Method fetch

src/query.cpp:1765–1926

fetch rows up to and including the specified row, when available, i.e. do not block when pipe is non-blocking

// fetch rows up to and including the specified row, when available, i.e. do not block when pipe is non-blocking
bool Query::fetch(int row)
{
  int prev_rows = rows_;

  while (rows_ <= row)
  {
    bool incomplete = false;

    // look for the first newline character in the buffer
    char *nlptr = static_cast<char*>(memchr(buffer_, '\n', buflen_));

    if (nlptr == NULL)
    {
      // no newline and buffer is not full and not EOF reached yet, get more data
      if (buflen_ < QUERY_BUFFER_SIZE && !eof_)
      {
#ifdef OS_WIN

        // try to fetch more data from the non-blocking pipe when immediately available
        DWORD nread = 0;
        bool avail = !pending_;

        if (pending_)
        {
          pending_ = false;

          if (!GetOverlappedResult(hPipe_, &overlapped_, &nread, FALSE))
          {
            switch (GetLastError())
            {
              case ERROR_IO_INCOMPLETE:
                pending_ = true;
                break;

              case ERROR_MORE_DATA:
                break;

              case ERROR_HANDLE_EOF:
              default:
                close(search_pipe_[0]);
                eof_ = true;
                Static::cancel_ugrep();
            }
          }
        }

        if (avail)
        {
          pending_ = false;

          if (!ReadFile(hPipe_, buffer_ + buflen_, static_cast<DWORD>(QUERY_BUFFER_SIZE - buflen_), &nread, blocking_ ? NULL : &overlapped_))
          {
            switch (GetLastError())
            {
              case ERROR_IO_PENDING:
                pending_ = true;
                break;