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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/
   6  *
   7  *  Redistribution and use in source and binary forms, with or without
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   9  *  met:
  10  *
  11  *      * Redistributions of source code must retain the above copyright
  12  *  notice, this list of conditions and the following disclaimer.
  13  *
  14  *      * Redistributions in binary form must reproduce the above
  15  *  copyright notice, this list of conditions and the following disclaimer
  16  *  in the documentation and/or other materials provided with the
  17  *  distribution.
  18  *
  19  *      * The names of its contributors may not be used to endorse or
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  21  *  written permission.
  22  *
  23  *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  24  *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  25  *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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  33  *  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  34  *
  35  */
  36
  37 #include <libmemcached/common.h>
  38
  39 static memcached_return_t ascii_exist(memcached_st *memc, memcached_server_write_instance_st 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, memcached_server_write_instance_st 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   request.message.header.request.magic= PROTOCOL_BINARY_REQ;
  83   request.message.header.request.opcode= PROTOCOL_BINARY_CMD_ADD;
  84   request.message.header.request.keylen= htons((uint16_t)(key_length + memcached_array_size(memc->_namespace)));
  85   request.message.header.request.datatype= PROTOCOL_BINARY_RAW_BYTES;
  86   request.message.header.request.extlen= 8;
  87   request.message.body.flags= 0;
  88   request.message.body.expiration= htonl(2678400);
  89
  90   request.message.header.request.bodylen= htonl((uint32_t) (key_length
  91                                                             +memcached_array_size(memc->_namespace)
  92                                                             +request.message.header.request.extlen));
  93
  94   libmemcached_io_vector_st vector[]=
  95   {
  96     { NULL, 0 },
  97     { request.bytes, send_length },
  98     { memcached_array_string(memc->_namespace), memcached_array_size(memc->_namespace) },
  99     { key, key_length }
 100   };
 101
 102   /* write the header */
 103   memcached_return_t rc;
 104   if (memcached_fatal(rc= memcached_vdo(instance, vector, 4, true)))
 105   {
 106     return rc;
 107   }
 108
 109   rc= memcached_response(instance, NULL, 0, NULL);
 110
 111   if (rc == MEMCACHED_SUCCESS)
 112   {
 113     rc= MEMCACHED_NOTFOUND;
 114   }
 115
 116   if (rc == MEMCACHED_DATA_EXISTS)
 117   {
 118     rc= MEMCACHED_SUCCESS;
 119   }
 120
 121   return rc;
 122 }
 123
 124 memcached_return_t memcached_exist(memcached_st *memc, const char *key, size_t key_length)
 125 {
 126   return memcached_exist_by_key(memc, key, key_length, key, key_length);
 127 }
 128
 129 memcached_return_t memcached_exist_by_key(memcached_st *memc,
 130                                           const char *group_key, size_t group_key_length,
 131                                           const char *key, size_t key_length)
 132 {
 133   memcached_return_t rc;
 134   if (memcached_failed(rc= initialize_query(memc, true)))
 135   {
 136     return rc;
 137   }
 138
 139   if (memcached_is_udp(memc))
 140   {
 141     return memcached_set_error(*memc, MEMCACHED_NOT_SUPPORTED, MEMCACHED_AT);
 142   }
 143
 144   uint32_t server_key= memcached_generate_hash_with_redistribution(memc, group_key, group_key_length);
 145   memcached_server_write_instance_st instance= memcached_server_instance_fetch(memc, server_key);
 146
 147   if (memcached_is_binary(memc))
 148   {
 149     rc= binary_exist(memc, instance, key, key_length);
 150   }
 151   else
 152   {
 153     rc= ascii_exist(memc, instance, key, key_length);
 154   }
 155
 156   if (memcached_fatal(rc))
 157   {
 158     memcached_io_reset(instance);
 159   }
 160
 161   return rc;
 162 }