Registrar.h

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// kate: replace-tabs off; indent-width 4; indent-mode normal
// vim: ts=4:sw=4:noexpandtab
/*

Copyright (c) 2010--2012,
François Pomerleau and Stephane Magnenat, ASL, ETHZ, Switzerland
You can contact the authors at <f dot pomerleau at gmail dot com> and
<stephane at magnenat dot net>

All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
    * Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in the
      documentation and/or other materials provided with the distribution.
    * Neither the name of the <organization> nor the
      names of its contributors may be used to endorse or promote products
      derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL ETH-ASL BE LIABLE FOR ANY
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*/

#ifndef __POINTMATCHER_REGISTRAR_H
#define __POINTMATCHER_REGISTRAR_H

#include "Parametrizable.h"
#include "PointMatcher.h"
#include <boost/format.hpp>

#ifdef HAVE_YAML_CPP
    #include "yaml-cpp/yaml.h"
#endif // HAVE_YAML_CPP

namespace PointMatcherSupport
{
    struct InvalidElement: std::runtime_error
    {
        InvalidElement(const std::string& reason);
    };
    
    template<typename Interface>
    struct Registrar
    {
    public:
        typedef Interface TargetType; 
        
        struct ClassDescriptor
        {
            virtual ~ClassDescriptor() {}
            virtual Interface* createInstance(const std::string& className, const Parametrizable::Parameters& params) const = 0;
            virtual const std::string description() const = 0;
            virtual const Parametrizable::ParametersDoc availableParameters() const = 0;
        };
        
        template<typename C>
        struct GenericClassDescriptor: public ClassDescriptor
        {
            virtual Interface* createInstance(const std::string& className, const Parametrizable::Parameters& params) const
            {
                C* instance(new C(params));
                
                // check that there was no unsed parameter
                for (auto it(params.begin()); it != params.end() ;++it)
                {
                    if (instance->parametersUsed.find(it->first) == instance->parametersUsed.end())
                        throw Parametrizable::InvalidParameter(
                            (boost::format("Parameter %1% for module %2% was set but is not used") % it->first % className).str()
                        );
                }
                
                return instance;
            }
            virtual const std::string description() const
            {
                return C::description();
            }
            virtual const Parametrizable::ParametersDoc availableParameters() const
            {
                return C::availableParameters();
            }
        };
        
        template<typename C>
        struct GenericClassDescriptorNoParam: public ClassDescriptor
        {
            virtual Interface* createInstance(const std::string& className, const Parametrizable::Parameters& params) const
            {
                for (auto it(params.begin()); it != params.end() ;++it)
                    throw Parametrizable::InvalidParameter(
                            (boost::format("Parameter %1% was set but module %2% dos not use any parameter") % it->first % className).str()
                        );
                return new C();
            }
            virtual const std::string description() const
            {
                return C::description();
            }
            virtual const Parametrizable::ParametersDoc availableParameters() const
            {
                return {};
            }
        };
        
    protected:
        typedef std::map<std::string, ClassDescriptor*> DescriptorMap; 
        DescriptorMap classes; 
        
    public:
        ~Registrar()
        {
            for (auto it = classes.begin(); it != classes.end(); ++it)
                delete it->second;
        }
        void reg(const std::string &name, ClassDescriptor* descriptor)
        {
            classes[name] = descriptor;
        }
        
        const ClassDescriptor* getDescriptor(const std::string& name) const
        {
            auto it = classes.find(name);
            if (it == classes.end())
            {
                std::cerr << "No element named " << name << " is registered. Known ones are:\n";
                dump(std::cerr);
                throw InvalidElement(
                    (boost::format("Trying to instanciate unknown element %1% from registrar") % name).str()
                );
            }
            return it->second;
        }
        
        Interface* create(const std::string& name, const Parametrizable::Parameters& params = Parametrizable::Parameters()) const
        {
            return getDescriptor(name)->createInstance(name, params);
        }
        
        #ifdef HAVE_YAML_CPP
        
        Interface* createFromYAML(const YAML::Node& module) const
        {
            Parametrizable::Parameters params;
            std::string name;
            
            if (module.size() != 1)
            {
                // parameter-less entry
                name = module.to<std::string>();
            }
            else
            {
                // get parameters
                YAML::Iterator mapIt(module.begin());
                mapIt.first() >> name;
                for(YAML::Iterator paramIt = mapIt.second().begin(); paramIt != mapIt.second().end(); ++paramIt)
                {
                    std::string key, value;
                    paramIt.first() >> key;
                    paramIt.second() >> value;
                    params[key] = value;
                }
            }
            
            return create(name, params);
        }
        
        #endif // HAVE_YAML_CPP
        
        const std::string getDescription(const std::string& name) const
        {
            return getDescriptor(name)->description();
        }
        
        void dump(std::ostream &stream) const
        {
            for (auto it = classes.begin(); it != classes.end(); ++it)
                stream << "- " << it->first << "\n";
        }
        
        typename DescriptorMap::const_iterator begin() const
        {
            return classes.begin();
        }
        typename DescriptorMap::const_iterator end() const
        {
            return classes.end();
        }
    };

    #define REG(name) name##Registrar
    #define DEF_REGISTRAR(name) PointMatcherSupport::Registrar< name > name##Registrar;
    #define DEF_REGISTRAR_IFACE(name, ifaceName) PointMatcherSupport::Registrar< ifaceName > name##Registrar;
    #define ADD_TO_REGISTRAR(name, elementName, element) { \
        typedef typename PointMatcherSupport::Registrar< name >::template GenericClassDescriptor< element > Desc; \
        name##Registrar.reg(# elementName, new Desc() ); \
    }
    #define ADD_TO_REGISTRAR_NO_PARAM(name, elementName, element) { \
        typedef typename PointMatcherSupport::Registrar< name >::template GenericClassDescriptorNoParam< element > Desc; \
        name##Registrar.reg(# elementName, new Desc() ); \
    }
} // namespace PointMatcherSupport

#endif // __POINTMATCHER_REGISTRAR_H