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// Copyright The OpenTelemetry Authors
// SPDX-License-Identifier: Apache-2.0
#pragma once
#include <iterator>
#include <type_traits>
#include <utility>
#include "opentelemetry/common/key_value_iterable.h"
#include "opentelemetry/nostd/utility.h"
#include "opentelemetry/version.h"
OPENTELEMETRY_BEGIN_NAMESPACE
namespace common
{
// NOTE - code within `detail` namespace implements internal details, and not part
// of the public interface.
namespace detail
{
inline void take_key_value(nostd::string_view, common::AttributeValue) {}
template <class T>
auto is_key_value_iterable_impl(T iterable)
-> decltype(take_key_value(std::begin(iterable)->first, std::begin(iterable)->second),
nostd::size(iterable),
std::true_type{});
std::false_type is_key_value_iterable_impl(...);
template <class T>
struct is_key_value_iterable
{
static const bool value = decltype(detail::is_key_value_iterable_impl(std::declval<T>()))::value;
};
} // namespace detail
/**
* @brief Container for key-value pairs that can transform every value in it to one of types
* listed in common::AttributeValue. It may contain value types that are not directly map'able
* to primitive value types. In that case the `ForEachKeyValue` method acts as a transform to
* convert the value type to one listed under AtributeValue (bool, int32_t, int64_t, uint32_t,
* uint64_t, double, nostd::string_view, or arrays of primite types). For example, if UUID,
* GUID, or UTF-16 string type is passed as one of values stored inside this container, the
* container itself may provide a custom implementation of `ForEachKeyValue` to transform the
* 'non-standard' type to one of the standard types.
*/
template <class T>
class KeyValueIterableView final : public KeyValueIterable
{
public:
explicit KeyValueIterableView(const T &container) noexcept : container_{&container} {}
// KeyValueIterable
bool ForEachKeyValue(nostd::function_ref<bool(nostd::string_view, common::AttributeValue)>
callback) const noexcept override
{
auto iter = std::begin(*container_);
auto last = std::end(*container_);
for (; iter != last; ++iter)
{
if (!callback(iter->first, iter->second))
{
return false;
}
}
return true;
}
size_t size() const noexcept override { return nostd::size(*container_); }
private:
const T *container_;
};
} // namespace common
OPENTELEMETRY_END_NAMESPACE
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