git.m6w6.name Git - awesomized/libmemcached/blob - libmemcached/exist.cc

   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
   8  *  modification, are permitted provided that the following conditions are
   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
  20  *  promote products derived from this software without specific prior
  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
  26  *  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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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   struct libmemcached_io_vector_st vector[]=
  42   {
  43     { memcached_literal_param("add ") },
  44     { memcached_array_string(memc->_namespace), memcached_array_size(memc->_namespace) },
  45     { key, key_length },
  46     { memcached_literal_param(" 0") },
  47     { memcached_literal_param(" 2678400") },
  48     { memcached_literal_param(" 0") },
  49     { memcached_literal_param("\r\n") },
  50     { memcached_literal_param("\r\n") }
  51   };
  52
  53   /* Send command header */
  54   memcached_return_t rc=  memcached_vdo(instance, vector, 8, true);
  55   if (rc == MEMCACHED_SUCCESS)
  56   {
  57     char buffer[MEMCACHED_DEFAULT_COMMAND_SIZE];
  58     rc= memcached_response(instance, buffer, MEMCACHED_DEFAULT_COMMAND_SIZE, NULL);
  59
  60     if (rc == MEMCACHED_NOTSTORED)
  61       rc= MEMCACHED_SUCCESS;
  62
  63     if (rc == MEMCACHED_STORED)
  64       rc= MEMCACHED_NOTFOUND;
  65   }
  66
  67   if (rc == MEMCACHED_WRITE_FAILURE)
  68     memcached_io_reset(instance);
  69
  70   return rc;
  71 }
  72
  73 static memcached_return_t binary_exist(memcached_st *memc, memcached_server_write_instance_st instance, const char *key, size_t key_length)
  74 {
  75   protocol_binary_request_set request= {};
  76   size_t send_length= sizeof(request.bytes);
  77
  78   request.message.header.request.magic= PROTOCOL_BINARY_REQ;
  79   request.message.header.request.opcode= PROTOCOL_BINARY_CMD_ADD;
  80   request.message.header.request.keylen= htons((uint16_t)(key_length + memcached_array_size(memc->_namespace)));
  81   request.message.header.request.datatype= PROTOCOL_BINARY_RAW_BYTES;
  82   request.message.header.request.extlen= 8;
  83   request.message.body.flags= 0;
  84   request.message.body.expiration= htonl(2678400);
  85
  86   request.message.header.request.bodylen= htonl((uint32_t) (key_length
  87                                                             +memcached_array_size(memc->_namespace)
  88                                                             +request.message.header.request.extlen));
  89
  90   struct libmemcached_io_vector_st vector[]=
  91   {
  92     { request.bytes, send_length },
  93     { memcached_array_string(memc->_namespace), memcached_array_size(memc->_namespace) },
  94     { key, key_length }
  95   };
  96
  97   /* write the header */
  98   memcached_return_t rc;
  99   if ((rc= memcached_vdo(instance, vector, 3, true)) != MEMCACHED_SUCCESS)
 100   {
 101     memcached_io_reset(instance);
 102     return (rc == MEMCACHED_SUCCESS) ? MEMCACHED_WRITE_FAILURE : rc;
 103   }
 104
 105   rc= memcached_response(instance, NULL, 0, NULL);
 106
 107   if (rc == MEMCACHED_SUCCESS)
 108     rc= MEMCACHED_NOTFOUND;
 109
 110   if (rc == MEMCACHED_DATA_EXISTS)
 111     rc= MEMCACHED_SUCCESS;
 112
 113   return rc;
 114 }
 115
 116 memcached_return_t memcached_exist(memcached_st *memc, const char *key, size_t key_length)
 117 {
 118   return memcached_exist_by_key(memc, key, key_length, key, key_length);
 119 }
 120
 121 memcached_return_t memcached_exist_by_key(memcached_st *memc,
 122                                           const char *group_key, size_t group_key_length,
 123                                           const char *key, size_t key_length)
 124 {
 125   memcached_return_t rc;
 126   if (memcached_failed(rc= initialize_query(memc)))
 127   {
 128     return rc;
 129   }
 130
 131   if (memc->flags.use_udp)
 132   {
 133     return MEMCACHED_NOT_SUPPORTED;
 134   }
 135
 136
 137   uint32_t server_key= memcached_generate_hash_with_redistribution(memc, group_key, group_key_length);
 138   memcached_server_write_instance_st instance;
 139   instance= memcached_server_instance_fetch(memc, server_key);
 140
 141   if (memc->flags.binary_protocol)
 142   {
 143     return binary_exist(memc, instance, key, key_length);
 144   }
 145   else
 146   {
 147     return ascii_exist(memc, instance, key, key_length);
 148   }
 149 }