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

   1 /*
   2     +--------------------------------------------------------------------+
   3     | libmemcached-awesome - C/C++ Client Library for memcached          |
   4     +--------------------------------------------------------------------+
   5     | Redistribution and use in source and binary forms, with or without |
   6     | modification, are permitted under the terms of the BSD license.    |
   7     | You should have received a copy of the license in a bundled file   |
   8     | named LICENSE; in case you did not receive a copy you can review   |
   9     | the terms online at: https://opensource.org/licenses/BSD-3-Clause  |
  10     +--------------------------------------------------------------------+
  11     | Copyright (c) 2006-2014 Brian Aker   https://datadifferential.com/ |
  12     | Copyright (c) 2020-2021 Michael Wallner        https://awesome.co/ |
  13     +--------------------------------------------------------------------+
  14 */
  15
  16 #include "libmemcached/common.h"
  17
  18 #define memcached_set_purging(object_, value_) ((object_)->state.is_purging = (value_))
  19
  20 class Purge {
  21 public:
  22   Purge(Memcached *arg)
  23   : _memc(arg) {
  24     memcached_set_purging(_memc, true);
  25   }
  26
  27   ~Purge() {
  28     memcached_set_purging(_memc, false);
  29   }
  30
  31 private:
  32   Memcached *_memc;
  33 };
  34
  35 class PollTimeout {
  36 public:
  37   PollTimeout(Memcached *arg, int32_t ms = 50)
  38   : _timeout(arg->poll_timeout)
  39   , _origin(arg->poll_timeout) {
  40     _origin = ms;
  41   }
  42
  43   ~PollTimeout() {
  44     _origin = _timeout;
  45   }
  46
  47 private:
  48   int32_t _timeout;
  49   int32_t &_origin;
  50 };
  51
  52 bool memcached_purge(memcached_instance_st *ptr) {
  53   Memcached *root = (Memcached *) ptr->root;
  54
  55   if (memcached_is_purging(ptr->root) || /* already purging */
  56       (memcached_server_response_count(ptr) < ptr->root->io_msg_watermark
  57        && ptr->io_bytes_sent < ptr->root->io_bytes_watermark)
  58       || (ptr->io_bytes_sent >= ptr->root->io_bytes_watermark
  59           && memcached_server_response_count(ptr) < 2))
  60   {
  61     return true;
  62   }
  63
  64   /*
  65     memcached_io_write and memcached_response may call memcached_purge
  66     so we need to be able stop any recursion..
  67   */
  68   Purge set_purge(root);
  69
  70   WATCHPOINT_ASSERT(ptr->fd != INVALID_SOCKET);
  71   /*
  72     Force a flush of the buffer to ensure that we don't have the n-1 pending
  73     requests buffered up..
  74   */
  75   if (memcached_io_write(ptr) == false) {
  76     memcached_io_reset(ptr);
  77     memcached_set_error(*ptr, MEMCACHED_WRITE_FAILURE, MEMCACHED_AT);
  78     return false;
  79   }
  80   WATCHPOINT_ASSERT(ptr->fd != INVALID_SOCKET);
  81
  82   bool is_successful = true;
  83   uint32_t no_msg = memcached_server_response_count(ptr);
  84   if (no_msg > 1) {
  85     memcached_result_st result;
  86
  87     /*
  88      * We need to increase the timeout, because we might be waiting for
  89      * data to be sent from the server (the commands was in the output buffer
  90      * and just flushed
  91      */
  92     PollTimeout poll_timeout(ptr->root);
  93
  94     memcached_result_st *result_ptr = memcached_result_create(root, &result);
  95     assert(result_ptr);
  96
  97     for (uint32_t x = 0; x < no_msg - 1; x++) {
  98       memcached_result_reset(result_ptr);
  99       memcached_return_t rc = memcached_read_one_response(ptr, result_ptr);
 100       /*
 101        * Purge doesn't care for what kind of command results that is received.
 102        * The only kind of errors I care about if is I'm out of sync with the
 103        * protocol or have problems reading data from the network..
 104        */
 105       if (rc == MEMCACHED_PROTOCOL_ERROR or rc == MEMCACHED_UNKNOWN_READ_FAILURE
 106           or rc == MEMCACHED_READ_FAILURE)
 107       {
 108         WATCHPOINT_ERROR(rc);
 109         is_successful = false;
 110       }
 111
 112       if (ptr->root->callbacks) {
 113         memcached_callback_st cb = *ptr->root->callbacks;
 114         if (memcached_success(rc)) {
 115           for (uint32_t y = 0; y < cb.number_of_callback; y++) {
 116             if (memcached_fatal((*cb.callback[y])(ptr->root, result_ptr, cb.context))) {
 117               break;
 118             }
 119           }
 120         }
 121       }
 122     }
 123
 124     memcached_result_free(result_ptr);
 125   }
 126
 127   return is_successful;
 128 }