/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Copyright 2023 Red Hat
 */

#ifndef UDS_OPEN_CHAPTER_H
#define UDS_OPEN_CHAPTER_H

#include "chapter-index.h"
#include "geometry.h"
#include "index.h"
#include "volume.h"

/*
 * The open chapter tracks the newest records in memory. Like the index as a whole, each open
 * chapter is divided into a number of independent zones which are interleaved when the chapter is
 * committed to the volume.
 */

enum {
        OPEN_CHAPTER_RECORD_NUMBER_BITS = 23,
};

struct open_chapter_zone_slot {
        /* If non-zero, the record number addressed by this hash slot */
        unsigned int record_number : OPEN_CHAPTER_RECORD_NUMBER_BITS;
        /* If true, the record at the index of this hash slot was deleted */
        bool deleted : 1;
} __packed;

struct open_chapter_zone {
        /* The maximum number of records that can be stored */
        unsigned int capacity;
        /* The number of records stored */
        unsigned int size;
        /* The number of deleted records */
        unsigned int deletions;
        /* Array of chunk records, 1-based */
        struct uds_volume_record *records;
        /* The number of slots in the hash table */
        unsigned int slot_count;
        /* The hash table slots, referencing virtual record numbers */
        struct open_chapter_zone_slot slots[];
};

int __must_check uds_make_open_chapter(const struct index_geometry *geometry,
                                       unsigned int zone_count,
                                       struct open_chapter_zone **open_chapter_ptr);

void uds_reset_open_chapter(struct open_chapter_zone *open_chapter);

void uds_search_open_chapter(struct open_chapter_zone *open_chapter,
                             const struct uds_record_name *name,
                             struct uds_record_data *metadata, bool *found);

int __must_check uds_put_open_chapter(struct open_chapter_zone *open_chapter,
                                      const struct uds_record_name *name,
                                      const struct uds_record_data *metadata);

void uds_remove_from_open_chapter(struct open_chapter_zone *open_chapter,
                                  const struct uds_record_name *name);

void uds_free_open_chapter(struct open_chapter_zone *open_chapter);

int __must_check uds_close_open_chapter(struct open_chapter_zone **chapter_zones,
                                        unsigned int zone_count, struct volume *volume,
                                        struct open_chapter_index *chapter_index,
                                        struct uds_volume_record *collated_records,
                                        u64 virtual_chapter_number);

int __must_check uds_save_open_chapter(struct uds_index *index,
                                       struct buffered_writer *writer);

int __must_check uds_load_open_chapter(struct uds_index *index,
                                       struct buffered_reader *reader);

u64 uds_compute_saved_open_chapter_size(struct index_geometry *geometry);

#endif /* UDS_OPEN_CHAPTER_H */