Function cont_bg_fetch

plugins/experimental/cache_fill/background_fetch.cc:247–335

///////////////////////////////////////////////////////////////////////// Continuation to perform a background fill of a URL. This is pretty expensive (memory allocations etc.), we could eliminate maybe the std::string, but I think it's fine for now.

// expensive (memory allocations etc.), we could eliminate maybe the
// std::string, but I think it's fine for now.
static int
cont_bg_fetch(TSCont contp, TSEvent event, void * /* edata ATS_UNUSED */)
{
  BgFetchData *data = static_cast<BgFetchData *>(TSContDataGet(contp));
  int64_t      avail;

  switch (event) {
  case TS_EVENT_IMMEDIATE:
  case TS_EVENT_TIMEOUT:
    // Debug info for this particular bg fetch (put all debug in here please)
    if (dbg_ctl.on()) {
      char            buf[INET6_ADDRSTRLEN];
      const sockaddr *sockaddress = reinterpret_cast<const sockaddr *>(&data->client_ip);

      switch (sockaddress->sa_family) {
      case AF_INET:
        inet_ntop(AF_INET, &(((struct sockaddr_in *)sockaddress)->sin_addr), buf, INET_ADDRSTRLEN);
        Dbg(dbg_ctl, "Client IPv4 = %s", buf);
        break;
      case AF_INET6:
        inet_ntop(AF_INET6, &(((struct sockaddr_in6 *)sockaddress)->sin6_addr), buf, INET6_ADDRSTRLEN);
        Dbg(dbg_ctl, "Client IPv6 = %s", buf);
        break;
      default:
        TSError("[%s] Unknown address family %d", PLUGIN_NAME, sockaddress->sa_family);
        break;
      }
      Dbg(dbg_ctl, "Starting background fetch, replaying:");
      dump_headers(data->hdr_loc);
    }

    // Setup the NetVC for background fetch
    TSAssert(nullptr == data->vc);
    if ((data->vc = TSHttpConnectWithPluginId(reinterpret_cast<sockaddr *>(&data->client_ip), PLUGIN_NAME, 0)) != nullptr) {
      TSHttpHdrPrint(data->mbuf, data->hdr_loc, data->req_io_buf);
      // We never send a body with the request. ToDo: Do we ever need to support that ?
      TSIOBufferWrite(data->req_io_buf, "\r\n", 2);

      data->r_vio = TSVConnRead(data->vc, contp, data->resp_io_buf, INT64_MAX);
      data->w_vio = TSVConnWrite(data->vc, contp, data->req_io_buf_reader, TSIOBufferReaderAvail(data->req_io_buf_reader));
    } else {
      delete data;
      TSError("[%s] Failed to connect to internal process, major malfunction", PLUGIN_NAME);
    }
    break;

  case TS_EVENT_VCONN_WRITE_COMPLETE:
    // TSVConnShutdown(data->vc, 0, 1);
    // TSVIOReenable(data->w_vio);
    Dbg(dbg_ctl, "Write Complete");
    break;

  case TS_EVENT_VCONN_READ_READY:
    avail = TSIOBufferReaderAvail(data->resp_io_buf_reader);
    data->addBytes(avail);
    TSIOBufferReaderConsume(data->resp_io_buf_reader, avail);
    TSVIONDoneSet(data->r_vio, TSVIONDoneGet(data->r_vio) + avail);
    TSVIOReenable(data->r_vio);