daw_to_json.h

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// Copyright (c) Darrell Wright
//
// Distributed under the Boost Software License, version 1.0. (see accompanying
// file LICENSE or copy at http://www.boost.org/LICENSE_1_0.txt)
//
// Official repository: https://github.com/beached/daw_json_link
//
 
#pragma once
 
#include "daw/json/impl/version.h"
 
#include "daw/json/concepts/daw_writable_output.h"
#include "daw/json/daw_to_json_fwd.h"
#include "daw/json/impl/daw_json_container_appender.h"
#include "daw/json/impl/daw_json_link_types_fwd.h"
#include "daw/json/impl/to_daw_json_string.h"
 
#include <daw/daw_enable_requires.h>
#include <daw/daw_traits.h>
 
#include <iterator>
#include <string>
#include <type_traits>
 
namespace daw::json {
  inline namespace DAW_JSON_VER {
    namespace json_details {
      template<typename output_t, auto... PolicyFlags, typename WritableType>
      DAW_ATTRIB_INLINE constexpr auto apply_policy_flags( WritableType &&it ) {
        if constexpr( is_serialization_policy_v<
                        daw::remove_cvref_t<WritableType>> ) {
          if constexpr( sizeof...( PolicyFlags ) == 0 ) {
            return it;
          } else {
            return serialization_policy<typename output_t::iterator_type,
                                        json_details::serialization::set_bits(
                                          output_t::policy_flags( ),
                                          PolicyFlags... )>( it.get( ) );
          }
        } else {
          return serialization_policy<
            daw::remove_cvref_t<WritableType>,
            options::output_flags_t<PolicyFlags...>::value>( it );
        }
      }
    } // namespace json_details
 
    template<
      typename JsonClass, typename Value, typename WritableType,
      auto... PolicyFlags DAW_ENABLEIF2( concepts::is_writable_output_type_v<
                                         daw::remove_cvref_t<WritableType>> )>
    DAW_REQUIRES(
      concepts::is_writable_output_type_v<daw::remove_cvref_t<WritableType>> )
    constexpr daw::rvalue_to_value_t<WritableType> to_json(
      Value const &value, WritableType &&it,
      options::output_flags_t<PolicyFlags...> ) {
 
      using json_class_t = typename daw::conditional_t<
        std::is_same_v<use_default, JsonClass>,
        json_details::ident_trait<json_details::json_deduced_type, Value>,
        json_details::ident_trait<json_details::json_deduced_type,
                                  JsonClass>>::type;
 
      using output_t = daw::rvalue_to_value_t<WritableType>;
      if constexpr( std::is_pointer_v<daw::remove_cvref_t<WritableType>> ) {
        daw_json_ensure( it != nullptr, ErrorReason::NullOutputIterator );
      }
      auto out_it =
        json_details::apply_policy_flags<output_t, PolicyFlags...>( it );
 
      return json_details::member_to_string<json_class_t>( out_it, value )
        .get( );
    }
 
    template<typename JsonClass, typename Value, auto... PolicyFlags>
    DAW_CPP20_CX_ALLOC std::string
    to_json( Value const &value,
             options::output_flags_t<PolicyFlags...> flgs ) {
      std::string result{ };
      result.reserve( 4096 );
      (void)to_json( value, result, flgs );
      result.shrink_to_fit( );
      return result;
    }
 
    template<
      typename JsonElement, typename Container, typename WritableType,
      auto... PolicyFlags DAW_ENABLEIF2( concepts::is_writable_output_type_v<
                                         daw::remove_cvref_t<WritableType>> )>
    DAW_REQUIRES(
      concepts::is_writable_output_type_v<daw::remove_cvref_t<WritableType>> )
    constexpr daw::rvalue_to_value_t<WritableType> to_json_array(
      Container const &c, WritableType &&it,
      options::output_flags_t<PolicyFlags...> ) {
      static_assert(
        daw::traits::is_container_like_v<daw::remove_cvref_t<Container>>,
        "Supplied container must support begin( )/end( )" );
      using output_t = daw::rvalue_to_value_t<WritableType>;
 
      if constexpr( std::is_pointer_v<daw::remove_cvref_t<output_t>> ) {
        daw_json_ensure( it != nullptr, ErrorReason::InvalidNull );
      }
      auto out_it = [&] {
        if constexpr( is_serialization_policy_v<
                        daw::remove_cvref_t<WritableType>> ) {
          if constexpr( sizeof...( PolicyFlags ) == 0 ) {
            return it;
          } else {
            return serialization_policy<typename output_t::iterator_type,
                                        json_details::serialization::set_bits(
                                          output_t::policy_flags( ),
                                          PolicyFlags... )>( it.get( ) );
          }
        } else {
          return serialization_policy<
            daw::remove_cvref_t<WritableType>,
            options::output_flags_t<PolicyFlags...>::value>( it );
        }
      }( );
      out_it.put( '[' );
      out_it.add_indent( );
      // Not const & as some types(vector<bool>::const_reference are not ref
      // types
      auto first = std::begin( c );
      auto last = std::end( c );
      bool const has_elements = first != last;
      while( first != last ) {
        (void)[&out_it]( auto &&v ) {
          using v_type = DAW_TYPEOF( v );
          using JsonMember = typename daw::conditional_t<
            std::is_same_v<JsonElement, use_default>,
            json_details::ident_trait<json_details::json_deduced_type, v_type>,
            json_details::ident_trait<json_details::json_deduced_type,
                                      JsonElement>>::type;
 
          static_assert(
            not std::is_same_v<
              JsonMember,
              missing_json_data_contract_for_or_unknown_type<JsonElement>>,
            "Unable to detect unnamed mapping" );
          // static_assert( not std::is_same_v<JsonElement, JsonMember> );
          out_it.next_member( );
 
          out_it = json_details::member_to_string<JsonMember>( out_it, v );
        }
        ( *first );
        ++first;
        if( first != last ) {
          out_it.put( ',' );
        }
      }
      // The last character will be a ',' prior to this
      out_it.del_indent( );
      if( has_elements ) {
        out_it.output_newline( );
      }
      out_it.put( ']' );
      return out_it.get( );
    }
 
    template<typename JsonElement, typename Container, auto... PolicyFlags>
    DAW_CPP20_CX_ALLOC std::string
    to_json_array( Container const &c,
                   options::output_flags_t<PolicyFlags...> flgs ) {
      static_assert( not std::is_same_v<std::string, JsonElement> );
      auto result = std::string{ };
      result.reserve( 4096 );
      (void)to_json_array( c, result, flgs );
      result.shrink_to_fit( );
      return result;
    }
  } // namespace DAW_JSON_VER
} // namespace daw::json