/* This file is in the public domain. */

/*
 * Filesystem backend implementation that presents as an empty
 *  directory, mdoe 555.
 */

#include <stdlib.h>

#include <fstree.h>

static void fatal(void) __attribute__((__noreturn__));
static void fatal(void)
{
 abort();
}

static int fstree_empty_start(void *p __attribute__((__unused__)))
{
 return(FE_SUCCESS);
}

static void fstree_empty_done(void *p __attribute__((__unused__)))
{
}

static void fstree_empty_release(void *p __attribute__((__unused__)), FSTREE_NODE n __attribute__((__unused__)))
{
}

static FSTREE_STAT fstree_empty_stat(void *p __attribute__((__unused__)), FSTREE_NODE nn)
{
 if (nn == FSTREE_EMPTY_ROOT) return((FSTREE_STAT){.type=FST_DIR,.u={.dir={.mode=0555}}});
 fatal();
}

static FSTREE_NODESTAT fstree_empty_lookup(void *p __attribute__((__unused__)), FSTREE_NODE dn, const char *name, int namelen)
{
 if (dn != FSTREE_EMPTY_ROOT) fatal();
 if ( ((namelen == 1) && (name[0] == '.')) ||
      ((namelen == 2) && (name[0] == '.') && (name[1] == '.')) )
  { return((FSTREE_NODESTAT){.node=dn,.stat={.type=FST_DIR,.u={.dir={.mode=0555}}}});
  }
 return((FSTREE_NODESTAT){.stat={.type=FST_ERR,.u={.err={.err=FE_NOENT}}}});
}

static int fstree_empty_readdir(void *p __attribute__((__unused__)), FSTREE_NODE dn, long int *offp, FSTREE_DIRENT *ents, int nents, char *strbuf, int strsize)
{
 if (dn != FSTREE_EMPTY_ROOT) fatal();
 if (!ents && !nents && !strbuf && !strsize) *offp = 0;
 if (*offp != 0) return(-FE_INVAL);
 return(0);
}

static int fstree_empty_read(
	void *p __attribute__((__unused__)),
	FSTREE_NODE nn __attribute__((__unused__)),
	FSTREE_OFFSET o __attribute__((__unused__)),
	void *buf __attribute__((__unused__)),
	int len __attribute__((__unused__)) )
{
 return(-FE_NOTPLAIN);
}

static int fstree_empty_readlink(
	void *p __attribute__((__unused__)),
	FSTREE_NODE nn __attribute__((__unused__)),
	void *buf __attribute__((__unused__)),
	int len __attribute__((__unused__)) )
{
 return(-FE_NOTLINK);
}

const FSTREE_OPS fstree_empty_ops = FSTREE_OPS_INIT(fstree_empty);