build/cmake/util.cmake

##
## 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 (NOT AOM_BUILD_CMAKE_UTIL_CMAKE_)
set(AOM_BUILD_CMAKE_UTIL_CMAKE_ 1)

# Creates dummy source file in $AOM_CONFIG_DIR named $basename.$extension and
# returns the full path to the dummy source file via the $out_file_path
# parameter.
function (create_dummy_source_file basename extension out_file_path)
  set(dummy_source_file "${AOM_CONFIG_DIR}/${basename}_dummy.${extension}")
  file(WRITE "${dummy_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 ${target_name}_dummy_function(void) {}\n")
  set(${out_file_path} ${dummy_source_file} PARENT_SCOPE)
endfunction ()

# Convenience function for adding a dummy source file to $target_name using
# $extension as the file extension. Wraps create_dummy_source_file().
function (add_dummy_source_file_to_target target_name extension)
  create_dummy_source_file("${target_name}" "${extension}" "dummy_source_file")
  target_sources(${target_name} PRIVATE ${dummy_source_file})
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 $feature in some way.
function (change_config_and_warn feature value cause)
  set(${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 ()

endif()  # AOM_BUILD_CMAKE_UTIL_CMAKE_