git.m6w6.name Git - m6w6/libmemcached/blob - example/storage.cc

   1 /* -*- Mode: C; tab-width: 2; c-basic-offset: 2; indent-tabs-mode: nil -*- */
   2 #include "config.h"
   3 #include <stdlib.h>
   4 #include <inttypes.h>
   5 #include <time.h>
   6 #include <stdbool.h>
   7 #include <string.h>
   8 #include "storage.h"
   9
  10 struct list_entry {
  11   struct item item;
  12   struct list_entry *next;
  13   struct list_entry *prev;
  14 };
  15
  16 static struct list_entry *root;
  17 static uint64_t cas;
  18
  19 bool initialize_storage(void)
  20 {
  21   return true;
  22 }
  23
  24 void shutdown_storage(void)
  25 {
  26   /* Do nothing */
  27 }
  28
  29 void put_item(struct item* item)
  30 {
  31   struct list_entry* entry= (struct list_entry*)item;
  32
  33   update_cas(item);
  34
  35   if (root == NULL)
  36   {
  37     entry->next= entry->prev= entry;
  38   }
  39   else
  40   {
  41     entry->prev= root->prev;
  42     entry->next= root;
  43     entry->prev->next= entry;
  44     entry->next->prev= entry;
  45   }
  46
  47   root= entry;
  48 }
  49
  50 struct item* get_item(const void* key, size_t nkey)
  51 {
  52   struct list_entry *walker= root;
  53
  54   if (root == NULL)
  55   {
  56     return NULL;
  57   }
  58
  59   do
  60   {
  61     if (((struct item*)walker)->nkey == nkey &&
  62         memcmp(((struct item*)walker)->key, key, nkey) == 0)
  63     {
  64       return (struct item*)walker;
  65     }
  66     walker= walker->next;
  67   } while (walker != root);
  68
  69   return NULL;
  70 }
  71
  72 struct item* create_item(const void* key, size_t nkey, const void* data,
  73                          size_t size, uint32_t flags, time_t exp)
  74 {
  75   struct item* ret= (struct item*)calloc(1, sizeof(struct list_entry));
  76
  77   if (ret != NULL)
  78   {
  79     ret->key= malloc(nkey);
  80     if (size > 0)
  81     {
  82       ret->data= malloc(size);
  83     }
  84
  85     if (ret->key == NULL || (size > 0 && ret->data == NULL))
  86     {
  87       free(ret->key);
  88       free(ret->data);
  89       free(ret);
  90       return NULL;
  91     }
  92
  93     memcpy(ret->key, key, nkey);
  94     if (data != NULL)
  95     {
  96       memcpy(ret->data, data, size);
  97     }
  98
  99     ret->nkey= nkey;
 100     ret->size= size;
 101     ret->flags= flags;
 102     ret->exp= exp;
 103   }
 104
 105   return ret;
 106 }
 107
 108 bool delete_item(const void* key, size_t nkey)
 109 {
 110   struct item* item= get_item(key, nkey);
 111   bool ret= false;
 112
 113   if (item)
 114   {
 115     /* remove from linked list */
 116     struct list_entry *entry= (struct list_entry*)item;
 117
 118     if (entry->next == entry)
 119     {
 120       /* Only one object in the list */
 121       root= NULL;
 122     }
 123     else
 124     {
 125       /* ensure that we don't loose track of the root, and this will
 126        * change the start position for the next search ;-) */
 127       root= entry->next;
 128       entry->prev->next= entry->next;
 129       entry->next->prev= entry->prev;
 130     }
 131
 132     free(item->key);
 133     free(item->data);
 134     free(item);
 135     ret= true;
 136   }
 137
 138   return ret;
 139 }
 140
 141 void flush(uint32_t /* when */)
 142 {
 143   /* remove the complete linked list */
 144   if (root == NULL)
 145   {
 146     return;
 147   }
 148
 149   root->prev->next= NULL;
 150   while (root != NULL)
 151   {
 152     struct item* tmp= (struct item*)root;
 153     root= root->next;
 154
 155     free(tmp->key);
 156     free(tmp->data);
 157     free(tmp);
 158   }
 159 }
 160
 161 void update_cas(struct item* item)
 162 {
 163   item->cas= ++cas;
 164 }
 165
 166 void release_item(struct item* /* item */)
 167 {
 168 }