set(EXPAT_SHARED_LIBS ${BUILD_SHARED_LIBS})

#
# Configuration
#
set(EXPAT_CONTEXT_BYTES 1024 CACHE STRING "Define to specify how much context to retain around the current parse point")
mark_as_advanced(EXPAT_CONTEXT_BYTES)
option(EXPAT_DTD "Define to make parameter entity parsing functionality available" ON)
mark_as_advanced(EXPAT_DTD)
option(EXPAT_NS "Define to make XML Namespaces functionality available" ON)
mark_as_advanced(EXPAT_NS)
option(EXPAT_WARNINGS_AS_ERRORS "Treat all compiler warnings as errors" OFF)
if(UNIX OR _EXPAT_HELP)
    option(EXPAT_DEV_URANDOM "Define to include code reading entropy from `/dev/urandom'." ON)
    set(EXPAT_WITH_GETRANDOM "AUTO" CACHE STRING
            "Make use of getrandom function (ON|OFF|AUTO) [default=AUTO]")
    set(EXPAT_WITH_SYS_GETRANDOM "AUTO" CACHE STRING
            "Make use of syscall SYS_getrandom (ON|OFF|AUTO) [default=AUTO]")
    mark_as_advanced(EXPAT_DEV_URANDOM)
endif()
set(EXPAT_CHAR_TYPE "char" CACHE STRING "Character type to use (char|ushort|wchar_t) [default=char]")
option(EXPAT_ATTR_INFO "Define to allow retrieving the byte offsets for attribute names and values" OFF)
mark_as_advanced(EXPAT_ATTR_INFO)
option(EXPAT_LARGE_SIZE "Make XML_GetCurrent* functions return <(unsigned) long long> rather than <(unsigned) long>" OFF)
mark_as_advanced(EXPAT_LARGE_SIZE)
option(EXPAT_MIN_SIZE "Get a smaller (but slower) parser (in particular avoid multiple copies of the tokenizer)" OFF)
mark_as_advanced(EXPAT_MIN_SIZE)
if(MSVC OR _EXPAT_HELP)
    set(EXPAT_MSVC_STATIC_CRT OFF CACHE BOOL "Use /MT flag (static CRT) when compiling in MSVC")
endif()

if(MSVC)
    # For the three types of MSVC version values, please see:
    # - https://cmake.org/cmake/help/latest/variable/MSVC_VERSION.html
    # - https://sourceforge.net/p/predef/wiki/Compilers/
    # - https://en.wikipedia.org/wiki/Microsoft_Visual_Studio#History
    set(_EXPAT_MSVC_REQUIRED_INT 1800)  # i.e. 12.0/2013/1800; see PR #426
    set(_EXPAT_MSVC_SUPPORTED_INT 1910)
    set(_EXPAT_MSVC_SUPPORTED_DISPLAY "Visual Studio 15.0/2017/${_EXPAT_MSVC_SUPPORTED_INT}")

    if(MSVC_VERSION VERSION_LESS ${_EXPAT_MSVC_SUPPORTED_INT})
        if(MSVC_VERSION VERSION_LESS ${_EXPAT_MSVC_REQUIRED_INT})
            message(SEND_ERROR "MSVC_VERSION ${MSVC_VERSION} is TOO OLD to compile Expat without errors.")
            message(SEND_ERROR "Please use officially supported ${_EXPAT_MSVC_SUPPORTED_DISPLAY} or later.  Thank you!")
        else()
            message(WARNING "MSVC_VERSION ${MSVC_VERSION} is NOT OFFICIALLY SUPPORTED by Expat.")
            message(WARNING "Please use ${_EXPAT_MSVC_SUPPORTED_DISPLAY} or later.  Thank you!")
        endif()
    endif()
endif()

macro(_expat_copy_bool_int source_ref dest_ref)
    if(${source_ref})
        set(${dest_ref} 1)
    else()
        set(${dest_ref} 0)
    endif()
endmacro()

if(EXPAT_LARGE_SIZE)
    add_definitions(-DXML_LARGE_SIZE)
endif()

if(EXPAT_MIN_SIZE)
    add_definitions(-DXML_MIN_SIZE)
endif()

if(EXPAT_CHAR_TYPE STREQUAL "char")
    set(_EXPAT_UNICODE OFF)
    set(_EXPAT_UNICODE_WCHAR_T OFF)
elseif(EXPAT_CHAR_TYPE STREQUAL "ushort")
    set(_EXPAT_UNICODE ON)
    set(_EXPAT_UNICODE_WCHAR_T OFF)
elseif(EXPAT_CHAR_TYPE STREQUAL "wchar_t")
    set(_EXPAT_UNICODE ON)
    set(_EXPAT_UNICODE_WCHAR_T ON)
    if(NOT WIN32)
        string(FIND "${CMAKE_C_FLAGS}" "-fshort-wchar" _expat_short_wchar_found)
        if(${_expat_short_wchar_found} EQUAL "-1")
            message(SEND_ERROR "Configuration -DEXPAT_CHAR_TYPE=wchar_t requires -DCMAKE_{C,CXX}_FLAGS=-fshort-wchar (which was not found) and libc compiled with -fshort-wchar, too.")
        endif()
    endif()
else()
    message(SEND_ERROR "Option -DEXPAT_CHAR_TYPE=(char|ushort|wchar_t) cannot be \"${EXPAT_CHAR_TYPE}\".")
endif()

if(_EXPAT_UNICODE)
    add_definitions(-DXML_UNICODE)              # for unsigned short
    if(_EXPAT_UNICODE_WCHAR_T)
        add_definitions(-DXML_UNICODE_WCHAR_T)  # for wchar_t
    endif()
endif()

include(${CMAKE_CURRENT_LIST_DIR}/ConfigureChecks.cmake)

macro(evaluate_detection_results use_ref have_ref thing_lower thing_title)
    if(${use_ref} AND NOT (${use_ref} STREQUAL "AUTO") AND NOT ${have_ref})
        message(SEND_ERROR
                "Use of ${thing_lower} was enforced by ${use_ref}=ON but it could not be found.")
    elseif(NOT ${use_ref} AND ${have_ref})
        message("${thing_title} was found but it will not be used due to ${use_ref}=OFF.")
        set(${have_ref} 0)
    endif()
endmacro()

if(NOT WIN32)
    evaluate_detection_results(EXPAT_WITH_GETRANDOM HAVE_GETRANDOM "function getrandom" "Function getrandom")
    evaluate_detection_results(EXPAT_WITH_SYS_GETRANDOM HAVE_SYSCALL_GETRANDOM "syscall SYS_getrandom" "Syscall SYS_getrandom")
endif()

_expat_copy_bool_int(EXPAT_ATTR_INFO        XML_ATTR_INFO)
_expat_copy_bool_int(EXPAT_DTD              XML_DTD)
_expat_copy_bool_int(EXPAT_LARGE_SIZE       XML_LARGE_SIZE)
_expat_copy_bool_int(EXPAT_MIN_SIZE         XML_MIN_SIZE)
_expat_copy_bool_int(EXPAT_NS               XML_NS)
if(NOT WIN32)
    _expat_copy_bool_int(EXPAT_DEV_URANDOM  XML_DEV_URANDOM)
endif()
set(XML_CONTEXT_BYTES ${EXPAT_CONTEXT_BYTES})


configure_file(expat_config.h.cmake "${CMAKE_CURRENT_BINARY_DIR}/expat_config.h")

set(EXTRA_COMPILE_FLAGS)
if(FLAG_NO_STRICT_ALIASING)
    set(EXTRA_COMPILE_FLAGS "${EXTRA_COMPILE_FLAGS} -fno-strict-aliasing")
endif()
if(FLAG_VISIBILITY)
  add_definitions(-DXML_ENABLE_VISIBILITY=1)
  set(EXTRA_COMPILE_FLAGS "${EXTRA_COMPILE_FLAGS} -fvisibility=hidden")
endif()
if(MINGW)
    # Without __USE_MINGW_ANSI_STDIO the compiler produces a false positive
    set(EXTRA_COMPILE_FLAGS "${EXTRA_COMPILE_FLAGS} -Wno-pedantic-ms-format")
endif()
if (EXPAT_WARNINGS_AS_ERRORS)
    if(MSVC)
        add_definitions(/WX)
    else()
        set(EXTRA_COMPILE_FLAGS "${EXTRA_COMPILE_FLAGS} -Werror")
    endif()
endif()
set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${EXTRA_COMPILE_FLAGS}")
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${EXTRA_COMPILE_FLAGS}")

if (MSVC)
    if (EXPAT_MSVC_STATIC_CRT)
        message("-- Using static CRT ${EXPAT_MSVC_STATIC_CRT}")
        foreach(flag_var
                CMAKE_CXX_FLAGS_DEBUG
                CMAKE_CXX_FLAGS_RELEASE
                CMAKE_CXX_FLAGS_MINSIZEREL
                CMAKE_CXX_FLAGS_RELWITHDEBINFO
                CMAKE_C_FLAGS_DEBUG
                CMAKE_C_FLAGS_RELEASE
                CMAKE_C_FLAGS_MINSIZEREL
                CMAKE_C_FLAGS_RELWITHDEBINFO
                )
            string(REPLACE "/MD" "/MT" ${flag_var} "${${flag_var}}")
        endforeach()
    endif()
endif()

include_directories(${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR}/lib)
if(MSVC)
    add_definitions(-D_CRT_SECURE_NO_WARNINGS -wd4996)
endif()
if(WIN32)
    if(_EXPAT_UNICODE_WCHAR_T)
        set(_POSTFIX_WIDE "w")
    endif()

    if(MSVC AND NOT EXPAT_SHARED_LIBS)
        if(EXPAT_MSVC_STATIC_CRT)
            set(_POSTFIX_CRT "MT")
        else()
            set(_POSTFIX_CRT "MD")
        endif()
    endif()

    foreach(postfix_var
            CMAKE_DEBUG_POSTFIX
            CMAKE_RELEASE_POSTFIX
            CMAKE_MINSIZEREL_POSTFIX
            CMAKE_RELWITHDEBINFO_POSTFIX
            )
        if(postfix_var STREQUAL "CMAKE_DEBUG_POSTFIX")
            set(_POSTFIX_DEBUG "d")
        else()
            set(_POSTFIX_DEBUG "")
        endif()

        set(${postfix_var} "${_POSTFIX_WIDE}${_POSTFIX_DEBUG}${_POSTFIX_CRT}" CACHE STRING "Windows binary postfix, e.g. libexpat<postfix=[w][d][MD|MT]>.lib")
    endforeach()
endif()

#
# C library
#
set(expat_SRCS
    lib/xmlparse.c
    lib/xmlrole.c
    lib/xmltok.c
# NOTE: ISO C forbids an empty translation unit
#   lib/xmltok_impl.c
#   lib/xmltok_ns.c
)

if(EXPAT_SHARED_LIBS)
    set(_SHARED SHARED)
    if(MSVC)
        set(expat_SRCS ${expat_SRCS} lib/libexpat.def)
    endif()
else()
    set(_SHARED STATIC)
endif()

# Avoid colliding with Expat.dll of Perl's XML::Parser::Expat
if(WIN32 AND NOT MINGW)
    set(_EXPAT_OUTPUT_NAME libexpat)  # CMAKE_*_POSTFIX applies, see above
else()
    if(_EXPAT_UNICODE)
        set(_EXPAT_OUTPUT_NAME expatw)
    else()
        set(_EXPAT_OUTPUT_NAME expat)
    endif()
endif()

add_library(expat ${_SHARED} ${expat_SRCS})
if(EXPAT_WITH_LIBBSD)
    target_link_libraries(expat ${LIB_BSD})
endif()

set(LIBCURRENT 9)   # sync
set(LIBREVISION 1)  # with
set(LIBAGE 8)       # configure.ac!
math(EXPR LIBCURRENT_MINUS_AGE "${LIBCURRENT} - ${LIBAGE}")

set_property(TARGET expat PROPERTY OUTPUT_NAME "${_EXPAT_OUTPUT_NAME}")
if(NOT WIN32)
    set_property(TARGET expat PROPERTY VERSION ${LIBCURRENT_MINUS_AGE}.${LIBAGE}.${LIBREVISION})
    set_property(TARGET expat PROPERTY SOVERSION ${LIBCURRENT_MINUS_AGE})
    set_property(TARGET expat PROPERTY NO_SONAME ${NO_SONAME})
endif()

target_include_directories(expat
    INTERFACE
        $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/lib>
        $<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}>
        $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>
)

if(NOT EXPAT_SHARED_LIBS AND WIN32)
    target_compile_definitions(expat PUBLIC -DXML_STATIC)
endif()

install(TARGETS expat EXPORT ${targets_export_name})
