git.m6w6.name Git - m6w6/libmemcached/blob - libmemcached/purge.cc

   1 /*  vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
   2  *
   3  *  LibMemcached
   4  *
   5  *  Copyright (C) 2011 Data Differential, http://datadifferential.com/
   6  *  Copyright (C) 2006-2009 Brian Aker
   7  *  All rights reserved.
   8  *
   9  *  Redistribution and use in source and binary forms, with or without
  10  *  modification, are permitted provided that the following conditions are
  11  *  met:
  12  *
  13  *      * Redistributions of source code must retain the above copyright
  14  *  notice, this list of conditions and the following disclaimer.
  15  *
  16  *      * Redistributions in binary form must reproduce the above
  17  *  copyright notice, this list of conditions and the following disclaimer
  18  *  in the documentation and/or other materials provided with the
  19  *  distribution.
  20  *
  21  *      * The names of its contributors may not be used to endorse or
  22  *  promote products derived from this software without specific prior
  23  *  written permission.
  24  *
  25  *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  26  *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  27  *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  28  *  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  29  *  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  30  *  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  31  *  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  32  *  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  33  *  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  34  *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  35  *  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  36  *
  37  */
  38
  39
  40 #include <libmemcached/common.h>
  41
  42 #define memcached_set_purging(__object, __value) ((__object)->state.is_purging= (__value))
  43
  44 class Purge
  45 {
  46 public:
  47   Purge(memcached_st* arg) :
  48     _memc(arg)
  49   {
  50     memcached_set_purging(_memc, true);
  51   }
  52
  53   ~Purge()
  54   {
  55     memcached_set_purging(_memc, false);
  56   }
  57
  58 private:
  59   memcached_st* _memc;
  60 };
  61
  62 class PollTimeout
  63 {
  64 public:
  65   PollTimeout(memcached_st* arg) :
  66     _timeout(arg->poll_timeout),
  67     _origin(arg->poll_timeout)
  68   {
  69     _origin = 2000;
  70   }
  71
  72   ~PollTimeout()
  73   {
  74     _origin= _timeout;
  75   }
  76
  77 private:
  78   int32_t _timeout;
  79   int32_t& _origin;
  80 };
  81
  82 bool memcached_purge(org::libmemcached::Instance* ptr)
  83 {
  84   memcached_st *root= (memcached_st *)ptr->root;
  85
  86   if (memcached_is_purging(ptr->root) || /* already purging */
  87       (memcached_server_response_count(ptr) < ptr->root->io_msg_watermark &&
  88        ptr->io_bytes_sent < ptr->root->io_bytes_watermark) ||
  89       (ptr->io_bytes_sent >= ptr->root->io_bytes_watermark &&
  90        memcached_server_response_count(ptr) < 2))
  91   {
  92     return true;
  93   }
  94
  95   /*
  96     memcached_io_write and memcached_response may call memcached_purge
  97     so we need to be able stop any recursion..
  98   */
  99   Purge set_purge(root);
 100
 101   WATCHPOINT_ASSERT(ptr->fd != INVALID_SOCKET);
 102   /*
 103     Force a flush of the buffer to ensure that we don't have the n-1 pending
 104     requests buffered up..
 105   */
 106   if (memcached_io_write(ptr) == false)
 107   {
 108     memcached_set_error(*ptr, MEMCACHED_WRITE_FAILURE, MEMCACHED_AT);
 109     return false;
 110   }
 111   WATCHPOINT_ASSERT(ptr->fd != INVALID_SOCKET);
 112
 113   bool is_successful= true;
 114   uint32_t no_msg= memcached_server_response_count(ptr) - 1;
 115   if (no_msg > 0)
 116   {
 117     memcached_result_st result;
 118
 119     /*
 120      * We need to increase the timeout, because we might be waiting for
 121      * data to be sent from the server (the commands was in the output buffer
 122      * and just flushed
 123    */
 124     PollTimeout poll_timeout(ptr->root);
 125
 126     memcached_result_st* result_ptr= memcached_result_create(root, &result);
 127     assert(result_ptr);
 128
 129     for (uint32_t x= 0; x < no_msg; x++)
 130     {
 131       memcached_result_reset(result_ptr);
 132       memcached_return_t rc= memcached_read_one_response(ptr, result_ptr);
 133       /*
 134        * Purge doesn't care for what kind of command results that is received.
 135        * The only kind of errors I care about if is I'm out of sync with the
 136        * protocol or have problems reading data from the network..
 137      */
 138       if (rc== MEMCACHED_PROTOCOL_ERROR or rc == MEMCACHED_UNKNOWN_READ_FAILURE or rc == MEMCACHED_READ_FAILURE)
 139       {
 140         WATCHPOINT_ERROR(rc);
 141         memcached_io_reset(ptr);
 142         is_successful= false;
 143       }
 144
 145       if (ptr->root->callbacks != NULL)
 146       {
 147         memcached_callback_st cb = *ptr->root->callbacks;
 148         if (memcached_success(rc))
 149         {
 150           for (uint32_t y= 0; y < cb.number_of_callback; y++)
 151           {
 152             if (memcached_fatal((*cb.callback[y])(ptr->root, result_ptr, cb.context)))
 153             {
 154               break;
 155             }
 156           }
 157         }
 158       }
 159     }
 160
 161     memcached_result_free(result_ptr);
 162   }
 163
 164   return is_successful;
 165 }