ceph/src/common/buffer_seastar.h

   1 // -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
   2 // vim: ts=8 sw=2 smarttab
   3
   4 #include <seastar/core/temporary_buffer.hh>
   5 #include "include/buffer.h"
   6 #include "common/error_code.h"
   7
   8 namespace details {
   9
  10 template<bool is_const>
  11 class buffer_iterator_impl {
  12 public:
  13   using pointer = std::conditional_t<is_const, const char*, char *>;
  14   buffer_iterator_impl(pointer first, const char* last)
  15     : pos(first), end_ptr(last)
  16   {}
  17   pointer get_pos_add(size_t n) {
  18     auto r = pos;
  19     pos += n;
  20     if (pos > end_ptr) {
  21       throw buffer::end_of_buffer{};
  22     }
  23     return r;
  24   }
  25   pointer get() const {
  26     return pos;
  27   }
  28 protected:
  29   pointer pos;
  30   const char* end_ptr;
  31 };
  32 } // namespace details
  33
  34 class seastar_buffer_iterator : details::buffer_iterator_impl<false> {
  35   using parent = details::buffer_iterator_impl<false>;
  36   using temporary_buffer = seastar::temporary_buffer<char>;
  37 public:
  38   seastar_buffer_iterator(temporary_buffer& b)
  39     : parent(b.get_write(), b.end()), buf(b)
  40   {}
  41   using parent::pointer;
  42   using parent::get_pos_add;
  43   using parent::get;
  44   ceph::buffer::ptr get_ptr(size_t len);
  45
  46 private:
  47   // keep the reference to buf around, so it can be "shared" by get_ptr()
  48   temporary_buffer& buf;
  49 };
  50
  51 class const_seastar_buffer_iterator : details::buffer_iterator_impl<true> {
  52   using parent = details::buffer_iterator_impl<true>;
  53   using temporary_buffer = seastar::temporary_buffer<char>;
  54 public:
  55   const_seastar_buffer_iterator(temporary_buffer& b)
  56     : parent(b.get_write(), b.end())
  57   {}
  58   using parent::pointer;
  59   using parent::get_pos_add;
  60   using parent::get;
  61   ceph::buffer::ptr get_ptr(size_t len);
  62 };