2 +--------------------------------------------------------------------+
3 | libmemcached - C/C++ Client Library for memcached |
4 +--------------------------------------------------------------------+
5 | Redistribution and use in source and binary forms, with or without |
6 | modification, are permitted under the terms of the BSD license. |
7 | You should have received a copy of the license in a bundled file |
8 | named LICENSE; in case you did not receive a copy you can review |
9 | the terms online at: https://opensource.org/licenses/BSD-3-Clause |
10 +--------------------------------------------------------------------+
11 | Copyright (c) 2006-2014 Brian Aker https://datadifferential.com/ |
12 | Copyright (c) 2020 Michael Wallner <mike@php.net> |
13 +--------------------------------------------------------------------+
16 #include "libmemcached/common.h"
20 #include "libmemcached/virtual_bucket.h"
22 uint32_t memcached_generate_hash_value(const char *key
, size_t key_length
,
23 memcached_hash_t hash_algorithm
) {
24 return libhashkit_digest(key
, key_length
, (hashkit_hash_algorithm_t
) hash_algorithm
);
27 static inline uint32_t generate_hash(const Memcached
*ptr
, const char *key
, size_t key_length
) {
28 return hashkit_digest(&ptr
->hashkit
, key
, key_length
);
31 static uint32_t dispatch_host(const Memcached
*ptr
, uint32_t hash
) {
32 switch (ptr
->distribution
) {
33 case MEMCACHED_DISTRIBUTION_CONSISTENT
:
34 case MEMCACHED_DISTRIBUTION_CONSISTENT_WEIGHTED
:
35 case MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA
:
36 case MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA_SPY
: {
37 uint32_t num
= ptr
->ketama
.continuum_points_counter
;
38 WATCHPOINT_ASSERT(ptr
->ketama
.continuum
);
40 memcached_continuum_item_st
*begin
, *end
, *left
, *right
, *middle
;
41 begin
= left
= ptr
->ketama
.continuum
;
42 end
= right
= ptr
->ketama
.continuum
+ num
;
44 while (left
< right
) {
45 middle
= left
+ (right
- left
) / 2;
46 if (middle
->value
< hash
)
55 case MEMCACHED_DISTRIBUTION_MODULA
: return hash
% memcached_server_count(ptr
);
56 case MEMCACHED_DISTRIBUTION_RANDOM
: return (uint32_t) random() % memcached_server_count(ptr
);
57 case MEMCACHED_DISTRIBUTION_VIRTUAL_BUCKET
: {
58 return memcached_virtual_bucket_get(ptr
, hash
);
61 case MEMCACHED_DISTRIBUTION_CONSISTENT_MAX
:
62 WATCHPOINT_ASSERT(0); /* We have added a distribution without extending the logic */
63 return hash
% memcached_server_count(ptr
);
69 One version is public and will not modify the distribution hash, the other will.
71 static inline uint32_t _generate_hash_wrapper(const Memcached
*ptr
, const char *key
,
73 WATCHPOINT_ASSERT(memcached_server_count(ptr
));
75 if (memcached_server_count(ptr
) == 1)
78 if (ptr
->flags
.hash_with_namespace
) {
79 size_t temp_length
= memcached_array_size(ptr
->_namespace
) + key_length
;
80 char temp
[MEMCACHED_MAX_KEY
];
82 if (temp_length
> MEMCACHED_MAX_KEY
- 1)
85 strncpy(temp
, memcached_array_string(ptr
->_namespace
), memcached_array_size(ptr
->_namespace
));
86 strncpy(temp
+ memcached_array_size(ptr
->_namespace
), key
, key_length
);
88 return generate_hash(ptr
, temp
, temp_length
);
90 return generate_hash(ptr
, key
, key_length
);
94 static inline void _regen_for_auto_eject(Memcached
*ptr
) {
95 if (_is_auto_eject_host(ptr
) && ptr
->ketama
.next_distribution_rebuild
) {
98 if (gettimeofday(&now
, NULL
) == 0 and now
.tv_sec
> ptr
->ketama
.next_distribution_rebuild
) {
99 run_distribution(ptr
);
104 void memcached_autoeject(memcached_st
*ptr
) {
105 _regen_for_auto_eject(ptr
);
108 uint32_t memcached_generate_hash_with_redistribution(memcached_st
*ptr
, const char *key
,
110 uint32_t hash
= _generate_hash_wrapper(ptr
, key
, key_length
);
112 _regen_for_auto_eject(ptr
);
114 return dispatch_host(ptr
, hash
);
117 uint32_t memcached_generate_hash(const memcached_st
*shell
, const char *key
, size_t key_length
) {
118 const Memcached
*ptr
= memcached2Memcached(shell
);
120 return dispatch_host(ptr
, _generate_hash_wrapper(ptr
, key
, key_length
));
126 const hashkit_st
*memcached_get_hashkit(const memcached_st
*shell
) {
127 const Memcached
*ptr
= memcached2Memcached(shell
);
129 return &ptr
->hashkit
;
135 memcached_return_t
memcached_set_hashkit(memcached_st
*shell
, hashkit_st
*hashk
) {
136 Memcached
*self
= memcached2Memcached(shell
);
138 hashkit_free(&self
->hashkit
);
139 hashkit_clone(&self
->hashkit
, hashk
);
141 return MEMCACHED_SUCCESS
;
144 return MEMCACHED_INVALID_ARGUMENTS
;
147 const char *libmemcached_string_hash(memcached_hash_t type
) {
148 return libhashkit_string_hash((hashkit_hash_algorithm_t
) type
);