lws-settings.h

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/*
 * Generic Settings storage
 *
 * Copyright (C) 2020 Andy Green <andy@warmcat.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 *
 *
 * This is like an abstract class for non-volatile storage, whether in a file-
 * system or flash-backed blocks, etc.  Named blobs of variable size are stored
 * in nonvolatile media of some sort.  Typically, these are JSON objects under
 * a naming scheme like, eg, "network".
 *
 * There's a platform-specific storage identifier opaque_plat provided when the
 * storage object is instantiated, this describes eg the storage device or
 * partition in instantiation-specific terms.
 *
 * Blobs have a further "filename" associated with them.
 */
 
#define LSOOPEN_FLAG_WRITEABLE                          (1 << 0)
 
struct lws_settings_ops;
 
typedef struct {
        void                                            *handle_plat;
        const struct lws_settings_ops                   *so;
        uint8_t                                          refcount;
        void                                            *opaque_plat;
} lws_settings_instance_t;
 
typedef struct lws_settings_ops {
        int (*get)(lws_settings_instance_t *si, const char *name,
                   uint8_t *dest, size_t *max_actual);
        int (*set)(lws_settings_instance_t *si, const char *name,
                   const uint8_t *src, size_t len);
} lws_settings_ops_t;

LWS_VISIBLE LWS_EXTERN int
lws_settings_plat_get(lws_settings_instance_t *si, const char *name,
                      uint8_t *dest, size_t *max_actual);

LWS_VISIBLE LWS_EXTERN int
lws_settings_plat_set(lws_settings_instance_t *si, const char *name,
                      const uint8_t *src, size_t len);

LWS_VISIBLE LWS_EXTERN int
lws_settings_plat_printf(lws_settings_instance_t *si, const char *name,
                         const char *format, ...) LWS_FORMAT(3);
 
#define lws_settings_ops_plat \
        .get            = lws_settings_plat_get, \
        .set            = lws_settings_plat_set,
 
LWS_VISIBLE LWS_EXTERN lws_settings_instance_t *
lws_settings_init(const lws_settings_ops_t *so, void *opaque_plat);
 
LWS_VISIBLE LWS_EXTERN void
lws_settings_deinit(lws_settings_instance_t **si);