ceph/src/librbd/io/ReadResult.h

   1 // -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
   2 // vim: ts=8 sw=2 smarttab
   3
   4 #ifndef CEPH_LIBRBD_IO_READ_RESULT_H
   5 #define CEPH_LIBRBD_IO_READ_RESULT_H
   6
   7 #include "include/common_fwd.h"
   8 #include "include/int_types.h"
   9 #include "include/buffer_fwd.h"
  10 #include "include/Context.h"
  11 #include "librbd/io/Types.h"
  12 #include "osdc/Striper.h"
  13 #include <sys/uio.h>
  14 #include <boost/variant/variant.hpp>
  15
  16
  17 namespace librbd {
  18
  19 struct ImageCtx;
  20
  21 namespace io {
  22
  23 struct AioCompletion;
  24 template <typename> struct ObjectReadRequest;
  25
  26 class ReadResult {
  27 public:
  28   struct C_ImageReadRequest : public Context {
  29     AioCompletion *aio_completion;
  30     Extents image_extents;
  31     bufferlist bl;
  32
  33     C_ImageReadRequest(AioCompletion *aio_completion,
  34                        const Extents image_extents);
  35
  36     void finish(int r) override;
  37   };
  38
  39   struct C_ObjectReadRequest : public Context {
  40     AioCompletion *aio_completion;
  41     uint64_t object_off;
  42     uint64_t object_len;
  43     LightweightBufferExtents buffer_extents;
  44
  45     bufferlist bl;
  46     ExtentMap extent_map;
  47
  48     C_ObjectReadRequest(AioCompletion *aio_completion, uint64_t object_off,
  49                         uint64_t object_len,
  50                         LightweightBufferExtents&& buffer_extents);
  51
  52     void finish(int r) override;
  53   };
  54
  55   ReadResult();
  56   ReadResult(char *buf, size_t buf_len);
  57   ReadResult(const struct iovec *iov, int iov_count);
  58   ReadResult(ceph::bufferlist *bl);
  59   ReadResult(std::map<uint64_t, uint64_t> *extent_map, ceph::bufferlist *bl);
  60
  61   void set_clip_length(size_t length);
  62   void assemble_result(CephContext *cct);
  63
  64 private:
  65   struct Empty {
  66   };
  67
  68   struct Linear {
  69     char *buf;
  70     size_t buf_len;
  71
  72     Linear(char *buf, size_t buf_len) : buf(buf), buf_len(buf_len) {
  73     }
  74   };
  75
  76   struct Vector {
  77     const struct iovec *iov;
  78     int iov_count;
  79
  80     Vector(const struct iovec *iov, int iov_count)
  81       : iov(iov), iov_count(iov_count) {
  82     }
  83   };
  84
  85   struct Bufferlist {
  86     ceph::bufferlist *bl;
  87
  88     Bufferlist(ceph::bufferlist *bl) : bl(bl) {
  89     }
  90   };
  91
  92   struct SparseBufferlist {
  93     std::map<uint64_t, uint64_t> *extent_map;
  94     ceph::bufferlist *bl;
  95
  96     SparseBufferlist(std::map<uint64_t, uint64_t> *extent_map,
  97                      ceph::bufferlist *bl)
  98       : extent_map(extent_map), bl(bl) {
  99     }
 100   };
 101
 102   typedef boost::variant<Empty,
 103                          Linear,
 104                          Vector,
 105                          Bufferlist,
 106                          SparseBufferlist> Buffer;
 107   struct SetClipLengthVisitor;
 108   struct AssembleResultVisitor;
 109
 110   Buffer m_buffer;
 111   Striper::StripedReadResult m_destriper;
 112
 113 };
 114
 115 } // namespace io
 116 } // namespace librbd
 117
 118 #endif // CEPH_LIBRBD_IO_READ_RESULT_H
 119