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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  *  Copyright (C) 2006-2009 Brian Aker All rights reserved.
   7  *
   8  *  Redistribution and use in source and binary forms, with or without
   9  *  modification, are permitted provided that the following conditions are
  10  *  met:
  11  *
  12  *      * Redistributions of source code must retain the above copyright
  13  *  notice, this list of conditions and the following disclaimer.
  14  *
  15  *      * Redistributions in binary form must reproduce the above
  16  *  copyright notice, this list of conditions and the following disclaimer
  17  *  in the documentation and/or other materials provided with the
  18  *  distribution.
  19  *
  20  *      * The names of its contributors may not be used to endorse or
  21  *  promote products derived from this software without specific prior
  22  *  written permission.
  23  *
  24  *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  25  *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  26  *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  27  *  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  28  *  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  29  *  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  30  *  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  31  *  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  32  *  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  33  *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  34  *  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  35  *
  36  */
  37
  38 #include <libmemcached/common.h>
  39 #include <libmemcached/memcached/protocol_binary.h>
  40
  41 memcached_return_t memcached_delete(memcached_st *ptr, const char *key, size_t key_length,
  42                                     time_t expiration)
  43 {
  44   return memcached_delete_by_key(ptr, key, key_length,
  45                                  key, key_length, expiration);
  46 }
  47
  48 static inline memcached_return_t binary_delete(memcached_st *ptr,
  49                                                uint32_t server_key,
  50                                                const char *key,
  51                                                size_t key_length,
  52                                                bool flush);
  53
  54 memcached_return_t memcached_delete_by_key(memcached_st *ptr,
  55                                            const char *group_key, size_t group_key_length,
  56                                            const char *key, size_t key_length,
  57                                            time_t expiration)
  58 {
  59   bool to_write;
  60   char buffer[MEMCACHED_DEFAULT_COMMAND_SIZE];
  61   uint32_t server_key;
  62   memcached_server_write_instance_st instance;
  63
  64   LIBMEMCACHED_MEMCACHED_DELETE_START();
  65
  66   memcached_return_t rc;
  67   if ((rc= initialize_query(ptr)) != MEMCACHED_SUCCESS)
  68   {
  69     return rc;
  70   }
  71
  72   rc= memcached_validate_key_length(key_length,
  73                                     ptr->flags.binary_protocol);
  74   unlikely (rc != MEMCACHED_SUCCESS)
  75     return rc;
  76
  77   unlikely (memcached_server_count(ptr) == 0)
  78     return MEMCACHED_NO_SERVERS;
  79
  80   server_key= memcached_generate_hash_with_redistribution(ptr, group_key, group_key_length);
  81   instance= memcached_server_instance_fetch(ptr, server_key);
  82
  83   to_write= (ptr->flags.buffer_requests) ? false : true;
  84
  85   bool no_reply= (ptr->flags.no_reply);
  86
  87   if (ptr->flags.binary_protocol)
  88   {
  89     likely (! expiration)
  90     {
  91       rc= binary_delete(ptr, server_key, key, key_length, to_write);
  92     }
  93     else
  94     {
  95       rc= MEMCACHED_INVALID_ARGUMENTS;
  96     }
  97   }
  98   else
  99   {
 100     int send_length;
 101
 102     unlikely (expiration)
 103     {
 104        if ((instance->major_version == 1 &&
 105             instance->minor_version > 2) ||
 106            instance->major_version > 1)
 107        {
 108          rc= MEMCACHED_INVALID_ARGUMENTS;
 109          goto error;
 110        }
 111        else
 112        {
 113           /* ensure that we are connected, otherwise we might bump the
 114            * command counter before connection */
 115           if ((rc= memcached_connect(instance)) != MEMCACHED_SUCCESS)
 116           {
 117             WATCHPOINT_ERROR(rc);
 118             return rc;
 119           }
 120
 121           if (instance->minor_version == 0)
 122           {
 123              if (no_reply || ! to_write)
 124              {
 125                 /* We might get out of sync with the server if we
 126                  * send this command to a server newer than 1.2.x..
 127                  * disable no_reply and buffered mode.
 128                  */
 129                 to_write= true;
 130                 if (no_reply)
 131                    memcached_server_response_increment(instance);
 132                 no_reply= false;
 133              }
 134           }
 135           send_length= snprintf(buffer, MEMCACHED_DEFAULT_COMMAND_SIZE,
 136                                 "delete %.*s%.*s %u%s\r\n",
 137                                 memcached_print_array(ptr->prefix_key),
 138                                 (int) key_length, key,
 139                                 (uint32_t)expiration,
 140                                 no_reply ? " noreply" :"" );
 141        }
 142     }
 143     else
 144     {
 145       send_length= snprintf(buffer, MEMCACHED_DEFAULT_COMMAND_SIZE,
 146                             "delete %.*s%.*s%s\r\n",
 147                             memcached_print_array(ptr->prefix_key),
 148                             (int)key_length, key, no_reply ? " noreply" :"");
 149     }
 150
 151     if (send_length >= MEMCACHED_DEFAULT_COMMAND_SIZE || send_length < 0)
 152     {
 153       rc= MEMCACHED_WRITE_FAILURE;
 154       goto error;
 155     }
 156
 157     if (ptr->flags.use_udp && ! to_write)
 158     {
 159       if (send_length > MAX_UDP_DATAGRAM_LENGTH - UDP_DATAGRAM_HEADER_LENGTH)
 160         return MEMCACHED_WRITE_FAILURE;
 161
 162       if (send_length + instance->write_buffer_offset > MAX_UDP_DATAGRAM_LENGTH)
 163         memcached_io_write(instance, NULL, 0, true);
 164     }
 165
 166     rc= memcached_do(instance, buffer, (size_t)send_length, to_write);
 167   }
 168
 169   if (rc != MEMCACHED_SUCCESS)
 170     goto error;
 171
 172   if (! to_write)
 173   {
 174     rc= MEMCACHED_BUFFERED;
 175   }
 176   else if (!no_reply)
 177   {
 178     rc= memcached_response(instance, buffer, MEMCACHED_DEFAULT_COMMAND_SIZE, NULL);
 179     if (rc == MEMCACHED_DELETED)
 180       rc= MEMCACHED_SUCCESS;
 181   }
 182
 183   if (rc == MEMCACHED_SUCCESS && ptr->delete_trigger)
 184     ptr->delete_trigger(ptr, key, key_length);
 185
 186 error:
 187   LIBMEMCACHED_MEMCACHED_DELETE_END();
 188   return rc;
 189 }
 190
 191 static inline memcached_return_t binary_delete(memcached_st *ptr,
 192                                                uint32_t server_key,
 193                                                const char *key,
 194                                                size_t key_length,
 195                                                bool flush)
 196 {
 197   memcached_server_write_instance_st instance;
 198   protocol_binary_request_delete request= {};
 199
 200   instance= memcached_server_instance_fetch(ptr, server_key);
 201
 202   request.message.header.request.magic= PROTOCOL_BINARY_REQ;
 203   if (ptr->flags.no_reply)
 204   {
 205     request.message.header.request.opcode= PROTOCOL_BINARY_CMD_DELETEQ;
 206   }
 207   else
 208   {
 209     request.message.header.request.opcode= PROTOCOL_BINARY_CMD_DELETE;
 210   }
 211   request.message.header.request.keylen= htons((uint16_t)(key_length + memcached_array_size(ptr->prefix_key)));
 212   request.message.header.request.datatype= PROTOCOL_BINARY_RAW_BYTES;
 213   request.message.header.request.bodylen= htonl((uint32_t)(key_length + memcached_array_size(ptr->prefix_key)));
 214
 215   if (ptr->flags.use_udp && ! flush)
 216   {
 217     size_t cmd_size= sizeof(request.bytes) + key_length;
 218     if (cmd_size > MAX_UDP_DATAGRAM_LENGTH - UDP_DATAGRAM_HEADER_LENGTH)
 219       return MEMCACHED_WRITE_FAILURE;
 220
 221     if (cmd_size + instance->write_buffer_offset > MAX_UDP_DATAGRAM_LENGTH)
 222       memcached_io_write(instance, NULL, 0, true);
 223   }
 224
 225   struct libmemcached_io_vector_st vector[]=
 226   {
 227     { sizeof(request.bytes), request.bytes},
 228     { memcached_array_size(ptr->prefix_key), memcached_array_string(ptr->prefix_key) },
 229     { key_length, key },
 230   };
 231
 232   memcached_return_t rc= MEMCACHED_SUCCESS;
 233
 234   if ((rc= memcached_vdo(instance, vector,  3, flush)) != MEMCACHED_SUCCESS)
 235   {
 236     memcached_io_reset(instance);
 237     rc= (rc == MEMCACHED_SUCCESS) ? MEMCACHED_WRITE_FAILURE : rc;
 238   }
 239
 240   unlikely (ptr->number_of_replicas > 0)
 241   {
 242     request.message.header.request.opcode= PROTOCOL_BINARY_CMD_DELETEQ;
 243
 244     for (uint32_t x= 0; x < ptr->number_of_replicas; ++x)
 245     {
 246       memcached_server_write_instance_st replica;
 247
 248       ++server_key;
 249       if (server_key == memcached_server_count(ptr))
 250         server_key= 0;
 251
 252       replica= memcached_server_instance_fetch(ptr, server_key);
 253
 254       if (memcached_vdo(replica, vector, 3, flush) != MEMCACHED_SUCCESS)
 255       {
 256         memcached_io_reset(replica);
 257       }
 258       else
 259       {
 260         memcached_server_response_decrement(replica);
 261       }
 262     }
 263   }
 264
 265   return rc;
 266 }