// SPDX-License-Identifier: GPL-2.0-only

// Copyright (C) 2024-2026, Shu De Zheng <[email protected]>. All Rights Reserved.

#ifndef __UMEM_CACHE_KV_H

#define __UMEM_CACHE_KV_H

#include <sys/uio.h>

#include "slab.h"

#include "list.h"

struct concat_val {

struct slab_obj_offset *soo_ptr;

unsigned char data[];

};

/* memory migration requires this member shows first */

static_assert(offsetof(struct concat_val, soo_ptr) == 0);

struct kv_borrower {

struct hlist_node kv_ref_node;

struct kv *kv;

};

/**

* kv -

* @soo: it has a trick involved, see kv_malloc() and kv_is_concat()

* @lru: kv is on lru and is ready to serve command GET if kv_enabled()

* @borrower_list: the list of kv_borrower

* @val_size: value size

* @hash_node: resides in a hash_table if kv_enabled()

* @data: data of key and value

*/

struct kv {

struct slab_obj_offset soo;

struct list_head lru;

struct hlist_head borrower_list;

uint64_t on_s_lru : 1;

uint64_t val_size : 63;

struct hlist_node hash_node;

unsigned char data[];

};

/* this offset is required for hashtable to locate the key */

static_assert(offsetof(struct kv, data) - offsetof(struct kv, hash_node) ==

sizeof(struct hlist_node));

/* memory migration requires this member shows first */

static_assert(offsetof(struct kv, soo) == 0);

#define KV_KEY(kv) ((kv)->data)

#define KEY_SIZE(key) (1 + (int)((key)[0]))

#define KV_KEY_SIZE(kv) KEY_SIZE(KV_KEY(kv))

#define KV_VAL(kv) ((kv)->data + KV_KEY_SIZE(kv))

#define KV_SIZE(kv) (sizeof(struct kv) + KV_KEY_SIZE(kv) + (kv)->val_size)

void kv_init(struct kv *kv, const unsigned char *key, uint64_t val_size);

void kv_set_fake(struct kv *kv);

bool kv_enabled(struct kv *kv);

void kv_borrow(struct kv *kv, struct kv_borrower *borrower);

void kv_return(struct kv_borrower *borrower);

bool kv_is_concat(struct kv *kv);

void kv_borrower_init(struct kv_borrower *borrower);

bool kv_no_borrower(struct kv *kv);

int kv_val_to_iovec(struct kv *kv, uint64_t i, struct iovec *iov);

#endif