menu.c 9.94 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412
/*
 * Copyright 2010-2011 Calxeda, Inc.
 *
 * SPDX-License-Identifier:	GPL-2.0+
 */

#include <common.h>
#include <cli.h>
#include <malloc.h>
#include <errno.h>
#include <linux/list.h>

#include "menu.h"

/*
 * Internally, each item in a menu is represented by a struct menu_item.
 *
 * These items will be alloc'd and initialized by menu_item_add and destroyed
 * by menu_item_destroy, and the consumer of the interface never sees that
 * this struct is used at all.
 */
struct menu_item {
	char *key;
	void *data;
	struct list_head list;
};

/*
 * The menu is composed of a list of items along with settings and callbacks
 * provided by the user. An incomplete definition of this struct is available
 * in menu.h, but the full definition is here to prevent consumers from
 * relying on its contents.
 */
struct menu {
	struct menu_item *default_item;
	int timeout;
	char *title;
	int prompt;
	void (*item_data_print)(void *);
	char *(*item_choice)(void *);
	void *item_choice_data;
	struct list_head items;
};

/*
 * An iterator function for menu items. callback will be called for each item
 * in m, with m, a pointer to the item, and extra being passed to callback. If
 * callback returns a value other than NULL, iteration stops and the value
 * return by callback is returned from menu_items_iter.  This allows it to be
 * used for search type operations. It is also safe for callback to remove the
 * item from the list of items.
 */
static inline void *menu_items_iter(struct menu *m,
		void *(*callback)(struct menu *, struct menu_item *, void *),
		void *extra)
{
	struct list_head *pos, *n;
	struct menu_item *item;
	void *ret;

	list_for_each_safe(pos, n, &m->items) {
		item = list_entry(pos, struct menu_item, list);

		ret = callback(m, item, extra);

		if (ret)
			return ret;
	}

	return NULL;
}

/*
 * Print a menu_item. If the consumer provided an item_data_print function
 * when creating the menu, call it with a pointer to the item's private data.
 * Otherwise, print the key of the item.
 */
static inline void *menu_item_print(struct menu *m,
				struct menu_item *item,
				void *extra)
{
	if (!m->item_data_print) {
		puts(item->key);
		putc('\n');
	} else {
		m->item_data_print(item->data);
	}

	return NULL;
}

/*
 * Free the memory used by a menu item. This includes the memory used by its
 * key.
 */
static inline void *menu_item_destroy(struct menu *m,
				struct menu_item *item,
				void *extra)
{
	if (item->key)
		free(item->key);

	free(item);

	return NULL;
}

__weak void menu_display_statusline(struct menu *m)
{
}

/*
 * Display a menu so the user can make a choice of an item. First display its
 * title, if any, and then each item in the menu.
 */
static inline void menu_display(struct menu *m)
{
	if (m->title) {
		puts(m->title);
		putc('\n');
	}
	menu_display_statusline(m);

	menu_items_iter(m, menu_item_print, NULL);
}

/*
 * Check if an item's key matches a provided string, pointed to by extra. If
 * extra is NULL, an item with a NULL key will match. Otherwise, the item's
 * key has to match according to strcmp.
 *
 * This is called via menu_items_iter, so it returns a pointer to the item if
 * the key matches, and returns NULL otherwise.
 */
static inline void *menu_item_key_match(struct menu *m,
			struct menu_item *item, void *extra)
{
	char *item_key = extra;

	if (!item_key || !item->key) {
		if (item_key == item->key)
			return item;

		return NULL;
	}

	if (strcmp(item->key, item_key) == 0)
		return item;

	return NULL;
}

/*
 * Find the first item with a key matching item_key, if any exists.
 */
static inline struct menu_item *menu_item_by_key(struct menu *m,
							char *item_key)
{
	return menu_items_iter(m, menu_item_key_match, item_key);
}

/*
 * Set *choice to point to the default item's data, if any default item was
 * set, and returns 1. If no default item was set, returns -ENOENT.
 */
int menu_default_choice(struct menu *m, void **choice)
{
	if (m->default_item) {
		*choice = m->default_item->data;
		return 1;
	}

	return -ENOENT;
}

/*
 * Displays the menu and asks the user to choose an item. *choice will point
 * to the private data of the item the user chooses. The user makes a choice
 * by inputting a string matching the key of an item. Invalid choices will
 * cause the user to be prompted again, repeatedly, until the user makes a
 * valid choice. The user can exit the menu without making a choice via ^c.
 *
 * Returns 1 if the user made a choice, or -EINTR if they bail via ^c.
 */
static inline int menu_interactive_choice(struct menu *m, void **choice)
{
	char cbuf[CONFIG_SYS_CBSIZE];
	struct menu_item *choice_item = NULL;
	int readret;

	while (!choice_item) {
		cbuf[0] = '\0';

		menu_display(m);

		if (!m->item_choice) {
			readret = cli_readline_into_buffer("Enter choice: ",
							   cbuf,
							   m->timeout / 10);

			if (readret >= 0) {
				choice_item = menu_item_by_key(m, cbuf);
				if (!choice_item)
					printf("%s not found\n", cbuf);
			} else {
				return menu_default_choice(m, choice);
			}
		} else {
			char *key = m->item_choice(m->item_choice_data);

			if (key)
				choice_item = menu_item_by_key(m, key);
		}

		if (!choice_item)
			m->timeout = 0;
	}

	*choice = choice_item->data;

	return 1;
}

/*
 * menu_default_set() - Sets the default choice for the menu. This is safe to
 * call more than once on a menu.
 *
 * m - Points to a menu created by menu_create().
 *
 * item_key - Points to a string that, when compared using strcmp, matches the
 * key for an existing item in the menu.
 *
 * Returns 1 if successful, -EINVAL if m is NULL, or -ENOENT if no item with a
 * key matching item_key is found.
 */
int menu_default_set(struct menu *m, char *item_key)
{
	struct menu_item *item;

	if (!m)
		return -EINVAL;

	item = menu_item_by_key(m, item_key);

	if (!item)
		return -ENOENT;

	m->default_item = item;

	return 1;
}

/*
 * menu_get_choice() - Returns the user's selected menu entry, or the default
 * if the menu is set to not prompt or the timeout expires. This is safe to
 * call more than once.
 *
 * m - Points to a menu created by menu_create().
 *
 * choice - Points to a location that will store a pointer to the selected
 * menu item. If no item is selected or there is an error, no value will be
 * written at the location it points to.
 *
 * Returns 1 if successful, -EINVAL if m or choice is NULL, -ENOENT if no
 * default has been set and the menu is set to not prompt or the timeout
 * expires, or -EINTR if the user exits the menu via ^c.
 */
int menu_get_choice(struct menu *m, void **choice)
{
	if (!m || !choice)
		return -EINVAL;

	if (!m->prompt)
		return menu_default_choice(m, choice);

	return menu_interactive_choice(m, choice);
}

/*
 * menu_item_add() - Adds or replaces a menu item. Note that this replaces the
 * data of an item if it already exists, but doesn't change the order of the
 * item.
 *
 * m - Points to a menu created by menu_create().
 *
 * item_key - Points to a string that will uniquely identify the item.  The
 * string will be copied to internal storage, and is safe to discard after
 * passing to menu_item_add.
 *
 * item_data - An opaque pointer associated with an item. It is never
 * dereferenced internally, but will be passed to the item_data_print, and
 * will be returned from menu_get_choice if the menu item is selected.
 *
 * Returns 1 if successful, -EINVAL if m is NULL, or -ENOMEM if there is
 * insufficient memory to add the menu item.
 */
int menu_item_add(struct menu *m, char *item_key, void *item_data)
{
	struct menu_item *item;

	if (!m)
		return -EINVAL;

	item = menu_item_by_key(m, item_key);

	if (item) {
		item->data = item_data;
		return 1;
	}

	item = malloc(sizeof *item);
	if (!item)
		return -ENOMEM;

	item->key = strdup(item_key);

	if (!item->key) {
		free(item);
		return -ENOMEM;
	}

	item->data = item_data;

	list_add_tail(&item->list, &m->items);

	return 1;
}

/*
 * menu_create() - Creates a menu handle with default settings
 *
 * title - If not NULL, points to a string that will be displayed before the
 * list of menu items. It will be copied to internal storage, and is safe to
 * discard after passing to menu_create().
 *
 * timeout - A delay in seconds to wait for user input. If 0, timeout is
 * disabled, and the default choice will be returned unless prompt is 1.
 *
 * prompt - If 0, don't ask for user input unless there is an interrupted
 * timeout. If 1, the user will be prompted for input regardless of the value
 * of timeout.
 *
 * item_data_print - If not NULL, will be called for each item when the menu
 * is displayed, with the pointer to the item's data passed as the argument.
 * If NULL, each item's key will be printed instead.  Since an item's key is
 * what must be entered to select an item, the item_data_print function should
 * make it obvious what the key for each entry is.
 *
 * item_choice - If not NULL, will be called when asking the user to choose an
 * item. Returns a key string corresponding to the choosen item or NULL if
 * no item has been selected.
 *
 * item_choice_data - Will be passed as the argument to the item_choice function
 *
 * Returns a pointer to the menu if successful, or NULL if there is
 * insufficient memory available to create the menu.
 */
struct menu *menu_create(char *title, int timeout, int prompt,
				void (*item_data_print)(void *),
				char *(*item_choice)(void *),
				void *item_choice_data)
{
	struct menu *m;

	m = malloc(sizeof *m);

	if (!m)
		return NULL;

	m->default_item = NULL;
	m->prompt = prompt;
	m->timeout = timeout;
	m->item_data_print = item_data_print;
	m->item_choice = item_choice;
	m->item_choice_data = item_choice_data;

	if (title) {
		m->title = strdup(title);
		if (!m->title) {
			free(m);
			return NULL;
		}
	} else
		m->title = NULL;


	INIT_LIST_HEAD(&m->items);

	return m;
}

/*
 * menu_destroy() - frees the memory used by a menu and its items.
 *
 * m - Points to a menu created by menu_create().
 *
 * Returns 1 if successful, or -EINVAL if m is NULL.
 */
int menu_destroy(struct menu *m)
{
	if (!m)
		return -EINVAL;

	menu_items_iter(m, menu_item_destroy, NULL);

	if (m->title)
		free(m->title);

	free(m);

	return 1;
}