84 lines
2.4 KiB
C
84 lines
2.4 KiB
C
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/*
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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 the
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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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#include "backend/filehandlecache.h"
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NOBUG_DEFINE_FLAG (lumiera_filehandlecache);
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/* errors */
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LUMIERA_ERROR_DEFINE (FILEHANDLECACHE_NOHANDLE, "No filehandle available");
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/**/
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LumieraFilehandlecache
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lumiera_filehandlecache_init (LumieraFilehandlecache self, int max_entries)
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{
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lumiera_mrucache_init (&self->cache, lumiera_filehandle_destroy_node);
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self->available =max_entries;
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lumiera_mutex_init (&self->lock);
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return self;
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}
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LumieraFilehandlecache
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lumiera_filehandlecache_destroy (LumieraFilehandlecache self)
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{
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self->available += self->cache.cached;
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lumiera_mrucache_destroy (&self->cache);
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lumiera_mutex_destroy (&self->lock);
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return self;
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}
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LumieraFilehandle
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lumiera_filehandlecache_filehandle_acquire (LumieraFilehandlecache self)
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{
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LumieraFilehandle ret;
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LUMIERA_MUTEX_SECTION (&self->lock)
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{
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if (self->available <= 0 && self->cache.cached)
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{
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/* pop a filehandle from cache */
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ret = lumiera_mrucache_pop (&self->cache);
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if (self->available < 0)
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/* try to free overallocated filehandles */
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self->available -= self->available + lumiera_mrucache_age (&self->cache, -self->available);
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}
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else
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{
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/* allocate new filehandle if we are below the limit or no cached handles where available (overallocating) */
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ret = lumiera_filehandle_new ();
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if (!ret)
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LUMIERA_ERROR_SET (lumiera_filehandlecache, FILEHANDLECACHE_NOHANDLE);
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else
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--self->available;
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}
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}
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return ret;
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}
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void
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lumiera_filehandlecache_add (LumieraFilehandlecache self, LumieraFilehandle handle)
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{
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UNIMPLEMENTED ("");
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}
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