xref: /aosp_15_r20/external/mtools/streamcache.c (revision d5c9a868b113e0ec0db2f27bc2ce8a253e77c4b0)

/*  Copyright 1996,1997,2001,2002,2007,2009 Alain Knaff.
 *  This file is part of mtools.
 *
 *  Mtools 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 3 of the License, or
 *  (at your option) any later version.
 *
 *  Mtools 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 Mtools.  If not, see <http://www.gnu.org/licenses/>.
 *
 * streamcache.c
 * Managing a cache of open disks
 */

#include "sysincludes.h"
#include "msdos.h"
#include "mtools.h"
#include "vfat.h"
#include "fs.h"
#include "mainloop.h"
#include "plain_io.h"
#include "file.h"

static int is_initialized = 0;
static Stream_t *fss[256]; /* open drives */

static void finish_sc(void)
{
	int i;

	for(i=0; i<256; i++){
		if(fss[i] && fss[i]->refs != 1 )
			fprintf(stderr,"Streamcache allocation problem:%c %d\n",
				i, fss[i]->refs);
		FREE(&(fss[i]));
	}
}

static void init_streamcache(void)
{
	int i;

	if(is_initialized)
		return;
	is_initialized = 1;
	for(i=0; i<256; i++)
		fss[i]=0;
	atexit(finish_sc);
}

Stream_t *open_root_dir(char drive, int flags, int *isRop)
{
	Stream_t *Fs;

	init_streamcache();

	drive = (char)toupper(drive);

	/* open the drive */
	if(fss[(unsigned char)drive])
		Fs = fss[(unsigned char)drive];
	else {
		Fs = fs_init(drive, flags, isRop);
		if (!Fs){
			fprintf(stderr, "Cannot initialize '%c:'\n", drive);
			return NULL;
		}

		fss[(unsigned char)drive] = Fs;
	}

	return OpenRoot(Fs);
}