daw_json_switches.h

Go to the documentation of this file.

// 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
//
 
// This file will have all the preprocessor based switches that users can
// switch. Many are controllable from cmake via commandline options too.
 
#pragma once
 
#include <daw/daw_consteval.h>
#include <daw/daw_cpp_feature_check.h>
#include <daw/daw_is_detected.h>
#include <daw/stdinc/enable_if.h>
 
#if defined( DAW_HAS_GCC ) and not defined( DAW_JSON_FLATTEN )
#if not defined( DAW_NO_FLATTEN )
#define DAW_NO_FLATTEN
#endif
#endif
 
// Does json_link throw itself.  Other things like constructors for the user
// types may.
#if defined( DAW_USE_EXCEPTIONS )
#if defined( DAW_JSON_DONT_USE_EXCEPTIONS )
#error Conflicting defines DAW_USE_EXCEPTIONS and DAW_JSON_DONT_USE_EXCEPTIONS
#endif
#if defined( DAW_DONT_USE_EXCEPTIONS )
#error Conflicting defines DAW_USE_EXCEPTIONS and DAW_DONT_USE_EXCEPTIONS
#endif
#else
#if not defined( DAW_JSON_DONT_USE_EXCEPTIONS )
#define DAW_JSON_DONT_USE_EXCEPTIONS
#endif
#if not defined( DAW_DONT_USE_EXCEPTIONS )
#define DAW_JSON_DONT_USE_EXCEPTIONS
#endif
#endif
 
// Disable using guaranteed RVO to clean up after return value construction.
// Use DAW_NO_CONSTEXPR_SCOPE_GUARD to disable constexpr scope guard.
// DAW_HAS_CONSTEXPR_SCOPE_GUARD is defined when it is enabled and in
// <daw/daw_scope_guard.h>
// This has performance impacts on MSVC as on_exit_success calls
// std::uncaught_exceptions( ) which is very slow there
#if not defined( DAW_NO_CONSTEXPR_SCOPE_GUARD ) and \
  not defined( DAW_JSON_ENABLE_FULL_RVO )
#define DAW_NO_CONSTEXPR_SCOPE_GUARD
#endif
 
// DAW_IS_CONSTANT_EVALUATED is defined when a builtin or
// std::is_constant_evaluated( ) is available in
// <daw/daw_is_constant_evaluated.h>
 
// Show extra diagnostic information like unmapped members when parsing
// by defining DAW_JSON_PARSER_DIAGNOSTICS
 
// DAW_CAN_CONSTANT_EVAL is used to test if we are in a constant expression
#if defined( DAW_HAS_GCC_LIKE )
#define DAW_CAN_CONSTANT_EVAL( ... ) \
  ( __builtin_constant_p( __VA_ARGS__ ) == 1 )
#else
#define DAW_CAN_CONSTANT_EVAL( ... ) true
#endif
 
// If the compiler supports CNTTP types allow for strings in json data
// contracts.  Both support passing local char const[], but the type is
// different.  To keep old behaviour when using C++20, define
// DAW_USE_CPP17_ABI
#if not defined( DAW_USE_CPP17_ABI )
#if defined( __cpp_nontype_template_parameter_class )
#if not defined( DAW_JSON_CNTTP_JSON_NAME )
#define DAW_JSON_CNTTP_JSON_NAME
#endif
#endif
#if defined( __cpp_nontype_template_args )
#if __cpp_nontype_template_args >= 201911L
#if not defined( DAW_JSON_CNTTP_JSON_NAME )
#define DAW_JSON_CNTTP_JSON_NAME
#endif
#endif
#endif
#if DAW_HAS_CLANG_VER_GTE( 12, 0 ) and DAW_CPP_VERSION >= 202002L
// Clang 12 supports enough of CNTTP string literals and compiles the tests
// successfully, but does not define the feature macro
#if not defined( DAW_JSON_CNTTP_JSON_NAME )
#define DAW_JSON_CNTTP_JSON_NAME
#endif
#endif
#endif
 
#if defined( __cpp_constexpr_dynamic_alloc )
#define CPP20CONSTEXPR constexpr
#else
// TODO: rename in v4
#define CPP20CONSTEXPR
#endif
 
// Fix bug in MSVC
#if defined( DAW_HAS_MSVC )
#define DAW_JSON_MAKE_LOC_INFO_CONSTEVAL constexpr
#else
#define DAW_JSON_MAKE_LOC_INFO_CONSTEVAL DAW_CONSTEVAL
#endif
 
// Allow experimental SIMD paths, if available
// by defining DAW_ALLOW_SSE42 and using the parser policy ExecModeType simd
 
// Use strtod instead of from_chars when avialable by defining
// DAW_JSON_USE_STRTOD
#if not defined( DAW_JSON_USE_STRTOD ) and not defined( __cpp_lib_to_chars )
#define DAW_JSON_USE_STRTOD
#endif
 
// define DAW_JSON_DISABLE_RANDOM to disable creating random iterators when the
// size is known up front.  This is playing to the implementations prior to
// C++23 when range constructors are added to containers.  It is disabled on
// MSVC as that impl does not work with it
#if defined( DAW_HAS_MSVC )
#if not defined( DAW_JSON_DISABLE_RANDOM )
#define DAW_JSON_DISABLE_RANDOM
#endif
#endif
 
// DAW_JSON_HAS_BUILTIN_UADD is used to switch to a constexpr method of overflow
// addition when available
#if DAW_HAS_GCC_VER_GTE( 8, 0 ) or defined( DAW_HAS_CLANG ) or \
  ( DAW_HAS_BUILTIN( __builtin_uadd_overflow ) and             \
    DAW_HAS_BUILTIN( __builtin_uaddl_overflow ) and            \
    DAW_HAS_BUILTIN( __builtin_uaddll_overflow ) )
#define DAW_JSON_HAS_BUILTIN_UADD
#endif
 
// DAW_JSON_BUGFIX_FROM_JSON_001
// Defined for MSVC as it has been ICE'ing on daw_json_ensure in from_json
#if defined( DAW_HAS_MSVC )
#define DAW_JSON_BUGFIX_FROM_JSON_001
#endif
 
// DAW_JSON_BUGFIX_MSVC_EVAL_ORDER_002
// MSVC cannot always evaluate in the correct order as defined by the standard.
// JSON Link uses the left->right guarantees in places like constructors so that
// less state is needed.  In MSVC one must keep more state in places like
// parse_tuple_value
#if defined( DAW_HAS_MSVC )
#define DAW_JSON_BUGFIX_MSVC_EVAL_ORDER_002
#endif
 
// DAW_JSON_BUGFIX_MSVC_KNOWN_LOC_ICE_003
// MSVC in C++20 mode will ICE when known locations is evaluated at compile time
#if defined( DAW_HAS_MSVC ) and __cpp_constexpr > 201700L
#define DAW_JSON_BUGFIX_MSVC_KNOWN_LOC_ICE_003
#endif
 
#if not defined( NDEBUG ) or defined( DEBUG ) or \
  defined( DAW_JSON_PARSER_DIAGNOSTICS ) or defined( DAW_HAS_MSVC )
#if not defined( DAW_JSON_ALWAYS_FULL_NAME_MATCH )
#define DAW_JSON_ALWAYS_FULL_NAME_MATCH
#endif
#endif
 
// Allows pack expansions with get<Is> without separate methods.  This should
// improve symbol sizes
#if defined( __cpp_generic_lambdas )
#if __cpp_generic_lambdas >= 201707L
#define DAW_JSON_USE_GENERIC_LAMBDAS
#endif
#endif
 
// Use static operator( ) when supported
#if defined( __cpp_static_call_operator )
#if __cpp_static_call_operator >= 202207L
#define DAW_JSON_HAS_STATIC_CALL_OP
#endif
#endif
#if defined( DAW_JSON_HAS_STATIC_CALL_OP )
#define DAW_JSON_CPP23_STATIC_CALL_OP static
#define DAW_JSON_CPP23_STATIC_CALL_OP_CONST
 
#if DAW_HAS_CLANG_VER_GTE( 17, 0 )
#define DAW_JSON_CPP23_STATIC_CALL_OP_DISABLE_WARNING \
  _Pragma( "clang diagnostic push" )                  \
    _Pragma( "clang diagnostic ignored \"-Wc++23-extensions\"" )
 
#define DAW_JSON_CPP23_STATIC_CALL_OP_ENABLE_WARNING \
  _Pragma( "clang diagnostic pop" )
#else
#define DAW_JSON_CPP23_STATIC_CALL_OP_DISABLE_WARNING
#define DAW_JSON_CPP23_STATIC_CALL_OP_ENABLE_WARNING
#endif
#else
#define DAW_JSON_CPP23_STATIC_CALL_OP
#define DAW_JSON_CPP23_STATIC_CALL_OP_CONST const
#define DAW_JSON_CPP23_STATIC_CALL_OP_DISABLE_WARNING
#define DAW_JSON_CPP23_STATIC_CALL_OP_ENABLE_WARNING
#endif
 
#if defined( __cpp_constexpr_dynamic_alloc )
#if __cpp_constexpr_dynamic_alloc >= 201907L
#define DAW_JSON_HAS_CPP20_CX_ALLOC
#endif
#endif
 
#if defined( DAW_JSON_HAS_CPP20_CX_ALLOC )
#define DAW_JSON_HAS_CPP20_CX_DTOR
#define DAW_JSON_CPP20_CX_DTOR constexpr
#else
#define DAW_JSON_CPP20_CX_DTOR
#endif
 
#if defined( DAW_JSON_HAS_CPP20_CX_ALLOC ) and \
  defined( __cpp_lib_constexpr_vector )
#if __cpp_lib_constexpr_vector >= 201907L
#define DAW_JSON_HAS_CPP20_CX_VECTOR
#endif
#endif
 
#if defined( DAW_JSON_HAS_CPP20_CX_VECTOR )
#define DAW_JSON_CX_VECTOR constexpr
#else
#define DAW_JSON_CX_VECTOR
#endif
 
#if defined( DAW_JSON_HAS_CPP20_CX_ALLOC ) and \
  defined( __cpp_lib_constexpr_string )
#if __cpp_lib_constexpr_string >= 201907L
#define DAW_JSON_HAS_CPP20_CX_STRING
#endif
#endif
 
#if defined( DAW_JSON_HAS_CPP20_CX_STRING )
#define DAW_JSON_CX_STRING constexpr
#else
#define DAW_JSON_CX_STRING
#endif
 
#if defined( DAW_JSON_HAS_CPP20_CX_STRING ) and \
  defined( DAW_JSON_HAS_CPP20_CX_VECTOR )
#define DAW_JSON_HAS_CPP20_CX_STRVEC
#define DAW_JSON_CX_STRVEC constexpr
#else
#define DAW_JSON_CX_STRVEC
#endif
 
// Many of the iterators used offer some extra checking when this is set.  By
// default in debug mode they are enabled. Prior to C++20 affects the triviality
// of their destructors and can prevent their use in constexpr code.  Setting
// DAW_JSON_NO_FULL_DEBUG_ITERATORS disables the destructor checks when compiler
// support for constexpr destructors is unavailable
#if defined( DAW_JSON_HAS_CPP20_CX_DTOR )
#if not defined( NDEBUG ) and not defined( DAW_JSON_USE_FULL_DEBUG_ITERATORS )
#define DAW_JSON_USE_FULL_DEBUG_ITERATORS
#endif
#endif
 
#if defined( __cpp_lib_containers_ranges )
#if __cpp_lib_containers_ranges > 202202L
#define DAW_JSON_HAS_CPP23_RANGE_CTOR
#endif
#endif
 
#if defined( DAW_HAS_CONCEPTS ) and not defined( DAW_JSON_NO_REQUIRES )
#define DAW_JSON_USE_REQUIRES
#define DAW_JSON_ENABLEIF( ... )
#define DAW_JSON_ENABLEIF2( ... )
#define DAW_JSON_ENABLEIF_S( ... )
#define DAW_JSON_REQUIRES( ... ) requires( __VA_ARGS__ )
#else
#define DAW_JSON_ENABLEIF( ... ) \
  , std::enable_if_t<( __VA_ARGS__ ), std::nullptr_t> = nullptr
#define DAW_JSON_ENABLEIF2( ... ) \
  , std::enable_if_t<( __VA_ARGS__ ), std::nullptr_t>
#define DAW_JSON_ENABLEIF_S( ... ) , std::enable_if_t<( __VA_ARGS__ )>
#define DAW_JSON_REQUIRES( ... )
#endif