Function queue_list_entries

src/cls/queue/cls_queue_src.cc:263–467

}

int queue_list_entries(cls_method_context_t hctx, const cls_queue_list_op& op, cls_queue_list_ret& op_ret, cls_queue_head& head)
{
  // If queue is empty, return from here
  if ((head.front.offset == head.tail.offset) && (head.front.gen == head.tail.gen)) {
    CLS_LOG(20, "INFO: queue_list_entries(): Next offset is %s", head.front.to_str().c_str());
    op_ret.next_marker = head.front.to_str();
    op_ret.is_truncated = false;
    return 0;
  }

  cls_queue_marker start_marker;
  start_marker.from_str(op.start_marker.c_str());
  cls_queue_marker next_marker = {0, 0};

  uint64_t start_offset = 0, gen = 0;
  if (start_marker.offset == 0) {
    start_offset = head.front.offset;
    gen = head.front.gen;
  } else {
    start_offset = start_marker.offset;
    gen = start_marker.gen;
  }

  op_ret.is_truncated = true;
  uint64_t contiguous_data_size = 0, size_to_read = 0;
  bool wrap_around = false;

  //Calculate length of contiguous data to be read depending on front, tail and start offset
  if (head.tail.offset > head.front.offset) {
    contiguous_data_size = head.tail.offset - start_offset;
  } else if (head.front.offset >= head.tail.offset) {
    if (start_offset >= head.front.offset) {
      contiguous_data_size = head.queue_size - start_offset;
      wrap_around = true;
    } else if (start_offset <= head.tail.offset) {
      contiguous_data_size = head.tail.offset - start_offset;
    }
  }

  CLS_LOG(10, "INFO: queue_list_entries(): front is: %s, tail is %s", head.front.to_str().c_str(), head.tail.to_str().c_str());

  bool offset_populated = false, entry_start_processed = false;
  uint64_t data_size = 0, num_ops = 0;
  uint16_t entry_start = 0;
  bufferlist bl;
  string last_marker;
  do
  {
    CLS_LOG(10, "INFO: queue_list_entries(): start_offset is %lu", start_offset);
  
    bufferlist bl_chunk;
    //Read chunk size at a time, if it is less than contiguous data size, else read contiguous data size
    size_to_read = std::min(contiguous_data_size, large_chunk_size);
    CLS_LOG(10, "INFO: queue_list_entries(): size_to_read is %lu", size_to_read);
    if (size_to_read == 0) {
      next_marker = head.tail;
      op_ret.is_truncated = false;
      CLS_LOG(20, "INFO: queue_list_entries(): size_to_read is 0, hence breaking out!\n");