Skip to content
This repository

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
Fetching contributors…

Cannot retrieve contributors at this time

file 281 lines (231 sloc) 8.428 kb
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281
/*-
* Copyright (c) 2005 Michael Bushkov <bushman@rsu.ru>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD: src/usr.sbin/nscd/cachelib.h,v 1.3 2007/09/27 12:30:11 bushman Exp $
*/

#ifndef __NSCD_CACHELIB_H__
#define __NSCD_CACHELIB_H__

#include <sys/queue.h>
#include <sys/time.h>
#include <stdlib.h>
#include "hashtable.h"
#include "cacheplcs.h"

enum cache_entry_t {
CET_COMMON = 0, /* cache item is atomic */
CET_MULTIPART /* cache item is formed part by part */
};

enum cache_transformation_t {
CTT_FLUSH = 0, /* flush the cache - delete all obsolete items */
CTT_CLEAR = 1 /* delete all items in the cache */
};

/* cache deletion policy type enum */
enum cache_policy_t {
CPT_FIFO = 0, /* first-in first-out */
CPT_LRU = 1, /* least recently used */
CPT_LFU = 2 /* least frequently used */
};

/* multipart sessions can be used for reading and writing */
enum cache_mp_session_t {
CMPT_READ_SESSION,
CMPT_WRITE_SESSION
};

/*
* When doing partial transformations of entries (which are applied for
* elements with keys, that contain specified buffer in its left or
* right part), this enum will show the needed position of the key part.
*/
enum part_position_t {
KPPT_LEFT,
KPPT_RIGHT
};

/* num_levels attribute is obsolete, i think - user can always emulate it
* by using one entry.
* get_time_func is needed to have the clocks-independent counter
*/
struct cache_params
{
void (*get_time_func)(struct timeval *);
};

/*
* base structure - normal_cache_entry_params and multipart_cache_entry_params
* are "inherited" from it
*/
struct cache_entry_params
{
enum cache_entry_t entry_type;
char *entry_name;
};

/* params, used for most entries */
struct common_cache_entry_params
{
/* inherited fields */
enum cache_entry_t entry_type;

/* unique fields */
char *entry_name;
size_t cache_entries_size;

size_t max_elemsize; /* if 0 then no check is made */
size_t satisf_elemsize; /* if entry size is exceeded,
* this number of elements will be left,
* others will be deleted */
struct timeval max_lifetime; /* if 0 then no check is made */
enum cache_policy_t policy; /* policy used for transformations */
};

/* params, used for multipart entries */
struct mp_cache_entry_params
{
/* inherited fields */
enum cache_entry_t entry_type;
char *entry_name;

/* unique fields */
size_t max_elemsize; /* if 0 then no check is made */
size_t max_sessions; /* maximum number of active sessions */

struct timeval max_lifetime; /* maximum elements lifetime */
};

struct cache_ht_item_data_
{
/* key is the bytes sequence only - not the null-terminated string */
char *key;
size_t key_size;

char *value;
size_t value_size;

struct cache_policy_item_ *fifo_policy_item;
};

struct cache_ht_item_
{
HASHTABLE_ENTRY_HEAD(ht_item_, struct cache_ht_item_data_) data;
};

struct cache_entry_
{
char *name;
struct cache_entry_params *params;
};

struct cache_common_entry_
{
char *name;
struct cache_entry_params *params;

struct common_cache_entry_params common_params;

HASHTABLE_HEAD(cache_ht_, cache_ht_item_) items;
size_t items_size;

/*
* Entry always has the FIFO policy, that is used to eliminate old
* elements (the ones, with lifetime more than max_lifetime). Besides,
* user can specify another policy to be applied, when there are too
* many elements in the entry. So policies_size can be 1 or 2.
*/
struct cache_policy_ **policies;
size_t policies_size;

void (*get_time_func)(struct timeval *);
};

struct cache_mp_data_item_ {
char *value;
size_t value_size;

TAILQ_ENTRY(cache_mp_data_item_) entries;
};

struct cache_mp_write_session_
{
struct cache_mp_entry_ *parent_entry;

/*
* All items are accumulated in this queue. When the session is
* committed, they all will be copied to the multipart entry.
*/
TAILQ_HEAD(cache_mp_data_item_head, cache_mp_data_item_) items;
size_t items_size;

TAILQ_ENTRY(cache_mp_write_session_) entries;
};

struct cache_mp_read_session_
{
struct cache_mp_entry_ *parent_entry;
struct cache_mp_data_item_ *current_item;

TAILQ_ENTRY(cache_mp_read_session_) entries;
};

struct cache_mp_entry_
{
char *name;
struct cache_entry_params *params;

struct mp_cache_entry_params mp_params;

/* All opened write sessions */
TAILQ_HEAD(write_sessions_head, cache_mp_write_session_) ws_head;
size_t ws_size;

/* All opened read sessions */
TAILQ_HEAD(read_sessions_head, cache_mp_read_session_) rs_head;
size_t rs_size;

/*
* completed_write_session is the committed write sessions. All read
* sessions use data from it. If the completed_write_session is out of
* date, but still in use by some of the read sessions, the newly
* committed write session is stored in the pending_write_session.
* In such a case, completed_write_session will be substituted with
* pending_write_session as soon as it won't be used by any of
* the read sessions.
*/
struct cache_mp_write_session_ *completed_write_session;
struct cache_mp_write_session_ *pending_write_session;
struct timeval creation_time;
struct timeval last_request_time;

void (*get_time_func)(struct timeval *);
};

struct cache_
{
struct cache_params params;

struct cache_entry_ **entries;
size_t entries_capacity;
size_t entries_size;
};

/* simple abstractions - for not to write "struct" every time */
typedef struct cache_ *cache;
typedef struct cache_entry_ *cache_entry;
typedef struct cache_mp_write_session_ *cache_mp_write_session;
typedef struct cache_mp_read_session_ *cache_mp_read_session;

#define INVALID_CACHE (NULL)
#define INVALID_CACHE_ENTRY (NULL)
#define INVALID_CACHE_MP_WRITE_SESSION (NULL)
#define INVALID_CACHE_MP_READ_SESSION (NULL)

/*
* NOTE: all cache operations are thread-unsafe. You must ensure thread-safety
* externally, by yourself.
*/

/* cache initialization/destruction routines */
extern cache init_cache(struct cache_params const *);
extern void destroy_cache(cache);

/* cache entries manipulation routines */
extern int register_cache_entry(cache, struct cache_entry_params const *);
extern int unregister_cache_entry(cache, const char *);
extern cache_entry find_cache_entry(cache, const char *);

/* read/write operations used on common entries */
extern int cache_read(cache_entry, const char *, size_t, char *, size_t *);
extern int cache_write(cache_entry, const char *, size_t, char const *, size_t);

/* read/write operations used on multipart entries */
extern cache_mp_write_session open_cache_mp_write_session(cache_entry);
extern int cache_mp_write(cache_mp_write_session, char *, size_t);
extern void abandon_cache_mp_write_session(cache_mp_write_session);
extern void close_cache_mp_write_session(cache_mp_write_session);

extern cache_mp_read_session open_cache_mp_read_session(cache_entry);
extern int cache_mp_read(cache_mp_read_session, char *, size_t *);
extern void close_cache_mp_read_session(cache_mp_read_session);

/* transformation routines */
extern int transform_cache_entry(cache_entry, enum cache_transformation_t);
extern int transform_cache_entry_part(cache_entry, enum cache_transformation_t,
const char *, size_t, enum part_position_t);

#endif
Something went wrong with that request. Please try again.