ParsedCommand.ih

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//
// Copyright (c) 2020 Fraunhofer Institute for Applied Information Technology (FIT)
//                    Network Research Group (NET)
//                    Schloss Birlinghoven, 53754 Sankt Augustin, GERMANY
//                    Contact: support@wiback.org
//
// This file is part of the SENF code tree.
// It is licensed under the 3-clause BSD License (aka New BSD License).
// See LICENSE.txt in the top level directory for details or visit
// https://opensource.org/licenses/BSD-3-Clause
//


/** \file
    \brief ParsedCommand internal header */

#ifndef IH_SENF_Scheduler_Console_ParsedCommand_
#define IH_SENF_Scheduler_Console_ParsedCommand_ 1

// Custom includes
#include <boost/preprocessor/repetition/enum_trailing.hpp>
#include <boost/function.hpp>
#include <boost/intrusive_ptr.hpp>
#include "Parse.hh"

//-/////////////////////////////////////////////////////////////////////////////////////////////////

namespace senf {
namespace console {

    template < class FunctionTraits,
               class ReturnType=typename FunctionTraits::result_type,
               unsigned arity=FunctionTraits::arity >
    class ParsedCommandOverload;

    template < class Overload,
               unsigned index=0,
               bool flag=(index < unsigned(Overload::traits::arity)) >
    class ParsedArgumentAttributor;

namespace detail {

    /** \brief Internal: Argument information structure

        This class is used to hold argument information for automatically parsed commands.

        \see ParsedCommandOverloadBase
     */
    struct ArgumentInfoBase
        : public intrusive_refcount
    {
        typedef boost::intrusive_ptr<ArgumentInfoBase> ptr;

        std::string type;
        std::string name;
        std::string defaultDoc;
        bool hasDefault;
        std::string doc;
        bool singleToken;

        explicit ArgumentInfoBase(std::string const & type, bool singleToken=false);
        virtual ~ArgumentInfoBase();

        virtual std::string defaultValueStr() const = 0;
    };

    /** \brief Internal: Argument information structure

        This class is used to hold argument information for automatically parsed commands.

        \see ParsedCommandOverloadBase
     */
    template <class ParameterType>
    struct ArgumentInfo
        : public ArgumentInfoBase
    {
        typedef boost::intrusive_ptr<ArgumentInfo> ptr;
        typedef boost::function<void (ParseCommandInfo::TokensRange const &,
                                      ParameterType &)> Parser;

        static ptr create();
        ArgumentInfo();

        ParameterType defaultValue;
        Parser parser;

        virtual std::string defaultValueStr() const;
    };

#ifndef DOXYGEN

    // FirstArgType returns void, if the function has no arguments, otherwise it returns arg1_type

    template <class Traits, bool flag=(Traits::arity>0)>
    struct FirstArgType
    {
        typedef void type;
    };

    template <class Traits>
    struct FirstArgType<Traits,true>
    {
        typedef typename Traits::arg1_type type;
    };

    template <class FnunctionP, class Function, bool isFN=boost::is_function<Function>::value>
    struct ParsedCommandTraits_i
    {
        static const bool is_callable = false;
        static const bool is_member = false;
        static const bool is_simple = false;
    };

    template <class FunctionP, class Function>
    struct ParsedCommandTraits_i<FunctionP, Function, true>
    {
        typedef FunctionP base_type;
        typedef typename senf::remove_any_pointer<base_type>::type function_type;
        typedef boost::function_traits<function_type> base_traits;
        typedef typename FirstArgType<base_traits>::type first_arg_type;

        static const bool has_ostream_arg = boost::is_same<first_arg_type, std::ostream &>::value;

        typedef typename boost::mpl::if_c<
            has_ostream_arg,
            typename function_traits_remove_arg<base_traits>::type,
            base_traits>
        ::type traits;

        typedef typename senf::remove_cvref<typename base_traits::result_type>::type result_type;

        static const bool is_callable = true;
        static const bool is_member = boost::is_member_pointer<base_type>::value;
        static const bool is_simple = false;

        typedef typename senf::member_class<base_type>::type class_type;

        typedef ParsedCommandOverload<traits> Overload;
        typedef ParsedArgumentAttributor<Overload> Attributor;
    };

    // Disable auto-parsing for ParseCommandInfo arg -> register manually parsed command
    template <class FunctionP>
    struct ParsedCommandTraits_i<FunctionP, void (std::ostream &, ParseCommandInfo const &), true>
    {
        static const bool is_simple = true;
    };

    template <class FunctionP>
    struct ParsedCommandTraits
        : public ParsedCommandTraits_i< FunctionP,
                                        typename senf::remove_any_pointer<FunctionP>::type >
    {};

    struct ParsedCommandAddNodeAccess;

    // What is THIS about ??

    // Ok, here's the dope: parsed commands may optionally have an std::ostream & first argument. If
    // this argument is given, then the function will be called with the console output stream as
    // it's first argument.
    //
    // This is implemented in the following way: ParsedCommandOverload (the class responsible for
    // calling the callback) will ALWAYS pass the stream as first argument. If the user callback
    // expects os as it's first argument, 'ignoreOneArg' will be false and the user supplied
    // function will be directly passed to ParsedCommandOverload.
    //
    // If however, it does NOT take an std::ostream first argument, 'ignoreOneArg' will be true and
    // the create member will use boost::bind to DROP the first argument.

    template <class Traits,
              bool ignoreOneArg=! Traits::has_ostream_arg,
              unsigned arity=Traits::traits::arity>
    struct CreateParsedCommandOverload
    {};

    template <class Traits, unsigned arity>
    struct CreateParsedCommandOverload<Traits, false, arity>
    {
        typedef typename Traits::traits traits;

        template <class Function>
        static typename senf::console::ParsedCommandOverload<traits>::ptr create(Function fn)
            { return senf::console::ParsedCommandOverload<traits>::create(fn); };
    };

#   define BOOST_PP_ITERATION_PARAMS_1 (4, (0, SENF_CONSOLE_MAX_COMMAND_ARITY,                     \
                                            SENF_ABSOLUTE_INCLUDE_PATH(Utils/Console/ParsedCommand.mpp), \
                                            4))
#   include BOOST_PP_ITERATE()

#endif

}}}

//-/////////////////////////////////////////////////////////////////////////////////////////////////
#endif


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