From: Lennart Poettering <lennart@poettering.net>
Date: Mon, 11 May 2015 18:09:58 +0000 (+0200)
Subject: util: optimize free_and_strdup() if NOP
X-Git-Tag: v226.4~1^2~397
X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=commitdiff_plain;h=249a98a8ff9f9a3da30e977d347c14487088f738

util: optimize free_and_strdup() if NOP

Under the assumption that strcmp() is cheaper than memory allocation,
let's avoid the allocation, if the new value is identical to the old.
---

diff --git a/src/shared/util.c b/src/shared/util.c
index 275fdece1..b885a46e4 100644
--- a/src/shared/util.c
+++ b/src/shared/util.c
@@ -5683,6 +5683,9 @@ int free_and_strdup(char **p, const char *s) {
         /* Replaces a string pointer with an strdup()ed new string,
          * possibly freeing the old one. */
 
+        if (streq_ptr(*p, s))
+                return 0;
+
         if (s) {
                 t = strdup(s);
                 if (!t)
@@ -5693,7 +5696,7 @@ int free_and_strdup(char **p, const char *s) {
         free(*p);
         *p = t;
 
-        return 0;
+        return 1;
 }
 
 int sethostname_idempotent(const char *s) {