libretro-common/samples/net: fix bit-rot in net_http_test

The sample was still calling the old single-argument form
net_http_new(const char *url), which was refactored a while back
into the two-stage connection API:

    net_http_connection_new(url, method, data)  -- build handle
    net_http_connection_iterate(conn)           -- drive to ready
    net_http_connection_done(conn)              -- check success
    net_http_new(conn)                          -- transfer handle
    net_http_update(http, &pos, &tot)           -- drive xfer
    net_http_data(http, &len, false)            -- fetch body
    net_http_delete(http)
    net_http_connection_free(conn)

The sample compiled (CFLAGS is -Wall without -Werror in the
samples Makefile) but every CI build emitted two
"incompatible pointer type" warnings:

  net_http_test.c:40:25: warning: passing argument 1 of
    'net_http_new' from incompatible pointer type

Also fixed two secondary bit-rot issues in the same file:
  - net_http_data returns uint8_t* now, not char*.  The sample
    assigned into a char* without a cast.
  - %.9lu was used with size_t.  Cast to unsigned long before
    printf.

The canonical usage pattern is taken verbatim from
tasks/task_http.c (cb_http_conn_default plus
task_push_http_transfer).  The behaviour from the sample's
original intent -- fetch a URL, print the first 256 bytes -- is
preserved and factored into a helper so the two example URLs
exercise the same code path.

Verified:
  - CFLAGS += -Wall -Werror -pedantic -std=gnu99: clean compile
    (0 warnings, 0 errors)
  - CFLAGS += -Wall -Wextra -pedantic: clean compile
  - Full libretro-common samples CI dry-run:
      Built: 14  Ran: 13  Failed: 0
    The net_http_new warnings are gone.  Remaining warnings from
    the dry-run are pre-existing and unrelated (compat_snprintf
    empty translation unit, net_http_parse_test.c implicit
    declaration, rzip.c fgets return value).

Regression test: NONE.  http_test is a build-only sample -- it
makes live network requests to external hosts (wikipedia.org,
buildbot.libretro.com) and is not in the samples CI RUN_TARGETS
allowlist.  The patch is verified at build time under -Werror,
which is strictly stricter than the samples Makefile's current
-Wall.

Author: LibretroAdmin

libretro-common/samples/net/net_http_test.c

@@ -21,36 +21,76 @@
  */
 
 #include <stdio.h>
+#include <stdint.h>
 #include <net/net_http.h>
 #include <net/net_compat.h>
 
 #ifdef _WIN32
 #include <winsock2.h>
 #endif
 
-int main(void)
+/* Issue a single HTTP GET and print the first 256 bytes of the
+ * response.  Sample usage of the two-stage connection API:
+ *
+ *    1. net_http_connection_new(url, method, data)  -- handle
+ *    2. loop net_http_connection_iterate until connection is up
+ *    3. check net_http_connection_done for success
+ *    4. net_http_new(conn)  -- transfer handle
+ *    5. loop net_http_update until transfer is complete
+ *    6. net_http_data -- fetch the response body
+ *    7. net_http_delete + net_http_connection_free
+ */
+static int http_get_and_print(const char *url)
 {
-   char   *data;
-   struct http_t *http1, *http3;
-   size_t _len, pos = 0, tot = 0;
+   struct http_connection_t *conn;
+   struct http_t *http;
+   uint8_t *data;
+   size_t _len = 0, pos = 0, tot = 0;
 
-   if (!network_init())
+   conn = net_http_connection_new(url, "GET", NULL);
+   if (!conn)
+   {
+      fprintf(stderr, "net_http_connection_new failed for %s\n", url);
       return -1;
+   }
 
-   http1 = net_http_new("http://buildbot.libretro.com/nightly/windows/x86_64/latest/mednafen_psx_libretro.dll.zip");
+   /* Drive the connection state machine to completion. */
+   while (!net_http_connection_iterate(conn)) {}
+   if (!net_http_connection_done(conn))
+   {
+      fprintf(stderr, "net_http_connection_done failed for %s\n", url);
+      net_http_connection_free(conn);
+      return -1;
+   }
 
-   while (!net_http_update(http1, &pos, &tot))
-      printf("%.9lu / %.9lu        \r",pos,tot);
+   http = net_http_new(conn);
+   if (!http)
+   {
+      fprintf(stderr, "net_http_new failed for %s\n", url);
+      net_http_connection_free(conn);
+      return -1;
+   }
 
-   http3 = net_http_new("http://www.wikipedia.org/");
-   while (!net_http_update(http3, NULL, NULL)) {}
+   while (!net_http_update(http, &pos, &tot))
+      printf("%9lu / %9lu    \r", (unsigned long)pos, (unsigned long)tot);
+   printf("\n");
 
-   data  = (char*)net_http_data(http3, &_len, false);
+   data = net_http_data(http, &_len, false);
+   if (data && _len > 0)
+      printf("%.*s\n", (int)(_len < 256 ? _len : 256), (const char*)data);
 
-   printf("%.*s\n", (int)256, data);
+   net_http_delete(http);
+   net_http_connection_free(conn);
+   return 0;
+}
+
+int main(void)
+{
+   if (!network_init())
+      return -1;
 
-   net_http_delete(http1);
-   net_http_delete(http3);
+   http_get_and_print("http://buildbot.libretro.com/nightly/windows/x86_64/latest/mednafen_psx_libretro.dll.zip");
+   http_get_and_print("http://www.wikipedia.org/");
 
    return 0;
 }