
/*
 * Copyright (C) Igor Sysoev
 */


#ifndef _NGX_HTTP_CACHE_H_INCLUDED_
#define _NGX_HTTP_CACHE_H_INCLUDED_


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>


/**/
#define NGX_HTTP_CACHE_STALE         1
#define NGX_HTTP_CACHE_AGED          2
#define NGX_HTTP_CACHE_THE_SAME      3
/**/

#define NGX_HTTP_CACHE_KEY_LEN       16


typedef struct {
    ngx_uint_t                       status;
    time_t                           valid;
} ngx_http_cache_valid_t;


/* ngx_http_file_cache_node_t takes exactly 64 bytes on FreeBSD/i386 */

typedef struct {
    ngx_rbtree_node_t                node;
    ngx_queue_t                      queue;

    u_char                           key[NGX_HTTP_CACHE_KEY_LEN
                                         - sizeof(ngx_rbtree_key_t)];

    unsigned                         count:20;
    unsigned                         uses:10;
    unsigned                         valid_msec:10;
    unsigned                         error:10;
                                     /* 7 unused bits */
    unsigned                         exists:1;

    ngx_file_uniq_t                  uniq;
    time_t                           expire;
    time_t                           valid_sec;
    size_t                           body_start;
    off_t                            length;
} ngx_http_file_cache_node_t;


struct ngx_http_cache_s {
    ngx_file_t                       file;
    ngx_array_t                      keys;
    uint32_t                         crc32;
    u_char                           key[NGX_HTTP_CACHE_KEY_LEN];

    ngx_file_uniq_t                  uniq;
    time_t                           valid_sec;
    time_t                           last_modified;
    time_t                           date;

    size_t                           header_start;
    size_t                           body_start;
    off_t                            length;

    ngx_uint_t                       min_uses;
    ngx_uint_t                       uses;
    ngx_uint_t                       error;
    ngx_uint_t                       valid_msec;

    ngx_buf_t                       *buf;

    ngx_http_file_cache_t           *file_cache;
    ngx_http_file_cache_node_t      *node;

    unsigned                         updated:1;
    unsigned                         exists:1;
    unsigned                         temp_file:1;
};


typedef struct {
    time_t                           valid_sec;
    time_t                           last_modified;
    time_t                           date;
    uint32_t                         crc32;
    u_short                          valid_msec;
    u_short                          header_start;
    u_short                          body_start;
} ngx_http_file_cache_header_t;


struct ngx_http_file_cache_s {
    ngx_rbtree_t                    *rbtree;
    ngx_queue_t                     *queue;
    ngx_slab_pool_t                 *shpool;

    ngx_path_t                      *path;

    ngx_atomic_t                    *cold;
    off_t                           *size;

    off_t                            max_size;
    size_t                           bsize;

    time_t                           inactive;

    ngx_msec_t                       last;
    ngx_uint_t                       files;

    ngx_shm_zone_t                  *shm_zone;
};


void ngx_http_file_cache_create_key(ngx_http_request_t *r);
ngx_int_t ngx_http_file_cache_open(ngx_http_request_t *r);
void ngx_http_file_cache_set_header(ngx_http_request_t *r, u_char *buf);
void ngx_http_file_cache_update(ngx_http_request_t *r, ngx_temp_file_t *tf);
ngx_int_t ngx_http_cache_send(ngx_http_request_t *);
void ngx_http_file_cache_free(ngx_http_request_t *r, ngx_temp_file_t *tf);
time_t ngx_http_file_cache_valid(ngx_array_t *cache_valid, ngx_uint_t status);


char *ngx_http_file_cache_set_slot(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);
char *ngx_http_file_cache_valid_set_slot(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);


#endif /* _NGX_HTTP_CACHE_H_INCLUDED_ */