lib/CMakeLists.txt

#***************************************************************************
#                                  _   _ ____  _
#  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
#
###########################################################################
set(LIB_NAME "libcurl")
set(LIBCURL_OUTPUT_NAME "libcurl" CACHE STRING "Basename of the curl library")
add_definitions("-DBUILDING_LIBCURL")

configure_file("curl_config.h.cmake" "${CMAKE_CURRENT_BINARY_DIR}/curl_config.h")

# Get 'CSOURCES', 'HHEADERS' variables
transform_makefile_inc("Makefile.inc" "${CMAKE_CURRENT_BINARY_DIR}/Makefile.inc.cmake")
include("${CMAKE_CURRENT_BINARY_DIR}/Makefile.inc.cmake")

# DllMain is added later for DLL builds only.
list(REMOVE_ITEM CSOURCES "dllmain.c")

list(APPEND HHEADERS "${CMAKE_CURRENT_BINARY_DIR}/curl_config.h")

# The rest of the build

include_directories(
  "${PROJECT_BINARY_DIR}/lib"  # for "curl_config.h"
  "${PROJECT_SOURCE_DIR}/lib"  # for "curl_setup.h"
)
if(USE_ARES)
  include_directories(SYSTEM ${CARES_INCLUDE_DIRS})
endif()

if(CURL_BUILD_TESTING)
  add_library(
    curlu  # special libcurlu library just for unittests
    STATIC
    EXCLUDE_FROM_ALL
    ${HHEADERS} ${CSOURCES}
  )
  target_compile_definitions(curlu PUBLIC "UNITTESTS" "CURL_STATICLIB")
  target_link_libraries(curlu PRIVATE ${CURL_LIBS})
endif()

if(ENABLE_CURLDEBUG)
  # We must compile these sources separately to avoid memdebug.h redefinitions
  # applying to them.
  set_source_files_properties("memdebug.c" "curl_multibyte.c" PROPERTIES SKIP_UNITY_BUILD_INCLUSION ON)
endif()

## Library definition

# Add "_imp" as a suffix before the extension to avoid conflicting with
# the statically linked "libcurl.lib" (typically with MSVC)
if(WIN32 AND
   NOT IMPORT_LIB_SUFFIX AND
   CMAKE_STATIC_LIBRARY_SUFFIX STREQUAL CMAKE_IMPORT_LIBRARY_SUFFIX)
  set(IMPORT_LIB_SUFFIX "_imp")
endif()

# Whether to do a single compilation pass for libcurl sources and reuse these
# objects to generate both static and shared target.
if(NOT DEFINED SHARE_LIB_OBJECT)
  # Enable it by default on platforms where PIC is the default for both shared
  # and static and there is a way to tell the linker which libcurl symbols it
  # should export (vs. marking these symbols exportable at compile-time).
  if(WIN32)
    set(SHARE_LIB_OBJECT ON)
  else()
    # On other platforms, make it an option disabled by default
    set(SHARE_LIB_OBJECT OFF)
  endif()
endif()

if(SHARE_LIB_OBJECT)
  set(LIB_OBJECT "libcurl_object")
  add_library(${LIB_OBJECT} OBJECT ${HHEADERS} ${CSOURCES})
  if(WIN32)
    # Define CURL_STATICLIB always, to disable __declspec(dllexport) for
    # exported libcurl symbols. We handle exports via libcurl.def instead.
    # Except with symbol hiding disabled or debug mode enabled, when we export
    # _all_ symbols from libcurl DLL, without using libcurl.def.
    set_property(TARGET ${LIB_OBJECT} APPEND PROPERTY COMPILE_DEFINITIONS "CURL_STATICLIB")
  endif()
  target_link_libraries(${LIB_OBJECT} PRIVATE ${CURL_LIBS})
  set_target_properties(${LIB_OBJECT} PROPERTIES
    POSITION_INDEPENDENT_CODE ON)
  if(CURL_HIDES_PRIVATE_SYMBOLS)
    set_property(TARGET ${LIB_OBJECT} APPEND PROPERTY COMPILE_FLAGS "${CURL_CFLAG_SYMBOLS_HIDE}")
    set_property(TARGET ${LIB_OBJECT} APPEND PROPERTY COMPILE_DEFINITIONS "CURL_HIDDEN_SYMBOLS")
  endif()
  if(CURL_HAS_LTO)
    set_target_properties(${LIB_OBJECT} PROPERTIES
      INTERPROCEDURAL_OPTIMIZATION_RELEASE TRUE
      INTERPROCEDURAL_OPTIMIZATION_RELWITHDEBINFO TRUE)
  endif()

  target_include_directories(${LIB_OBJECT} INTERFACE
    "$<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>"
    "$<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>")

  set(LIB_SOURCE $<TARGET_OBJECTS:${LIB_OBJECT}>)
else()
  set(LIB_SOURCE ${HHEADERS} ${CSOURCES})
endif()

# We want it to be called libcurl on all platforms
if(BUILD_STATIC_LIBS)
  list(APPEND libcurl_export ${LIB_STATIC})
  add_library(${LIB_STATIC} STATIC ${LIB_SOURCE})
  add_library(${PROJECT_NAME}::${LIB_STATIC} ALIAS ${LIB_STATIC})
  if(WIN32)
    set_property(TARGET ${LIB_OBJECT} APPEND PROPERTY COMPILE_DEFINITIONS "CURL_STATICLIB")
  endif()
  target_link_libraries(${LIB_STATIC} PRIVATE ${CURL_LIBS})
  # Remove the "lib" prefix since the library is already named "libcurl".
  set_target_properties(${LIB_STATIC} PROPERTIES
    PREFIX "" OUTPUT_NAME "${LIBCURL_OUTPUT_NAME}"
    SUFFIX "${STATIC_LIB_SUFFIX}${CMAKE_STATIC_LIBRARY_SUFFIX}"
    INTERFACE_COMPILE_DEFINITIONS "CURL_STATICLIB")
  if(CURL_HIDES_PRIVATE_SYMBOLS)
    set_property(TARGET ${LIB_STATIC} APPEND PROPERTY COMPILE_FLAGS "${CURL_CFLAG_SYMBOLS_HIDE}")
    set_property(TARGET ${LIB_STATIC} APPEND PROPERTY COMPILE_DEFINITIONS "CURL_HIDDEN_SYMBOLS")
  endif()
  if(CURL_HAS_LTO)
    set_target_properties(${LIB_STATIC} PROPERTIES
      INTERPROCEDURAL_OPTIMIZATION_RELEASE TRUE
      INTERPROCEDURAL_OPTIMIZATION_RELWITHDEBINFO TRUE)
  endif()

  target_include_directories(${LIB_STATIC} INTERFACE
    "$<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>"
    "$<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>")
endif()

if(BUILD_SHARED_LIBS)
  list(APPEND libcurl_export ${LIB_SHARED})
  add_library(${LIB_SHARED} SHARED ${LIB_SOURCE})
  add_library(${PROJECT_NAME}::${LIB_SHARED} ALIAS ${LIB_SHARED})
  if(WIN32 OR CYGWIN)
    if(CYGWIN)
      # For Cygwin always compile dllmain.c as a separate unit since it
      # includes windows.h, which should not be included in other units.
      set_source_files_properties("dllmain.c" PROPERTIES SKIP_UNITY_BUILD_INCLUSION ON)
    endif()
    set_property(TARGET ${LIB_SHARED} APPEND PROPERTY SOURCES "dllmain.c")
  endif()
  if(WIN32)
    set_property(TARGET ${LIB_SHARED} APPEND PROPERTY SOURCES "libcurl.rc")
    if(CURL_HIDES_PRIVATE_SYMBOLS)
      set_property(TARGET ${LIB_SHARED} APPEND PROPERTY SOURCES "${PROJECT_SOURCE_DIR}/lib/libcurl.def")
    endif()
  endif()
  target_link_libraries(${LIB_SHARED} PRIVATE ${CURL_LIBS})
  # Remove the "lib" prefix since the library is already named "libcurl".
  set_target_properties(${LIB_SHARED} PROPERTIES
    PREFIX "" OUTPUT_NAME "${LIBCURL_OUTPUT_NAME}"
    IMPORT_PREFIX "" IMPORT_SUFFIX "${IMPORT_LIB_SUFFIX}${CMAKE_IMPORT_LIBRARY_SUFFIX}"
    POSITION_INDEPENDENT_CODE ON)
  if(CURL_HIDES_PRIVATE_SYMBOLS)
    set_property(TARGET ${LIB_SHARED} APPEND PROPERTY COMPILE_FLAGS "${CURL_CFLAG_SYMBOLS_HIDE}")
    set_property(TARGET ${LIB_SHARED} APPEND PROPERTY COMPILE_DEFINITIONS "CURL_HIDDEN_SYMBOLS")
  endif()
  if(CURL_HAS_LTO)
    set_target_properties(${LIB_SHARED} PROPERTIES
      INTERPROCEDURAL_OPTIMIZATION_RELEASE TRUE
      INTERPROCEDURAL_OPTIMIZATION_RELWITHDEBINFO TRUE)
  endif()

  target_include_directories(${LIB_SHARED} INTERFACE
    "$<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>"
    "$<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>")

  if(CMAKE_DLL_NAME_WITH_SOVERSION OR
    CYGWIN OR
    APPLE OR
    CMAKE_SYSTEM_NAME STREQUAL "AIX" OR
    CMAKE_SYSTEM_NAME STREQUAL "Linux" OR
    CMAKE_SYSTEM_NAME STREQUAL "SunOS" OR
    CMAKE_SYSTEM_NAME STREQUAL "Haiku" OR
    CMAKE_SYSTEM_NAME STREQUAL "GNU/kFreeBSD" OR
    # FreeBSD comes with the a.out and ELF flavours but a.out was supported
    # up to v3.x and ELF from v3.x. I cannot imagine someone running CMake
    # on those ancient systems.
    CMAKE_SYSTEM_NAME STREQUAL "FreeBSD")
    set(_soversion_default TRUE)
  else()
    set(_soversion_default FALSE)
  endif()

  option(CURL_LIBCURL_SOVERSION "Enable libcurl SOVERSION" ${_soversion_default})
  option(CURL_LIBCURL_VERSIONED_SYMBOLS "Enable libcurl versioned symbols" OFF)

  if(CURL_LIBCURL_SOVERSION OR CURL_LIBCURL_VERSIONED_SYMBOLS)
    # Get 'VERSIONCHANGE', 'VERSIONADD', 'VERSIONDEL', 'VERSIONINFO' variables
    transform_makefile_inc("Makefile.soname" "${CMAKE_CURRENT_BINARY_DIR}/Makefile.soname.cmake")
    include("${CMAKE_CURRENT_BINARY_DIR}/Makefile.soname.cmake")

    math(EXPR _cmakesoname "${VERSIONCHANGE} - ${VERSIONDEL}")
    set(_cmakeversion "${_cmakesoname}.${VERSIONDEL}.${VERSIONADD}")
  endif()

  if(CURL_LIBCURL_SOVERSION)
    set_target_properties(${LIB_SHARED} PROPERTIES
      VERSION "${_cmakeversion}" SOVERSION "${_cmakesoname}")
  endif()

  ## Versioned symbols

  if(CURL_LIBCURL_VERSIONED_SYMBOLS)
    if(NOT DEFINED CURL_LIBCURL_VERSIONED_SYMBOLS_PREFIX)
      # Default to prefixes used by autotools
      if(CURL_WITH_MULTI_SSL)
        set(CURL_LIBCURL_VERSIONED_SYMBOLS_PREFIX "MULTISSL_")
      elseif(CURL_USE_OPENSSL)
        set(CURL_LIBCURL_VERSIONED_SYMBOLS_PREFIX "OPENSSL_")
      elseif(CURL_USE_MBEDTLS)
        set(CURL_LIBCURL_VERSIONED_SYMBOLS_PREFIX "MBEDTLS_")
      elseif(CURL_USE_BEARSSL)
        set(CURL_LIBCURL_VERSIONED_SYMBOLS_PREFIX "BEARSSL_")
      elseif(CURL_USE_WOLFSSL)
        set(CURL_LIBCURL_VERSIONED_SYMBOLS_PREFIX "WOLFSSL_")
      elseif(CURL_USE_GNUTLS)
        set(CURL_LIBCURL_VERSIONED_SYMBOLS_PREFIX "GNUTLS_")
      elseif(CURL_USE_RUSTLS)
        set(CURL_LIBCURL_VERSIONED_SYMBOLS_PREFIX "RUSTLS_")
      endif()
    endif()
    # Generate version script for the linker, for versioned symbols.
    # Consumed variables:
    #   CURL_LIBCURL_VERSIONED_SYMBOLS_PREFIX
    #   CURL_LIBCURL_VERSIONED_SYMBOLS_SONAME
    set(CURL_LIBCURL_VERSIONED_SYMBOLS_SONAME ${_cmakesoname})
    configure_file(
      "${CMAKE_CURRENT_SOURCE_DIR}/libcurl.vers.in"
      "${CMAKE_CURRENT_BINARY_DIR}/libcurl.vers" @ONLY)
    include(CMakePushCheckState)
    include(CheckCSourceCompiles)
    cmake_push_check_state()
    set(CMAKE_REQUIRED_LINK_OPTIONS "-Wl,--version-script=${CMAKE_CURRENT_BINARY_DIR}/libcurl.vers")
    check_c_source_compiles("int main(void) { return 0; }" HAVE_VERSIONED_SYMBOLS)
    if(HAVE_VERSIONED_SYMBOLS)
      # Superseded by LINK_OPTIONS in CMake 3.13 and later.
      set_target_properties(${LIB_SHARED} PROPERTIES LINK_FLAGS "${CMAKE_REQUIRED_LINK_OPTIONS}")
    else()
      message(WARNING "Versioned symbols requested, but not supported by the toolchain.")
    endif()
    cmake_pop_check_state()
  endif()
endif()

add_library(${LIB_NAME} ALIAS ${LIB_SELECTED})
add_library(${PROJECT_NAME}::${LIB_NAME} ALIAS ${LIB_SELECTED})

if(CURL_ENABLE_EXPORT_TARGET)
  if(BUILD_STATIC_LIBS)
    install(TARGETS ${LIB_STATIC}
      EXPORT ${TARGETS_EXPORT_NAME}
      ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
      LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
      RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
    )
  endif()
  if(BUILD_SHARED_LIBS)
    install(TARGETS ${LIB_SHARED}
      EXPORT ${TARGETS_EXPORT_NAME}
      ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
      LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
      RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
    )
  endif()

  export(TARGETS ${libcurl_export}
    FILE "${PROJECT_BINARY_DIR}/libcurl-target.cmake"
    NAMESPACE ${PROJECT_NAME}::
  )
endif()