1/*
2 * Generic Settings storage
3 *
4 * Copyright (C) 2020 Andy Green <andy@warmcat.com>
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to
8 * deal in the Software without restriction, including without limitation the
9 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
10 * sell copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
22 * IN THE SOFTWARE.
23 *
24 *
25 * This is like an abstract class for non-volatile storage, whether in a file-
26 * system or flash-backed blocks, etc. Named blobs of variable size are stored
27 * in nonvolatile media of some sort. Typically, these are JSON objects under
28 * a naming scheme like, eg, "network".
29 *
30 * There's a platform-specific storage identifier opaque_plat provided when the
31 * storage object is instantiated, this describes eg the storage device or
32 * partition in instantiation-specific terms.
33 *
34 * Blobs have a further "filename" associated with them.
35 */
36
37#define LSOOPEN_FLAG_WRITEABLE (1 << 0)
38
39struct lws_settings_ops;
40
41typedef struct {
42 void *handle_plat;
43 const struct lws_settings_ops *so;
44 uint8_t refcount;
45 void *opaque_plat;
46} lws_settings_instance_t;
47
48typedef struct lws_settings_ops {
49 int (*get)(lws_settings_instance_t *si, const char *name,
50 uint8_t *dest, size_t *max_actual);
51 /**< if dest is NULL, max_actual is set to the actual length without
52 * copying anything out */
53 int (*set)(lws_settings_instance_t *si, const char *name,
54 const uint8_t *src, size_t len);
55} lws_settings_ops_t;
56
57/**
58 * lws_settings_plat_get() - read a named blob from a settings instance
59 *
60 * \param si: the settings instance
61 * \param name: the name of the setting blob in the instance
62 * \param dest: NULL, or the buffer to copy the setting blob info
63 * \param max_actual: point to size of dest, or zero; actual blob size on exit
64 *
65 * If the named blob doesn't exist in the si, or can't read, returns nonzero.
66 * Otherwise, returns 0 and sets *max_actual to the true blob size. If dest is
67 * non-NULL, as much of the blob as will fit in the amount specified by
68 * *max_actual on entry is copied to dest.
69 */
70LWS_VISIBLE LWS_EXTERN int
71lws_settings_plat_get(lws_settings_instance_t *si, const char *name,
72 uint8_t *dest, size_t *max_actual);
73
74/**
75 * lws_settings_plat_get() - read a named blob from a settings instance
76 *
77 * \param si: the settings instance
78 * \param name: the name of the setting blob in the instance
79 * \param src: blob to copy to settings instance
80 * \param len: length of blob to copy
81 *
82 * Creates or replaces a settings blob of the given name made up of the \p len
83 * bytes of data from \p src.
84 */
85LWS_VISIBLE LWS_EXTERN int
86lws_settings_plat_set(lws_settings_instance_t *si, const char *name,
87 const uint8_t *src, size_t len);
88
89/**
90 * lws_settings_plat_printf() - read a named blob from a settings instance
91 *
92 * \param si: the settings instance
93 * \param name: the name of the setting blob in the instance
94 * \param format: printf-style format string
95 *
96 * Creates or replaces a settings blob of the given name from the printf-style
97 * format string and arguments provided. There's no specific limit to the size,
98 * the size is computed and then a temp heap buffer used.
99 */
100LWS_VISIBLE LWS_EXTERN int
101lws_settings_plat_printf(lws_settings_instance_t *si, const char *name,
102 const char *format, ...) LWS_FORMAT(3);
103
104#define lws_settings_ops_plat \
105 .get = lws_settings_plat_get, \
106 .set = lws_settings_plat_set,
107
108LWS_VISIBLE LWS_EXTERN lws_settings_instance_t *
109lws_settings_init(const lws_settings_ops_t *so, void *opaque_plat);
110
111LWS_VISIBLE LWS_EXTERN void
112lws_settings_deinit(lws_settings_instance_t **si);
113