Ichthyostega
9c21164ae6
This changeset fixes a huge pile of problems, as indicated in the error log of the Doxygen run after merging all the recent Doxygen improvements unfortunately, auto-linking does still not work at various places. There is no clear indication what might be the problem. Possibly the rather unstable Sqlite support in this Doxygen version is the cause. Anyway, needs to be investigated further.
99 lines
3 KiB
C
99 lines
3 KiB
C
/*
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FILEHANDLECACHE - filehandle management and caching
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Copyright (C) Lumiera.org
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2008, Christian Thaeter <ct@pipapo.org>
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of
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the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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/** @file filehandlecache.h
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** Caching and management of filehandles.
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** The number of filehandles a program can held open is usually limited, since we want to support
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** using a less limited number of files and closing/opening for each operation is expensive, we
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** provide a cache to keep the most frequent used files open and gracefully close/recycle unused filehandles.
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** The filehandle cache defined here protects all operations on the cache with a mutex.
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*/
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#ifndef BACKEND_FILEHANDLECACHE_H
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#define BACKEND_FILEHANDLECACHE_H
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#include "lib/error.h"
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#include "lib/mrucache.h"
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#include "lib/mutex.h"
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typedef struct lumiera_filehandlecache_struct lumiera_filehandlecache;
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typedef lumiera_filehandlecache* LumieraFilehandlecache;
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#include "backend/filehandle.h"
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/** File handle cache manages file handles */
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struct lumiera_filehandlecache_struct
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{
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lumiera_mrucache cache;
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int available;
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int checked_out;
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lumiera_mutex lock;
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};
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/**
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* Initialises the filehandle cache.
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* @param max_entries number how much filehandles shall be managed
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* The number of elements the cache can hold is static and should be
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* determined by sysconf (_SC_OPEN_MAX) minus some (big) safety margin.
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*/
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void
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lumiera_filehandlecache_new (int max_entries);
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/**
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* Delete the filehandle cache.
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* No filehandles in the cache must be locked, this would be a fatal error.
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* The handles are closed automatically.
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*/
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void
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lumiera_filehandlecache_delete (void);
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/**
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* Get a fresh filehandle.
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* @param self pointer to the cache
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* @return the new filehandle
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*/
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LumieraFilehandle
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lumiera_filehandlecache_handle_acquire (LumieraFiledescriptor desc);
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/**
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* Remove a filehandle from cache aging
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* Filehandles which are subject of cache aging must be checked out before they can be used.
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* @param self the filehandlecache
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* @param handle the filehandle to be checked out
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*/
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LumieraFilehandle
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lumiera_filehandlecache_checkout (LumieraFilehandle handle);
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/**
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* Put a filehandle into the cache
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* Filehandles which are checked in are subject of cache aging and might get destroyed and reused.
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* @param handle the filehandle to be checked in
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*/
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void
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lumiera_filehandlecache_checkin (LumieraFilehandle handle);
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#endif /*BACKEND_FILEHANDLECACHE_H*/
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