src/rdb.h

   1 /*
   2  * Copyright (c) 2009-2012, Salvatore Sanfilippo <antirez at gmail dot com>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions are met:
   7  *
   8  *   * Redistributions of source code must retain the above copyright notice,
   9  *     this list of conditions and the following disclaimer.
  10  *   * Redistributions in binary form must reproduce the above copyright
  11  *     notice, this list of conditions and the following disclaimer in the
  12  *     documentation and/or other materials provided with the distribution.
  13  *   * Neither the name of Redis nor the names of its contributors may be used
  14  *     to endorse or promote products derived from this software without
  15  *     specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  18  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  21  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  22  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  23  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  24  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  25  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  26  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  27  * POSSIBILITY OF SUCH DAMAGE.
  28  */
  29
  30 #ifndef __REDIS_RDB_H
  31 #define __REDIS_RDB_H
  32
  33 #include <stdio.h>
  34 #include "rio.h"
  35
  36 /* TBD: include only necessary headers. */
  37 #include "redis.h"
  38
  39 /* The current RDB version. When the format changes in a way that is no longer
  40  * backward compatible this number gets incremented. */
  41 #define REDIS_RDB_VERSION 6
  42
  43 /* Defines related to the dump file format. To store 32 bits lengths for short
  44  * keys requires a lot of space, so we check the most significant 2 bits of
  45  * the first byte to interpreter the length:
  46  *
  47  * 00|000000 => if the two MSB are 00 the len is the 6 bits of this byte
  48  * 01|000000 00000000 =>  01, the len is 14 byes, 6 bits + 8 bits of next byte
  49  * 10|000000 [32 bit integer] => if it's 01, a full 32 bit len will follow
  50  * 11|000000 this means: specially encoded object will follow. The six bits
  51  *           number specify the kind of object that follows.
  52  *           See the REDIS_RDB_ENC_* defines.
  53  *
  54  * Lenghts up to 63 are stored using a single byte, most DB keys, and may
  55  * values, will fit inside. */
  56 #define REDIS_RDB_6BITLEN 0
  57 #define REDIS_RDB_14BITLEN 1
  58 #define REDIS_RDB_32BITLEN 2
  59 #define REDIS_RDB_ENCVAL 3
  60 #define REDIS_RDB_LENERR UINT_MAX
  61
  62 /* When a length of a string object stored on disk has the first two bits
  63  * set, the remaining two bits specify a special encoding for the object
  64  * accordingly to the following defines: */
  65 #define REDIS_RDB_ENC_INT8 0        /* 8 bit signed integer */
  66 #define REDIS_RDB_ENC_INT16 1       /* 16 bit signed integer */
  67 #define REDIS_RDB_ENC_INT32 2       /* 32 bit signed integer */
  68 #define REDIS_RDB_ENC_LZF 3         /* string compressed with FASTLZ */
  69
  70 /* Dup object types to RDB object types. Only reason is readability (are we
  71  * dealing with RDB types or with in-memory object types?). */
  72 #define REDIS_RDB_TYPE_STRING 0
  73 #define REDIS_RDB_TYPE_LIST   1
  74 #define REDIS_RDB_TYPE_SET    2
  75 #define REDIS_RDB_TYPE_ZSET   3
  76 #define REDIS_RDB_TYPE_HASH   4
  77
  78 /* Object types for encoded objects. */
  79 #define REDIS_RDB_TYPE_HASH_ZIPMAP    9
  80 #define REDIS_RDB_TYPE_LIST_ZIPLIST  10
  81 #define REDIS_RDB_TYPE_SET_INTSET    11
  82 #define REDIS_RDB_TYPE_ZSET_ZIPLIST  12
  83 #define REDIS_RDB_TYPE_HASH_ZIPLIST  13
  84
  85 /* Test if a type is an object type. */
  86 #define rdbIsObjectType(t) ((t >= 0 && t <= 4) || (t >= 9 && t <= 13))
  87
  88 /* Special RDB opcodes (saved/loaded with rdbSaveType/rdbLoadType). */
  89 #define REDIS_RDB_OPCODE_EXPIRETIME_MS 252
  90 #define REDIS_RDB_OPCODE_EXPIRETIME 253
  91 #define REDIS_RDB_OPCODE_SELECTDB   254
  92 #define REDIS_RDB_OPCODE_EOF        255
  93
  94 int rdbSaveType(rio *rdb, unsigned char type);
  95 int rdbLoadType(rio *rdb);
  96 int rdbSaveTime(rio *rdb, time_t t);
  97 time_t rdbLoadTime(rio *rdb);
  98 int rdbSaveLen(rio *rdb, uint32_t len);
  99 uint32_t rdbLoadLen(rio *rdb, int *isencoded);
 100 int rdbSaveObjectType(rio *rdb, robj *o);
 101 int rdbLoadObjectType(rio *rdb);
 102 int rdbLoad(char *filename);
 103 int rdbSaveBackground(char *filename);
 104 void rdbRemoveTempFile(pid_t childpid);
 105 int rdbSave(char *filename);
 106 int rdbSaveObject(rio *rdb, robj *o);
 107 off_t rdbSavedObjectLen(robj *o);
 108 off_t rdbSavedObjectPages(robj *o);
 109 robj *rdbLoadObject(int type, rio *rdb);
 110 void backgroundSaveDoneHandler(int exitcode, int bysignal);
 111 int rdbSaveKeyValuePair(rio *rdb, robj *key, robj *val, long long expiretime, long long now);
 112 robj *rdbLoadStringObject(rio *rdb);
 113
 114 #endif