git.m6w6.name Git - awesomized/libmemcached/blob - lib/memcached_get.c

   1 #include "common.h"
   2 #include "memcached_io.h"
   3
   4 /*
   5   What happens if no servers exist?
   6 */
   7 char *memcached_get(memcached_st *ptr, char *key, size_t key_length,
   8                     size_t *value_length,
   9                     uint32_t *flags,
  10                     memcached_return *error)
  11 {
  12   return memcached_get_by_key(ptr, NULL, 0, key, key_length, value_length,
  13                               flags, error);
  14 }
  15
  16 char *memcached_get_by_key(memcached_st *ptr,
  17                            char *master_key, size_t master_key_length,
  18                            char *key, size_t key_length,
  19                            size_t *value_length,
  20                            uint32_t *flags,
  21                            memcached_return *error)
  22 {
  23   unsigned int server_key;
  24   size_t send_length;
  25   char buffer[MEMCACHED_DEFAULT_COMMAND_SIZE];
  26   memcached_result_st *result_buffer= &ptr->result;
  27   memcached_return rc[MEMCACHED_MAX_REPLICAS];
  28   uint8_t replicas= 0;
  29
  30   if (ptr->number_of_hosts == 0)
  31   {
  32     *error= MEMCACHED_NO_SERVERS;
  33     return NULL;
  34   }
  35
  36   if ((ptr->flags & MEM_VERIFY_KEY) && (memcachd_key_test(&key, &key_length, 1) == MEMCACHED_BAD_KEY_PROVIDED))
  37   {
  38     *value_length= 0;
  39     *error= MEMCACHED_BAD_KEY_PROVIDED;
  40     return NULL;
  41   }
  42
  43   if (master_key)
  44     server_key= memcached_generate_hash(ptr, master_key, master_key_length);
  45   else
  46     server_key= memcached_generate_hash(ptr, key, key_length);
  47
  48   send_length= snprintf(buffer, MEMCACHED_DEFAULT_COMMAND_SIZE,
  49                         "get %.*s\r\n", (int)key_length, key);
  50
  51   do
  52   {
  53     char response_buffer[MEMCACHED_DEFAULT_COMMAND_SIZE];
  54
  55     if (memcached_server_response_count(&ptr->hosts[server_key]))
  56     {
  57       if (ptr->flags & MEM_NO_BLOCK)
  58         (void)memcached_io_write(&ptr->hosts[server_key], NULL, 0, 1);
  59
  60       while(memcached_server_response_count(&ptr->hosts[server_key]))
  61         (void)memcached_response(&ptr->hosts[server_key], response_buffer, MEMCACHED_DEFAULT_COMMAND_SIZE, result_buffer);
  62     }
  63
  64     rc[replicas]= memcached_do(&ptr->hosts[server_key], buffer, send_length, 1);
  65     if (rc[replicas] != MEMCACHED_SUCCESS)
  66       goto error;
  67
  68     rc[replicas]= memcached_response(&ptr->hosts[server_key], response_buffer, MEMCACHED_DEFAULT_COMMAND_SIZE, result_buffer);
  69
  70     /* On no key found, we check the replica */
  71     if (rc[replicas] == MEMCACHED_END) /* END means that we move on to the next */
  72     {
  73       memcached_server_response_reset(&ptr->hosts[server_key]);
  74     }
  75     else if (rc[replicas] == MEMCACHED_SUCCESS)
  76     {
  77       *value_length= memcached_string_length(&result_buffer->value);
  78
  79       if (result_buffer->flags)
  80         *flags= result_buffer->flags;
  81
  82       *error= MEMCACHED_SUCCESS;
  83       return  memcached_string_c_copy(&result_buffer->value);
  84     }
  85
  86     /* On error we just jump to the next potential server */
  87 error:
  88     if (ptr->number_of_replicas > 1)
  89     {
  90       if (server_key == (ptr->number_of_hosts - 1))
  91         server_key= 0;
  92       else
  93         server_key++;
  94     }
  95   } while ((++replicas) < ptr->number_of_replicas);
  96
  97   /* TODO: An error on replica 1 of host down, but not found on 2, will give wrong error */
  98   /* This is for historical reasons */
  99   if (rc[0] == MEMCACHED_END)
 100     *error= MEMCACHED_NOTFOUND;
 101   else
 102     *error= rc[0];
 103
 104   *value_length= 0;
 105
 106   return NULL;
 107 }