/*
  backend  -  common lumiera backend things

  Copyright (C)         Lumiera.org
    2008,               Christian Thaeter <ct@pipapo.org>

  This program is free software; you can redistribute it and/or
  modify it under the terms of the GNU General Public License as
  published by the Free Software Foundation; either version 2 of the
  License, or (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "lib/safeclib.h"

#include "backend/backend.h"
#include "lib/config.h"
#include "backend/filehandlecache.h"
#include "backend/filedescriptor.h"
#include "backend/mmapcache.h"

#include <unistd.h>
#include <sys/resource.h>

//NOBUG_DEFINE_FLAG_PARENT (backend, lumiera); TODO
NOBUG_DEFINE_FLAG (backend);
NOBUG_DEFINE_FLAG_PARENT (file_all, backend);
NOBUG_DEFINE_FLAG_PARENT (filehandle, file_all);

NOBUG_DEFINE_FLAG_PARENT (mmapings, mmap_all);



NOBUG_DECLARE_FLAG (file);

NOBUG_DECLARE_FLAG (mmap_all);
NOBUG_DECLARE_FLAG (mmap);
NOBUG_DECLARE_FLAG (mmapings);
NOBUG_DECLARE_FLAG (mmapcache);


size_t lumiera_backend_pagesize;

int
lumiera_backend_init (void)
{
  NOBUG_INIT_FLAG (backend);
  NOBUG_INIT_FLAG (file_all);
  NOBUG_INIT_FLAG (file);
  NOBUG_INIT_FLAG (filehandle);
  NOBUG_INIT_FLAG (mmap_all);
  NOBUG_INIT_FLAG (mmap);
  NOBUG_INIT_FLAG (mmapings);
  NOBUG_INIT_FLAG (mmapcache);

  TRACE (backend);
  lumiera_filedescriptor_registry_init ();

  lumiera_backend_pagesize = sysconf(_SC_PAGESIZE);

  TODO ("add config options to override following defaults");


  const char* filehandles = lumiera_tmpbuf_snprintf (SIZE_MAX,
                                                     "backend.file.max_handles = %d",
                                                     /* roughly 2/3 of all availables filehandles are managed by the backend */
                                                     (sysconf (_SC_OPEN_MAX)-10)*2/3);

  lumiera_config_setdefault (filehandles);

  long long max_entries;
  lumiera_config_number_get ("backend.file.max_handles", &max_entries);
  lumiera_filehandlecache_new (max_entries);

#if SIZE_MAX <= 4294967295UL
  lumiera_config_setdefault ("backend.mmap.as_limit = 3221225469");
#else
  lumiera_config_setdefault ("backend.mmap.as_limit = 211106232532992");
#endif

  struct rlimit as_rlimit;
  getrlimit (RLIMIT_AS, &as_rlimit);

  long long as_limit = (long long)as_rlimit.rlim_cur;
  if (as_rlimit.rlim_cur == RLIM_INFINITY)
    {
      lumiera_config_number_get ("backend.mmap.as_limit", &as_limit);
    }
  else
    {
      INFO (backend, "address space limited to %luMiB", as_rlimit.rlim_cur/1024/1024);
    }

  lumiera_mmapcache_new (as_limit);

  return 0;
}

void
lumiera_backend_destroy (void)
{
  TRACE (backend);
  lumiera_mmapcache_delete ();
  lumiera_filehandlecache_delete ();
  lumiera_filedescriptor_registry_destroy ();
}