http: allow short response byte range

RFC9110 specifies that a client must handle a shorter response range
than requested in all circumstanges. Previously, RFC7233 only required
that behaviour for multipart ranges, which VLC did not use.

This matches the newer specification: VLC will try to resume from the
last received offset not only on unexpected error, but also on short
response.

Fixes #28627.

(cherry picked from commit 90dc0a023f)

modules/access/http/file.c

@@ -235,20 +235,21 @@ block_t *vlc_http_file_read(struct vlc_http_resource *res)
     block_t *block = vlc_http_res_read(res);
 
     if (block == vlc_http_error)
-    {   /* Automatically reconnect on error if server supports seek */
-        if (res->response != NULL
-         && vlc_http_msg_can_seek(res->response)
-         && file->offset < vlc_http_msg_get_file_size(res->response)
-         && vlc_http_file_seek(res, file->offset) == 0)
-            block = vlc_http_res_read(res);
+        block = NULL;
+
+    /* Automatically resume on short response or error if possible */
+    if (block == NULL && res->response != NULL
+     && vlc_http_msg_can_seek(res->response)
+     && file->offset < vlc_http_msg_get_file_size(res->response)
+     && vlc_http_file_seek(res, file->offset) == 0)
+    {
+        block = vlc_http_res_read(res);
 
         if (block == vlc_http_error)
-            return NULL;
+            block = NULL; /* Non-recovered error */
     }
 
-    if (block == NULL)
-        return NULL; /* End of stream */
-
-    file->offset += block->i_buffer;
+    if (block != NULL)
+        file->offset += block->i_buffer;
     return block;
 }