plan9fox/sys/src/cmd/rc/tree.c
cinap_lenrek a2f7d03d4e rc: fix slow Xqdol(), avoid recursion in conclist(), estrdup(), avoid copying
Xqdol() used to take quadratic time because of strcat(),
the code isnt really needed as list2str() aready does the
same thing in linear time without the strcat().

add estrdup() which uses emalloc() so allocation error are
catched.

move strdups() of name from callers into newvar().

avoid recursion of conclist(), and avoid copying of word
strings by providing Newword() function which doesnt copy
the word string.
2014-07-23 15:28:37 +02:00

149 lines
2 KiB
C

#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;
}
void
freenodes(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 = estrdup((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;
}
void
freetree(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);
}