/*
	rehash.c of gulam -- rehash executable file names  08/03/86

	copyright (c) 1987 pm@cwru.edu
*/

#include "gu.h"

/*	uses a table created by tbl.c:
	key == 	leaf name of the executable
	elm ==	full path name, incl drive
*/

local struct TBLE	*hp[2]; 
local int		hx;

/* see if fnm p is in hash table hp[0], or hp[1] and return its full
path */

	uchar *
hashlookup(i, p)		
register uchar	*p;
register int	i;
{
	register struct TBLE *h;

	h = tblfind(hp[i], p);
	return (h ? h->elm : NULL);
}

/* Add to hash table: prg-name, full pathname full path == dir | pnm
*/
	local
addname(dir, pnm)
uchar	*dir, *pnm;
{
	register uchar	*p, *nm, *pt;
	extern   uchar	DS0[];

	pt = str3cat(dir, DS0, pnm);
	nm = strdup(pnm);
	if ((nm == NULL) || (pt == NULL)) return;
	/* freeing? forget it!	*/
	deleteext(nm, p);	/* delete extensions (in some OS) */
	tblinsert(hp[hx], nm, pt);
}

	local
findexecs(p)		/* find exec files in dir p; dont alter p */
register uchar	*p;
{
	register uchar	*q, *pbs, *cwd;
	register int	n;

	if (p[0] == '.' && p[1] == '\000') hx = 0;
	if (hp[hx] == NULL) hp[hx] = tblcreate();
	cwd = gfgetcwd(); cd(p); if (emsg || (valu < 0)) goto freecwd;

	wls(0);			/* don't use wlstbl */
	if (q = strg)
	{	pbs = p + strlen(p) - 1;
		if (*pbs != DSC) pbs = NULL; else *pbs = '\000';
		n = executables(q);
		for (; *q && (n-- > 0); q += strlen(q)+1) addname(p, q);
		gfree(strg);	/* got this from wls(0) */
		strg = NULL;	/* ow we will try to output it */
		if (pbs) *pbs = DSC;
	}
	freecwd: if (cwd) {cd(cwd);  gfree(cwd);}
	emsg = NULL; valu = 0L;
}

which(f)
{	register WS	*ws;

	ws = initws();
	strwcat(ws, tblstr(hp[0], f), 0);
	strwcat(ws, "\r\n** cwd **\r\n", 0);
	strwcat(ws, tblstr(hp[1], f), 0);
	if (ws) strg = ws->ps;
	gfree(ws);
}

cmdwhich()
{	register uchar	*p, *q;
	register struct TBLE	*a;
	register int	i;

	p = lexgetword();
	if (*p)
	{	for (q=NULL, i=0; i < 2; i++)
		    if (a = tblfind(hp[i], p))
			q = sprintp("%s is external cmd %s", p, a->elm);
		if (q == NULL) q = sprintp("%s is not in hash tbl", p);
		strg = strdup(q);
	}
	else	which(1);
}

rehash()		/* rebuild the table of executable file names */
{
	register uchar	*q, *p;
	register int	n;
	register WS	*ws;

	for (n=0; n < 2; ) {if (hp[n]) tblfree(hp[n]); hp[n++] = NULL;}
	q = ggetenv("PATH");  if (q == NULL) return;
	hx = 1; ws = lex(q, COMMA, EMPTY2); p = ws->ps; n = ws->ns;
	while ((n > 0) && (q = nthstr(p, --n)) && *q)
	{	findexecs(q); 
		n--;	/* skip the ',' separator */
	}
	if (hx == 1) {hp[0] = hp[1]; hp[1] = NULL;}
}

/* -eof- */