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