 269  * expires, or -EINTR if the user exits the menu via ^c.
 270  */
 271 int menu_get_choice(struct menu *m, void **choice)
 272 {
 273         if (!m || !choice)
 274                 return -EINVAL;
 275
 276         if (!m->prompt)
 277                 return menu_default_choice(m, choice);
 278
 279         return menu_interactive_choice(m, choice);
 280 }
 281
 282 /*
 283  * menu_item_add() - Adds or replaces a menu item. Note that this replaces the
 284  * data of an item if it already exists, but doesn't change the order of the
 285  * item.
 286  *
 287  * m - Points to a menu created by menu_create().
 288  *
 289  * item_key - Points to a string that will uniquely identify the item.  The
 290  * string will be copied to internal storage, and is safe to discard after
 291  * passing to menu_item_add.
 292  *
 293  * item_data - An opaque pointer associated with an item. It is never
 294  * dereferenced internally, but will be passed to the item_data_print, and
 295  * will be returned from menu_get_choice if the menu item is selected.
 296  *
 297  * Returns 1 if successful, -EINVAL if m is NULL, or -ENOMEM if there is
 298  * insufficient memory to add the menu item.
 299  */
 300 int menu_item_add(struct menu *m, char *item_key, void *item_data)
 301 {
 302         struct menu_item *item;
 303
 304         if (!m)
 305                 return -EINVAL;
 306
 307         item = menu_item_by_key(m, item_key);
 308
 309         if (item) {
 310                 item->data = item_data;
 311                 return 1;
 312         }
 313
 314         item = malloc(sizeof *item);
 315         if (!item)
 316                 return -ENOMEM;
 317
 318         item->key = strdup(item_key);
 319
 320         if (!item->key) {
 321                 free(item);
 322                 return -ENOMEM;
 323         }
 324
 325         item->data = item_data;
 326
 327         list_add_tail(&item->list, &m->items);
 328
 329         return 1;
 330 }
 331
 332 /*
 333  * menu_create() - Creates a menu handle with default settings
 334  *
 335  * title - If not NULL, points to a string that will be displayed before the
 336  * list of menu items. It will be copied to internal storage, and is safe to
 337  * discard after passing to menu_create().
 338  *
 339  * timeout - A delay in seconds to wait for user input. If 0, timeout is
 340  * disabled, and the default choice will be returned unless prompt is 1.
 341  *
 342  * prompt - If 0, don't ask for user input unless there is an interrupted
 343  * timeout. If 1, the user will be prompted for input regardless of the value
 344  * of timeout.
 345  *
 346  * item_data_print - If not NULL, will be called for each item when the menu
 347  * is displayed, with the pointer to the item's data passed as the argument.
 348  * If NULL, each item's key will be printed instead.  Since an item's key is
 349  * what must be entered to select an item, the item_data_print function should
 350  * make it obvious what the key for each entry is.
 351  *
 352  * item_choice - If not NULL, will be called when asking the user to choose an
 353  * item. Returns a key string corresponding to the chosen item or NULL if
 354  * no item has been selected.
 355  *
 356  * item_choice_data - Will be passed as the argument to the item_choice function
 357  *
 358  * Returns a pointer to the menu if successful, or NULL if there is
 359  * insufficient memory available to create the menu.
 360  */
 361 struct menu *menu_create(char *title, int timeout, int prompt,
 362                                 void (*item_data_print)(void *),
 363                                 char *(*item_choice)(void *),
 364                                 void *item_choice_data)
 365 {
 366         struct menu *m;
 367
 368         m = malloc(sizeof *m);
 369
 370         if (!m)
 371                 return NULL;
 372
 373         m->default_item = NULL;
 374         m->prompt = prompt;
 375         m->timeout = timeout;
 376         m->item_data_print = item_data_print;
 377         m->item_choice = item_choice;
 378         m->item_choice_data = item_choice_data;
 379
 380         if (title) {
 381                 m->title = strdup(title);
 382                 if (!m->title) {
 383                         free(m);
 384                         return NULL;
 385                 }
 386         } else
 387                 m->title = NULL;
 388
 389
 390         INIT_LIST_HEAD(&m->items);
 391
 392         return m;
 393 }
 394
 395 /*
 396  * menu_destroy() - frees the memory used by a menu and its items.
 397  *
 398  * m - Points to a menu created by menu_create().
 399  *
 400  * Returns 1 if successful, or -EINVAL if m is NULL.
 401  */
 402 int menu_destroy(struct menu *m)
 403 {
 404         if (!m)
 405                 return -EINVAL;
 406
 407         menu_items_iter(m, menu_item_destroy, NULL);
 408
 409         if (m->title)
 410                 free(m->title);
 411
 412         free(m);
 413
 414         return 1;
 415 }