url: alloc the download buffer at transfer start

... and free it as soon as the transfer is done. It removes the extra
alloc when a new size is set with setopt() and reduces memory for unused
easy handles.

In addition: the closure_handle now doesn't use an allocated buffer at
all but the smallest supported size as a stack based one.

Closes #5472

2 files changed, 16 insertions, 52 deletions

diff --git a/tests/data/test509 b/tests/data/test509
index 5de1599e1..0e0dd212b 100644
--- a/tests/data/test509
+++ b/tests/data/test509
@@ -34,10 +34,7 @@ nothing
 # Verify data after the test has been "shot"
 <verify>
 <stdout>
-seen custom_calloc()
-seen custom_malloc()
-seen custom_realloc()
-seen custom_free()
+Callbacks were invoked!
 </stdout>
 </verify>
 
diff --git a/tests/libtest/lib509.c b/tests/libtest/lib509.c
index e8e803ffc..1fb2d3445 100644
--- a/tests/libtest/lib509.c
+++ b/tests/libtest/lib509.c
@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -34,70 +34,35 @@
  * memory callbacks which should be calling 'the real thing'.
  */
 
-/*
-#include "memdebug.h"
-*/
-
-static int seen_malloc = 0;
-static int seen_free = 0;
-static int seen_realloc = 0;
-static int seen_strdup = 0;
-static int seen_calloc = 0;
-
-void *custom_malloc(size_t size);
-void custom_free(void *ptr);
-void *custom_realloc(void *ptr, size_t size);
-char *custom_strdup(const char *ptr);
-void *custom_calloc(size_t nmemb, size_t size);
+static int seen;
 
-
-void *custom_calloc(size_t nmemb, size_t size)
+static void *custom_calloc(size_t nmemb, size_t size)
 {
-  if(!seen_calloc) {
-    printf("seen custom_calloc()\n");
-    seen_calloc = 1;
-  }
+  seen++;
   return (calloc)(nmemb, size);
 }
 
-void *custom_malloc(size_t size)
+static void *custom_malloc(size_t size)
 {
-  if(!seen_malloc && seen_calloc) {
-    printf("seen custom_malloc()\n");
-    seen_malloc = 1;
-  }
+  seen++;
   return (malloc)(size);
 }
 
-char *custom_strdup(const char *ptr)
+static char *custom_strdup(const char *ptr)
 {
-  if(!seen_strdup && seen_malloc) {
-    /* currently (2013.03.13), memory tracking enabled builds do not call
-       the strdup callback, in this case malloc callback and memcpy are used
-       instead. If some day this is changed the following printf() should be
-       uncommented, and a line added to test definition.
-    printf("seen custom_strdup()\n");
-    */
-    seen_strdup = 1;
-  }
+  seen++;
   return (strdup)(ptr);
 }
 
-void *custom_realloc(void *ptr, size_t size)
+static void *custom_realloc(void *ptr, size_t size)
 {
-  if(!seen_realloc && seen_malloc) {
-    printf("seen custom_realloc()\n");
-    seen_realloc = 1;
-  }
+  seen++;
   return (realloc)(ptr, size);
 }
 
-void custom_free(void *ptr)
+static void custom_free(void *ptr)
 {
-  if(!seen_free && seen_realloc) {
-    printf("seen custom_free()\n");
-    seen_free = 1;
-  }
+  seen++;
   (free)(ptr);
 }
 
@@ -110,7 +75,6 @@ int test(char *URL)
   CURL *curl;
   int asize;
   char *str = NULL;
-
   (void)URL;
 
   res = curl_global_init_mem(CURL_GLOBAL_ALL,
@@ -136,6 +100,9 @@ int test(char *URL)
   asize = (int)sizeof(a);
   str = curl_easy_escape(curl, (char *)a, asize); /* uses realloc() */
 
+  if(seen)
+    printf("Callbacks were invoked!\n");
+
 test_cleanup:
 
   if(str)