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   1 /*  vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
   2  *
   3  *  Libmemcached library
   4  *
   5  *  Copyright (C) 2011 Data Differential, http://datadifferential.com/
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   7  *  Redistribution and use in source and binary forms, with or without
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  11  *      * Redistributions of source code must retain the above copyright
  12  *  notice, this list of conditions and the following disclaimer.
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  14  *      * Redistributions in binary form must reproduce the above
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  19  *      * The names of its contributors may not be used to endorse or
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  23  *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  24  *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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  33  *  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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  35  */
  36
  37 #include <libmemcached/common.h>
  38
  39 static memcached_return_t ascii_exist(memcached_st *memc, org::libmemcached::Instance* instance, const char *key, size_t key_length)
  40 {
  41   libmemcached_io_vector_st vector[]=
  42   {
  43     { NULL, 0 },
  44     { memcached_literal_param("add ") },
  45     { memcached_array_string(memc->_namespace), memcached_array_size(memc->_namespace) },
  46     { key, key_length },
  47     { memcached_literal_param(" 0") },
  48     { memcached_literal_param(" 2678400") },
  49     { memcached_literal_param(" 0") },
  50     { memcached_literal_param("\r\n") },
  51     { memcached_literal_param("\r\n") }
  52   };
  53
  54   /* Send command header */
  55   memcached_return_t rc;
  56   if (memcached_fatal(rc= memcached_vdo(instance, vector, 9, true)))
  57   {
  58     return rc;
  59   }
  60
  61   char buffer[MEMCACHED_DEFAULT_COMMAND_SIZE];
  62   rc= memcached_response(instance, buffer, MEMCACHED_DEFAULT_COMMAND_SIZE, NULL);
  63
  64   if (rc == MEMCACHED_NOTSTORED)
  65   {
  66     rc= MEMCACHED_SUCCESS;
  67   }
  68
  69   if (rc == MEMCACHED_STORED)
  70   {
  71     rc= MEMCACHED_NOTFOUND;
  72   }
  73
  74   return rc;
  75 }
  76
  77 static memcached_return_t binary_exist(memcached_st *memc, org::libmemcached::Instance* instance, const char *key, size_t key_length)
  78 {
  79   protocol_binary_request_set request= {};
  80   size_t send_length= sizeof(request.bytes);
  81
  82   initialize_binary_request(instance, request.message.header);
  83
  84   request.message.header.request.opcode= PROTOCOL_BINARY_CMD_ADD;
  85   request.message.header.request.keylen= htons((uint16_t)(key_length + memcached_array_size(memc->_namespace)));
  86   request.message.header.request.datatype= PROTOCOL_BINARY_RAW_BYTES;
  87   request.message.header.request.extlen= 8;
  88   request.message.body.flags= 0;
  89   request.message.body.expiration= htonl(2678400);
  90
  91   request.message.header.request.bodylen= htonl((uint32_t) (key_length
  92                                                             +memcached_array_size(memc->_namespace)
  93                                                             +request.message.header.request.extlen));
  94
  95   libmemcached_io_vector_st vector[]=
  96   {
  97     { NULL, 0 },
  98     { request.bytes, send_length },
  99     { memcached_array_string(memc->_namespace), memcached_array_size(memc->_namespace) },
 100     { key, key_length }
 101   };
 102
 103   /* write the header */
 104   memcached_return_t rc;
 105   if (memcached_fatal(rc= memcached_vdo(instance, vector, 4, true)))
 106   {
 107     return rc;
 108   }
 109
 110   rc= memcached_response(instance, NULL, 0, NULL);
 111
 112   if (rc == MEMCACHED_SUCCESS)
 113   {
 114     rc= MEMCACHED_NOTFOUND;
 115   }
 116
 117   if (rc == MEMCACHED_DATA_EXISTS)
 118   {
 119     rc= MEMCACHED_SUCCESS;
 120   }
 121
 122   return rc;
 123 }
 124
 125 memcached_return_t memcached_exist(memcached_st *memc, const char *key, size_t key_length)
 126 {
 127   return memcached_exist_by_key(memc, key, key_length, key, key_length);
 128 }
 129
 130 memcached_return_t memcached_exist_by_key(memcached_st *memc,
 131                                           const char *group_key, size_t group_key_length,
 132                                           const char *key, size_t key_length)
 133 {
 134   memcached_return_t rc;
 135   if (memcached_failed(rc= initialize_query(memc, true)))
 136   {
 137     return rc;
 138   }
 139
 140   if (memcached_is_udp(memc))
 141   {
 142     return memcached_set_error(*memc, MEMCACHED_NOT_SUPPORTED, MEMCACHED_AT);
 143   }
 144
 145   uint32_t server_key= memcached_generate_hash_with_redistribution(memc, group_key, group_key_length);
 146   org::libmemcached::Instance* instance= memcached_instance_fetch(memc, server_key);
 147
 148   if (memcached_is_binary(memc))
 149   {
 150     rc= binary_exist(memc, instance, key, key_length);
 151   }
 152   else
 153   {
 154     rc= ascii_exist(memc, instance, key, key_length);
 155   }
 156
 157   if (memcached_fatal(rc))
 158   {
 159     memcached_io_reset(instance);
 160   }
 161
 162   return rc;
 163 }