Bug #165: Deletion of unnecessary null pointer checks

The function "free" performs input parameter validation.
http://pubs.opengroup.org/onlinepubs/9699919799/functions/free.html

It is therefore not needed to check a passed pointer before this function call.
A corresponding update suggestion was generated by the software "Coccinelle"
from the following semantic patch approach.
http://coccinelle.lip6.fr/

@Remove_unnecessary_pointer_checks1@
expression x;
@@
-if (x != \(0 \| NULL\))
    free(x);

@Remove_unnecessary_pointer_checks2@
expression x;
@@
-if (x != \(0 \| NULL\)) {
    free(x);
    x = \(0 \| NULL\);
-}

@Remove_unnecessary_pointer_checks3@
expression a, b;
@@
-if (a != \(0 \| NULL\) && b != \(0 \| NULL\))
+if (a)
    free(b);

@Remove_unnecessary_pointer_checks4@
expression a, b;
@@
-if (a != \(0 \| NULL\) && b != \(0 \| NULL\)) {
+if (a) {
    free(b);
    b = \(0 \| NULL\);
 }

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>

1 files changed, 3 insertions, 6 deletions

diff --git a/thumbs.c b/thumbs.c
index ea91292..3f13af0 100644
--- a/thumbs.c
+++ b/thumbs.c
@@ -176,8 +176,7 @@ void tns_init(tns_t *tns, const fileinfo_t *files, int cnt, int *sel, win_t *win
 		dsuffix = "/.cache";
 	}
 	if (homedir != NULL) {
-		if (cache_dir != NULL)
-			free(cache_dir);
+		free(cache_dir);
 		len = strlen(homedir) + strlen(dsuffix) + 6;
 		cache_dir = (char*) s_malloc(len);
 		snprintf(cache_dir, len, "%s%s/sxiv", homedir, dsuffix);
@@ -204,10 +203,8 @@ void tns_free(tns_t *tns)
 		tns->thumbs = NULL;
 	}
 
-	if (cache_dir != NULL) {
-		free(cache_dir);
-		cache_dir = NULL;
-	}
+	free(cache_dir);
+	cache_dir = NULL;
 }
 
 bool tns_load(tns_t *tns, int n, bool force)