Method handle_cache_write_lock

src/proxy/http/HttpTransact.cc:3137–3250

////////////////////////////////////////////////////////////////////////// Name : handle_cache_write_lock Description: Details : Possible Next States From Here: - result of how_to_open_connection //////////////////////////////////////////////////////////////////////////

//
///////////////////////////////////////////////////////////////////////////////
void
HttpTransact::handle_cache_write_lock(State *s)
{
  bool remove_ims = false;

  ink_assert(s->cache_info.action == CACHE_PREPARE_TO_DELETE || s->cache_info.action == CACHE_PREPARE_TO_UPDATE ||
             s->cache_info.action == CACHE_PREPARE_TO_WRITE);

  switch (s->cache_info.write_lock_state) {
  case CACHE_WL_SUCCESS:
    // We were able to get the lock for the URL vector in the cache
    SET_UNPREPARE_CACHE_ACTION(s->cache_info);
    break;
  case CACHE_WL_FAIL:
    // No write lock, ignore the cache and proxy only;
    // FIX: Should just serve from cache if this is a revalidate
    Metrics::Counter::increment(http_rsb.cache_open_write_fail_count);
    s->cache_info.action = CACHE_DO_NO_ACTION;
    switch (s->cache_open_write_fail_action) {
    case CACHE_WL_FAIL_ACTION_ERROR_ON_MISS:
    case CACHE_WL_FAIL_ACTION_ERROR_ON_MISS_STALE_ON_REVALIDATE:
    case CACHE_WL_FAIL_ACTION_ERROR_ON_MISS_OR_REVALIDATE:
      TxnDbg(dbg_ctl_http_error, "cache_open_write_fail_action %d, cache miss, return error", s->cache_open_write_fail_action);
      s->cache_info.write_status = CACHE_WRITE_ERROR;
      build_error_response(s, HTTP_STATUS_BAD_GATEWAY, "Connection Failed", "connect#failed_connect");
      MIMEField *ats_field;
      HTTPHdr   *header;
      header = &(s->hdr_info.client_response);
      if ((ats_field = header->field_find(MIME_FIELD_ATS_INTERNAL, MIME_LEN_ATS_INTERNAL)) == nullptr) {
        if (likely((ats_field = header->field_create(MIME_FIELD_ATS_INTERNAL, MIME_LEN_ATS_INTERNAL)) != nullptr)) {
          header->field_attach(ats_field);
        }
      }
      if (likely(ats_field)) {
        int value = (s->cache_info.object_read) ? 1 : 0;
        TxnDbg(dbg_ctl_http_error, "Adding Ats-Internal-Messages: %d", value);
        header->field_value_set_int(ats_field, value);
      } else {
        TxnDbg(dbg_ctl_http_error, "failed to add Ats-Internal-Messages");
      }

      TRANSACT_RETURN(SM_ACTION_SEND_ERROR_CACHE_NOOP, nullptr);
    default:
      s->cache_info.write_status = CACHE_WRITE_LOCK_MISS;
      remove_ims                 = true;
      break;
    }
    break;
  case CACHE_WL_READ_RETRY:
    s->request_sent_time      = UNDEFINED_TIME;
    s->response_received_time = UNDEFINED_TIME;
    s->cache_info.action      = CACHE_DO_LOOKUP;
    if (!s->cache_info.object_read) {
      //  Write failed and read retry triggered
      //  Clean up server_request and re-initiate
      //  Cache Lookup
      ink_assert(s->cache_open_write_fail_action == CACHE_WL_FAIL_ACTION_READ_RETRY);
      s->cache_info.write_status = CACHE_WRITE_LOCK_MISS;