.. _program_listing_file_include_opentelemetry_context_propagation_composite_propagator.h:

Program Listing for File composite_propagator.h
===============================================

|exhale_lsh| :ref:`Return to documentation for file <file_include_opentelemetry_context_propagation_composite_propagator.h>` (``include/opentelemetry/context/propagation/composite_propagator.h``)

.. |exhale_lsh| unicode:: U+021B0 .. UPWARDS ARROW WITH TIP LEFTWARDS

.. code-block:: cpp

   // Copyright The OpenTelemetry Authors
   // SPDX-License-Identifier: Apache-2.0
   
   #include <initializer_list>
   #include <memory>
   #include <vector>
   #include "opentelemetry/context/propagation/text_map_propagator.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))
     {}
   
     void Inject(TextMapCarrier &carrier, const context::Context &context) noexcept override
     {
       for (auto &p : propagators_)
       {
         p->Inject(carrier, context);
       }
     }
   
     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;
     }
   
   private:
     std::vector<std::unique_ptr<TextMapPropagator>> propagators_;
   };
   }  // namespace propagation
   }  // namespace context
   OPENTELEMETRY_END_NAMESPACE;