git.m6w6.name Git - awesomized/libmemcached/blob - libmemcached/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, const char *key,
   8                     size_t key_length,
   9                     size_t *value_length,
  10                     uint32_t *flags,
  11                     memcached_return *error)
  12 {
  13   return memcached_get_by_key(ptr, NULL, 0, key, key_length, value_length,
  14                               flags, error);
  15 }
  16
  17 char *memcached_get_by_key(memcached_st *ptr,
  18                            const char *master_key,
  19                            size_t master_key_length,
  20                            const char *key, size_t key_length,
  21                            size_t *value_length,
  22                            uint32_t *flags,
  23                            memcached_return *error)
  24 {
  25   char *value;
  26   size_t dummy_length;
  27   uint32_t dummy_flags;
  28   memcached_return dummy_error;
  29
  30   /* Request the key */
  31   *error= memcached_mget_by_key(ptr,
  32                                 master_key,
  33                                 master_key_length,
  34                                 (char **)&key, &key_length, 1);
  35
  36   value= memcached_fetch(ptr, NULL, NULL,
  37                          value_length, flags, error);
  38   /* This is for historical reasons */
  39   if (*error == MEMCACHED_END)
  40     *error= MEMCACHED_NOTFOUND;
  41
  42   if (value == NULL)
  43   {
  44     if (ptr->get_key_failure && *error == MEMCACHED_NOTFOUND)
  45     {
  46       memcached_return rc;
  47
  48       memcached_result_reset(&ptr->result);
  49       rc= ptr->get_key_failure(ptr, key, key_length, &ptr->result);
  50
  51       /* On all failure drop to returning NULL */
  52       if (rc == MEMCACHED_SUCCESS || rc == MEMCACHED_BUFFERED)
  53       {
  54         if (rc == MEMCACHED_BUFFERED)
  55         {
  56           uint8_t latch; /* We use latch to track the state of the original socket */
  57           latch= memcached_behavior_get(ptr, MEMCACHED_BEHAVIOR_BUFFER_REQUESTS);
  58           if (latch == 0)
  59             memcached_behavior_set(ptr, MEMCACHED_BEHAVIOR_BUFFER_REQUESTS, 1);
  60
  61           rc= memcached_set(ptr, key, key_length,
  62                             memcached_result_value(&ptr->result),
  63                             memcached_result_length(&ptr->result),
  64                             0, memcached_result_flags(&ptr->result));
  65
  66           if (rc == MEMCACHED_BUFFERED && latch == 0)
  67             memcached_behavior_set(ptr, MEMCACHED_BEHAVIOR_BUFFER_REQUESTS, 0);
  68         }
  69         else
  70         {
  71           rc= memcached_set(ptr, key, key_length,
  72                             memcached_result_value(&ptr->result),
  73                             memcached_result_length(&ptr->result),
  74                             0, memcached_result_flags(&ptr->result));
  75         }
  76
  77         if (rc == MEMCACHED_SUCCESS || rc == MEMCACHED_BUFFERED)
  78         {
  79           *error= rc;
  80           *value_length= memcached_result_length(&ptr->result);
  81           *flags= memcached_result_flags(&ptr->result);
  82           return memcached_string_c_copy(&ptr->result.value);
  83         }
  84       }
  85     }
  86
  87     return NULL;
  88   }
  89
  90   (void)memcached_fetch(ptr, NULL, NULL,
  91                         &dummy_length, &dummy_flags,
  92                         &dummy_error);
  93   WATCHPOINT_ASSERT(dummy_length == 0);
  94
  95   return value;
  96 }
  97
  98 memcached_return memcached_mget(memcached_st *ptr,
  99                                 char **keys, size_t *key_length,
 100                                 unsigned int number_of_keys)
 101 {
 102   return memcached_mget_by_key(ptr, NULL, 0, keys, key_length, number_of_keys);
 103 }
 104
 105 memcached_return memcached_mget_by_key(memcached_st *ptr,
 106                                        const char *master_key,
 107                                        size_t master_key_length,
 108                                        char **keys,
 109                                        size_t *key_length,
 110                                        unsigned int number_of_keys)
 111 {
 112   unsigned int x;
 113   memcached_return rc= MEMCACHED_NOTFOUND;
 114   char *get_command= "get ";
 115   uint8_t get_command_length= 4;
 116   unsigned int master_server_key= 0;
 117
 118   LIBMEMCACHED_MEMCACHED_MGET_START();
 119   ptr->cursor_server= 0;
 120
 121   if (number_of_keys == 0)
 122     return MEMCACHED_NOTFOUND;
 123
 124   if (ptr->number_of_hosts == 0)
 125     return MEMCACHED_NO_SERVERS;
 126
 127   if ((ptr->flags & MEM_VERIFY_KEY) && (memcachd_key_test(keys, key_length, number_of_keys) == MEMCACHED_BAD_KEY_PROVIDED))
 128     return MEMCACHED_BAD_KEY_PROVIDED;
 129
 130   if (ptr->flags & MEM_SUPPORT_CAS)
 131   {
 132     get_command= "gets ";
 133     get_command_length= 5;
 134   }
 135
 136   if (master_key && master_key_length)
 137     master_server_key= memcached_generate_hash(ptr, master_key, master_key_length);
 138
 139   /*
 140     Here is where we pay for the non-block API. We need to remove any data sitting
 141     in the queue before we start our get.
 142
 143     It might be optimum to bounce the connection if count > some number.
 144   */
 145   for (x= 0; x < ptr->number_of_hosts; x++)
 146   {
 147     if (memcached_server_response_count(&ptr->hosts[x]))
 148     {
 149       char buffer[MEMCACHED_DEFAULT_COMMAND_SIZE];
 150
 151       if (ptr->flags & MEM_NO_BLOCK)
 152         (void)memcached_io_write(&ptr->hosts[x], NULL, 0, 1);
 153
 154       while(memcached_server_response_count(&ptr->hosts[x]))
 155         (void)memcached_response(&ptr->hosts[x], buffer, MEMCACHED_DEFAULT_COMMAND_SIZE, &ptr->result);
 156     }
 157   }
 158
 159   /*
 160     If a server fails we warn about errors and start all over with sending keys
 161     to the server.
 162   */
 163   for (x= 0; x < number_of_keys; x++)
 164   {
 165     unsigned int server_key;
 166
 167     if (master_server_key)
 168       server_key= master_server_key;
 169     else
 170       server_key= memcached_generate_hash(ptr, keys[x], key_length[x]);
 171
 172     if (memcached_server_response_count(&ptr->hosts[server_key]) == 0)
 173     {
 174       rc= memcached_connect(&ptr->hosts[server_key]);
 175
 176       if (rc != MEMCACHED_SUCCESS)
 177         continue;
 178
 179       if ((memcached_io_write(&ptr->hosts[server_key], get_command, get_command_length, 0)) == -1)
 180       {
 181         rc= MEMCACHED_SOME_ERRORS;
 182         continue;
 183       }
 184       WATCHPOINT_ASSERT(ptr->hosts[server_key].cursor_active == 0);
 185       memcached_server_response_increment(&ptr->hosts[server_key]);
 186       WATCHPOINT_ASSERT(ptr->hosts[server_key].cursor_active == 1);
 187     }
 188
 189     /* Only called when we have a prefix key */
 190     if (ptr->prefix_key[0] != 0)
 191     {
 192       if ((memcached_io_write(&ptr->hosts[server_key], ptr->prefix_key, ptr->prefix_key_length, 0)) == -1)
 193       {
 194         memcached_server_response_reset(&ptr->hosts[server_key]);
 195         rc= MEMCACHED_SOME_ERRORS;
 196         continue;
 197       }
 198     }
 199
 200     if ((memcached_io_write(&ptr->hosts[server_key], keys[x], key_length[x], 0)) == -1)
 201     {
 202       memcached_server_response_reset(&ptr->hosts[server_key]);
 203       rc= MEMCACHED_SOME_ERRORS;
 204       continue;
 205     }
 206
 207     if ((memcached_io_write(&ptr->hosts[server_key], " ", 1, 0)) == -1)
 208     {
 209       memcached_server_response_reset(&ptr->hosts[server_key]);
 210       rc= MEMCACHED_SOME_ERRORS;
 211       continue;
 212     }
 213   }
 214
 215   /*
 216     Should we muddle on if some servers are dead?
 217   */
 218   for (x= 0; x < ptr->number_of_hosts; x++)
 219   {
 220     if (memcached_server_response_count(&ptr->hosts[x]))
 221     {
 222       /* We need to do something about non-connnected hosts in the future */
 223       if ((memcached_io_write(&ptr->hosts[x], "\r\n", 2, 1)) == -1)
 224       {
 225         rc= MEMCACHED_SOME_ERRORS;
 226       }
 227     }
 228   }
 229
 230   LIBMEMCACHED_MEMCACHED_MGET_END();
 231   return rc;
 232 }