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// Copyright The OpenTelemetry Authors
// SPDX-License-Identifier: Apache-2.0
#pragma once
#include "opentelemetry/common/attribute_value.h"
#include "opentelemetry/common/key_value_iterable_view.h"
#include "opentelemetry/nostd/function_ref.h"
#include "opentelemetry/trace/span_context.h"
#include "opentelemetry/version.h"
OPENTELEMETRY_BEGIN_NAMESPACE
namespace trace
{
/**
* Supports internal iteration over a collection of SpanContext/key-value pairs.
*/
class SpanContextKeyValueIterable
{
public:
virtual ~SpanContextKeyValueIterable() = default;
/**
* Iterate over SpanContext/key-value pairs
* @param callback a callback to invoke for each key-value for each SpanContext.
* If the callback returns false, the iteration is aborted.
* @return true if every SpanContext/key-value pair was iterated over
*/
virtual bool ForEachKeyValue(
nostd::function_ref<bool(SpanContext, const common::KeyValueIterable &)> callback)
const noexcept = 0;
/**
* @return the number of key-value pairs
*/
virtual size_t size() const noexcept = 0;
};
/**
* @brief Null Span context that does not carry any information.
*/
class NullSpanContext : public SpanContextKeyValueIterable
{
public:
bool ForEachKeyValue(nostd::function_ref<bool(SpanContext, const common::KeyValueIterable &)>
/* callback */) const noexcept override
{
return true;
}
size_t size() const noexcept override { return 0; }
};
} // namespace trace
OPENTELEMETRY_END_NAMESPACE
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