build/cmake/util.cmake - aom - Git at Google

 #
 # Copyright (c) 2017, Alliance for Open Media. All rights reserved.
 #
 # This source code is subject to the terms of the BSD 2 Clause License and the
 # Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License was
 # not distributed with this source code in the LICENSE file, you can obtain it
 # at www.aomedia.org/license/software. If the Alliance for Open Media Patent
 # License 1.0 was not distributed with this source code in the PATENTS file, you
 # can obtain it at www.aomedia.org/license/patent.
 #
 if(AOM_BUILD_CMAKE_UTIL_CMAKE_)
   return()
 endif() # AOM_BUILD_CMAKE_UTIL_CMAKE_
 set(AOM_BUILD_CMAKE_UTIL_CMAKE_ 1)

 # Directory where generated sources will be written.
 set(AOM_GEN_SRC_DIR "${AOM_CONFIG_DIR}/gen_src")

 # Creates a no-op source file in $AOM_GEN_SRC_DIR named $basename.$extension and
 # returns the full path to the source file via appending it to the list variable
 # referred to by $out_file_list_var parameter.
 macro(create_no_op_source_file basename extension out_file_list_var)
   set(no_op_source_file "${AOM_GEN_SRC_DIR}/${basename}_no_op.${extension}")
   file(WRITE "${no_op_source_file}"
        "// Generated file. DO NOT EDIT!\n"
        "// ${target_name} needs a ${extension} file to force link language, \n"
        "// or to silence a harmless CMake warning: Ignore me.\n"
        "void aom_${target_name}_no_op_function(void);\n"
        "void aom_${target_name}_no_op_function(void) {}\n")
   list(APPEND "${out_file_list_var}" "${no_op_source_file}")
 endmacro()

 # Convenience function for adding a no-op source file to $target_name using
 # $extension as the file extension. Wraps create_no_op_source_file().
 function(add_no_op_source_file_to_target target_name extension)
   create_no_op_source_file("${target_name}" "${extension}"
                            "no_op_source_file_list")
   target_sources(${target_name} PRIVATE ${no_op_source_file_list})
 endfunction()

 # Sets the value of the variable referenced by $feature to $value, and reports
 # the change to the user via call to message(WARNING ...). $cause is expected to
 # be a configuration variable that conflicts with $feature in some way. This
 # function is a no-op if $feature is already set to $value.
 function(change_config_and_warn feature value cause)
   if(${feature} EQUAL ${value})
     return()
   endif()
   set(${feature} ${value} PARENT_SCOPE)
   if(${value} EQUAL 1)
     set(verb "Enabled")
     set(reason "required for")
   else()
     set(verb "Disabled")
     set(reason "incompatible with")
   endif()
   set(warning_message "${verb} ${feature}, ${reason} ${cause}.")
   message(WARNING "--- ${warning_message}")
 endfunction()

 # Extracts the version string from $version_file and returns it to the user via
 # $version_string_out_var. To achieve this VERSION_STRING_NOSP is located in
 # $version_file and then everything but the string literal assigned to the
 # variable is removed. Quotes and the leading 'v' are stripped from the returned
 # string.
 function(extract_version_string version_file version_string_out_var)
   file(STRINGS "${version_file}" aom_version REGEX "VERSION_STRING_NOSP")
   string(REPLACE "#define VERSION_STRING_NOSP " "" aom_version "${aom_version}")
   string(REPLACE "\"" "" aom_version "${aom_version}")
   string(REPLACE " " "" aom_version "${aom_version}")
   string(FIND "${aom_version}" "v" v_pos)
   if(${v_pos} EQUAL 0)
     string(SUBSTRING "${aom_version}" 1 -1 aom_version)
   endif()
   set("${version_string_out_var}" "${aom_version}" PARENT_SCOPE)
 endfunction()

 # Sets CMake compiler launcher to $launcher_name when $launcher_name is found in
 # $PATH. Warns user about ignoring build flag $launcher_flag when $launcher_name
 # is not found in $PATH.
 function(set_compiler_launcher launcher_flag launcher_name)
   find_program(launcher_path "${launcher_name}")
   if(launcher_path)
     set(CMAKE_C_COMPILER_LAUNCHER "${launcher_path}" PARENT_SCOPE)
     set(CMAKE_CXX_COMPILER_LAUNCHER "${launcher_path}" PARENT_SCOPE)
     message("--- Using ${launcher_name} as compiler launcher.")
   else()
     message(
       WARNING "--- Cannot find ${launcher_name}, ${launcher_flag} ignored.")
   endif()
 endfunction()

 # Sentinel value used to detect when a variable has been set via the -D argument
 # passed to CMake on the command line.
 set(cmake_cmdline_helpstring "No help, variable specified on the command line.")

 # Wrapper macro for set() that does some book keeping to help with storage of
 # build configuration information.
 #
 # Sets the default value for variable $name when the value of $name has not
 # already been set via the CMake command line.
 #
 # The names of variables defaulted through this macro are added to
 # $AOM_DETECT_VARS to facilitate build logging and diagnostics.
 macro(set_aom_detect_var name value helpstring)
   unset(list_index)
   list(FIND AOM_DETECT_VARS ${name} list_index)
   if(${list_index} EQUAL -1)
     list(APPEND AOM_DETECT_VARS ${name})
   endif()

   # Update the variable only when it does not carry the CMake assigned help
   # string for variables specified via the command line.
   unset(cache_helpstring)
   get_property(cache_helpstring CACHE ${name} PROPERTY HELPSTRING)
   if(NOT "${cache_helpstring}" STREQUAL "${cmake_cmdline_helpstring}")
     set(${name} ${value} CACHE STRING "${helpstring}")
     mark_as_advanced(${name})
   else()
     message(
       WARNING
         "${name} has been set by CMake, but it may be overridden by the build "
         "system during environment detection")
   endif()
 endmacro()

 # Wrapper macro for set() that does some book keeping to help with storage of
 # build configuration information.
 #
 # Sets the default value for variable $name when the value of $name has not
 # already been set via the CMake command line.
 #
 # The names of variables defaulted through this macro are added to
 # $AOM_CONFIG_VARS to facilitate build logging and diagnostics.
 macro(set_aom_config_var name value helpstring)
   unset(list_index)
   list(FIND AOM_CONFIG_VARS ${name} list_index)
   if(${list_index} EQUAL -1)
     list(APPEND AOM_CONFIG_VARS ${name})
   endif()

   # Update the variable only when it does not carry the CMake assigned help
   # string for variables specified via the command line.
   unset(cache_helpstring)
   get_property(cache_helpstring CACHE ${name} PROPERTY HELPSTRING)
   if(NOT "${cache_helpstring}" STREQUAL "${cmake_cmdline_helpstring}")
     set(${name} ${value} CACHE STRING "${helpstring}")
   endif()
 endmacro()

 # Wrapper macro for option() that does some book keeping to help with storage of
 # build configuration information.
 #
 # Sets the default value for variable $name when the value of $name has not
 # already been set via the CMake command line.
 #
 # The names of variables defaulted through this macro are added to
 # $AOM_OPTION_VARS to facilitate build logging and diagnostics.
 macro(set_aom_option_var name helpstring value)
   unset(list_index)
   list(FIND AOM_OPTION_VARS ${name} list_index)
   if(${list_index} EQUAL -1)
     list(APPEND AOM_OPTION_VARS ${name})
   endif()

   # Update the variable only when it does not carry the CMake assigned help
   # string for variables specified via the command line.
   unset(cache_helpstring)
   get_property(cache_helpstring CACHE ${name} PROPERTY HELPSTRING)
   if(NOT "${cache_helpstring}" STREQUAL "${cmake_cmdline_helpstring}")
     option(${name} "${helpstring}" ${value})
   endif()
 endmacro()
	#
	# Copyright (c) 2017, Alliance for Open Media. All rights reserved.
	#
	# This source code is subject to the terms of the BSD 2 Clause License and the
	# Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License was
	# not distributed with this source code in the LICENSE file, you can obtain it
	# at www.aomedia.org/license/software. If the Alliance for Open Media Patent
	# License 1.0 was not distributed with this source code in the PATENTS file, you
	# can obtain it at www.aomedia.org/license/patent.
	#
	if(AOM_BUILD_CMAKE_UTIL_CMAKE_)
	return()
	endif() # AOM_BUILD_CMAKE_UTIL_CMAKE_
	set(AOM_BUILD_CMAKE_UTIL_CMAKE_ 1)

	# Directory where generated sources will be written.
	set(AOM_GEN_SRC_DIR "${AOM_CONFIG_DIR}/gen_src")

	# Creates a no-op source file in $AOM_GEN_SRC_DIR named $basename.$extension and
	# returns the full path to the source file via appending it to the list variable
	# referred to by $out_file_list_var parameter.
	macro(create_no_op_source_file basename extension out_file_list_var)
	set(no_op_source_file "${AOM_GEN_SRC_DIR}/${basename}_no_op.${extension}")
	file(WRITE "${no_op_source_file}"
	"// Generated file. DO NOT EDIT!\n"
	"// ${target_name} needs a ${extension} file to force link language, \n"
	"// or to silence a harmless CMake warning: Ignore me.\n"
	"void aom_${target_name}_no_op_function(void);\n"
	"void aom_${target_name}_no_op_function(void) {}\n")
	list(APPEND "${out_file_list_var}" "${no_op_source_file}")
	endmacro()

	# Convenience function for adding a no-op source file to $target_name using
	# $extension as the file extension. Wraps create_no_op_source_file().
	function(add_no_op_source_file_to_target target_name extension)
	create_no_op_source_file("${target_name}" "${extension}"
	"no_op_source_file_list")
	target_sources(${target_name} PRIVATE ${no_op_source_file_list})
	endfunction()

	# Sets the value of the variable referenced by $feature to $value, and reports
	# the change to the user via call to message(WARNING ...). $cause is expected to
	# be a configuration variable that conflicts with $feature in some way. This
	# function is a no-op if $feature is already set to $value.
	function(change_config_and_warn feature value cause)
	if(${feature} EQUAL ${value})
	return()
	endif()
	set(${feature} ${value} PARENT_SCOPE)
	if(${value} EQUAL 1)
	set(verb "Enabled")
	set(reason "required for")
	else()
	set(verb "Disabled")
	set(reason "incompatible with")
	endif()
	set(warning_message "${verb} ${feature}, ${reason} ${cause}.")
	message(WARNING "--- ${warning_message}")
	endfunction()

	# Extracts the version string from $version_file and returns it to the user via
	# $version_string_out_var. To achieve this VERSION_STRING_NOSP is located in
	# $version_file and then everything but the string literal assigned to the
	# variable is removed. Quotes and the leading 'v' are stripped from the returned
	# string.
	function(extract_version_string version_file version_string_out_var)
	file(STRINGS "${version_file}" aom_version REGEX "VERSION_STRING_NOSP")
	string(REPLACE "#define VERSION_STRING_NOSP " "" aom_version "${aom_version}")
	string(REPLACE "\"" "" aom_version "${aom_version}")
	string(REPLACE " " "" aom_version "${aom_version}")
	string(FIND "${aom_version}" "v" v_pos)
	if(${v_pos} EQUAL 0)
	string(SUBSTRING "${aom_version}" 1 -1 aom_version)
	endif()
	set("${version_string_out_var}" "${aom_version}" PARENT_SCOPE)
	endfunction()

	# Sets CMake compiler launcher to $launcher_name when $launcher_name is found in
	# $PATH. Warns user about ignoring build flag $launcher_flag when $launcher_name
	# is not found in $PATH.
	function(set_compiler_launcher launcher_flag launcher_name)
	find_program(launcher_path "${launcher_name}")
	if(launcher_path)
	set(CMAKE_C_COMPILER_LAUNCHER "${launcher_path}" PARENT_SCOPE)
	set(CMAKE_CXX_COMPILER_LAUNCHER "${launcher_path}" PARENT_SCOPE)
	message("--- Using ${launcher_name} as compiler launcher.")
	else()
	message(
	WARNING "--- Cannot find ${launcher_name}, ${launcher_flag} ignored.")
	endif()
	endfunction()

	# Sentinel value used to detect when a variable has been set via the -D argument
	# passed to CMake on the command line.
	set(cmake_cmdline_helpstring "No help, variable specified on the command line.")

	# Wrapper macro for set() that does some book keeping to help with storage of
	# build configuration information.
	#
	# Sets the default value for variable $name when the value of $name has not
	# already been set via the CMake command line.
	#
	# The names of variables defaulted through this macro are added to
	# $AOM_DETECT_VARS to facilitate build logging and diagnostics.
	macro(set_aom_detect_var name value helpstring)
	unset(list_index)
	list(FIND AOM_DETECT_VARS ${name} list_index)
	if(${list_index} EQUAL -1)
	list(APPEND AOM_DETECT_VARS ${name})
	endif()

	# Update the variable only when it does not carry the CMake assigned help
	# string for variables specified via the command line.
	unset(cache_helpstring)
	get_property(cache_helpstring CACHE ${name} PROPERTY HELPSTRING)
	if(NOT "${cache_helpstring}" STREQUAL "${cmake_cmdline_helpstring}")
	set(${name} ${value} CACHE STRING "${helpstring}")
	mark_as_advanced(${name})
	else()
	message(
	WARNING
	"${name} has been set by CMake, but it may be overridden by the build "
	"system during environment detection")
	endif()
	endmacro()

	# Wrapper macro for set() that does some book keeping to help with storage of
	# build configuration information.
	#
	# Sets the default value for variable $name when the value of $name has not
	# already been set via the CMake command line.
	#
	# The names of variables defaulted through this macro are added to
	# $AOM_CONFIG_VARS to facilitate build logging and diagnostics.
	macro(set_aom_config_var name value helpstring)
	unset(list_index)
	list(FIND AOM_CONFIG_VARS ${name} list_index)
	if(${list_index} EQUAL -1)
	list(APPEND AOM_CONFIG_VARS ${name})
	endif()

	# Update the variable only when it does not carry the CMake assigned help
	# string for variables specified via the command line.
	unset(cache_helpstring)
	get_property(cache_helpstring CACHE ${name} PROPERTY HELPSTRING)
	if(NOT "${cache_helpstring}" STREQUAL "${cmake_cmdline_helpstring}")
	set(${name} ${value} CACHE STRING "${helpstring}")
	endif()
	endmacro()

	# Wrapper macro for option() that does some book keeping to help with storage of
	# build configuration information.
	#
	# Sets the default value for variable $name when the value of $name has not
	# already been set via the CMake command line.
	#
	# The names of variables defaulted through this macro are added to
	# $AOM_OPTION_VARS to facilitate build logging and diagnostics.
	macro(set_aom_option_var name helpstring value)
	unset(list_index)
	list(FIND AOM_OPTION_VARS ${name} list_index)
	if(${list_index} EQUAL -1)
	list(APPEND AOM_OPTION_VARS ${name})
	endif()

	# Update the variable only when it does not carry the CMake assigned help
	# string for variables specified via the command line.
	unset(cache_helpstring)
	get_property(cache_helpstring CACHE ${name} PROPERTY HELPSTRING)
	if(NOT "${cache_helpstring}" STREQUAL "${cmake_cmdline_helpstring}")
	option(${name} "${helpstring}" ${value})
	endif()
	endmacro()