ceph/src/jaegertracing/opentelemetry-cpp/api/include/opentelemetry/trace/span_context_kv_iterable_view.h

   1 // Copyright The OpenTelemetry Authors
   2 // SPDX-License-Identifier: Apache-2.0
   3
   4 #pragma once
   5
   6 #include <iterator>
   7 #include <type_traits>
   8 #include <utility>
   9
  10 #include "opentelemetry/common/key_value_iterable_view.h"
  11 #include "opentelemetry/nostd/utility.h"
  12 #include "opentelemetry/trace/span_context_kv_iterable.h"
  13 #include "opentelemetry/version.h"
  14
  15 OPENTELEMETRY_BEGIN_NAMESPACE
  16 namespace trace
  17 {
  18 // NOTE - code within `detail` namespace implements internal details, and not part
  19 // of the public interface.
  20 namespace detail
  21 {
  22 template <class T>
  23 inline void take_span_context_kv(SpanContext, common::KeyValueIterableView<T>)
  24 {}
  25
  26 template <class T, nostd::enable_if_t<common::detail::is_key_value_iterable<T>::value> * = nullptr>
  27 inline void take_span_context_kv(SpanContext, T &)
  28 {}
  29
  30 inline void take_span_context_kv(
  31     SpanContext,
  32     std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>>)
  33 {}
  34
  35 template <class T>
  36 auto is_span_context_kv_iterable_impl(T iterable)
  37     -> decltype(take_span_context_kv(std::begin(iterable)->first, std::begin(iterable)->second),
  38                 nostd::size(iterable),
  39                 std::true_type{});
  40
  41 std::false_type is_span_context_kv_iterable_impl(...);
  42
  43 template <class T>
  44 struct is_span_context_kv_iterable
  45 {
  46   static const bool value =
  47       decltype(detail::is_span_context_kv_iterable_impl(std::declval<T>()))::value;
  48 };
  49 }  // namespace detail
  50
  51 template <class T>
  52 class SpanContextKeyValueIterableView final : public SpanContextKeyValueIterable
  53 {
  54   static_assert(detail::is_span_context_kv_iterable<T>::value,
  55                 "Must be a context/key-value iterable");
  56
  57 public:
  58   explicit SpanContextKeyValueIterableView(const T &links) noexcept : container_{&links} {}
  59
  60   bool ForEachKeyValue(
  61       nostd::function_ref<bool(SpanContext, const opentelemetry::common::KeyValueIterable &)>
  62           callback) const noexcept override
  63   {
  64     auto iter = std::begin(*container_);
  65     auto last = std::end(*container_);
  66     for (; iter != last; ++iter)
  67     {
  68       if (!this->do_callback(iter->first, iter->second, callback))
  69       {
  70         return false;
  71       }
  72     }
  73     return true;
  74   }
  75
  76   size_t size() const noexcept override { return nostd::size(*container_); }
  77
  78 private:
  79   const T *container_;
  80
  81   bool do_callback(
  82       SpanContext span_context,
  83       const common::KeyValueIterable &attributes,
  84       nostd::function_ref<bool(SpanContext, const opentelemetry::common::KeyValueIterable &)>
  85           callback) const noexcept
  86   {
  87     if (!callback(span_context, attributes))
  88     {
  89       return false;
  90     }
  91     return true;
  92   }
  93
  94   template <class U,
  95             nostd::enable_if_t<common::detail::is_key_value_iterable<U>::value> * = nullptr>
  96   bool do_callback(SpanContext span_context,
  97                    const U &attributes,
  98                    nostd::function_ref<bool(SpanContext, const common::KeyValueIterable &)>
  99                        callback) const noexcept
 100   {
 101     return do_callback(span_context, common::KeyValueIterableView<U>(attributes), callback);
 102   }
 103
 104   bool do_callback(
 105       SpanContext span_context,
 106       std::initializer_list<std::pair<nostd::string_view, common::AttributeValue>> attributes,
 107       nostd::function_ref<bool(SpanContext, const common::KeyValueIterable &)> callback)
 108       const noexcept
 109   {
 110     return do_callback(span_context,
 111                        nostd::span<const std::pair<nostd::string_view, common::AttributeValue>>{
 112                            attributes.begin(), attributes.end()},
 113                        callback);
 114   }
 115 };
 116 }  // namespace trace
 117 OPENTELEMETRY_END_NAMESPACE