/*  * This file is part of the UCB release of Plan 9. It is subject to the license * terms in the LICENSE file found in the top-level directory of this * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No * part of the UCB release of Plan 9, including this file, may be copied, * modified, propagated, or distributed except according to the terms contained * in the LICENSE file. */ #include "rc.h"#include "exec.h"#include "io.h"#include "fns.h"tree *treenodes;/* * create and clear a new tree node, and add it * to the node list. */ tree*newtree(void){	tree *t = new(tree);	t->iskw = 0;	t->str = 0;	t->child[0] = t->child[1] = t->child[2] = 0;	t->next = treenodes;	treenodes = t;	return t;} voidfreenodes(void){	tree *t, *u;	for(t = treenodes;t;t = u){		u = t->next;		if(t->str)			efree(t->str);		efree((char *)t);	}	treenodes = 0;} tree*tree1(int type, tree *c0){	return tree3(type, c0, (tree *)0, (tree *)0);} tree*tree2(int type, tree *c0, tree *c1){	return tree3(type, c0, c1, (tree *)0);} tree*tree3(int type, tree *c0, tree *c1, tree *c2){	tree *t;	if(type==';'){		if(c0==0)			return c1;		if(c1==0)			return c0;	}	t = newtree();	t->type = type;	t->child[0] = c0;	t->child[1] = c1;	t->child[2] = c2;	return t;} tree*mung1(tree *t, tree *c0){	t->child[0] = c0;	return t;} tree*mung2(tree *t, tree *c0, tree *c1){	t->child[0] = c0;	t->child[1] = c1;	return t;} tree*mung3(tree *t, tree *c0, tree *c1, tree *c2){	t->child[0] = c0;	t->child[1] = c1;	t->child[2] = c2;	return t;} tree*epimung(tree *comp, tree *epi){	tree *p;	if(epi==0)		return comp;	for(p = epi;p->child[1];p = p->child[1]);	p->child[1] = comp;	return epi;}/* * Add a SIMPLE node at the root of t and percolate all the redirections * up to the root. */ tree*simplemung(tree *t){	tree *u;	struct io *s; 	t = tree1(SIMPLE, t);	s = openstr();	pfmt(s, "%t", t);	t->str = strdup((char *)s->strp);	closeio(s);	for(u = t->child[0];u->type==ARGLIST;u = u->child[0]){		if(u->child[1]->type==DUP		|| u->child[1]->type==REDIR){			u->child[1]->child[1] = t;			t = u->child[1];			u->child[1] = 0;		}	}	return t;} tree*token(char *str, int type){	tree *t = newtree(); 	t->type = type;	t->str = strdup(str);	return t;} voidfreetree(tree *p){	if(p==0)		return;		freetree(p->child[0]);	freetree(p->child[1]);	freetree(p->child[2]);	if(p->str)		efree(p->str);	efree((char *)p);}