Files
curl/CMake/FindCares.cmake
Viktor Szakats 16f073ef49 cmake: define dependencies as IMPORTED interface targets
Rework the way curl's custom Find modules advertise their properties.

Before this patch, Find modules returned detected dependency properties
(header dirs, libs, libdirs, C flags, etc.) via global variables. curl's
main `CMakeLists.txt` copied their values into global lists, which it
later applied to targets. This solution worked internally, but it was
unsuited for the public, distributed `CURLConfig.cmake` and publishing
curl's Find modules with it, due to polluting the namespace of consumer
projects. It's also impractical to apply the many individual variables
to every targets depending on libcurl.

To allow using Find modules in consumer projects, this patch makes them
define as imported interface targets, named `CURL::<dependency>`. Then
store dependency information as target properties. It avoids namespace
pollution and makes the dependency information apply automatically
to all targets using `CURL::libcurl_static`.

Find modules continue to return `*_FOUND` and `*_VERSION` variables.

For dependencies detected via `pkg-config`, CMake 3.16+ is recommended.
Older CMake versions have a varying degree of support for
propagating/handling library directories. This may cause issues in envs
where dependencies reside in non-system locations and detected via
`pkg-config` (e.g. macOS + Homebrew). Use `CURL_USE_PKGCONFIG=OFF`
to fix these issues. Or upgrade to newer CMake, or link libcurl
dynamically.

Also:
- re-enable `pkg-config` for old cmake `find_library()` integration
  tests.
- make `curlinfo` build after these changes.
- distribute local Find modules.
- export the raw list of lib dependencies via `CURL_LIBRARIES_PRIVATE`.
- `CURLconfig.cmake`: use curl's Find modules to detect dependencies in
  the consumer env.
- add custom property to target property debug function.
- the curl build process no longer modifies `CMAKE_C_FLAGS`.
  Follow-up to e86542038d #17047

Ref: #14930
Ref: https://github.com/libssh2/libssh2/pull/1535
Ref: https://github.com/libssh2/libssh2/pull/1571
Ref: https://github.com/libssh2/libssh2/pull/1581
Ref: https://github.com/libssh2/libssh2/pull/1623

Closes #16973
2025-11-29 01:41:40 +01:00

111 lines
4.0 KiB
CMake

#***************************************************************************
# _ _ ____ _
# Project ___| | | | _ \| |
# / __| | | | |_) | |
# | (__| |_| | _ <| |___
# \___|\___/|_| \_\_____|
#
# Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
#
# This software is licensed as described in the file COPYING, which
# you should have received as part of this distribution. The terms
# are also available at https://curl.se/docs/copyright.html.
#
# You may opt to use, copy, modify, merge, publish, distribute and/or sell
# copies of the Software, and permit persons to whom the Software is
# furnished to do so, under the terms of the COPYING file.
#
# This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
# KIND, either express or implied.
#
# SPDX-License-Identifier: curl
#
###########################################################################
# Find the c-ares library
#
# Input variables:
#
# - `CARES_INCLUDE_DIR`: Absolute path to c-ares include directory.
# - `CARES_LIBRARY`: Absolute path to `cares` library.
#
# Defines:
#
# - `CARES_FOUND`: System has c-ares.
# - `CARES_VERSION`: Version of c-ares.
# - `CURL::cares`: c-ares library target.
set(_cares_pc_requires "libcares")
if(CURL_USE_PKGCONFIG AND
NOT DEFINED CARES_INCLUDE_DIR AND
NOT DEFINED CARES_LIBRARY)
find_package(PkgConfig QUIET)
pkg_check_modules(_cares ${_cares_pc_requires})
endif()
if(_cares_FOUND)
set(Cares_FOUND TRUE)
set(CARES_FOUND TRUE)
set(CARES_VERSION ${_cares_VERSION})
message(STATUS "Found Cares (via pkg-config): ${_cares_INCLUDE_DIRS} (found version \"${CARES_VERSION}\")")
else()
find_path(CARES_INCLUDE_DIR NAMES "ares.h")
find_library(CARES_LIBRARY NAMES ${CARES_NAMES} "cares")
unset(CARES_VERSION CACHE)
if(CARES_INCLUDE_DIR AND EXISTS "${CARES_INCLUDE_DIR}/ares_version.h")
set(_version_regex1 "#[\t ]*define[\t ]+ARES_VERSION_MAJOR[\t ]+([0-9]+).*")
set(_version_regex2 "#[\t ]*define[\t ]+ARES_VERSION_MINOR[\t ]+([0-9]+).*")
set(_version_regex3 "#[\t ]*define[\t ]+ARES_VERSION_PATCH[\t ]+([0-9]+).*")
file(STRINGS "${CARES_INCLUDE_DIR}/ares_version.h" _version_str1 REGEX "${_version_regex1}")
file(STRINGS "${CARES_INCLUDE_DIR}/ares_version.h" _version_str2 REGEX "${_version_regex2}")
file(STRINGS "${CARES_INCLUDE_DIR}/ares_version.h" _version_str3 REGEX "${_version_regex3}")
string(REGEX REPLACE "${_version_regex1}" "\\1" _version_str1 "${_version_str1}")
string(REGEX REPLACE "${_version_regex2}" "\\1" _version_str2 "${_version_str2}")
string(REGEX REPLACE "${_version_regex3}" "\\1" _version_str3 "${_version_str3}")
set(CARES_VERSION "${_version_str1}.${_version_str2}.${_version_str3}")
unset(_version_regex1)
unset(_version_regex2)
unset(_version_regex3)
unset(_version_str1)
unset(_version_str2)
unset(_version_str3)
endif()
include(FindPackageHandleStandardArgs)
find_package_handle_standard_args(Cares
REQUIRED_VARS
CARES_INCLUDE_DIR
CARES_LIBRARY
VERSION_VAR
CARES_VERSION
)
if(CARES_FOUND)
set(_cares_INCLUDE_DIRS ${CARES_INCLUDE_DIR})
set(_cares_LIBRARIES ${CARES_LIBRARY})
endif()
mark_as_advanced(CARES_INCLUDE_DIR CARES_LIBRARY)
endif()
if(CARES_FOUND)
if(WIN32)
list(APPEND _cares_LIBRARIES "iphlpapi") # for if_indextoname and others
endif()
if(CMAKE_VERSION VERSION_LESS 3.13)
link_directories(${_cares_LIBRARY_DIRS})
endif()
if(NOT TARGET CURL::cares)
add_library(CURL::cares INTERFACE IMPORTED)
set_target_properties(CURL::cares PROPERTIES
INTERFACE_LIBCURL_PC_MODULES "${_cares_pc_requires}"
INTERFACE_COMPILE_OPTIONS "${_cares_CFLAGS}"
INTERFACE_INCLUDE_DIRECTORIES "${_cares_INCLUDE_DIRS}"
INTERFACE_LINK_DIRECTORIES "${_cares_LIBRARY_DIRS}"
INTERFACE_LINK_LIBRARIES "${_cares_LIBRARIES}")
endif()
endif()