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/int_types.h"
   8 #include "include/buffer_fwd.h"
   9 #include "include/Context.h"
  10 #include "librbd/io/Types.h"
  11 #include "osdc/Striper.h"
  12 #include <sys/uio.h>
  13 #include <boost/variant/variant.hpp>
  14
  15 struct CephContext;
  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 private:
  28   struct C_ReadRequest : public Context {
  29     AioCompletion *aio_completion;
  30     bufferlist bl;
  31
  32     C_ReadRequest(AioCompletion *aio_completion);
  33
  34     void finish(int r) override;
  35   };
  36
  37 public:
  38
  39   struct C_ImageReadRequest : public C_ReadRequest {
  40     Extents image_extents;
  41
  42     C_ImageReadRequest(AioCompletion *aio_completion,
  43                        const Extents image_extents)
  44       : C_ReadRequest(aio_completion), image_extents(image_extents) {
  45     }
  46
  47     void finish(int r) override;
  48   };
  49
  50   struct C_SparseReadRequestBase : public C_ReadRequest {
  51     bool ignore_enoent;
  52
  53     C_SparseReadRequestBase(AioCompletion *aio_completion, bool ignore_enoent)
  54       : C_ReadRequest(aio_completion), ignore_enoent(ignore_enoent) {
  55     }
  56
  57     using C_ReadRequest::finish;
  58     void finish(ExtentMap &extent_map, const Extents &buffer_extents,
  59                 uint64_t offset, size_t length, bufferlist &bl, int r);
  60   };
  61
  62   template <typename ImageCtxT = ImageCtx>
  63   struct C_SparseReadRequest : public C_SparseReadRequestBase {
  64     ObjectReadRequest<ImageCtxT> *request;
  65     Extents buffer_extents;
  66
  67     C_SparseReadRequest(AioCompletion *aio_completion, Extents&& buffer_extents,
  68                         bool ignore_enoent)
  69       : C_SparseReadRequestBase(aio_completion, ignore_enoent),
  70         buffer_extents(std::move(buffer_extents)) {
  71     }
  72
  73     void finish(int r) override {
  74       C_SparseReadRequestBase::finish(request->get_extent_map(), buffer_extents,
  75                                       request->get_offset(),
  76                                       request->get_length(), request->data(),
  77                                       r);
  78     }
  79   };
  80
  81   ReadResult();
  82   ReadResult(char *buf, size_t buf_len);
  83   ReadResult(const struct iovec *iov, int iov_count);
  84   ReadResult(ceph::bufferlist *bl);
  85
  86   void set_clip_length(size_t length);
  87   void assemble_result(CephContext *cct);
  88
  89 private:
  90   struct Empty {
  91   };
  92
  93   struct Linear {
  94     char *buf;
  95     size_t buf_len;
  96
  97     Linear(char *buf, size_t buf_len) : buf(buf), buf_len(buf_len) {
  98     }
  99   };
 100
 101   struct Vector {
 102     const struct iovec *iov;
 103     int iov_count;
 104
 105     Vector(const struct iovec *iov, int iov_count)
 106       : iov(iov), iov_count(iov_count) {
 107     }
 108   };
 109
 110   struct Bufferlist {
 111     ceph::bufferlist *bl;
 112
 113     Bufferlist(ceph::bufferlist *bl) : bl(bl) {
 114     }
 115   };
 116
 117   typedef boost::variant<Empty,
 118                          Linear,
 119                          Vector,
 120                          Bufferlist> Buffer;
 121   struct SetClipLengthVisitor;
 122   struct AssembleResultVisitor;
 123
 124   Buffer m_buffer;
 125   Striper::StripedReadResult m_destriper;
 126
 127 };
 128
 129 } // namespace io
 130 } // namespace librbd
 131
 132 #endif // CEPH_LIBRBD_IO_READ_RESULT_H
 133