ceph/src/librbd/AsyncRequest.h

   1 // -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
   2 // vim: ts=8 sw=2 smarttab
   3 #ifndef CEPH_LIBRBD_ASYNC_REQUEST_H
   4 #define CEPH_LIBRBD_ASYNC_REQUEST_H
   5
   6 #include "include/Context.h"
   7 #include "include/rados/librados.hpp"
   8 #include "include/xlist.h"
   9 #include "include/compat.h"
  10
  11 namespace librbd {
  12
  13 class ImageCtx;
  14
  15 template <typename ImageCtxT = ImageCtx>
  16 class AsyncRequest
  17 {
  18 public:
  19   AsyncRequest(ImageCtxT &image_ctx, Context *on_finish);
  20   virtual ~AsyncRequest();
  21
  22   void complete(int r) {
  23     if (should_complete(r)) {
  24       r = filter_return_code(r);
  25       finish_and_destroy(r);
  26     }
  27   }
  28
  29   virtual void send() = 0;
  30
  31   inline bool is_canceled() const {
  32     return m_canceled;
  33   }
  34   inline void cancel() {
  35     m_canceled = true;
  36   }
  37
  38 protected:
  39   ImageCtxT &m_image_ctx;
  40
  41   librados::AioCompletion *create_callback_completion();
  42   Context *create_callback_context();
  43   Context *create_async_callback_context();
  44
  45   void async_complete(int r);
  46
  47   virtual bool should_complete(int r) = 0;
  48   virtual int filter_return_code(int r) const {
  49     return r;
  50   }
  51
  52   // NOTE: temporary until converted to new state machine format
  53   virtual void finish_and_destroy(int r) {
  54     finish(r);
  55     delete this;
  56   }
  57
  58   virtual void finish(int r) {
  59     finish_request();
  60     m_on_finish->complete(r);
  61   }
  62
  63 private:
  64   Context *m_on_finish;
  65   bool m_canceled;
  66   typename xlist<AsyncRequest<ImageCtxT> *>::item m_xlist_item;
  67
  68   void start_request();
  69   void finish_request();
  70 };
  71
  72 } // namespace librbd
  73
  74 extern template class librbd::AsyncRequest<librbd::ImageCtx>;
  75
  76 #endif //CEPH_LIBRBD_ASYNC_REQUEST_H