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// Copyright The OpenTelemetry Authors
// SPDX-License-Identifier: Apache-2.0
#pragma once
#include <memory>
#include <vector>
#include "opentelemetry/context/propagation/text_map_propagator.h"
#include "opentelemetry/version.h"
OPENTELEMETRY_BEGIN_NAMESPACE
namespace context
{
namespace propagation
{
class CompositePropagator : public TextMapPropagator
{
public:
CompositePropagator(std::vector<std::unique_ptr<TextMapPropagator>> propagators)
: propagators_(std::move(propagators))
{}
/**
* Run each of the configured propagators with the given context and carrier.
* Propagators are run in the order they are configured, so if multiple
* propagators write the same carrier key, the propagator later in the list
* will "win".
*
* @param carrier Carrier into which context will be injected
* @param context Context to inject
*
*/
void Inject(TextMapCarrier &carrier, const context::Context &context) noexcept override
{
for (auto &p : propagators_)
{
p->Inject(carrier, context);
}
}
/**
* Run each of the configured propagators with the given context and carrier.
* Propagators are run in the order they are configured, so if multiple
* propagators write the same context key, the propagator later in the list
* will "win".
*
* @param carrier Carrier from which to extract context
* @param context Context to add values to
*/
context::Context Extract(const TextMapCarrier &carrier,
context::Context &context) noexcept override
{
auto first = true;
context::Context tmp_context;
for (auto &p : propagators_)
{
if (first)
{
tmp_context = p->Extract(carrier, context);
first = false;
}
else
{
tmp_context = p->Extract(carrier, tmp_context);
}
}
return propagators_.size() ? tmp_context : context;
}
/**
* Invoke callback with fields set to carrier by `inject` method for all the
* configured propagators
* Returns true if all invocation return true
*/
bool Fields(nostd::function_ref<bool(nostd::string_view)> callback) const noexcept override
{
bool status = true;
for (auto &p : propagators_)
{
status = status && p->Fields(callback);
}
return status;
}
private:
std::vector<std::unique_ptr<TextMapPropagator>> propagators_;
};
} // namespace propagation
} // namespace context
OPENTELEMETRY_END_NAMESPACE
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