Merge pull request #77 from stephen-sorley/cmake_modernize

Updated CMake minimum version to 2.8.12.

.travis.yml

@@ -4,8 +4,10 @@ addons:
     apt:
         sources:
             - ubuntu-toolchain-r-test
+            - kubuntu-backports           # For CMake 2.8.12
             - llvm-toolchain-precise-3.7
         packages:
+            - cmake
             - gcc-4.8
             - g++-4.8
             - lcov

CMakeLists.txt

@@ -1,4 +1,11 @@
-CMAKE_MINIMUM_REQUIRED (VERSION 2.8)
+CMAKE_MINIMUM_REQUIRED (VERSION 2.8.12)
+
+# Fix for CMake policy warning when building with CMake >= 3.0.
+# TODO: remove this fix once minimum version is updated to 3.0 or newer.
+IF (NOT CMAKE_VERSION VERSION_LESS 3.0)
+	CMAKE_POLICY (SET CMP0048 NEW)
+ENDIF ()
+
 INCLUDE (CheckIncludeFiles)
 INCLUDE (CheckTypeSize)
 INCLUDE (CheckFunctionExists)
@@ -48,17 +55,6 @@ IF (NOT DEFINED CARES_INSTALL_LOCATION_BIN)
 ENDIF ()
 
 
-# When chain building C-Ares, we should set some of the same variables that a 
-# standard Find_Package(CAres) would set.  It just references the internal
-# build paths rather than an already-installed version.
-SET (CARES_FOUND 1 CACHE INTERNAL "CARES LIBRARY FOUND")
-SET (CARES_INCLUDE_DIRS "${PROJECT_BINARY_DIR};${CMAKE_CURRENT_SOURCE_DIR}" CACHE INTERNAL "CARES INCLUDE DIRECTORIES")
-SET (CARES_LIBRARIES ${PROJECT_NAME} CACHE INTERNAL "CARES LIBRARIES")
-IF (CARES_STATIC AND NOT CARES_SHARED)
-	SET (CARES_DEFINITIONS "-DCARES_STATICLIB" CACHE INTERNAL "CARES DEFINITIONS")
-ENDIF ()
-
-
 # Look for dependent/required libraries
 CHECK_LIBRARY_EXISTS (resolv res_servicename "" HAVE_RES_SERVICENAME_IN_LIBRESOLV)
 IF (HAVE_RES_SERVICENAME_IN_LIBRESOLV)
@@ -493,11 +489,6 @@ CONFIGURE_FILE (ares_build.h.cmake ${PROJECT_BINARY_DIR}/ares_build.h)
 CONFIGURE_FILE (ares_config.h.cmake ${PROJECT_BINARY_DIR}/ares_config.h)
 
 
-INCLUDE_DIRECTORIES (
-	${CARES_INCLUDE_DIRS}
-)
-
-
 # TRANSFORM_MAKEFILE_INC
 #
 # This function consumes the "Makefile.inc" autotools file, and converts it into
@@ -538,7 +529,6 @@ include(${PROJECT_BINARY_DIR}/Makefile.inc.cmake)
 # Build the dynamic/shared library
 IF (CARES_SHARED)
 	ADD_LIBRARY (${PROJECT_NAME} SHARED ${CSOURCES})
-	SET_TARGET_PROPERTIES (${PROJECT_NAME} PROPERTIES COMPILE_FLAGS "-DHAVE_CONFIG_H=1 -DCARES_BUILDING_LIBRARY" OUTPUT_NAME cares)
 
 	# Convert CARES_LIB_VERSIONINFO libtool version format into VERSION and SOVERSION
 	# Convert from ":" separated into CMake list format using ";"
@@ -549,26 +539,57 @@ IF (CARES_SHARED)
 	MATH (EXPR CARES_LIB_VERSION_MAJOR "${CARES_LIB_VERSION_CURRENT} - ${CARES_LIB_VERSION_AGE}")
 	SET  (CARES_LIB_VERSION_MINOR "${CARES_LIB_VERSION_AGE}")
 	SET  (CARES_LIB_VERSION_RELEASE "${CARES_LIB_VERSION_REVISION}")
-	SET_TARGET_PROPERTIES (${PROJECT_NAME} PROPERTIES VERSION "${CARES_LIB_VERSION_MAJOR}.${CARES_LIB_VERSION_MINOR}.${CARES_LIB_VERSION_RELEASE}")
-	SET_TARGET_PROPERTIES (${PROJECT_NAME} PROPERTIES SOVERSION "${CARES_LIB_VERSION_MAJOR}")
 
-	TARGET_LINK_LIBRARIES (${PROJECT_NAME} ${CARES_DEPENDENT_LIBS})
+	SET_TARGET_PROPERTIES (${PROJECT_NAME} PROPERTIES
+		OUTPUT_NAME cares
+		VERSION     "${CARES_LIB_VERSION_MAJOR}.${CARES_LIB_VERSION_MINOR}.${CARES_LIB_VERSION_RELEASE}"
+		SOVERSION   "${CARES_LIB_VERSION_MAJOR}"
+	)
+
+	TARGET_INCLUDE_DIRECTORIES (${PROJECT_NAME} PUBLIC "${PROJECT_BINARY_DIR}" "${CMAKE_CURRENT_SOURCE_DIR}")
+
+	TARGET_COMPILE_DEFINITIONS (${PROJECT_NAME} PRIVATE HAVE_CONFIG_H=1 CARES_BUILDING_LIBRARY)
+
+	TARGET_LINK_LIBRARIES (${PROJECT_NAME} PUBLIC ${CARES_DEPENDENT_LIBS})
+
 	IF (CARES_INSTALL)
 		INSTALL (TARGETS ${PROJECT_NAME} DESTINATION ${CARES_INSTALL_LOCATION_LIBS})
 	ENDIF ()
 	SET (STATIC_SUFFIX "_static")
+
+	# For chain building: add alias targets that look like import libs that would be returned by find_package(Cares).
+	ADD_LIBRARY (Cares::cares_shared ALIAS ${PROJECT_NAME})
+	ADD_LIBRARY (Cares::cares        ALIAS ${PROJECT_NAME})
 ENDIF ()
 
 # Build the static library
 IF (CARES_STATIC)
-	ADD_LIBRARY (${PROJECT_NAME}${STATIC_SUFFIX} STATIC ${CSOURCES})
+	SET (LIBNAME ${PROJECT_NAME}${STATIC_SUFFIX})
-	SET_TARGET_PROPERTIES (${PROJECT_NAME}${STATIC_SUFFIX} PROPERTIES COMPILE_FLAGS "-DHAVE_CONFIG_H=1 -DCARES_STATICLIB" OUTPUT_NAME cares)
+
+	ADD_LIBRARY (${LIBNAME} STATIC ${CSOURCES})
+
+	SET_TARGET_PROPERTIES (${LIBNAME} PROPERTIES OUTPUT_NAME cares)
 	IF (CARES_STATIC_PIC)
-		SET_TARGET_PROPERTIES (${PROJECT_NAME}${STATIC_SUFFIX} PROPERTIES POSITION_INDEPENDENT_CODE True)
+		SET_TARGET_PROPERTIES (${LIBNAME} PROPERTIES POSITION_INDEPENDENT_CODE True)
 	ENDIF ()
-	TARGET_LINK_LIBRARIES (${PROJECT_NAME}${STATIC_SUFFIX} ${CARES_DEPENDENT_LIBS})
+
+	TARGET_INCLUDE_DIRECTORIES (${LIBNAME} PUBLIC "${PROJECT_BINARY_DIR}" "${CMAKE_CURRENT_SOURCE_DIR}")
+
+	TARGET_COMPILE_DEFINITIONS (${LIBNAME}
+		PUBLIC  CARES_STATICLIB
+		PRIVATE HAVE_CONFIG_H=1
+	)
+
+	TARGET_LINK_LIBRARIES (${LIBNAME} PUBLIC ${CARES_DEPENDENT_LIBS})
 	IF (CARES_INSTALL)
-		INSTALL (TARGETS ${PROJECT_NAME}${STATIC_SUFFIX} DESTINATION ${CARES_INSTALL_LOCATION_LIBS})
+		INSTALL (TARGETS ${LIBNAME} DESTINATION ${CARES_INSTALL_LOCATION_LIBS})
+	ENDIF ()
+
+	# For chain building: add alias targets that look like import libs that would be returned by find_package(Cares).
+	ADD_LIBRARY (Cares::cares_static ALIAS ${LIBNAME})
+	IF (NOT TARGET Cares::cares)
+		# Only use static for the generic alias if shared lib wasn't built.
+		ADD_LIBRARY (Cares::cares ALIAS ${LIBNAME})
 	ENDIF ()
 ENDIF ()
 
@@ -580,10 +601,16 @@ IF (CARES_INSTALL)
 ENDIF ()
 
 
+# Legacy chain-building variables (provided for compatibility with old code).
+# Don't use these, external code should be updated to refer to the aliases directly (e.g., Cares::cares).
+SET (CARES_FOUND 1 CACHE INTERNAL "CARES LIBRARY FOUND")
+SET (CARES_LIBRARIES Cares::cares CACHE INTERNAL "CARES LIBRARIES")
+
+
 # Build ahost
 ADD_EXECUTABLE (ahost ahost.c ${SAMPLESOURCES})
-SET_TARGET_PROPERTIES(ahost PROPERTIES COMPILE_FLAGS "-DHAVE_CONFIG_H=1 ${CARES_DEFINITIONS}")
+TARGET_COMPILE_DEFINITIONS (ahost PRIVATE HAVE_CONFIG_H=1)
-TARGET_LINK_LIBRARIES (ahost ${CARES_LIBRARIES} ${CARES_DEPENDENT_LIBS})
+TARGET_LINK_LIBRARIES (ahost PRIVATE ${PROJECT_NAME})
 IF (CARES_INSTALL)
 	INSTALL (TARGETS ahost RUNTIME DESTINATION ${CARES_INSTALL_LOCATION_BIN})
 ENDIF ()
@@ -591,8 +618,8 @@ ENDIF ()
 
 # Build adig
 ADD_EXECUTABLE (adig adig.c ${SAMPLESOURCES})
-SET_TARGET_PROPERTIES(adig PROPERTIES COMPILE_FLAGS "-DHAVE_CONFIG_H=1 ${CARES_DEFINITIONS}")
+TARGET_COMPILE_DEFINITIONS (adig PRIVATE HAVE_CONFIG_H=1)
-TARGET_LINK_LIBRARIES (adig ${CARES_LIBRARIES} ${CARES_DEPENDENT_LIBS})
+TARGET_LINK_LIBRARIES (adig PRIVATE ${PROJECT_NAME})
 IF (CARES_INSTALL)
 	INSTALL (TARGETS adig RUNTIME DESTINATION ${CARES_INSTALL_LOCATION_BIN})
 ENDIF ()
@@ -600,8 +627,8 @@ ENDIF ()
 
 # Build acountry
 ADD_EXECUTABLE (acountry acountry.c ${SAMPLESOURCES})
-SET_TARGET_PROPERTIES(acountry PROPERTIES COMPILE_FLAGS "-DHAVE_CONFIG_H=1 ${CARES_DEFINITIONS}")
+TARGET_COMPILE_DEFINITIONS (acountry PRIVATE HAVE_CONFIG_H=1)
-TARGET_LINK_LIBRARIES (acountry ${CARES_LIBRARIES} ${CARES_DEPENDENT_LIBS})
+TARGET_LINK_LIBRARIES (acountry PRIVATE ${PROJECT_NAME})
 IF (CARES_INSTALL)
 	INSTALL (TARGETS acountry RUNTIME DESTINATION ${CARES_INSTALL_LOCATION_BIN})
 ENDIF ()