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// Copyright The OpenTelemetry Authors
// SPDX-License-Identifier: Apache-2.0
#pragma once
#include "opentelemetry/common/attribute_value.h"
#include "opentelemetry/nostd/function_ref.h"
#include "opentelemetry/nostd/string_view.h"
#include "opentelemetry/version.h"
OPENTELEMETRY_BEGIN_NAMESPACE
namespace common
{
/**
* Supports internal iteration over a collection of key-value pairs.
*/
class KeyValueIterable
{
public:
virtual ~KeyValueIterable() = default;
/**
* Iterate over key-value pairs
* @param callback a callback to invoke for each key-value. If the callback returns false,
* the iteration is aborted.
* @return true if every key-value pair was iterated over
*/
virtual bool ForEachKeyValue(nostd::function_ref<bool(nostd::string_view, common::AttributeValue)>
callback) const noexcept = 0;
/**
* @return the number of key-value pairs
*/
virtual size_t size() const noexcept = 0;
};
/**
* Supports internal iteration over a collection of key-value pairs.
*/
class NoopKeyValueIterable : public KeyValueIterable
{
public:
~NoopKeyValueIterable() override = default;
/**
* No-op implementation: does not invoke the callback, even if key-value pairs are present.
* @return true without iterating or invoking the callback
*/
bool ForEachKeyValue(
nostd::function_ref<bool(nostd::string_view, common::AttributeValue)> /*callback*/)
const noexcept override
{
return true;
}
/**
* @return the number of key-value pairs
*/
size_t size() const noexcept override { return 0; }
};
} // namespace common
OPENTELEMETRY_END_NAMESPACE
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