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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.
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   8  *  Redistribution and use in source and binary forms, with or without
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  24  *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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  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, key, key_length, expiration);
  45 }
  46
  47 static inline memcached_return_t ascii_delete(memcached_st *ptr,
  48                                               memcached_server_write_instance_st instance,
  49                                               uint32_t ,
  50                                               const char *key,
  51                                               size_t key_length,
  52                                               bool& reply,
  53                                               bool& flush)
  54 {
  55   char buffer[MEMCACHED_DEFAULT_COMMAND_SIZE];
  56   int send_length= snprintf(buffer, MEMCACHED_DEFAULT_COMMAND_SIZE,
  57                             "delete %.*s%.*s%s\r\n",
  58                             memcached_print_array(ptr->_namespace),
  59                             (int)key_length, key,
  60                             reply ? "" :  " noreply");
  61
  62   if (send_length >= MEMCACHED_DEFAULT_COMMAND_SIZE || send_length < 0)
  63   {
  64     return memcached_set_error(*ptr, MEMCACHED_MEMORY_ALLOCATION_FAILURE, MEMCACHED_AT,
  65                                memcached_literal_param("snprintf(MEMCACHED_DEFAULT_COMMAND_SIZE)"));
  66   }
  67
  68   if (ptr->flags.use_udp and flush == false)
  69   {
  70     if (send_length > MAX_UDP_DATAGRAM_LENGTH - UDP_DATAGRAM_HEADER_LENGTH)
  71     {
  72       return MEMCACHED_WRITE_FAILURE;
  73     }
  74
  75     if (send_length +instance->write_buffer_offset > MAX_UDP_DATAGRAM_LENGTH)
  76     {
  77       memcached_io_write(instance, NULL, 0, true);
  78     }
  79   }
  80
  81   return memcached_do(instance, buffer, (size_t)send_length, flush);
  82 }
  83
  84 static inline memcached_return_t binary_delete(memcached_st *ptr,
  85                                                memcached_server_write_instance_st instance,
  86                                                uint32_t server_key,
  87                                                const char *key,
  88                                                size_t key_length,
  89                                                bool& reply,
  90                                                bool& flush)
  91 {
  92   protocol_binary_request_delete request= {};
  93
  94   request.message.header.request.magic= PROTOCOL_BINARY_REQ;
  95   if (reply)
  96   {
  97     request.message.header.request.opcode= PROTOCOL_BINARY_CMD_DELETE;
  98   }
  99   else
 100   {
 101     request.message.header.request.opcode= PROTOCOL_BINARY_CMD_DELETEQ;
 102   }
 103   request.message.header.request.keylen= htons((uint16_t)(key_length + memcached_array_size(ptr->_namespace)));
 104   request.message.header.request.datatype= PROTOCOL_BINARY_RAW_BYTES;
 105   request.message.header.request.bodylen= htonl((uint32_t)(key_length + memcached_array_size(ptr->_namespace)));
 106
 107   if (ptr->flags.use_udp and flush == false)
 108   {
 109     size_t cmd_size= sizeof(request.bytes) + key_length;
 110     if (cmd_size > MAX_UDP_DATAGRAM_LENGTH - UDP_DATAGRAM_HEADER_LENGTH)
 111     {
 112       return MEMCACHED_WRITE_FAILURE;
 113     }
 114
 115     if (cmd_size +instance->write_buffer_offset > MAX_UDP_DATAGRAM_LENGTH)
 116     {
 117       memcached_io_write(instance, NULL, 0, true);
 118     }
 119   }
 120
 121   struct libmemcached_io_vector_st vector[]=
 122   {
 123     { request.bytes, sizeof(request.bytes) },
 124     { memcached_array_string(ptr->_namespace), memcached_array_size(ptr->_namespace) },
 125     { key, key_length }
 126   };
 127
 128   memcached_return_t rc= MEMCACHED_SUCCESS;
 129
 130   if ((rc= memcached_vdo(instance, vector,  3, flush)) != MEMCACHED_SUCCESS)
 131   {
 132     memcached_io_reset(instance);
 133   }
 134
 135   if (ptr->number_of_replicas > 0)
 136   {
 137     request.message.header.request.opcode= PROTOCOL_BINARY_CMD_DELETEQ;
 138
 139     for (uint32_t x= 0; x < ptr->number_of_replicas; ++x)
 140     {
 141       memcached_server_write_instance_st replica;
 142
 143       ++server_key;
 144       if (server_key == memcached_server_count(ptr))
 145         server_key= 0;
 146
 147       replica= memcached_server_instance_fetch(ptr, server_key);
 148
 149       if (memcached_vdo(replica, vector, 3, flush) != MEMCACHED_SUCCESS)
 150       {
 151         memcached_io_reset(replica);
 152       }
 153       else
 154       {
 155         memcached_server_response_decrement(replica);
 156       }
 157     }
 158   }
 159
 160   return rc;
 161 }
 162
 163 memcached_return_t memcached_delete_by_key(memcached_st *ptr,
 164                                            const char *group_key, size_t group_key_length,
 165                                            const char *key, size_t key_length,
 166                                            time_t expiration)
 167 {
 168   LIBMEMCACHED_MEMCACHED_DELETE_START();
 169
 170   memcached_return_t rc;
 171   if (memcached_failed(rc= initialize_query(ptr)))
 172   {
 173     return rc;
 174   }
 175
 176   rc= memcached_validate_key_length(key_length, ptr->flags.binary_protocol);
 177   if (memcached_failed(rc))
 178   {
 179     return rc;
 180   }
 181
 182   if (expiration)
 183   {
 184     return memcached_set_error(*ptr, MEMCACHED_INVALID_ARGUMENTS, MEMCACHED_AT,
 185                                memcached_literal_param("Memcached server version does not allow expiration of deleted items"));
 186   }
 187
 188   // If a delete trigger exists, we need a response, so no buffering/noreply
 189   if (ptr->delete_trigger)
 190   {
 191     if (ptr->flags.buffer_requests)
 192     {
 193       return memcached_set_error(*ptr, MEMCACHED_INVALID_ARGUMENTS, MEMCACHED_AT,
 194                                  memcached_literal_param("Delete triggers cannot be used if buffering is enabled"));
 195     }
 196
 197     if (ptr->flags.no_reply)
 198     {
 199       return memcached_set_error(*ptr, MEMCACHED_INVALID_ARGUMENTS, MEMCACHED_AT,
 200                                  memcached_literal_param("Delete triggers cannot be used if MEMCACHED_BEHAVIOR_NOREPLY is set"));
 201     }
 202   }
 203
 204
 205   uint32_t server_key= memcached_generate_hash_with_redistribution(ptr, group_key, group_key_length);
 206   memcached_server_write_instance_st instance= memcached_server_instance_fetch(ptr, server_key);
 207
 208   bool to_write= (ptr->flags.buffer_requests) ? false : true;
 209
 210   // Invert the logic to make it simpler to read the code
 211   bool reply= (ptr->flags.no_reply) ? false : true;
 212
 213   if (ptr->flags.binary_protocol)
 214   {
 215     rc= binary_delete(ptr, instance, server_key, key, key_length, reply, to_write);
 216   }
 217   else
 218   {
 219     rc= ascii_delete(ptr, instance, server_key, key, key_length, reply, to_write);
 220   }
 221
 222   if (rc == MEMCACHED_SUCCESS)
 223   {
 224     if (to_write == false)
 225     {
 226       rc= MEMCACHED_BUFFERED;
 227     }
 228     else if (reply)
 229     {
 230       char buffer[MEMCACHED_DEFAULT_COMMAND_SIZE];
 231       rc= memcached_response(instance, buffer, MEMCACHED_DEFAULT_COMMAND_SIZE, NULL);
 232       if (rc == MEMCACHED_DELETED)
 233       {
 234         rc= MEMCACHED_SUCCESS;
 235       }
 236     }
 237
 238     if (rc == MEMCACHED_SUCCESS and ptr->delete_trigger)
 239     {
 240       ptr->delete_trigger(ptr, key, key_length);
 241     }
 242   }
 243
 244   LIBMEMCACHED_MEMCACHED_DELETE_END();
 245   return rc;
 246 }