CMake build now has support for non-relocatable builds

Although the previous build was not defining ENABLE_RELOCATION, it was treating
the build as relocatable by default, setting an RPATH based on $ORIGIN and
never defining PKGLIBDIR, PKGDATADIR etc in the source code. Although this
works fine on Debian, the assumption that the libraries are ALWAYS available at
$ORIGIN/../lib/darkradiant might not be suitable for all systems.

We now expose an additional CMake option ENABLE_RELOCATION which defaults to
ON; by setting this to OFF the build becomes the more usual Unix-style build
with hard-coded absolute data and library paths. In addition, when making a
relocatable build the expected ENABLE_RELOCATION macro is also defined in
config.h.

CMakeLists.txt

@@ -7,10 +7,30 @@ project(darkradiant VERSION 2.9.1)
 set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_STANDARD_REQUIRED True)
 
+# Expose some build options
+option(SKIP_DM_PLUGINS "Don't build Dark Mod specific plugins" OFF)
+option(ENABLE_RELOCATION
+       "Avoid hard-coded absolute paths to libraries or resources"
+       ON)
+
+# Define GNU-style directory structure by default
+include(GNUInstallDirs)
+
+# Set up core build paths
+set(CORE_MODULE_LIBRARY "libradiantcore")
+set(PKGDATADIR "${CMAKE_INSTALL_FULL_DATADIR}/darkradiant")
+if (NOT ${ENABLE_RELOCATION})
+    set(PKGLIBDIR "${CMAKE_INSTALL_FULL_LIBDIR}/darkradiant")
+    set(HTMLDIR "${CMAKE_INSTALL_FULL_DATADIR}/doc/darkradiant")
+endif()
+
 # Build shared libraries by default
 option(BUILD_SHARED_LIBS "Build shared libraries" ON)
-option(SKIP_DM_PLUGINS "Don't build Dark Mod specific plugins" OFF)
-set(CMAKE_INSTALL_RPATH "$ORIGIN/../lib/darkradiant")
+if (${ENABLE_RELOCATION})
+    set(CMAKE_INSTALL_RPATH "$ORIGIN/../lib/darkradiant")
+else()
+    set(CMAKE_INSTALL_RPATH "${PKGLIBDIR}")
+endif()
 
 # Debug or release mode
 if(NOT CMAKE_BUILD_TYPE)
@@ -21,10 +41,6 @@ add_compile_definitions(
     $<$<CONFIG:Release>:NDEBUG>
 )
 
-# Define GNU-style directory structure by default, and pass directories to the
-# code with defines
-include(GNUInstallDirs)
-
 # Locate system packages
 include(FindPkgConfig)
 pkg_check_modules(XML libxml-2.0 REQUIRED)
@@ -57,7 +73,6 @@ add_compile_definitions(POSIX
 add_link_options(LINKER:-z,defs)
 
 # Generate config.h
-set(CORE_MODULE_LIBRARY "libradiantcore")
 configure_file(config.h.in config.h)
 add_compile_definitions(HAVE_CONFIG_H)
 include_directories(${CMAKE_CURRENT_BINARY_DIR})
@@ -107,21 +122,19 @@ install(FILES ${CMAKE_CURRENT_BINARY_DIR}/install/darkradiant.desktop
         DESTINATION ${CMAKE_INSTALL_DATADIR}/applications)
 
 # Install resources
-set(PKG_DATA_DIR "${CMAKE_INSTALL_DATADIR}/darkradiant")
-
 file(GLOB XML_FILES "${PROJECT_SOURCE_DIR}/install/*.xml")
-install(FILES ${XML_FILES} DESTINATION ${PKG_DATA_DIR})
+install(FILES ${XML_FILES} DESTINATION ${PKGDATADIR})
 
-install(DIRECTORY install/games DESTINATION ${PKG_DATA_DIR})
-install(DIRECTORY install/bitmaps DESTINATION ${PKG_DATA_DIR})
-install(DIRECTORY install/gl DESTINATION ${PKG_DATA_DIR})
-install(DIRECTORY install/ui DESTINATION ${PKG_DATA_DIR}
+install(DIRECTORY install/games DESTINATION ${PKGDATADIR})
+install(DIRECTORY install/bitmaps DESTINATION ${PKGDATADIR})
+install(DIRECTORY install/gl DESTINATION ${PKGDATADIR})
+install(DIRECTORY install/ui DESTINATION ${PKGDATADIR}
         FILES_MATCHING PATTERN "*.ttf" PATTERN "*.xrc")
 
 # Install locale data
 install(DIRECTORY install/i18n/de TYPE LOCALE
         FILES_MATCHING PATTERN "*.mo")
 
 # Install scripts
-install(DIRECTORY install/scripts DESTINATION ${PKG_DATA_DIR}
+install(DIRECTORY install/scripts DESTINATION ${PKGDATADIR}
         FILES_MATCHING PATTERN "*.py")

config.h.in

@@ -5,5 +5,17 @@
 /* Project version */
 #define PACKAGE_VERSION "@CMAKE_PROJECT_VERSION@"
 
+/* Defined if this is a relocatable build */
+#cmakedefine ENABLE_RELOCATION
+
 /* Locale directory */
 #define LOCALEDIR "@CMAKE_INSTALL_FULL_LOCALEDIR@"
+
+/* Package library directory (e.g. /usr/lib/darkradiant) */
+#cmakedefine PKGLIBDIR "@PKGLIBDIR@"
+
+/* Package data directory (e.g. /usr/share/darkradiant) */
+#cmakedefine PKGDATADIR "@PKGDATADIR@"
+
+/* HTML directory (e.g. /usr/share/doc/darkradiant) */
+#cmakedefine HTMLDIR "@HTMLDIR@"

libs/module/ApplicationContextBase.cpp

@@ -32,15 +32,15 @@ std::string ApplicationContextBase::getApplicationPath() const
 std::vector<std::string> ApplicationContextBase::getLibraryPaths() const
 {
 	auto libBasePath = os::standardPathWithSlash(getLibraryBasePath());
-	
+
 #if defined(__APPLE__) && defined(DR_MODULES_NEXT_TO_APP)
 	// Xcode output goes to the application folder right now
 	return { libBasePath };
 #else
-	return 
-	{ 
-		libBasePath + MODULES_DIR, 
-		libBasePath + PLUGINS_DIR 
+	return
+	{
+		libBasePath + MODULES_DIR,
+		libBasePath + PLUGINS_DIR
 	};
 #endif
 }
@@ -50,10 +50,12 @@ std::string ApplicationContextBase::getLibraryBasePath() const
 #if defined(__APPLE__)
 	return _appPath;
 #elif defined(POSIX)
-#   if defined(PKGLIBDIR) && !defined(ENABLE_RELOCATION)
+#   if defined(PKGLIBDIR)
 	return PKGLIBDIR;
-#   else
+#   elif defined(ENABLE_RELOCATION)
 	return _appPath + "../lib/darkradiant/";
+#   else
+#   error "Either PKGLIBDIR or ENABLE_RELOCATION must be defined"
 #   endif
 #else // !defined(POSIX)
 	return _appPath;
@@ -66,20 +68,22 @@ std::string ApplicationContextBase::getRuntimeDataPath() const
     // The Resources are in the Bundle folder Contents/Resources/, whereas the
     // application binary is located in Contents/MacOS/
     std::string path = getApplicationPath() + "../Resources/";
-    
+
     // When launching the app from Xcode, the Resources/ folder
     // is next to the binary
     if (!fs::exists(path))
     {
         path = getApplicationPath() + "Resources/";
     }
-    
+
     return path;
 #elif defined(POSIX)
-#   if defined(PKGDATADIR) && !defined(ENABLE_RELOCATION)
+#   if defined(PKGDATADIR)
     return std::string(PKGDATADIR) + "/";
-#   else
+#   elif defined(ENABLE_RELOCATION)
     return _appPath + "../share/darkradiant/";
+#   else
+#   error "Either PKGDATADIR or ENABLE_RELOCATION must be defined"
 #   endif
 #else
     return getApplicationPath();
@@ -89,10 +93,12 @@ std::string ApplicationContextBase::getRuntimeDataPath() const
 std::string ApplicationContextBase::getHTMLPath() const
 {
 #if defined(POSIX)
-#if defined(HTMLDIR) && !defined(ENABLE_RELOCATION)
+#if defined(HTMLDIR)
     return std::string(HTMLDIR) + "/";
-#else
+#elif defined(ENABLE_RELOCATION)
     return _appPath + "../share/doc/darkradiant/";
+#else
+#error "Either HTMLDIR or ENABLE_RELOCATION must be defined"
 #endif
 #else
     // TODO: implement correct path for macOS and Windows