CMake: Configure: Implement config_package and mangle_package functions with test-case uses.

cmake/modules/ConfigurePackage.cmake

@@ -0,0 +1,75 @@
+# Filename: ConfigurePackage.cmake
+# Author: kestred (30 Nov, 2013)
+#
+# This modules defines a function which finds and configures libraries
+# and packages for Panda3Ds configuration file headers (.h files).
+#
+# Additionally, it defines a macro for including Mangle modules.
+#
+# Assumes the file has already been found with find_package().
+#
+
+# Usage:
+#   mangle_package(LIBRARY_NAME)
+macro(mangle_package PKG_NAME)
+	include(Mangle${PKG_NAME})
+endmacro()
+
+# Usage:
+#   config_package(PACKAGE_NAME [REQUIRED] [COMMENT <display-name>])
+function(config_package PKG_NAME)
+	# Set function vars to defaults
+	set(DISPLAY_NAME ${PKG_NAME})
+
+	# Handle optional function arguments
+	foreach(arg ${ARGN})
+		if(ARG_IS_LIBRARY)
+			unset(ARG_IS_LIBRARY)
+			set(LIB_NAME ${arg})
+			break()
+		elseif(ARG_IS_COMMENT)
+			unset(ARG_IS_COMMENT)
+			set(DISPLAY_NAME ${arg})
+			break()
+		endif()
+
+		if(arg MATCHES "REQUIRED")
+			# TODO: Implement currently ignored
+		elseif(arg MATCHES "COMMENT")
+			set(ARG_IS_COMMENT TRUE)
+		else()
+			message(AUTHOR_WARNING "configure_package() unexpected argument: '${arg}'")
+			return()
+		endif()
+	endforeach()
+	if(ARG_IS_COMMENT)
+		message(AUTHOR_WARNING "configure_package() expected display-name after 'COMMENT'")
+	endif()
+
+	if(FOUND_${PKG_NAME})
+		# Output success after finding the package for the first time
+		if(NOT DEFINED USE_${PKG_NAME})
+		endif()
+
+		# Add a USE_XYZZY config variable to the cache
+		set(USE_${PKG_NAME} TRUE CACHE BOOL "If true, compile Panda3D with ${DISPLAY_NAME}")
+		if(USE_${PKG_NAME})
+			set(HAVE_${PKG_NAME} TRUE PARENT_SCOPE)
+		endif()
+
+	elseif(DEFINED USE_${PKG_NAME})
+		# If we were compiling with a particular package, but we can't find it;
+		#     then inform the user the package was lost.
+		if(USE_${PKG_NAME})
+			message(STATUS "- Can no longer find ${DISPLAY_NAME}")
+
+			# Only unset if USE_XYZZY is true;
+			# This allows us to set USE_XYZZY to false to silence the output
+			unset(USE_${PKG_NAME})
+		endif()
+
+	else()
+		# Output failure to find package
+		message(STATUS "- Did not find ${DISPLAY_NAME}")
+	endif()
+endfunction()

dtool/Configure.cmake

@@ -1,6 +1,7 @@
 message(STATUS "")
 message("Configuring support for the following optional third-party packages:")
 
+include(ConfigurePackage)
 
 # Check for and configure Eigen library
 find_package(Eigen3)
@@ -91,7 +92,7 @@ endif()
 # Check for and configure TIFF library
 # Mangle the builtin FindTIFF output to match Panda3D's config-style
 find_package(TIFF QUIET COMPONENTS tiff z)
-include(MangleTIFF)
+mangle_package(TIFF)
 if(FOUND_TIFF)
 	set(USE_TIFF TRUE CACHE BOOL "If true, compile Panda3D with libtiff")
 	if(USE_TIFF)
@@ -107,17 +108,7 @@ endif()
 
 # Check for and configure Tar library
 find_package(Tar)
-if(FOUND_TAR)
-	set(USE_TAR TRUE CACHE BOOL "If true, compile Panda3D with libtar")
-	if(USE_TAR)
-		set(HAVE_TAR TRUE)
-	endif()
-endif()
-if(HAVE_TAR)
-	message(STATUS "+ libtar")
-else()
-	message(STATUS "- Did not find libtar")
-endif()
+config_package(TAR COMMENT "libtar")
 
 
 # Check for and configure FFTW library