lws-settings.h (4448B)
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);