07f06d0d88
Acquiring mutexes is now wraped in a easy to use MUTEX_SECTION macro. This scheme will be extended for chained lock propagation soon. Notes: * NoBug resourcemanagement is now part of the lower layer, RESOURCE_ENTER/RESOUCE_LEAVE are maintained automatically * one must still call RESOURCE_ANNOUNCE/RESOURCE_FORGET, because we want to maintain high level information about resources. * MUTEX_SECTIONS must not be left with any kind of jump
107 lines
3.4 KiB
C
107 lines
3.4 KiB
C
/*
|
|
filehandlecache - filehandle management and caching
|
|
|
|
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.
|
|
*/
|
|
#ifndef LUMIERA_FILEHANDLECACHE_H
|
|
#define LUMIERA_FILEHANDLECACHE_H
|
|
|
|
#include "lib/error.h"
|
|
#include "lib/mrucache.h"
|
|
#include "lib/mutex.h"
|
|
|
|
typedef struct lumiera_filehandlecache_struct lumiera_filehandlecache;
|
|
typedef lumiera_filehandlecache* LumieraFilehandlecache;
|
|
|
|
#include "backend/filehandle.h"
|
|
|
|
/**
|
|
* @file
|
|
* Filehandle management and caching
|
|
* The number of filehandles a program can held open is usually limited, since we want to support
|
|
* using a less limited number of files and closing/opening for each operation is expensive, we
|
|
* provide a cache to keep the most frequent used files open and gracefully close/recycle unused filehandles.
|
|
* The filehandlecache defined here protects all operations on the cache with a mutex.
|
|
*/
|
|
|
|
|
|
/*
|
|
File handle cache manages file handles
|
|
*/
|
|
struct lumiera_filehandlecache_struct
|
|
{
|
|
lumiera_mrucache cache;
|
|
int available;
|
|
int checked_out;
|
|
lumiera_mutex lock;
|
|
};
|
|
|
|
extern LumieraFilehandlecache lumiera_fhcache;
|
|
|
|
/**
|
|
* Initializes the filehandle cache.
|
|
* @param max_entries number how much filehandles shall be managed
|
|
* The number of elements the cache can hold is static and should be
|
|
* determined by sysconf (_SC_OPEN_MAX) minus some (big) safety margin.
|
|
*/
|
|
void
|
|
lumiera_filehandlecache_new (int max_entries);
|
|
|
|
/**
|
|
* Delete the filehandle cache.
|
|
* No filehandles in the cache must be locked, this would be a fatal error.
|
|
* The handles are closed automatically.
|
|
*/
|
|
void
|
|
lumiera_filehandlecache_delete (void);
|
|
|
|
/**
|
|
* Get a fresh filehandle.
|
|
* @param self pointer to the cache
|
|
* @return the new filehandle
|
|
*/
|
|
LumieraFilehandle
|
|
lumiera_filehandlecache_handle_acquire (LumieraFilehandlecache self, LumieraFiledescriptor desc);
|
|
|
|
/**
|
|
* Add filehande back to cache, the filehandle becomes subject of aging.
|
|
* @param self pointer to the cache
|
|
* @param handle filehandle to be put back
|
|
*/
|
|
void
|
|
lumiera_filehandlecache_add_filehandle (LumieraFilehandlecache self, LumieraFilehandle handle);
|
|
|
|
/**
|
|
* Remove a filehandle from cache aging
|
|
* Filehandles which are subject of cache aging must be checked out before they can be used.
|
|
* @param self the filehandlecache
|
|
* @param handle the filehandle to be checked out
|
|
*/
|
|
LumieraFilehandle
|
|
lumiera_filehandlecache_checkout (LumieraFilehandlecache self, LumieraFilehandle handle);
|
|
|
|
/**
|
|
* Put a filehandle into the cache
|
|
* Filehandles which are checked in are subject of cache aging and might get destroyed and reused.
|
|
* @param self the filehandlecache
|
|
* @param handle the filehandle to be checked in
|
|
*/
|
|
void
|
|
lumiera_filehandlecache_checkin (LumieraFilehandlecache self, LumieraFilehandle handle);
|
|
|
|
#endif
|