#
# Copyright 2017 The Abseil Authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
# https://github.com/google/oss-policies-info/blob/main/foundational-cxx-support-matrix.md
# As of 2024-07-01, CMake 3.16 is the minimum supported version.
cmake_minimum_required(VERSION 3.16)
# Allow the user to specify the CMAKE_MSVC_DEBUG_INFORMATION_FORMAT
if (POLICY CMP0141)
cmake_policy(SET CMP0141 NEW)
endif (POLICY CMP0141)
project(absl LANGUAGES CXX)
set(ABSL_SOVERSION 0)
include(CTest)
# Output directory is correct by default for most build setups. However, when
# building Abseil as a DLL, it is important to have the DLL in the same
# directory as the executable using it. Thus, we put all executables in a single
# /bin directory.
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
# when absl is included as subproject (i.e. using add_subdirectory(abseil-cpp))
# in the source tree of a project that uses it, install rules are disabled.
if(NOT CMAKE_SOURCE_DIR STREQUAL PROJECT_SOURCE_DIR)
option(ABSL_ENABLE_INSTALL "Enable install rule" OFF)
else()
option(ABSL_ENABLE_INSTALL "Enable install rule" ON)
endif()
set(CMAKE_INSTALL_RPATH "$ORIGIN")
set(CMAKE_INSTALL_RPATH_USE_LINK_PATH ON)
set(CMAKE_BUILD_RPATH_USE_ORIGIN ON)
option(ABSL_PROPAGATE_CXX_STD
"Use CMake C++ standard meta features (e.g. cxx_std_14) that propagate to targets that link to Abseil"
OFF) # TODO: Default to ON for CMake 3.8 and greater.
if(NOT ABSL_PROPAGATE_CXX_STD)
message(WARNING "A future Abseil release will default ABSL_PROPAGATE_CXX_STD to ON for CMake 3.8 and up. We recommend enabling this option to ensure your project still builds correctly.")
endif()
option(ABSL_USE_SYSTEM_INCLUDES
"Silence warnings in Abseil headers by marking them as SYSTEM includes"
OFF)
list(APPEND CMAKE_MODULE_PATH
${CMAKE_CURRENT_LIST_DIR}/CMake
${CMAKE_CURRENT_LIST_DIR}/absl/copts
)
option(ABSL_MSVC_STATIC_RUNTIME
"Link static runtime libraries"
OFF)
if(ABSL_MSVC_STATIC_RUNTIME)
set(CMAKE_MSVC_RUNTIME_LIBRARY "MultiThreaded$<$<CONFIG:Debug>:Debug>")
else()
set(CMAKE_MSVC_RUNTIME_LIBRARY "MultiThreaded$<$<CONFIG:Debug>:Debug>DLL")
endif()
include(CMakePackageConfigHelpers)
include(GNUInstallDirs)
include(AbseilDll)
include(AbseilHelpers)
##
## Using absl targets
##
## all public absl targets are
## exported with the absl:: prefix
##
## e.g absl::base absl::synchronization absl::strings ....
##
## DO NOT rely on the internal targets outside of the prefix
# include current path
list(APPEND ABSL_COMMON_INCLUDE_DIRS ${CMAKE_CURRENT_SOURCE_DIR})
if("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang")
set(ABSL_USING_CLANG ON)
else()
set(ABSL_USING_CLANG OFF)
endif()
# find dependencies
## pthread
find_package(Threads REQUIRED)
include(CMakeDependentOption)
option(ABSL_BUILD_TESTING
"If ON, Abseil will build all of Abseil's own tests." OFF)
option(ABSL_BUILD_TEST_HELPERS
"If ON, Abseil will build libraries that you can use to write tests against Abseil code. This option requires that Abseil is configured to use GoogleTest."
OFF)
option(ABSL_USE_EXTERNAL_GOOGLETEST
"If ON, Abseil will assume that the targets for GoogleTest are already provided by the including project. This makes sense when Abseil is used with add_subdirectory." OFF)
cmake_dependent_option(ABSL_FIND_GOOGLETEST
"If ON, Abseil will use find_package(GTest) rather than assuming that GoogleTest is already provided by the including project."
ON
"ABSL_USE_EXTERNAL_GOOGLETEST"
OFF)
option(ABSL_USE_GOOGLETEST_HEAD
"If ON, abseil will download HEAD from GoogleTest at config time." OFF)
set(ABSL_GOOGLETEST_DOWNLOAD_URL "" CACHE STRING "If set, download GoogleTest from this URL")
set(ABSL_LOCAL_GOOGLETEST_DIR "/usr/src/googletest" CACHE PATH
"If ABSL_USE_GOOGLETEST_HEAD is OFF and ABSL_GOOGLETEST_URL is not set, specifies the directory of a local GoogleTest checkout."
)
option(ABSL_BUILD_MONOLITHIC_SHARED_LIBS
"Build Abseil as a single shared library (always enabled for Windows)"
OFF
)
if(NOT BUILD_SHARED_LIBS AND ABSL_BUILD_MONOLITHIC_SHARED_LIBS)
message(WARNING "Not building a shared library because BUILD_SHARED_LIBS is not set. Ignoring ABSL_BUILD_MONOLITHIC_SHARED_LIBS.")
endif()
if((BUILD_TESTING AND ABSL_BUILD_TESTING) OR ABSL_BUILD_TEST_HELPERS)
if (ABSL_USE_EXTERNAL_GOOGLETEST)
if (ABSL_FIND_GOOGLETEST)
find_package(GTest REQUIRED)
elseif(NOT TARGET GTest::gtest)
if(TARGET gtest)
# When Google Test is included directly rather than through find_package, the aliases are missing.
add_library(GTest::gtest ALIAS gtest)
add_library(GTest::gtest_main ALIAS gtest_main)
add_library(GTest::gmock ALIAS gmock)
add_library(GTest::gmock_main ALIAS gmock_main)
else()
message(FATAL_ERROR "ABSL_USE_EXTERNAL_GOOGLETEST is ON and ABSL_FIND_GOOGLETEST is OFF, which means that the top-level project must build the Google Test project. However, the target gtest was not found.")
endif()
endif()
else()
set(absl_gtest_build_dir ${CMAKE_BINARY_DIR}/googletest-build)
if(ABSL_USE_GOOGLETEST_HEAD AND ABSL_GOOGLETEST_DOWNLOAD_URL)
message(FATAL_ERROR "Do not set both ABSL_USE_GOOGLETEST_HEAD and ABSL_GOOGLETEST_DOWNLOAD_URL")
endif()
if(ABSL_USE_GOOGLETEST_HEAD)
set(absl_gtest_download_url "https://github.com/google/googletest/archive/main.zip")
elseif(ABSL_GOOGLETEST_DOWNLOAD_URL)
set(absl_gtest_download_url ${ABSL_GOOGLETEST_DOWNLOAD_URL})
endif()
if(absl_gtest_download_url)
set(absl_gtest_src_dir ${CMAKE_BINARY_DIR}/googletest-src)
else()
set(absl_gtest_src_dir ${ABSL_LOCAL_GOOGLETEST_DIR})
endif()
include(CMake/Googletest/DownloadGTest.cmake)
endif()
endif()
add_subdirectory(absl)
if(ABSL_ENABLE_INSTALL)
# absl:lts-remove-begin(system installation is supported for LTS releases)
# We don't support system-wide installation
list(APPEND SYSTEM_INSTALL_DIRS "/usr/local" "/usr" "/opt/" "/opt/local" "c:/Program Files/${PROJECT_NAME}")
if(NOT DEFINED CMAKE_INSTALL_PREFIX OR CMAKE_INSTALL_PREFIX IN_LIST SYSTEM_INSTALL_DIRS)
message(WARNING "\
The default and system-level install directories are unsupported except in LTS \
releases of Abseil. Please set CMAKE_INSTALL_PREFIX to install Abseil in your \
source or build tree directly.\
")
endif()
# absl:lts-remove-end
# install as a subdirectory only
install(EXPORT ${PROJECT_NAME}Targets
NAMESPACE absl::
DESTINATION "${CMAKE_INSTALL_LIBDIR}/cmake/${PROJECT_NAME}"
)
configure_package_config_file(
CMake/abslConfig.cmake.in
"${PROJECT_BINARY_DIR}/${PROJECT_NAME}Config.cmake"
INSTALL_DESTINATION "${CMAKE_INSTALL_LIBDIR}/cmake/${PROJECT_NAME}"
)
install(FILES "${PROJECT_BINARY_DIR}/${PROJECT_NAME}Config.cmake"
DESTINATION "${CMAKE_INSTALL_LIBDIR}/cmake/${PROJECT_NAME}"
)
# Abseil only has a version in LTS releases. This mechanism is accomplished
# Abseil's internal Copybara (https://github.com/google/copybara) workflows and
# isn't visible in the CMake buildsystem itself.
if(absl_VERSION)
write_basic_package_version_file(
"${PROJECT_BINARY_DIR}/${PROJECT_NAME}ConfigVersion.cmake"
COMPATIBILITY ExactVersion
)
install(FILES "${PROJECT_BINARY_DIR}/${PROJECT_NAME}ConfigVersion.cmake"
DESTINATION "${CMAKE_INSTALL_LIBDIR}/cmake/${PROJECT_NAME}"
)
endif() # absl_VERSION
install(DIRECTORY absl
DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
FILES_MATCHING
PATTERN "*.inc"
PATTERN "*.h"
PATTERN "copts" EXCLUDE
PATTERN "testdata" EXCLUDE
)
# Rewrite options.h to use the compiled ABI.
file(READ "absl/base/options.h" ABSL_INTERNAL_OPTIONS_H_CONTENTS)
# Handle features that require at least C++20.
if (ABSL_INTERNAL_AT_LEAST_CXX20)
foreach(FEATURE "ORDERING")
string(REPLACE
"#define ABSL_OPTION_USE_STD_${FEATURE} 2"
"#define ABSL_OPTION_USE_STD_${FEATURE} 1"
ABSL_INTERNAL_OPTIONS_H_PINNED
"${ABSL_INTERNAL_OPTIONS_H_CONTENTS}")
set(ABSL_INTERNAL_OPTIONS_H_CONTENTS "${ABSL_INTERNAL_OPTIONS_H_PINNED}")
endforeach()
endif()
# Handle features that require at least C++17.
if (ABSL_INTERNAL_AT_LEAST_CXX17)
foreach(FEATURE "ANY" "OPTIONAL" "STRING_VIEW" "VARIANT")
string(REPLACE
"#define ABSL_OPTION_USE_STD_${FEATURE} 2"
"#define ABSL_OPTION_USE_STD_${FEATURE} 1"
ABSL_INTERNAL_OPTIONS_H_PINNED
"${ABSL_INTERNAL_OPTIONS_H_CONTENTS}")
set(ABSL_INTERNAL_OPTIONS_H_CONTENTS "${ABSL_INTERNAL_OPTIONS_H_PINNED}")
endforeach()
endif()
# Any feature that still has the value of 2 (because it was not handled above)
# should be set to 0.
string(REGEX REPLACE
"#define ABSL_OPTION_USE_STD_([^ ]*) 2"
"#define ABSL_OPTION_USE_STD_\\1 0"
ABSL_INTERNAL_OPTIONS_H_PINNED
"${ABSL_INTERNAL_OPTIONS_H_CONTENTS}")
file(GENERATE OUTPUT "${CMAKE_BINARY_DIR}/options-pinned.h" CONTENT "${ABSL_INTERNAL_OPTIONS_H_PINNED}")
install(FILES "${CMAKE_BINARY_DIR}/options-pinned.h"
DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/absl/base
RENAME "options.h")
endif() # ABSL_ENABLE_INSTALL
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