# - Try to find precompiled headers support for GCC 3.4 and 4.x
# Once done this will define:
#
# Variable:
#   PCHSupport_FOUND
#   PCH_TARGETS_{target} (set by ADD_PRECOMPILED_HEADER): All the PCH targets generated for a main target
#
# Macro:
#   ADD_PRECOMPILED_HEADER  _targetName _input  _dowarn (preferably call this always)
#   ADD_PRECOMPILED_HEADER_TO_TARGET _targetName _input _pch_output_to_use _dowarn
#   ADD_NATIVE_PRECOMPILED_HEADER _targetName _input _dowarn
#   GET_NATIVE_PRECOMPILED_HEADER _targetName _input

IF(CMAKE_COMPILER_IS_GNUCXX)

    EXEC_PROGRAM(${CMAKE_CXX_COMPILER}
                 ARGS ${CMAKE_CXX_COMPILER_ARG1} -dumpversion
                 OUTPUT_VARIABLE gcc_compiler_version)

    # MESSAGE("GCC Version: ${gcc_compiler_version}")
    IF(gcc_compiler_version MATCHES "4\\.[0-9]\\.[0-9]")
      SET(PCHSupport_FOUND TRUE)
    ELSE(gcc_compiler_version MATCHES "4\\.[0-9]\\.[0-9]")
      IF(gcc_compiler_version MATCHES "3\\.4\\.[0-9]")
        SET(PCHSupport_FOUND TRUE)
      ENDIF(gcc_compiler_version MATCHES "3\\.4\\.[0-9]")
    ENDIF(gcc_compiler_version MATCHES "4\\.[0-9]\\.[0-9]")

  SET(_PCH_include_prefix "-I")

ELSE(CMAKE_COMPILER_IS_GNUCXX)

  IF(WIN32)
    SET(PCHSupport_FOUND TRUE) # for experimental msvc support
    SET(_PCH_include_prefix "/I")
  ELSE(WIN32)
    SET(PCHSupport_FOUND FALSE)
  ENDIF(WIN32)

ENDIF(CMAKE_COMPILER_IS_GNUCXX)


MACRO(_PCH_GET_COMPILE_FLAGS _out_compile_flags)

  STRING(TOUPPER "CMAKE_CXX_FLAGS_${CMAKE_BUILD_TYPE}" _flags_var_name)
  SET(${_out_compile_flags} ${${_flags_var_name}})

  IF(CMAKE_COMPILER_IS_GNUCXX)

    GET_TARGET_PROPERTY(_targetType ${_PCH_current_target} TYPE)
    IF(${_targetType} STREQUAL SHARED_LIBRARY)
      LIST(APPEND ${_out_compile_flags} "${${_out_compile_flags}} -fPIC")
    ENDIF(${_targetType} STREQUAL SHARED_LIBRARY)

  ELSE(CMAKE_COMPILER_IS_GNUCXX)
    ## TODO ... ? or does it work out of the box
  ENDIF(CMAKE_COMPILER_IS_GNUCXX)

  GET_DIRECTORY_PROPERTY(DIRINC INCLUDE_DIRECTORIES)
  FOREACH(item ${DIRINC})
    LIST(APPEND ${_out_compile_flags} "${_PCH_include_prefix}${item}")
  ENDFOREACH(item)

  GET_DIRECTORY_PROPERTY(_directory_flags DEFINITIONS)
  # MESSAGE("_directory_flags ${_directory_flags}")
  LIST(APPEND ${_out_compile_flags} ${_directory_flags})
  LIST(APPEND ${_out_compile_flags} ${CMAKE_CXX_FLAGS})

  SEPARATE_ARGUMENTS(${_out_compile_flags})

ENDMACRO(_PCH_GET_COMPILE_FLAGS)


MACRO(_PCH_WRITE_PCHDEP_CXX _targetName _include_file _dephelp)

  SET(${_dephelp} "${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/${_targetName}_pch_dephelp.cxx")
  FILE(WRITE  ${${_dephelp}}
    "#include \"${_include_file}\"
    int testfunction()
    {
        return 0;
    }
    "
  )

ENDMACRO(_PCH_WRITE_PCHDEP_CXX)


MACRO(_PCH_GET_COMPILE_COMMAND out_command _input _output)

  FILE(TO_NATIVE_PATH ${_input} _native_input)
  FILE(TO_NATIVE_PATH ${_output} _native_output)


  IF(CMAKE_COMPILER_IS_GNUCXX)

    IF(CMAKE_CXX_COMPILER_ARG1)
      # remove leading space in compiler argument
      STRING(REGEX REPLACE "^ +" "" pchsupport_compiler_cxx_arg1 ${CMAKE_CXX_COMPILER_ARG1})

      SET(${out_command}
          ${CMAKE_CXX_COMPILER} ${pchsupport_compiler_cxx_arg1} ${_compile_FLAGS}  -x c++-header -o ${_output} ${_input}
      )
    ELSE(CMAKE_CXX_COMPILER_ARG1)
      SET(${out_command}
          ${CMAKE_CXX_COMPILER}  ${_compile_FLAGS}  -x c++-header -o ${_output} ${_input}
      )
    ENDIF(CMAKE_CXX_COMPILER_ARG1)

  ELSE(CMAKE_COMPILER_IS_GNUCXX)

    SET(_dummy_str "#include <${_input}>")
    FILE(WRITE "${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/pch_dummy.cpp" ${_dummy_str})

    SET(${out_command}
        ${CMAKE_CXX_COMPILER} ${_compile_FLAGS} /c /Fp${_native_output} /Yc${_native_input} pch_dummy.cpp
    )
    #/out:${_output}

  ENDIF(CMAKE_COMPILER_IS_GNUCXX)

ENDMACRO(_PCH_GET_COMPILE_COMMAND)


MACRO(_PCH_GET_TARGET_COMPILE_FLAGS _cflags  _header_name _pch_path _dowarn)

  FILE(TO_NATIVE_PATH ${_pch_path} _native_pch_path)

  IF(CMAKE_COMPILER_IS_GNUCXX)
    # for use with distcc and gcc >4.0.1 if preprocessed files are accessible
    # on all remote machines set
    # PCH_ADDITIONAL_COMPILER_FLAGS to -fpch-preprocess
    # if you want warnings for invalid header files (which is very inconvenient
    # if you have different versions of the headers for different build types
    # you may set _pch_dowarn
    IF (_dowarn)
      SET(${_cflags}
          "${PCH_ADDITIONAL_COMPILER_FLAGS} -include ${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/${_header_name} -Winvalid-pch ")
    ELSE (_dowarn)
      SET(${_cflags} "${PCH_ADDITIONAL_COMPILER_FLAGS} -include ${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/${_header_name} ")
    ENDIF (_dowarn)
  ELSE(CMAKE_COMPILER_IS_GNUCXX)

    set(${_cflags} "/Fp${_native_pch_path} /Yu${_header_name}")

  ENDIF(CMAKE_COMPILER_IS_GNUCXX)

ENDMACRO(_PCH_GET_TARGET_COMPILE_FLAGS)

MACRO(GET_PRECOMPILED_HEADER_OUTPUT _targetName _input _output)
  GET_FILENAME_COMPONENT(_name ${_input} NAME)
  GET_FILENAME_COMPONENT(_path ${_input} PATH)
  SET(_output "${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/${_name}.gch/${_targetName}_${CMAKE_BUILD_TYPE}.h++")
ENDMACRO(GET_PRECOMPILED_HEADER_OUTPUT _targetName _input)


MACRO(ADD_PRECOMPILED_HEADER_TO_TARGET _targetName _input _pch_output_to_use)

  # to do: test whether compiler flags match between target  _targetName
  # and _pch_output_to_use
  GET_FILENAME_COMPONENT(_name ${_input} NAME)

  IF("${ARGN}" STREQUAL "0")
    SET(_dowarn 0)
  ELSE("${ARGN}" STREQUAL "0")
    SET(_dowarn 1)
  ENDIF("${ARGN}" STREQUAL "0")

  _PCH_GET_TARGET_COMPILE_FLAGS(_target_cflags ${_name} ${_pch_output_to_use} ${_dowarn})
  #   MESSAGE("Add flags ${_target_cflags} to ${_targetName} ")
  SET_TARGET_PROPERTIES(${_targetName}
                        PROPERTIES
                        COMPILE_FLAGS ${_target_cflags}
  )

  ADD_CUSTOM_TARGET(pch_Generate_${_targetName}
                    DEPENDS ${_pch_output_to_use}
  )

  ADD_DEPENDENCIES(${_targetName} pch_Generate_${_targetName})
  LIST(APPEND PCH_TARGETS_${_targetName} pch_Generate_${_targetName})

ENDMACRO(ADD_PRECOMPILED_HEADER_TO_TARGET)


MACRO(ADD_PRECOMPILED_HEADER _targetName _input)

  SET(_PCH_current_target ${_targetName})
  SET(PCH_TARGETS_${_targetName} "")

  IF(NOT CMAKE_BUILD_TYPE)
    MESSAGE(FATAL_ERROR "This is the ADD_PRECOMPILED_HEADER macro. You must set CMAKE_BUILD_TYPE!" )
  ENDIF(NOT CMAKE_BUILD_TYPE)

  IF("${ARGN}" STREQUAL "0")
    SET(_dowarn 0)
  ELSE("${ARGN}" STREQUAL "0")
    SET(_dowarn 1)
  ENDIF("${ARGN}" STREQUAL "0")

  GET_FILENAME_COMPONENT(_name ${_input} NAME)
  GET_FILENAME_COMPONENT(_path ${_input} PATH)
  GET_PRECOMPILED_HEADER_OUTPUT(${_targetName} ${_input} _output)

  GET_FILENAME_COMPONENT(_outdir ${_output} PATH)

  GET_TARGET_PROPERTY(_targetType ${_PCH_current_target} TYPE)
  _PCH_WRITE_PCHDEP_CXX(${_targetName} ${_input} _pch_dephelp_cxx)

  IF(${_targetType} STREQUAL SHARED_LIBRARY)
    ADD_LIBRARY(${_targetName}_pch_dephelp SHARED ${_pch_dephelp_cxx})
  ELSE(${_targetType} STREQUAL SHARED_LIBRARY)
    ADD_LIBRARY(${_targetName}_pch_dephelp STATIC ${_pch_dephelp_cxx})
  ENDIF(${_targetType} STREQUAL SHARED_LIBRARY)

  LIST(APPEND PCH_TARGETS_${_targetName} ${_targetName}_pch_dephelp)

  FILE(MAKE_DIRECTORY ${_outdir})

  _PCH_GET_COMPILE_FLAGS(_compile_FLAGS)

  #MESSAGE("_compile_FLAGS: ${_compile_FLAGS}")
  #message("COMMAND ${CMAKE_CXX_COMPILER}  ${_compile_FLAGS} -x c++-header -o ${_output} ${_input}")
  SET_SOURCE_FILES_PROPERTIES("${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/${_name}" PROPERTIES GENERATED 1)
  ADD_CUSTOM_COMMAND(
    OUTPUT  "${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/${_name}"
    COMMAND ${CMAKE_COMMAND} -E copy  ${_input} "${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/${_name}"
                                                                                      # ensure same directory! Required by gcc
    DEPENDS ${_input}
  )

  #message("_command  ${_input} ${_output}")
  _PCH_GET_COMPILE_COMMAND(_command  "${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/${_name}" ${_output})

  #message(${_input})
  #message("_output ${_output}")

  ADD_CUSTOM_COMMAND(
    OUTPUT ${_output}
    COMMAND ${_command}
    DEPENDS ${_input} "${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/${_name}" ${_targetName}_pch_dephelp
  )

  ADD_PRECOMPILED_HEADER_TO_TARGET(${_targetName} ${_input}  ${_output})

ENDMACRO(ADD_PRECOMPILED_HEADER)


# Generates the use of precompiled in a target,
# without using depency targets (2 extra for each target)
# Using Visual Studio, must also add ${_targetName}_pch to sources
# Not needed by Xcode
MACRO(GET_NATIVE_PRECOMPILED_HEADER _targetName _input)

  IF(CMAKE_GENERATOR MATCHES Visual*)

    SET(_dummy_str "#include \"${_input}\"\n"
                    "// This is required to suppress LNK4221.  Very annoying.\n"
                    "void *g_${_targetName}Dummy = 0\;\n")

    # Use of cxx extension for generated files (as Qt does)
    SET(${_targetName}_pch "${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/${_targetName}_pch.cxx")
    IF(EXISTS ${${_targetName}_pch})
      # Check if contents is the same, if not rewrite
      # todo
    ELSE(EXISTS ${${_targetName}_pch})
      FILE(WRITE ${${_targetName}_pch} ${_dummy_str})
    ENDIF(EXISTS ${${_targetName}_pch})
  ENDIF(CMAKE_GENERATOR MATCHES Visual*)

ENDMACRO(GET_NATIVE_PRECOMPILED_HEADER)


MACRO(ADD_NATIVE_PRECOMPILED_HEADER _targetName _input)

  IF("${ARGN}" STREQUAL "0")
    SET(_dowarn 0)
  ELSE("${ARGN}" STREQUAL "0")
    SET(_dowarn 1)
  ENDIF("${ARGN}" STREQUAL "0")

  IF(CMAKE_GENERATOR MATCHES Visual*)
    # Auto include the precompile (useful for moc processing, since the use of
    # precompiled is specified at the target level
    # and I don't want to specifiy /F- for each moc/res/ui generated files (using Qt)

    GET_TARGET_PROPERTY(oldProps ${_targetName} COMPILE_FLAGS)
    IF(${oldProps} MATCHES NOTFOUND)
      SET(oldProps "")
    ENDIF(${oldProps} MATCHES NOTFOUND)

    SET(newProperties "${oldProps} /Yu\"${_input}\" /FI\"${_input}\"")
    SET_TARGET_PROPERTIES(${_targetName} PROPERTIES COMPILE_FLAGS "${newProperties}")

    #also inlude ${oldProps} to have the same compile options
    SET_SOURCE_FILES_PROPERTIES(${${_targetName}_pch} PROPERTIES COMPILE_FLAGS "${oldProps} /Yc\"${_input}\"")

  ELSE(CMAKE_GENERATOR MATCHES Visual*)

    IF(CMAKE_GENERATOR MATCHES Xcode)
      # For Xcode, cmake needs my patch to process
      # GCC_PREFIX_HEADER and GCC_PRECOMPILE_PREFIX_HEADER as target properties

      GET_TARGET_PROPERTY(oldProps ${_targetName} COMPILE_FLAGS)
      IF(${oldProps} MATCHES NOTFOUND)
        SET(oldProps "")
      ENDIF(${oldProps} MATCHES NOTFOUND)

      # When buiding out of the tree, precompiled may not be located
      # Use full path instead.
      GET_FILENAME_COMPONENT(fullPath ${_input} ABSOLUTE)

      SET_TARGET_PROPERTIES(${_targetName} PROPERTIES XCODE_ATTRIBUTE_GCC_PREFIX_HEADER "${fullPath}")
      SET_TARGET_PROPERTIES(${_targetName} PROPERTIES XCODE_ATTRIBUTE_GCC_PRECOMPILE_PREFIX_HEADER "YES")

    ELSE(CMAKE_GENERATOR MATCHES Xcode)

      #Fallback to the "old" precompiled suppport
      #ADD_PRECOMPILED_HEADER(${_targetName} ${_input} ${_dowarn})

    ENDIF(CMAKE_GENERATOR MATCHES Xcode)
  ENDIF(CMAKE_GENERATOR MATCHES Visual*)

ENDMACRO(ADD_NATIVE_PRECOMPILED_HEADER)
