Fix segmentation fault when set nil to Nginx::Headers_{in,out}. Fixed m…

…atsumotory#473.

src/http/ngx_http_mruby_request.c

@@ -227,18 +227,28 @@ static ngx_int_t ngx_mrb_set_request_header(mrb_state *mrb, ngx_list_t *headers,
  ngx_http_request_t *r = ngx_mrb_get_request();
 
  key_len = (size_t)RSTRING_LEN(mrb_key);
- val_len = (size_t)RSTRING_LEN(mrb_val);
-
  key = ngx_pnalloc(pool, key_len);
  if (key == NULL) {
  return NGX_ERROR;
  }
+ ngx_memcpy(key, (u_char *)RSTRING_PTR(mrb_key), key_len);
+
+ /* TODO:optimize later(linear-search is slow) */
+ if (update || mrb_nil_p(mrb_val)) {
+ while (!mrb_nil_p(ngx_mrb_get_request_header(mrb, headers, (char *)key, key_len))) {
+ ngx_mrb_del_request_header(mrb, headers, (char *)key, key_len);
+ }
+ }
+ if (mrb_nil_p(mrb_val)) {
+ /* If the value is nil, just remove the key from the headers. */
+ return NGX_OK;
+ }
+
+ val_len = (size_t)RSTRING_LEN(mrb_val);
  val = ngx_pnalloc(pool, val_len);
  if (val == NULL) {
  return NGX_ERROR;
  }
-
- ngx_memcpy(key, (u_char *)RSTRING_PTR(mrb_key), key_len);
  ngx_memcpy(val, (u_char *)RSTRING_PTR(mrb_val), val_len);
 
  switch (ngx_mruby_builtin_header_lookup_token(key, key_len)) {
@@ -260,13 +270,6 @@ static ngx_int_t ngx_mrb_set_request_header(mrb_state *mrb, ngx_list_t *headers,
  break;
  }
 
- /* TODO:optimize later(linear-search is slow) */
- if (update) {
- while (!mrb_nil_p(ngx_mrb_get_request_header(mrb, headers, (char *)key, key_len))) {
- ngx_mrb_del_request_header(mrb, headers, (char *)key, key_len);
- }
- }
-
  new_header = ngx_list_push(headers);
  if (new_header == NULL) {
  return NGX_ERROR;