url: make Curl_close() NULLify the pointer too

This is the common pattern used in the code and by a unified approach we
avoid mistakes.

Closes #4534

1 files changed, 8 insertions, 6 deletions

diff --git a/lib/url.c b/lib/url.c
index bbae273fd..8285474fd 100644
--- a/lib/url.c
+++ b/lib/url.c
@@ -317,13 +317,17 @@ static void up_free(struct Curl_easy *data)
  * when curl_easy_perform() is invoked.
  */
 
-CURLcode Curl_close(struct Curl_easy *data)
+CURLcode Curl_close(struct Curl_easy **datap)
 {
   struct Curl_multi *m;
+  struct Curl_easy *data;
 
-  if(!data)
+  if(!datap || !*datap)
     return CURLE_OK;
 
+  data = *datap;
+  *datap = NULL;
+
   Curl_expire_clear(data); /* shut off timers */
 
   m = data->multi;
@@ -1983,10 +1987,8 @@ void Curl_free_request_state(struct Curl_easy *data)
 {
   Curl_safefree(data->req.protop);
   Curl_safefree(data->req.newurl);
-  Curl_close(data->req.doh.probe[0].easy);
-  data->req.doh.probe[0].easy = NULL;
-  Curl_close(data->req.doh.probe[1].easy);
-  data->req.doh.probe[1].easy = NULL;
+  Curl_close(&data->req.doh.probe[0].easy);
+  Curl_close(&data->req.doh.probe[1].easy);
 }