.. _program_listing_file__tmp_ws_src_message_filters_include_message_filters_chain.h:

Program Listing for File chain.h
================================

|exhale_lsh| :ref:`Return to documentation for file <file__tmp_ws_src_message_filters_include_message_filters_chain.h>` (``/tmp/ws/src/message_filters/include/message_filters/chain.h``)

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

.. code-block:: cpp

   /*********************************************************************
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   *     from this software without specific prior written permission.
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   *********************************************************************/
   
   #ifndef MESSAGE_FILTERS__CHAIN_H
   #define MESSAGE_FILTERS__CHAIN_H
   
   #include <vector>
   
   #include "message_filters/simple_filter.h"
   #include "message_filters/pass_through.h"
   
   namespace message_filters
   {
   class ChainBase
   {
   public:
     virtual ~ChainBase() {}
   
     template<typename F>
     std::shared_ptr<F> getFilter(size_t index) const
     {
       std::shared_ptr<void> filter = getFilterForIndex(index);
       if (filter)
       {
         return std::static_pointer_cast<F>(filter);
       }
   
       return std::shared_ptr<F>();
     }
   
   protected:
     virtual std::shared_ptr<void> getFilterForIndex(size_t index) const = 0;
   };
   typedef std::shared_ptr<ChainBase> ChainBasePtr;
   
   template<typename M>
   class Chain : public ChainBase, public SimpleFilter<M>
   {
   public:
     typedef std::shared_ptr<M const> MConstPtr;
     typedef MessageEvent<M const> EventType;
   
     Chain()
     {
     }
   
     template<typename F>
     Chain(F& f)
     {
       connectInput(f);
     }
   
     struct NullDeleter
     {
       void operator()(void const*) const
       {
       }
     };
   
     template<class F>
     size_t addFilter(F* filter)
     {
       std::shared_ptr<F> ptr(filter, NullDeleter());
       return addFilter(ptr);
     }
   
     template<class F>
     size_t addFilter(const std::shared_ptr<F>& filter)
     {
       FilterInfo info;
       info.add_func = std::bind((void(F::*)(const EventType&))&F::add, filter.get(), std::placeholders::_1);
       info.filter = filter;
       info.passthrough = std::make_shared<PassThrough<M> >();
   
       last_filter_connection_.disconnect();
       info.passthrough->connectInput(*filter);
       last_filter_connection_ = info.passthrough->registerCallback(typename SimpleFilter<M>::EventCallback(std::bind(&Chain::lastFilterCB, this, std::placeholders::_1)));
       if (!filters_.empty())
       {
         filter->connectInput(*filters_.back().passthrough);
       }
   
       size_t count = filters_.size();
       filters_.push_back(info);
       return count;
     }
   
     template<typename F>
     std::shared_ptr<F> getFilter(size_t index) const
     {
       if (index >= filters_.size())
       {
         return std::shared_ptr<F>();
       }
   
       return std::static_pointer_cast<F>(filters_[index].filter);
     }
   
     template<class F>
     void connectInput(F& f)
     {
       incoming_connection_.disconnect();
       incoming_connection_ = f.registerCallback(typename SimpleFilter<M>::EventCallback(std::bind(&Chain::incomingCB, this, std::placeholders::_1)));
     }
   
     void add(const MConstPtr& msg)
     {
       add(EventType(msg));
     }
   
     void add(const EventType& evt)
     {
       if (!filters_.empty())
       {
         filters_[0].add_func(evt);
       }
     }
   
   protected:
     virtual std::shared_ptr<void> getFilterForIndex(size_t index) const
     {
       if (index >= filters_.size())
       {
         return std::shared_ptr<void>();
       }
   
       return filters_[index].filter;
     }
   
   private:
     void incomingCB(const EventType& evt)
     {
       add(evt);
     }
   
     void lastFilterCB(const EventType& evt)
     {
       this->signalMessage(evt);
     }
   
     struct FilterInfo
     {
       std::function<void(const EventType&)> add_func;
       std::shared_ptr<void> filter;
       std::shared_ptr<PassThrough<M> > passthrough;
     };
     typedef std::vector<FilterInfo> V_FilterInfo;
   
     V_FilterInfo filters_;
   
     Connection incoming_connection_;
     Connection last_filter_connection_;
   };
   }  // namespace message_filters
   
   #endif  // MESSAGE_FILTERS__CHAIN_H_