Method fetch

plugins/slice/prefetch.cc:43–103

* Initialize and schedule the background fetch */

 * Initialize and schedule the background fetch
 */
bool
BgBlockFetch::fetch(Data *const data)
{
  if (m_stream.m_read.isOpen()) {
    // should never happen since the connection was just initialized
    ERROR_LOG("Background block request already in flight!");
    return false;
  }

  int64_t const blockbeg = (data->m_config->m_blockbytes * m_blocknum);
  Range         blockbe(blockbeg, blockbeg + data->m_config->m_blockbytes);

  char       rangestr[1024];
  int        rangelen = sizeof(rangestr);
  bool const rpstat   = blockbe.toStringClosed(rangestr, &rangelen);
  TSAssert(rpstat);

  DEBUG_LOG("Request background block: %s", rangestr);

  // reuse the incoming client header, just change the range
  HttpHeader header(data->m_req_hdrmgr.m_buffer, data->m_req_hdrmgr.m_lochdr);

  // add/set sub range key and add slicer tag
  bool const rangestat = header.setKeyVal(TS_MIME_FIELD_RANGE, TS_MIME_LEN_RANGE, rangestr, rangelen);

  if (!rangestat) {
    ERROR_LOG("Error trying to set range request header %s", rangestr);
    return false;
  }
  TSAssert(nullptr == m_cont);

  // Setup the continuation
  m_cont = TSContCreate(handler, TSMutexCreate());
  TSContDataSet(m_cont, static_cast<void *>(this));

  // create virtual connection back into ATS
  TSHttpConnectOptions options = TSHttpConnectOptionsGet(TS_CONNECT_PLUGIN);
  options.addr                 = reinterpret_cast<sockaddr *>(&data->m_client_ip);
  options.tag                  = PLUGIN_NAME;
  options.id                   = 0;
  options.buffer_index         = data->m_buffer_index;
  options.buffer_water_mark    = data->m_buffer_water_mark;

  TSVConn const upvc = TSHttpConnectPlugin(&options);

  int const hlen = TSHttpHdrLengthGet(header.m_buffer, header.m_lochdr);

  // set up connection with the HttpConnect server
  m_stream.setupConnection(upvc);
  m_stream.setupVioWrite(m_cont, hlen);
  TSHttpHdrPrint(header.m_buffer, header.m_lochdr, m_stream.m_write.m_iobuf);

  if (dbg_ctl.on()) {
    std::string const headerstr(header.toString());
    DEBUG_LOG("Headers\n%s", headerstr.c_str());
  }
  // ensure blocks are pulled through to cache
  m_stream.setupVioRead(m_cont, INT64_MAX);