better handling of environment variables, and set more of them

diff --git a/build_system.py b/build_system.py
index 971cf7b17ecffaff0293b32997a998bbbba4a6c4..478503ef9a900fbcc4954018dce5b61fe2d9c397 100644 (file)
--- a/build_system.py
+++ b/build_system.py
@@ -9,6 +9,27 @@ class CMake:
                self.buildFolder = os.path.abspath(buildFolder)
                self.config = config
        
+       def setEnv(self, name, val):
+               '''Set the given environment variable, return old value'''
+               oldVal = os.getenv(name)
+               os.putenv(name, val)
+               return oldVal
+       
+       def prependDirToEnv(self, name, dir, default):
+               '''Prepends the given directory to the environment variable. If the variable is empty, dir isprepended to the default.
+                  Returns the old value.'''
+               oldVal = os.getenv(name)
+               oldPaths = default if oldVal is None else oldVal
+               os.putenv(name, dir+':'+oldPaths)
+               return oldVal
+       
+       def restoreEnv(self, name, oldVal):
+               '''Restore environment variable to previous value'''
+               if oldVal is None:
+                       os.unsetenv(name)
+               else:
+                       os.putenv(name, oldVal)
+       
        def build(self, reconfigure, waitAfterConfig):
                # Make sure we have a build directory
                if not os.path.exists(self.buildFolder): os.makedirs(self.buildFolder)
@@ -16,13 +37,17 @@ class CMake:
                # In case of reconfiguration, delete cache file if it exists
                cacheFile = 'CMakeCache.txt'
                if os.path.exists(cacheFile) and reconfigure: os.remove(cacheFile)
-               # Run cmake
-               os.putenv('PKG_CONFIG_PATH', os.path.join(self.config['installDir'], 'lib', 'pkgconfig')) # I found no way to do this within cmake
-               os.putenv('CMAKE_PREFIX_PATH', self.config['installDir'])
+               # Run cmake, in the proper environment, then restore old environment
+               oldPKGConfigPath = self.setEnv('PKG_CONFIG_PATH', os.path.join(self.config['installDir'], 'lib', 'pkgconfig'))
+               oldCMakePrefixPath = self.setEnv('CMAKE_PREFIX_PATH', self.config['installDir'])
+               oldXDGDataDirs = self.prependDirToEnv('XDG_DATA_DIRS', os.path.join(self.config['installDir'], 'share'), '/usr/share')
+               oldXDGConfigDirs = self.prependDirToEnv('XDG_CONFIG_DIRS', os.path.join(self.config['installDir'], 'etc', 'xdg'), '/etc/xdg')
                subprocess.check_call(['cmake', self.sourceFolder, '-DCMAKE_BUILD_TYPE='+self.config['buildType'],
                        '-DCMAKE_INSTALL_PREFIX='+self.config['installDir']]+self.config.get('cmakeParameters', []))
-               os.unsetenv('PKG_CONFIG_PATH')
-               os.unsetenv('CMAKE_PREFIX_PATH')
+               self.restoreEnv('PKG_CONFIG_PATH', oldPKGConfigPath)
+               self.restoreEnv('CMAKE_PREFIX_PATH', oldCMakePrefixPath)
+               self.restoreEnv('XDG_DATA_DIRS', oldXDGDataDirs)
+               self.restoreEnv('XDG_CONFIG_DIRS', oldXDGConfigDirs)
                # if asked to do so, wait
                if waitAfterConfig:
                        raw_input('Configuration done. Hit "Enter" to build the project. ')