run-command.c: fix broken list iteration in clear_child_for_cleanup

David Gould · gitster · commit bdee397d7c23 · 2012-09-11T10:30:31.000-07:00
Iterate through children_to_clean using 'next' fields but with an
extra level of indirection. This allows us to update the chain when
we remove a child and saves us managing several variables around
the loop mechanism.

Signed-off-by: David Gould &lt;david@optimisefitness.com&gt;
Acked-by: Jeff King &lt;peff@peff.net&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
diff --git a/run-command.c b/run-command.c
@@ -49,13 +49,14 @@ static void mark_child_for_cleanup(pid_t pid)
 
 static void clear_child_for_cleanup(pid_t pid)
 {
-	struct child_to_clean **last, *p;
+	struct child_to_clean **pp;
 
-	last = &children_to_clean;
-	for (p = children_to_clean; p; p = p->next) {
-		if (p->pid == pid) {
-			*last = p->next;
-			free(p);
+	for (pp = &children_to_clean; *pp; pp = &(*pp)->next) {
+		struct child_to_clean *clean_me = *pp;
+
+		if (clean_me->pid == pid) {
+			*pp = clean_me->next;
+			free(clean_me);
 			return;
 		}
 	}

Original file line number	Diff line number	Diff line change
`@@ -49,13 +49,14 @@ static void mark_child_for_cleanup(pid_t pid)`
`49`	`49`
`50`	`50`	`static void clear_child_for_cleanup(pid_t pid)`
`51`	`51`	`{`
`52`		`- struct child_to_clean *last, p;`
	`52`	`+ struct child_to_clean **pp;`
`53`	`53`
`54`		`- last = &children_to_clean;`
`55`		`- for (p = children_to_clean; p; p = p->next) {`
`56`		`- if (p->pid == pid) {`
`57`		`- *last = p->next;`
`58`		`- free(p);`
	`54`	`+ for (pp = &children_to_clean; pp; pp = &(pp)->next) {`
	`55`	`+ struct child_to_clean clean_me = pp;`
	`56`	`+`
	`57`	`+ if (clean_me->pid == pid) {`
	`58`	`+ *pp = clean_me->next;`
	`59`	`+ free(clean_me);`
`59`	`60`	`return;`
`60`	`61`	`}`
`61`	`62`	`}`