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

   1 /*
   2     +--------------------------------------------------------------------+
   3     | libmemcached - 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 Michael Wallner   <mike@php.net>                |
  13     +--------------------------------------------------------------------+
  14 */
  15
  16 #include "libmemcached/common.h"
  17 #include "p9y/socket.hpp"
  18
  19 #define memcached_set_purging(__object, __value) ((__object)->state.is_purging = (__value))
  20
  21 class Purge {
  22 public:
  23   Purge(Memcached *arg)
  24   : _memc(arg) {
  25     memcached_set_purging(_memc, true);
  26   }
  27
  28   ~Purge() {
  29     memcached_set_purging(_memc, false);
  30   }
  31
  32 private:
  33   Memcached *_memc;
  34 };
  35
  36 class PollTimeout {
  37 public:
  38   PollTimeout(Memcached *arg, int32_t ms = 50)
  39   : _timeout(arg->poll_timeout)
  40   , _origin(arg->poll_timeout) {
  41     _origin = ms;
  42   }
  43
  44   ~PollTimeout() {
  45     _origin = _timeout;
  46   }
  47
  48 private:
  49   int32_t _timeout;
  50   int32_t &_origin;
  51 };
  52
  53 bool memcached_purge(memcached_instance_st *ptr) {
  54   Memcached *root = (Memcached *) ptr->root;
  55
  56   if (memcached_is_purging(ptr->root) || /* already purging */
  57       (memcached_server_response_count(ptr) < ptr->root->io_msg_watermark
  58        && ptr->io_bytes_sent < ptr->root->io_bytes_watermark)
  59       || (ptr->io_bytes_sent >= ptr->root->io_bytes_watermark
  60           && memcached_server_response_count(ptr) < 2))
  61   {
  62     return true;
  63   }
  64
  65   /*
  66     memcached_io_write and memcached_response may call memcached_purge
  67     so we need to be able stop any recursion..
  68   */
  69   Purge set_purge(root);
  70
  71   WATCHPOINT_ASSERT(ptr->fd != INVALID_SOCKET);
  72   /*
  73     Force a flush of the buffer to ensure that we don't have the n-1 pending
  74     requests buffered up..
  75   */
  76   if (memcached_io_write(ptr) == false) {
  77     memcached_io_reset(ptr);
  78     memcached_set_error(*ptr, MEMCACHED_WRITE_FAILURE, MEMCACHED_AT);
  79     return false;
  80   }
  81   WATCHPOINT_ASSERT(ptr->fd != INVALID_SOCKET);
  82
  83   bool is_successful = true;
  84   uint32_t no_msg = memcached_server_response_count(ptr);
  85   if (no_msg > 1) {
  86     memcached_result_st result;
  87
  88     /*
  89      * We need to increase the timeout, because we might be waiting for
  90      * data to be sent from the server (the commands was in the output buffer
  91      * and just flushed
  92      */
  93     PollTimeout poll_timeout(ptr->root);
  94
  95     memcached_result_st *result_ptr = memcached_result_create(root, &result);
  96     assert(result_ptr);
  97
  98     for (uint32_t x = 0; x < no_msg - 1; x++) {
  99       memcached_result_reset(result_ptr);
 100       memcached_return_t rc = memcached_read_one_response(ptr, result_ptr);
 101       /*
 102        * Purge doesn't care for what kind of command results that is received.
 103        * The only kind of errors I care about if is I'm out of sync with the
 104        * protocol or have problems reading data from the network..
 105        */
 106       if (rc == MEMCACHED_PROTOCOL_ERROR or rc == MEMCACHED_UNKNOWN_READ_FAILURE
 107           or rc == MEMCACHED_READ_FAILURE)
 108       {
 109         WATCHPOINT_ERROR(rc);
 110         is_successful = false;
 111       }
 112       if (rc == MEMCACHED_TIMEOUT) {
 113         break;
 114       }
 115
 116       if (ptr->root->callbacks) {
 117         memcached_callback_st cb = *ptr->root->callbacks;
 118         if (memcached_success(rc)) {
 119           for (uint32_t y = 0; y < cb.number_of_callback; y++) {
 120             if (memcached_fatal((*cb.callback[y])(ptr->root, result_ptr, cb.context))) {
 121               break;
 122             }
 123           }
 124         }
 125       }
 126     }
 127
 128     memcached_result_free(result_ptr);
 129   }
 130
 131   return is_successful;
 132 }