memcachedpersist.cpp

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//-----------------------------------------------------------------------------------------
/*

Fix8 is released under the GNU LESSER GENERAL PUBLIC LICENSE Version 3.

Fix8 Open Source FIX Engine.
Copyright (C) 2010-16 David L. Dight <fix@fix8.org>

Fix8 is free software: you can  redistribute it and / or modify  it under the  terms of the
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even the  implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

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If not, see <http://www.gnu.org/licenses/>.

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*/
//-----------------------------------------------------------------------------------------
#include "precomp.hpp"
#include <fix8/f8includes.hpp>

#if defined FIX8_HAVE_LIBMEMCACHED
//-------------------------------------------------------------------------------------------------
using namespace FIX8;
using namespace std;

//-------------------------------------------------------------------------------------------------
bool MemcachedPersister::initialise(const f8String& config_str, const f8String& key_base, bool purge)
{
   if (_cache)
      return true;
   _key_base = key_base;
   _cache = memcached(config_str.c_str(), config_str.size());
   if (!(_server_count = memcached_server_count(_cache)))
   {
      glout_error << "Error: no memcached servers were configured for " << _key_base;
      return false;
   }
   return purge ? memcached_success(memcached_flush(_cache, 0)) : true;
}

//-------------------------------------------------------------------------------------------------
MemcachedPersister::~MemcachedPersister()
{
   memcached_free(_cache);
   _cache = 0;
}

//-------------------------------------------------------------------------------------------------
unsigned MemcachedPersister::get_last_seqnum(unsigned& sequence) const
{
   unsigned sender_seqnum, target_seqnum;
   return get(sender_seqnum, target_seqnum) ? sequence = sender_seqnum : 0;
}

//-------------------------------------------------------------------------------------------------
unsigned MemcachedPersister::get(const unsigned from, const unsigned to, Session& session,
      bool (Session::*callback)(const Session::SequencePair& with, Session::RetransmissionContext& rctx)) const
{
   unsigned last_seq(0);
   get_last_seqnum(last_seq);
   unsigned recs_sent(0), startSeqNum(find_nearest_highest_seqnum (from, last_seq));
   const unsigned finish(to == 0 ? last_seq : to);
   Session::RetransmissionContext rctx(from, to, session.get_next_send_seq());

   if (!startSeqNum || from > finish)
   {
      glout_warn << "No records found";
      rctx._no_more_records = true;
      (session.*callback)(Session::SequencePair(0, ""), rctx);
      return 0;
   }

   for (; startSeqNum <= finish; ++startSeqNum)
   {
      string target, key(generate_seq_key(startSeqNum));
      if (get_from_cache(key, target))
      {
         Session::SequencePair txresult(startSeqNum, f8String(target.c_str(), target.size()));
         ++recs_sent;
         if (!(session.*callback)(txresult, rctx))
            break;
      }
   }

   rctx._no_more_records = true;
   (session.*callback)(Session::SequencePair(0, ""), rctx);

   return recs_sent;
}

//-------------------------------------------------------------------------------------------------
bool MemcachedPersister::put(const unsigned sender_seqnum, const unsigned target_seqnum)
{
   if (!_cache)
      return false;
   const string key(generate_seq_key(0)), payload(generate_ctrl_record(sender_seqnum, target_seqnum));
   if (!put_to_cache(key, payload))
   {
      glout_error << "Error: could not write control record to memcached for " << _key_base;
      return false;
   }
   return true;
}

//-------------------------------------------------------------------------------------------------
bool MemcachedPersister::put(const unsigned seqnum, const f8String& what)
{
   if (!_cache || !seqnum)
      return false;

   const string key(generate_seq_key(seqnum));
   if (!put_to_cache(key, what))
   {
      glout_error << "Error: could not write record for seqnum " << seqnum << " for " << _key_base;
      return false;
   }

   return true;
}

//-------------------------------------------------------------------------------------------------
bool MemcachedPersister::put(const f8String& inkey, const f8String& what)
{
   if (!_cache)
      return false;

   const string key(_key_base + inkey);
   if (!put_to_cache(key, what))
   {
      glout_error << "Error: could not write record for key " << inkey << " for " << _key_base;
      return false;
   }

   return true;
}

//-------------------------------------------------------------------------------------------------
bool MemcachedPersister::get(unsigned& sender_seqnum, unsigned& target_seqnum) const
{
   if (!_cache)
      return false;

   const string key(generate_seq_key(0));
   string target;
   if (!get_from_cache(key, target))
   {
      glout_warn << "Warning: memcached does not have control record for " << _key_base;
      return false;
   }

   extract_ctrl_record(target, sender_seqnum, target_seqnum);
   return true;
}

//-------------------------------------------------------------------------------------------------
bool MemcachedPersister::get(const unsigned seqnum, f8String& to) const
{
   if (!_cache || !seqnum)
      return false;
   const string key(generate_seq_key(seqnum));
   if (!get_from_cache(key, to))
   {
      glout_warn << "Warning: could not get message record with seqnum " << seqnum << " for " << _key_base;
      return false;
   }

   return true;
}

//-------------------------------------------------------------------------------------------------
bool MemcachedPersister::get(const f8String& inkey, f8String& to) const
{
   if (!_cache)
      return false;
   const string key(_key_base + inkey);
   if (!get_from_cache(key, to))
   {
      glout_warn << "Warning: could not get message record with key " << inkey << " for " << _key_base;
      return false;
   }

   return true;
}

//---------------------------------------------------------------------------------------------------
unsigned MemcachedPersister::find_nearest_highest_seqnum (const unsigned requested, const unsigned last) const
{
   if (last)
   {
      for (unsigned startseqnum(requested); startseqnum <= last; ++startseqnum)
      {
         string target;
         if (get(startseqnum, target))
            return startseqnum;
      }
   }

   return 0;
}

//---------------------------------------------------------------------------------------------------
unsigned MemcachedPersister::find_nearest_seqnum (unsigned requested) const
{
   for (; requested > 0; --requested)
   {
      string target;
      if (get(requested, target))
         return requested;
   }

   return 0;
}

#endif // FIX8_HAVE_LIBMEMCACHED