1 /*
2 * Copyright (c) 2018 Nordic Semiconductor ASA
3 *
4 * SPDX-License-Identifier: Apache-2.0
5 */
6
7 #include <zephyr/shell/shell_history.h>
8 #include <string.h>
9
10 /*
11 * History must store strings (commands) and allow traversing them and adding
12 * new string. When new item is added then first it is compared if it is not
13 * the same as the last one (then it is not stored). If there is no room in the
14 * buffer to store the new item, oldest one is removed until there is a room.
15 */
16
17 struct shell_history_item {
18 sys_dnode_t dnode;
19 uint16_t len;
20 char data[];
21 };
22
z_shell_history_mode_exit(struct shell_history * history)23 void z_shell_history_mode_exit(struct shell_history *history)
24 {
25 history->current = NULL;
26 }
27
z_shell_history_get(struct shell_history * history,bool up,uint8_t * dst,uint16_t * len)28 bool z_shell_history_get(struct shell_history *history, bool up,
29 uint8_t *dst, uint16_t *len)
30 {
31 struct shell_history_item *h_item; /* history item */
32 sys_dnode_t *l_item; /* list item */
33
34 if (up) { /* button up */
35 l_item = (history->current == NULL) ?
36 sys_dlist_peek_head(&history->list) :
37 sys_dlist_peek_next_no_check(&history->list, history->current);
38 } else { /* button down */
39 l_item = sys_dlist_peek_prev(&history->list, history->current);
40 }
41
42 history->current = l_item;
43 if (l_item == NULL) {
44 /* Reached the end of history. */
45 *len = 0U;
46 return false;
47 }
48
49 h_item = CONTAINER_OF(l_item, struct shell_history_item, dnode);
50 memcpy(dst, h_item->data, h_item->len);
51 *len = h_item->len;
52 dst[*len] = '\0';
53 return true;
54 }
55
56 /* Returns true if element was removed. */
remove_from_tail(struct shell_history * history)57 static bool remove_from_tail(struct shell_history *history)
58 {
59 sys_dnode_t *node;
60
61 if (sys_dlist_is_empty(&history->list)) {
62 return false;
63 }
64
65 node = sys_dlist_peek_tail(&history->list);
66 sys_dlist_remove(node);
67 k_heap_free(history->heap, CONTAINER_OF(node, struct shell_history_item, dnode));
68 return true;
69 }
70
z_shell_history_put(struct shell_history * history,uint8_t * line,size_t len)71 void z_shell_history_put(struct shell_history *history, uint8_t *line,
72 size_t len)
73 {
74 sys_dnode_t *node;
75 struct shell_history_item *new, *h_prev_item;
76 uint32_t total_len = len + offsetof(struct shell_history_item, data);
77
78 z_shell_history_mode_exit(history);
79 if (len == 0) {
80 return;
81 }
82
83 node = sys_dlist_peek_head(&history->list);
84 h_prev_item = CONTAINER_OF(node, struct shell_history_item, dnode);
85
86 if (node &&
87 (h_prev_item->len == len) &&
88 (memcmp(h_prev_item->data, line, len) == 0)) {
89 /* Same command as before, do not store */
90 return;
91 }
92
93 for (;;) {
94 new = k_heap_alloc(history->heap, total_len, K_NO_WAIT);
95 if (new) {
96 /* Got memory, add new item */
97 break;
98 } else if (!remove_from_tail(history)) {
99 /* Nothing to remove, cannot allocate memory. */
100 return;
101 }
102 }
103
104 new->len = len;
105 memcpy(new->data, line, len);
106 sys_dlist_prepend(&history->list, &new->dnode);
107 }
108
z_shell_history_purge(struct shell_history * history)109 void z_shell_history_purge(struct shell_history *history)
110 {
111 while (remove_from_tail(history)) {
112 }
113 history->current = NULL;
114 }
115
