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/* Remote file contents caching
Copyright (C) 1997 Free Software Foundation, Inc.
Written by Miles Bader <miles@gnu.ai.mit.edu>
This file is part of the GNU Hurd.
The GNU Hurd 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, or (at
your option) any later version.
The GNU Hurd 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., 59 Temple Place - Suite 330, Boston, MA 02111, USA. */
#ifndef __CCACHE_H__
#define __CCACHE_H__
#include "ftpfs.h"
struct ccache
{
/* The filesystem node this is a cache of. */
struct node *node;
/* In memory file image, alloced using vm_allocate. */
char *image;
/* Size of data. */
off_t size;
/* Upper bounds of fetched image. */
off_t max;
/* Amount of IMAGE that has been allocated. */
size_t alloced;
pthread_mutex_t lock;
/* People can wait for a reading thread on this condition. */
pthread_cond_t wakeup;
/* True if some thread is now fetching data. Only that thread should
modify the DATA_CONN, DATA_CONN_POS, and MAX fields. */
int fetching_active;
/* Ftp connection over which data is being fetched, or 0. */
struct ftp_conn *conn;
/* File descriptor over which data is being fetched. */
int data_conn;
/* Where DATA_CONN points in the file. */
off_t data_conn_pos;
};
/* Read LEN bytes at OFFS in the file referred to by CC into DATA, or return
an error. */
error_t ccache_read (struct ccache *cc, off_t offs, size_t len, void *data);
/* Discard any cached contents in CC. */
error_t ccache_invalidate (struct ccache *cc);
/* Return a ccache object for NODE in CC. */
error_t ccache_create (struct node *node, struct ccache **cc);
/* Free all resources used by CC. */
void ccache_free (struct ccache *cc);
#endif /* __CCACHE_H__ */
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