cmake/ExternalProject-OpenSSL.cmake - cassandra-cpp-driver - Git at Google

 # Copyright (c) DataStax, Inc.
 #
 # 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
 #
 # http://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.
 cmake_minimum_required(VERSION 3.10 FATAL_ERROR)
 include(ExternalProject)
 include(Windows-Environment)
 if(NOT MSVC_ENVIRONMENT_SCRIPT)
   message(FATAL_ERROR "Visual Studio environment script is required to build OpenSSL")
 endif()

 # OpenSSL related CMake options
 option(OPENSSL_VERSION "OpenSSL version to build and install")
 if(NOT OPENSSL_VERSION)
   # TODO: Should we default to OpenSSL 1.1 (e.g. 1.1.1c)?
   set(OPENSSL_VERSION "1.0.2s")
 endif()
 option(OPENSSL_INSTALL_PREFIX "OpenSSL installation prefix location")
 if(CASS_USE_ZLIB)
   include(ExternalProject-zlib)
 endif()
 set(OPENSSL_VERSION ${OPENSSL_VERSION} CACHE STRING "OpenSSL version to build and install" FORCE)

 # Determine the major and minor version of OpenSSL used
 string(REPLACE "." ";" OPENSSL_VERSION_LIST ${OPENSSL_VERSION})
 list(GET OPENSSL_VERSION_LIST 0 OPENSSL_VERSION_MAJOR)
 list(GET OPENSSL_VERSION_LIST 1 OPENSSL_VERSION_MINOR)
 set(OPENSSL_MAJOR_MINOR_VERSION "${OPENSSL_VERSION_MAJOR}.${OPENSSL_VERSION_MINOR}")

 # Determine the OpenSSL archive name to download
 string(REPLACE "." "_" OPENSSL_ARCHIVE_VERSION ${OPENSSL_VERSION})
 set(OPENSSL_ARCHIVE_NAME OpenSSL_${OPENSSL_ARCHIVE_VERSION} CACHE STRING "OpenSSL archive name" FORCE)

 # Determine if OpenSSL installation directory should be set
 if(NOT OPENSSL_INSTALL_PREFIX)
   set(OPENSSL_INSTALL_PREFIX "${CMAKE_BINARY_DIR}/libs/openssl" CACHE STRING "OpenSSL installation prefix" FORCE)
 endif()

 # OpenSSL external project variables
 set(OPENSSL_LIBRARY_NAME "openssl-${OPENSSL_VERSION}-library")
 set(OPENSSL_PROJECT_PREFIX ${CMAKE_BINARY_DIR}/external/openssl)
 set(OPENSSL_ARCHIVE_URL_PREFIX "https://github.com/openssl/openssl/archive/")
 set(OPENSSL_ARCHIVE_URL_SUFFIX ".tar.gz")
 set(OPENSSL_ARCHIVE_URL "${OPENSSL_ARCHIVE_URL_PREFIX}${OPENSSL_ARCHIVE_NAME}${OPENSSL_ARCHIVE_URL_SUFFIX}")

 # Make sure Visual Studio is available
 if(NOT MSVC)
   message(FATAL_ERROR "Visual Studio is required to build OpenSSL")
 endif()

 # Perl is required to create NMake files for OpenSSL build
 find_package(Perl REQUIRED)
 if(OPENSSL_MAJOR_MINOR_VERSION STREQUAL "1.1")
   if(PERL_VERSION_STRING VERSION_LESS "5.10.0")
     message(FATAL_ERROR "Invalid Perl Version: OpenSSL v1.1.0+ requires Perl v5.10.0+")
   endif()
 endif()
 if(CYGWIN_INSTALL_PATH)
   if(PERL_EXECUTABLE MATCHES "${CYGWIN_INSTALL_PATH}")
     message(FATAL_ERROR "Cygwin Perl Executable Found: Please install Strawberry Perl [http://strawberryperl.com/releases.html]")
   endif()
 endif()
 get_filename_component(PERL_PATH ${PERL_EXECUTABLE} DIRECTORY)
 file(TO_NATIVE_PATH ${PERL_PATH} PERL_PATH)

 message(STATUS "OpenSSL: ${OPENSSL_VERSION}")

 # OpenSSL library configuration variables
 set(OPENSSL_INSTALL_DIR "${OPENSSL_INSTALL_PREFIX}" CACHE STRING "OpenSSL installation directory" FORCE)
 set(OPENSSL_BINARY_DIR "${OPENSSL_INSTALL_DIR}/bin" CACHE STRING "OpenSSL binary directory" FORCE)
 set(OPENSSL_INCLUDE_DIR "${OPENSSL_INSTALL_DIR}/include" CACHE STRING "OpenSSL include directory" FORCE)
 set(OPENSSL_INCLUDE_DIRS "${OPENSSL_INCLUDE_DIR}" CACHE STRING "OpenSSL include directory" FORCE) # Alias to stay consistent with FindOpenSSL
 set(OPENSSL_LIBRARY_DIR "${OPENSSL_INSTALL_DIR}/lib" CACHE STRING "OpenSSL library directory" FORCE)
 if(OPENSSL_MAJOR_MINOR_VERSION STREQUAL "1.0")
   set(OPENSSL_LIBRARIES ${OPENSSL_LIBRARY_DIR}/libeay32.lib
                         ${OPENSSL_LIBRARY_DIR}/ssleay32.lib
                         CACHE STRING "OpenSSL libraries" FORCE)
 else()
   set(OPENSSL_LIBRARIES ${OPENSSL_LIBRARY_DIR}/libcrypto.lib
                         ${OPENSSL_LIBRARY_DIR}/libssl.lib
                         CACHE STRING "OpenSSL libraries" FORCE)
 endif()
 set(OPENSSL_ROOT_DIR "${OPENSSL_INSTALL_DIR}" CACHE STRING "OpenSSL root directory" FORCE)

 # Create build options for the platform build scripts
 if(BUILD_SHARED_LIBS)
   if(CASS_USE_ZLIB)
     set(OPENSSL_ZLIB_CONFIGURE_ARGUMENT "zlib-dynamic")
     set(ZLIB_LIB zlib.lib)
   endif()
 else()
   if(CASS_USE_ZLIB)
     set(OPENSSL_ZLIB_CONFIGURE_ARGUMENT "no-zlib-dynamic")
     set(ZLIB_LIB zlibstatic.lib)
   endif()
 endif()

 # Determine if shared or static library should be built
 set(OPENSSL_CONFIGURE_COMPILER "no-asm no-ssl2")
 if(BUILD_SHARED_LIBS)
   set(OPENSSL_CONFIGURE_COMPILER "${OPENSSL_CONFIGURE_COMPILER} shared")
   set(OPENSSL_1_0_MAKEFILE "ms\\ntdll.mak")
   set(OPENSSL_1_1_MAKEFILE "makefile.shared")
 else()
   set(OPENSSL_CONFIGURE_COMPILER "${OPENSSL_CONFIGURE_COMPILER} no-shared")
   set(OPENSSL_1_0_MAKEFILE "ms\\nt.mak")
   set(OPENSSL_1_1_MAKEFILE "makefile")
 endif()

 # Determine which compiler to use for configuration script
 if(CMAKE_CL_64)
   set(OPENSSL_CONFIGURE_COMPILER "${OPENSSL_CONFIGURE_COMPILER} VC-WIN64A")
   set(OPENSSL_1_0_CONFIGURE_MAKEFILE_SCRIPT "ms\\do_win64a.bat")
 else()
   set(OPENSSL_CONFIGURE_COMPILER "${OPENSSL_CONFIGURE_COMPILER} VC-WIN32")
   set(OPENSSL_1_0_CONFIGURE_MAKEFILE_SCRIPT "ms\\do_ms.bat")
 endif()

 # Determine which Makefile is being used
 if(OPENSSL_MAJOR_MINOR_VERSION STREQUAL "1.0")
   set(OPENSSL_MAKEFILE ${OPENSSL_1_0_MAKEFILE})
 else()
   set(OPENSSL_MAKEFILE ${OPENSSL_1_1_MAKEFILE})
 endif()

 # Create a package name for the binaries
 set(OPENSSL_PACKAGE_NAME "openssl-${OPENSSL_VERSION}-${PACKAGE_BUILD_TYPE}-${PACKAGE_ARCH_TYPE}-msvc${VS_INTERNAL_VERSION}.zip" CACHE STRING "OpenSSL package name" FORCE)

 # Create a place holder for the configure script (source_dir property required from external project)
 set(OPENSSL_CONFIGURE_SCRIPT "${OPENSSL_PROJECT_PREFIX}/scripts/configure_openssl.bat")
 set(OPENSSL_CONFIGURE_COMMAND "${OPENSSL_CONFIGURE_SCRIPT}")

 # Create the make script
 set(OPENSSL_MAKE_SCRIPT "${OPENSSL_PROJECT_PREFIX}/scripts/make_openssl.bat")
 file(REMOVE ${OPENSSL_MAKE_SCRIPT})
 file(WRITE ${OPENSSL_MAKE_SCRIPT}
   "@REM Generated make script for OpenSSL\r\n"
   "@ECHO OFF\r\n"
   "SETLOCAL ENABLEDELAYEDEXPANSION\r\n"
   "PUSHD .\r\n")
 if(DEFINED ENV{APPVEYOR} AND CMAKE_CL_64)
   file(APPEND ${OPENSSL_MAKE_SCRIPT}
     "CALL \"C:\\Program Files\\Microsoft SDKs\\Windows\\v7.1\\Bin\\SetEnv.cmd\" /x64\r\n"
     "CALL \"${MSVC_ENVIRONMENT_SCRIPT}\" ${MSVC_ENVIRONMENT_ARCH}\r\n")
 else()
   file(APPEND ${OPENSSL_MAKE_SCRIPT}
     "CALL \"${MSVC_ENVIRONMENT_SCRIPT}\"\r\n")
 endif()
 file(APPEND ${OPENSSL_MAKE_SCRIPT}
   "POPD\r\n")
 if(OPENSSL_MAJOR_MINOR_VERSION STREQUAL "1.0")
   file(APPEND ${OPENSSL_MAKE_SCRIPT}
     "NMake /F \"${OPENSSL_1_0_MAKEFILE}\"\r\n")
 else()
   file(APPEND ${OPENSSL_MAKE_SCRIPT}
     "NMake\r\n")
 endif()
 file(APPEND ${OPENSSL_MAKE_SCRIPT}
   "IF NOT %ERRORLEVEL% EQU 0 (\r\n"
   "  ENDLOCAL\r\n"
   "  EXIT /B 1\r\n"
   ")\r\n"
   "ENDLOCAL\r\n"
   "EXIT /B\r\n")
 set(OPENSSL_BUILD_COMMAND "${OPENSSL_MAKE_SCRIPT}")

 # Create the install script
 file(TO_NATIVE_PATH ${OPENSSL_BINARY_DIR} OPENSSL_NATIVE_BINARY_DIR)
 file(TO_NATIVE_PATH ${OPENSSL_INCLUDE_DIR} OPENSSL_NATIVE_INCLUDE_DIR)
 file(TO_NATIVE_PATH ${OPENSSL_INSTALL_DIR} OPENSSL_NATIVE_INSTALL_DIR)
 file(TO_NATIVE_PATH ${OPENSSL_LIBRARY_DIR} OPENSSL_NATIVE_LIBRARY_DIR)
 set(OPENSSL_INSTALL_SCRIPT "${OPENSSL_PROJECT_PREFIX}/scripts/install_openssl.bat")
 file(REMOVE ${OPENSSL_INSTALL_SCRIPT})
 file(WRITE ${OPENSSL_INSTALL_SCRIPT}
   "@REM Generated install script for OpenSSL\r\n"
   "@ECHO OFF\r\n"
   "SETLOCAL ENABLEDELAYEDEXPANSION\r\n"
   "PUSHD .\r\n")
 if(DEFINED ENV{APPVEYOR} AND CMAKE_CL_64)
   file(APPEND ${OPENSSL_INSTALL_SCRIPT}
     "CALL \"C:\\Program Files\\Microsoft SDKs\\Windows\\v7.1\\Bin\\SetEnv.cmd\" /x64\r\n"
     "CALL \"${MSVC_ENVIRONMENT_SCRIPT}\" ${MSVC_ENVIRONMENT_ARCH}\r\n")
 else()
   file(APPEND ${OPENSSL_INSTALL_SCRIPT}
     "CALL \"${MSVC_ENVIRONMENT_SCRIPT}\"\r\n")
 endif()
 file(APPEND ${OPENSSL_INSTALL_SCRIPT}
   "POPD\r\n"
   "CALL :SHORTENPATH \"${OPENSSL_NATIVE_BINARY_DIR}\" SHORTENED_OPENSSL_BINARY_DIR\r\n"
   "CALL :SHORTENPATH \"${OPENSSL_NATIVE_INCLUDE_DIR}\" SHORTENED_OPENSSL_INCLUDE_DIR\r\n"
   "CALL :SHORTENPATH \"${OPENSSL_NATIVE_INSTALL_DIR}\" SHORTENED_OPENSSL_INSTALL_DIR\r\n"
   "CALL :SHORTENPATH \"${OPENSSL_NATIVE_LIBRARY_DIR}\" SHORTENED_OPENSSL_LIBRARY_DIR\r\n")
 if(OPENSSL_MAJOR_MINOR_VERSION STREQUAL "1.0")
   file(APPEND ${OPENSSL_INSTALL_SCRIPT}
     "NMake /F \"${OPENSSL_1_0_MAKEFILE}\" install\r\n")
 else()
   file(APPEND ${OPENSSL_INSTALL_SCRIPT}
     "NMake install\r\n")
 endif()
 file(APPEND ${OPENSSL_INSTALL_SCRIPT}
   "IF NOT %ERRORLEVEL% EQU 0 (\r\n"
   "  ENDLOCAL\r\n"
   "  EXIT /B 1\r\n"
   ")\r\n"
   "IF EXIST ms\\applink,c (\r\n"
   "  COPY /Y ms\\applink.c \"!SHORTENED_OPENSSL_INCLUDE_DIR!\\openssl\"\r\n"
   "  IF NOT %ERRORLEVEL% EQU 0 (\r\n"
   "    ENDLOCAL\r\n"
   "    EXIT /B 1\r\n"
   "  )\r\n"
   ")\r\n"
   "IF EXIST tmp32dll\\lib.pdb (\r\n"
   "  COPY /Y tmp32dll\\lib.pdb \"!SHORTENED_OPENSSL_BINARY_DIR!\"\r\n"
   "  IF NOT %ERRORLEVEL% EQU 0 (\r\n"
   "    ENDLOCAL\r\n"
   "    EXIT /B 1\r\n"
   "  )\r\n"
   ")\r\n"
   "IF EXIST tmp32\\lib.pdb (\r\n"
   "  COPY /Y tmp32\\lib.pdb \"!SHORTENED_OPENSSL_LIBRARY_DIR!\"\r\n"
   "  IF NOT %ERRORLEVEL% EQU 0 (\r\n"
   "    ENDLOCAL\r\n"
   "    EXIT /B 1\r\n"
   "  )\r\n"
   ")\r\n"
   "COPY /Y LICENSE \"!SHORTENED_OPENSSL_INSTALL_DIR!\"\r\n"
   "ENDLOCAL\r\n"
   "EXIT /B\r\n"
   ":SHORTENPATH\r\n"
   "  FOR %%A IN (\"%~1\") DO SET %~2=%%~SA\r\n"
   "  EXIT /B\r\n")
 set(OPENSSL_INSTALL_COMMAND "${OPENSSL_INSTALL_SCRIPT}")

 # Add OpenSSL as an external project
 externalproject_add(${OPENSSL_LIBRARY_NAME}
   PREFIX ${OPENSSL_PROJECT_PREFIX}
   URL ${OPENSSL_ARCHIVE_URL}
   DOWNLOAD_DIR ${OPENSSL_PROJECT_PREFIX}
   CONFIGURE_COMMAND "${OPENSSL_CONFIGURE_COMMAND}"
   BUILD_COMMAND "${OPENSSL_BUILD_COMMAND}"
   INSTALL_COMMAND "${OPENSSL_INSTALL_COMMAND}"
   BUILD_IN_SOURCE 1
   LOG_DOWNLOAD 1
   LOG_CONFIGURE 1
   LOG_BUILD 1
   LOG_INSTALL 1)

 # Create the configure script
 file(REMOVE ${OPENSSL_CONFIGURE_SCRIPT})
 file(WRITE ${OPENSSL_CONFIGURE_SCRIPT}
   "@REM Generated configure script for OpenSSL\r\n"
   "@ECHO OFF\r\n"
   "SETLOCAL ENABLEDELAYEDEXPANSION\r\n"
   "PUSHD .\r\n")
 if(DEFINED ENV{APPVEYOR} AND CMAKE_CL_64)
   file(APPEND ${OPENSSL_CONFIGURE_SCRIPT}
     "CALL \"C:\\Program Files\\Microsoft SDKs\\Windows\\v7.1\\Bin\\SetEnv.cmd\" /x64\r\n"
     "CALL \"${MSVC_ENVIRONMENT_SCRIPT}\" ${MSVC_ENVIRONMENT_ARCH}\r\n")
 else()
   file(APPEND ${OPENSSL_CONFIGURE_SCRIPT}
     "CALL \"${MSVC_ENVIRONMENT_SCRIPT}\"\r\n")
 endif()
 file(APPEND ${OPENSSL_CONFIGURE_SCRIPT}
   "POPD\r\n"
   "SET PATH=${PERL_PATH};%PATH%\r\n"
   "CALL :SHORTENPATH \"${OPENSSL_NATIVE_INSTALL_DIR}\" SHORTENED_OPENSSL_INSTALL_DIR\r\n")
 if(CASS_USE_ZLIB)
   # OpenSSL requires zlib paths to be relative (otherwise build errors may occur)
   externalproject_get_property(${OPENSSL_LIBRARY_NAME} SOURCE_DIR)
   file(RELATIVE_PATH ZLIB_INCLUDE_RELATIVE_DIR ${SOURCE_DIR} ${ZLIB_INCLUDE_DIR})
   file(TO_NATIVE_PATH ${ZLIB_INCLUDE_RELATIVE_DIR} ZLIB_NATIVE_INCLUDE_RELATIVE_DIR)
   file(RELATIVE_PATH ZLIB_LIBRARY_RELATIVE_DIR ${SOURCE_DIR} ${ZLIB_LIBRARY_DIR})
   file(TO_NATIVE_PATH ${ZLIB_LIBRARY_RELATIVE_DIR} ZLIB_NATIVE_LIBRARY_RELATIVE_DIR)
   set(OPENSSL_WITH_ZLIB_ARGUMENT "zlib ${OPENSSL_ZLIB_CONFIGURE_ARGUMENT} --with-zlib-include=\"${ZLIB_NATIVE_INCLUDE_RELATIVE_DIR}\" --with-zlib-lib=\"${ZLIB_NATIVE_LIBRARY_RELATIVE_DIR}\\${ZLIB_LIB}\"")
   set(OPENSSL_WITH_ZLIB_ARGUMENT "zlib ${OPENSSL_ZLIB_CONFIGURE_ARGUMENT} --with-zlib-include=\"${ZLIB_INCLUDE_RELATIVE_DIR}\" --with-zlib-lib=\"${ZLIB_LIBRARY_RELATIVE_DIR}\\${ZLIB_LIB}\"")
 endif()
 file(APPEND ${OPENSSL_CONFIGURE_SCRIPT}
   "perl Configure ${OPENSSL_WITH_ZLIB_ARGUMENT} --openssldir=!SHORTENED_OPENSSL_INSTALL_DIR! --prefix=!SHORTENED_OPENSSL_INSTALL_DIR! ${OPENSSL_CONFIGURE_COMPILER}\r\n"
   "IF NOT %ERRORLEVEL% EQU 0 (\r\n"
   "  ENDLOCAL\r\n"
   "  EXIT /B 1\r\n"
   ")\r\n")
 if(OPENSSL_MAJOR_MINOR_VERSION STREQUAL "1.0")
   file(APPEND ${OPENSSL_CONFIGURE_SCRIPT}
     "CALL ${OPENSSL_1_0_CONFIGURE_MAKEFILE_SCRIPT}\r\n"
     "IF NOT %ERRORLEVEL% EQU 0 (\r\n"
     "  ENDLOCAL\r\n"
     "  EXIT /B 1\r\n"
     ")\r\n"
     "perl -p -i\".backup\" -e \"s/exe: \\$\\(T_EXE\\)/exe:/g\" ${OPENSSL_1_0_MAKEFILE}\r\n"
     "IF NOT %ERRORLEVEL% EQU 0 (\r\n"
     "  ENDLOCAL\r\n"
     "  EXIT /B 1\r\n"
     ")\r\n")
 endif()
 if(NOT BUILD_SHARED_LIBS)
   file(APPEND ${OPENSSL_CONFIGURE_SCRIPT}
     "perl -p -i\".backup\" -e \"s/\\/MT/\\/MD/g\" ${OPENSSL_MAKEFILE}\r\n"
     "IF NOT %ERRORLEVEL% EQU 0 (\r\n"
     "  ENDLOCAL\r\n"
     "  EXIT /B 1\r\n"
     ")\r\n")
 endif()
 file(APPEND ${OPENSSL_CONFIGURE_SCRIPT}
   "ENDLOCAL\r\n"
   "EXIT /B\r\n"
   ":SHORTENPATH\r\n"
   "  FOR %%A IN (\"%~1\") DO SET %~2=%%~SA\r\n"
   "  EXIT /B\r\n")

 # Determine if zlib should be added as a dependency
 if(CASS_USE_ZLIB)
   add_dependencies(${OPENSSL_LIBRARY_NAME} ${ZLIB_LIBRARY_NAME})
 endif()

 # Update the include directory to use OpenSSL
 include_directories(${OPENSSL_INCLUDE_DIR})
	# Copyright (c) DataStax, Inc.
	#
	# 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
	#
	# http://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.
	cmake_minimum_required(VERSION 3.10 FATAL_ERROR)
	include(ExternalProject)
	include(Windows-Environment)
	if(NOT MSVC_ENVIRONMENT_SCRIPT)
	message(FATAL_ERROR "Visual Studio environment script is required to build OpenSSL")
	endif()

	# OpenSSL related CMake options
	option(OPENSSL_VERSION "OpenSSL version to build and install")
	if(NOT OPENSSL_VERSION)
	# TODO: Should we default to OpenSSL 1.1 (e.g. 1.1.1c)?
	set(OPENSSL_VERSION "1.0.2s")
	endif()
	option(OPENSSL_INSTALL_PREFIX "OpenSSL installation prefix location")
	if(CASS_USE_ZLIB)
	include(ExternalProject-zlib)
	endif()
	set(OPENSSL_VERSION ${OPENSSL_VERSION} CACHE STRING "OpenSSL version to build and install" FORCE)

	# Determine the major and minor version of OpenSSL used
	string(REPLACE "." ";" OPENSSL_VERSION_LIST ${OPENSSL_VERSION})
	list(GET OPENSSL_VERSION_LIST 0 OPENSSL_VERSION_MAJOR)
	list(GET OPENSSL_VERSION_LIST 1 OPENSSL_VERSION_MINOR)
	set(OPENSSL_MAJOR_MINOR_VERSION "${OPENSSL_VERSION_MAJOR}.${OPENSSL_VERSION_MINOR}")

	# Determine the OpenSSL archive name to download
	string(REPLACE "." "_" OPENSSL_ARCHIVE_VERSION ${OPENSSL_VERSION})
	set(OPENSSL_ARCHIVE_NAME OpenSSL_${OPENSSL_ARCHIVE_VERSION} CACHE STRING "OpenSSL archive name" FORCE)

	# Determine if OpenSSL installation directory should be set
	if(NOT OPENSSL_INSTALL_PREFIX)
	set(OPENSSL_INSTALL_PREFIX "${CMAKE_BINARY_DIR}/libs/openssl" CACHE STRING "OpenSSL installation prefix" FORCE)
	endif()

	# OpenSSL external project variables
	set(OPENSSL_LIBRARY_NAME "openssl-${OPENSSL_VERSION}-library")
	set(OPENSSL_PROJECT_PREFIX ${CMAKE_BINARY_DIR}/external/openssl)
	set(OPENSSL_ARCHIVE_URL_PREFIX "https://github.com/openssl/openssl/archive/")
	set(OPENSSL_ARCHIVE_URL_SUFFIX ".tar.gz")
	set(OPENSSL_ARCHIVE_URL "${OPENSSL_ARCHIVE_URL_PREFIX}${OPENSSL_ARCHIVE_NAME}${OPENSSL_ARCHIVE_URL_SUFFIX}")

	# Make sure Visual Studio is available
	if(NOT MSVC)
	message(FATAL_ERROR "Visual Studio is required to build OpenSSL")
	endif()

	# Perl is required to create NMake files for OpenSSL build
	find_package(Perl REQUIRED)
	if(OPENSSL_MAJOR_MINOR_VERSION STREQUAL "1.1")
	if(PERL_VERSION_STRING VERSION_LESS "5.10.0")
	message(FATAL_ERROR "Invalid Perl Version: OpenSSL v1.1.0+ requires Perl v5.10.0+")
	endif()
	endif()
	if(CYGWIN_INSTALL_PATH)
	if(PERL_EXECUTABLE MATCHES "${CYGWIN_INSTALL_PATH}")
	message(FATAL_ERROR "Cygwin Perl Executable Found: Please install Strawberry Perl [http://strawberryperl.com/releases.html]")
	endif()
	endif()
	get_filename_component(PERL_PATH ${PERL_EXECUTABLE} DIRECTORY)
	file(TO_NATIVE_PATH ${PERL_PATH} PERL_PATH)

	message(STATUS "OpenSSL: ${OPENSSL_VERSION}")

	# OpenSSL library configuration variables
	set(OPENSSL_INSTALL_DIR "${OPENSSL_INSTALL_PREFIX}" CACHE STRING "OpenSSL installation directory" FORCE)
	set(OPENSSL_BINARY_DIR "${OPENSSL_INSTALL_DIR}/bin" CACHE STRING "OpenSSL binary directory" FORCE)
	set(OPENSSL_INCLUDE_DIR "${OPENSSL_INSTALL_DIR}/include" CACHE STRING "OpenSSL include directory" FORCE)
	set(OPENSSL_INCLUDE_DIRS "${OPENSSL_INCLUDE_DIR}" CACHE STRING "OpenSSL include directory" FORCE) # Alias to stay consistent with FindOpenSSL
	set(OPENSSL_LIBRARY_DIR "${OPENSSL_INSTALL_DIR}/lib" CACHE STRING "OpenSSL library directory" FORCE)
	if(OPENSSL_MAJOR_MINOR_VERSION STREQUAL "1.0")
	set(OPENSSL_LIBRARIES ${OPENSSL_LIBRARY_DIR}/libeay32.lib
	${OPENSSL_LIBRARY_DIR}/ssleay32.lib
	CACHE STRING "OpenSSL libraries" FORCE)
	else()
	set(OPENSSL_LIBRARIES ${OPENSSL_LIBRARY_DIR}/libcrypto.lib
	${OPENSSL_LIBRARY_DIR}/libssl.lib
	CACHE STRING "OpenSSL libraries" FORCE)
	endif()
	set(OPENSSL_ROOT_DIR "${OPENSSL_INSTALL_DIR}" CACHE STRING "OpenSSL root directory" FORCE)

	# Create build options for the platform build scripts
	if(BUILD_SHARED_LIBS)
	if(CASS_USE_ZLIB)
	set(OPENSSL_ZLIB_CONFIGURE_ARGUMENT "zlib-dynamic")
	set(ZLIB_LIB zlib.lib)
	endif()
	else()
	if(CASS_USE_ZLIB)
	set(OPENSSL_ZLIB_CONFIGURE_ARGUMENT "no-zlib-dynamic")
	set(ZLIB_LIB zlibstatic.lib)
	endif()
	endif()

	# Determine if shared or static library should be built
	set(OPENSSL_CONFIGURE_COMPILER "no-asm no-ssl2")
	if(BUILD_SHARED_LIBS)
	set(OPENSSL_CONFIGURE_COMPILER "${OPENSSL_CONFIGURE_COMPILER} shared")
	set(OPENSSL_1_0_MAKEFILE "ms\\ntdll.mak")
	set(OPENSSL_1_1_MAKEFILE "makefile.shared")
	else()
	set(OPENSSL_CONFIGURE_COMPILER "${OPENSSL_CONFIGURE_COMPILER} no-shared")
	set(OPENSSL_1_0_MAKEFILE "ms\\nt.mak")
	set(OPENSSL_1_1_MAKEFILE "makefile")
	endif()

	# Determine which compiler to use for configuration script
	if(CMAKE_CL_64)
	set(OPENSSL_CONFIGURE_COMPILER "${OPENSSL_CONFIGURE_COMPILER} VC-WIN64A")
	set(OPENSSL_1_0_CONFIGURE_MAKEFILE_SCRIPT "ms\\do_win64a.bat")
	else()
	set(OPENSSL_CONFIGURE_COMPILER "${OPENSSL_CONFIGURE_COMPILER} VC-WIN32")
	set(OPENSSL_1_0_CONFIGURE_MAKEFILE_SCRIPT "ms\\do_ms.bat")
	endif()

	# Determine which Makefile is being used
	if(OPENSSL_MAJOR_MINOR_VERSION STREQUAL "1.0")
	set(OPENSSL_MAKEFILE ${OPENSSL_1_0_MAKEFILE})
	else()
	set(OPENSSL_MAKEFILE ${OPENSSL_1_1_MAKEFILE})
	endif()

	# Create a package name for the binaries
	set(OPENSSL_PACKAGE_NAME "openssl-${OPENSSL_VERSION}-${PACKAGE_BUILD_TYPE}-${PACKAGE_ARCH_TYPE}-msvc${VS_INTERNAL_VERSION}.zip" CACHE STRING "OpenSSL package name" FORCE)

	# Create a place holder for the configure script (source_dir property required from external project)
	set(OPENSSL_CONFIGURE_SCRIPT "${OPENSSL_PROJECT_PREFIX}/scripts/configure_openssl.bat")
	set(OPENSSL_CONFIGURE_COMMAND "${OPENSSL_CONFIGURE_SCRIPT}")

	# Create the make script
	set(OPENSSL_MAKE_SCRIPT "${OPENSSL_PROJECT_PREFIX}/scripts/make_openssl.bat")
	file(REMOVE ${OPENSSL_MAKE_SCRIPT})
	file(WRITE ${OPENSSL_MAKE_SCRIPT}
	"@REM Generated make script for OpenSSL\r\n"
	"@ECHO OFF\r\n"
	"SETLOCAL ENABLEDELAYEDEXPANSION\r\n"
	"PUSHD .\r\n")
	if(DEFINED ENV{APPVEYOR} AND CMAKE_CL_64)
	file(APPEND ${OPENSSL_MAKE_SCRIPT}
	"CALL \"C:\\Program Files\\Microsoft SDKs\\Windows\\v7.1\\Bin\\SetEnv.cmd\" /x64\r\n"
	"CALL \"${MSVC_ENVIRONMENT_SCRIPT}\" ${MSVC_ENVIRONMENT_ARCH}\r\n")
	else()
	file(APPEND ${OPENSSL_MAKE_SCRIPT}
	"CALL \"${MSVC_ENVIRONMENT_SCRIPT}\"\r\n")
	endif()
	file(APPEND ${OPENSSL_MAKE_SCRIPT}
	"POPD\r\n")
	if(OPENSSL_MAJOR_MINOR_VERSION STREQUAL "1.0")
	file(APPEND ${OPENSSL_MAKE_SCRIPT}
	"NMake /F \"${OPENSSL_1_0_MAKEFILE}\"\r\n")
	else()
	file(APPEND ${OPENSSL_MAKE_SCRIPT}
	"NMake\r\n")
	endif()
	file(APPEND ${OPENSSL_MAKE_SCRIPT}
	"IF NOT %ERRORLEVEL% EQU 0 (\r\n"
	" ENDLOCAL\r\n"
	" EXIT /B 1\r\n"
	")\r\n"
	"ENDLOCAL\r\n"
	"EXIT /B\r\n")
	set(OPENSSL_BUILD_COMMAND "${OPENSSL_MAKE_SCRIPT}")

	# Create the install script
	file(TO_NATIVE_PATH ${OPENSSL_BINARY_DIR} OPENSSL_NATIVE_BINARY_DIR)
	file(TO_NATIVE_PATH ${OPENSSL_INCLUDE_DIR} OPENSSL_NATIVE_INCLUDE_DIR)
	file(TO_NATIVE_PATH ${OPENSSL_INSTALL_DIR} OPENSSL_NATIVE_INSTALL_DIR)
	file(TO_NATIVE_PATH ${OPENSSL_LIBRARY_DIR} OPENSSL_NATIVE_LIBRARY_DIR)
	set(OPENSSL_INSTALL_SCRIPT "${OPENSSL_PROJECT_PREFIX}/scripts/install_openssl.bat")
	file(REMOVE ${OPENSSL_INSTALL_SCRIPT})
	file(WRITE ${OPENSSL_INSTALL_SCRIPT}
	"@REM Generated install script for OpenSSL\r\n"
	"@ECHO OFF\r\n"
	"SETLOCAL ENABLEDELAYEDEXPANSION\r\n"
	"PUSHD .\r\n")
	if(DEFINED ENV{APPVEYOR} AND CMAKE_CL_64)
	file(APPEND ${OPENSSL_INSTALL_SCRIPT}
	"CALL \"C:\\Program Files\\Microsoft SDKs\\Windows\\v7.1\\Bin\\SetEnv.cmd\" /x64\r\n"
	"CALL \"${MSVC_ENVIRONMENT_SCRIPT}\" ${MSVC_ENVIRONMENT_ARCH}\r\n")
	else()
	file(APPEND ${OPENSSL_INSTALL_SCRIPT}
	"CALL \"${MSVC_ENVIRONMENT_SCRIPT}\"\r\n")
	endif()
	file(APPEND ${OPENSSL_INSTALL_SCRIPT}
	"POPD\r\n"
	"CALL :SHORTENPATH \"${OPENSSL_NATIVE_BINARY_DIR}\" SHORTENED_OPENSSL_BINARY_DIR\r\n"
	"CALL :SHORTENPATH \"${OPENSSL_NATIVE_INCLUDE_DIR}\" SHORTENED_OPENSSL_INCLUDE_DIR\r\n"
	"CALL :SHORTENPATH \"${OPENSSL_NATIVE_INSTALL_DIR}\" SHORTENED_OPENSSL_INSTALL_DIR\r\n"
	"CALL :SHORTENPATH \"${OPENSSL_NATIVE_LIBRARY_DIR}\" SHORTENED_OPENSSL_LIBRARY_DIR\r\n")
	if(OPENSSL_MAJOR_MINOR_VERSION STREQUAL "1.0")
	file(APPEND ${OPENSSL_INSTALL_SCRIPT}
	"NMake /F \"${OPENSSL_1_0_MAKEFILE}\" install\r\n")
	else()
	file(APPEND ${OPENSSL_INSTALL_SCRIPT}
	"NMake install\r\n")
	endif()
	file(APPEND ${OPENSSL_INSTALL_SCRIPT}
	"IF NOT %ERRORLEVEL% EQU 0 (\r\n"
	" ENDLOCAL\r\n"
	" EXIT /B 1\r\n"
	")\r\n"
	"IF EXIST ms\\applink,c (\r\n"
	" COPY /Y ms\\applink.c \"!SHORTENED_OPENSSL_INCLUDE_DIR!\\openssl\"\r\n"
	" IF NOT %ERRORLEVEL% EQU 0 (\r\n"
	" ENDLOCAL\r\n"
	" EXIT /B 1\r\n"
	" )\r\n"
	")\r\n"
	"IF EXIST tmp32dll\\lib.pdb (\r\n"
	" COPY /Y tmp32dll\\lib.pdb \"!SHORTENED_OPENSSL_BINARY_DIR!\"\r\n"
	" IF NOT %ERRORLEVEL% EQU 0 (\r\n"
	" ENDLOCAL\r\n"
	" EXIT /B 1\r\n"
	" )\r\n"
	")\r\n"
	"IF EXIST tmp32\\lib.pdb (\r\n"
	" COPY /Y tmp32\\lib.pdb \"!SHORTENED_OPENSSL_LIBRARY_DIR!\"\r\n"
	" IF NOT %ERRORLEVEL% EQU 0 (\r\n"
	" ENDLOCAL\r\n"
	" EXIT /B 1\r\n"
	" )\r\n"
	")\r\n"
	"COPY /Y LICENSE \"!SHORTENED_OPENSSL_INSTALL_DIR!\"\r\n"
	"ENDLOCAL\r\n"
	"EXIT /B\r\n"
	":SHORTENPATH\r\n"
	" FOR %%A IN (\"%~1\") DO SET %~2=%%~SA\r\n"
	" EXIT /B\r\n")
	set(OPENSSL_INSTALL_COMMAND "${OPENSSL_INSTALL_SCRIPT}")

	# Add OpenSSL as an external project
	externalproject_add(${OPENSSL_LIBRARY_NAME}
	PREFIX ${OPENSSL_PROJECT_PREFIX}
	URL ${OPENSSL_ARCHIVE_URL}
	DOWNLOAD_DIR ${OPENSSL_PROJECT_PREFIX}
	CONFIGURE_COMMAND "${OPENSSL_CONFIGURE_COMMAND}"
	BUILD_COMMAND "${OPENSSL_BUILD_COMMAND}"
	INSTALL_COMMAND "${OPENSSL_INSTALL_COMMAND}"
	BUILD_IN_SOURCE 1
	LOG_DOWNLOAD 1
	LOG_CONFIGURE 1
	LOG_BUILD 1
	LOG_INSTALL 1)

	# Create the configure script
	file(REMOVE ${OPENSSL_CONFIGURE_SCRIPT})
	file(WRITE ${OPENSSL_CONFIGURE_SCRIPT}
	"@REM Generated configure script for OpenSSL\r\n"
	"@ECHO OFF\r\n"
	"SETLOCAL ENABLEDELAYEDEXPANSION\r\n"
	"PUSHD .\r\n")
	if(DEFINED ENV{APPVEYOR} AND CMAKE_CL_64)
	file(APPEND ${OPENSSL_CONFIGURE_SCRIPT}
	"CALL \"C:\\Program Files\\Microsoft SDKs\\Windows\\v7.1\\Bin\\SetEnv.cmd\" /x64\r\n"
	"CALL \"${MSVC_ENVIRONMENT_SCRIPT}\" ${MSVC_ENVIRONMENT_ARCH}\r\n")
	else()
	file(APPEND ${OPENSSL_CONFIGURE_SCRIPT}
	"CALL \"${MSVC_ENVIRONMENT_SCRIPT}\"\r\n")
	endif()
	file(APPEND ${OPENSSL_CONFIGURE_SCRIPT}
	"POPD\r\n"
	"SET PATH=${PERL_PATH};%PATH%\r\n"
	"CALL :SHORTENPATH \"${OPENSSL_NATIVE_INSTALL_DIR}\" SHORTENED_OPENSSL_INSTALL_DIR\r\n")
	if(CASS_USE_ZLIB)
	# OpenSSL requires zlib paths to be relative (otherwise build errors may occur)
	externalproject_get_property(${OPENSSL_LIBRARY_NAME} SOURCE_DIR)
	file(RELATIVE_PATH ZLIB_INCLUDE_RELATIVE_DIR ${SOURCE_DIR} ${ZLIB_INCLUDE_DIR})
	file(TO_NATIVE_PATH ${ZLIB_INCLUDE_RELATIVE_DIR} ZLIB_NATIVE_INCLUDE_RELATIVE_DIR)
	file(RELATIVE_PATH ZLIB_LIBRARY_RELATIVE_DIR ${SOURCE_DIR} ${ZLIB_LIBRARY_DIR})
	file(TO_NATIVE_PATH ${ZLIB_LIBRARY_RELATIVE_DIR} ZLIB_NATIVE_LIBRARY_RELATIVE_DIR)
	set(OPENSSL_WITH_ZLIB_ARGUMENT "zlib ${OPENSSL_ZLIB_CONFIGURE_ARGUMENT} --with-zlib-include=\"${ZLIB_NATIVE_INCLUDE_RELATIVE_DIR}\" --with-zlib-lib=\"${ZLIB_NATIVE_LIBRARY_RELATIVE_DIR}\\${ZLIB_LIB}\"")
	set(OPENSSL_WITH_ZLIB_ARGUMENT "zlib ${OPENSSL_ZLIB_CONFIGURE_ARGUMENT} --with-zlib-include=\"${ZLIB_INCLUDE_RELATIVE_DIR}\" --with-zlib-lib=\"${ZLIB_LIBRARY_RELATIVE_DIR}\\${ZLIB_LIB}\"")
	endif()
	file(APPEND ${OPENSSL_CONFIGURE_SCRIPT}
	"perl Configure ${OPENSSL_WITH_ZLIB_ARGUMENT} --openssldir=!SHORTENED_OPENSSL_INSTALL_DIR! --prefix=!SHORTENED_OPENSSL_INSTALL_DIR! ${OPENSSL_CONFIGURE_COMPILER}\r\n"
	"IF NOT %ERRORLEVEL% EQU 0 (\r\n"
	" ENDLOCAL\r\n"
	" EXIT /B 1\r\n"
	")\r\n")
	if(OPENSSL_MAJOR_MINOR_VERSION STREQUAL "1.0")
	file(APPEND ${OPENSSL_CONFIGURE_SCRIPT}
	"CALL ${OPENSSL_1_0_CONFIGURE_MAKEFILE_SCRIPT}\r\n"
	"IF NOT %ERRORLEVEL% EQU 0 (\r\n"
	" ENDLOCAL\r\n"
	" EXIT /B 1\r\n"
	")\r\n"
	"perl -p -i\".backup\" -e \"s/exe: \\$\\(T_EXE\\)/exe:/g\" ${OPENSSL_1_0_MAKEFILE}\r\n"
	"IF NOT %ERRORLEVEL% EQU 0 (\r\n"
	" ENDLOCAL\r\n"
	" EXIT /B 1\r\n"
	")\r\n")
	endif()
	if(NOT BUILD_SHARED_LIBS)
	file(APPEND ${OPENSSL_CONFIGURE_SCRIPT}
	"perl -p -i\".backup\" -e \"s/\\/MT/\\/MD/g\" ${OPENSSL_MAKEFILE}\r\n"
	"IF NOT %ERRORLEVEL% EQU 0 (\r\n"
	" ENDLOCAL\r\n"
	" EXIT /B 1\r\n"
	")\r\n")
	endif()
	file(APPEND ${OPENSSL_CONFIGURE_SCRIPT}
	"ENDLOCAL\r\n"
	"EXIT /B\r\n"
	":SHORTENPATH\r\n"
	" FOR %%A IN (\"%~1\") DO SET %~2=%%~SA\r\n"
	" EXIT /B\r\n")

	# Determine if zlib should be added as a dependency
	if(CASS_USE_ZLIB)
	add_dependencies(${OPENSSL_LIBRARY_NAME} ${ZLIB_LIBRARY_NAME})
	endif()

	# Update the include directory to use OpenSSL
	include_directories(${OPENSSL_INCLUDE_DIR})