/*      $OpenBSD: btree.h,v 1.6 2010/07/02 01:43:00 martinh Exp $ */

/*
 * Copyright (c) 2009, 2010 Martin Hedenfalk <martin@bzero.se>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#ifndef _btree_h_
#define _btree_h_

#include <openssl/sha.h>

struct mpage;
struct cursor;
struct btree_txn;

struct btval {
        void            *data;
        size_t           size;
        int              free_data;             /* true if data malloc'd */
        struct mpage    *mp;                    /* ref'd memory page */
};

typedef int              (*bt_cmp_func)(const struct btval *a,
                                        const struct btval *b);
typedef void             (*bt_prefix_func)(const struct btval *a,
                                           const struct btval *b,
                                           struct btval *sep);

#define BT_NOOVERWRITE   1

enum cursor_op {                                /* cursor operations */
        BT_CURSOR,                              /* position at given key */
        BT_CURSOR_EXACT,                        /* position at key, or fail */
        BT_FIRST,
        BT_NEXT,
        BT_LAST,                                /* not implemented */
        BT_PREV                                 /* not implemented */
};

/* return codes */
#define BT_FAIL         -1
#define BT_SUCCESS       0

/* btree flags */
#define BT_NOSYNC                0x02           /* don't fsync after commit */
#define BT_RDONLY                0x04           /* read only */
#define BT_REVERSEKEY            0x08           /* use reverse string keys */

struct btree_stat {
        unsigned long long int   hits;          /* cache hits */
        unsigned long long int   reads;         /* page reads */
        unsigned int             max_cache;     /* max cached pages */
        unsigned int             cache_size;    /* current cache size */
        unsigned int             branch_pages;
        unsigned int             leaf_pages;
        unsigned int             overflow_pages;
        unsigned int             revisions;
        unsigned int             depth;
        unsigned long long int   entries;
        unsigned int             psize;
        time_t                   created_at;
};

struct btree            *btree_open_fd(int fd, unsigned int flags);
struct btree            *btree_open(const char *path, unsigned int flags,
                            mode_t mode);
void                     btree_close(struct btree *bt);
const struct btree_stat *btree_stat(struct btree *bt);

struct btree_txn        *btree_txn_begin(struct btree *bt, int rdonly);
int                      btree_txn_commit(struct btree_txn *txn);
void                     btree_txn_abort(struct btree_txn *txn);

int                      btree_txn_get(struct btree *bt, struct btree_txn *txn,
                            struct btval *key, struct btval *data);
int                      btree_txn_put(struct btree *bt, struct btree_txn *txn,
                            struct btval *key, struct btval *data,
                            unsigned int flags);
int                      btree_txn_del(struct btree *bt, struct btree_txn *txn,
                            struct btval *key, struct btval *data);

#define btree_get(bt, key, data)         \
                         btree_txn_get(bt, NULL, key, data)
#define btree_put(bt, key, data, flags)  \
                         btree_txn_put(bt, NULL, key, data, flags)
#define btree_del(bt, key, data)         \
                         btree_txn_del(bt, NULL, key, data)

void                     btree_set_cache_size(struct btree *bt,
                            unsigned int cache_size);
unsigned int             btree_get_flags(struct btree *bt);
const char              *btree_get_path(struct btree *bt);

#define btree_cursor_open(bt)    \
                         btree_txn_cursor_open(bt, NULL)
struct cursor           *btree_txn_cursor_open(struct btree *bt,
                            struct btree_txn *txn);
void                     btree_cursor_close(struct cursor *cursor);
int                      btree_cursor_get(struct cursor *cursor,
                            struct btval *key, struct btval *data,
                            enum cursor_op op);

int                      btree_sync(struct btree *bt);
int                      btree_compact(struct btree *bt);
int                      btree_revert(struct btree *bt);

int                      btree_cmp(struct btree *bt, const struct btval *a,
                             const struct btval *b);
void                     btval_reset(struct btval *btv);

#endif