From ca9f7861296b734673b388d61e0e2510fbcef625 Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Fri, 5 Oct 2012 15:05:59 +0200
Subject: [PATCH 1/1] better handling of environment variables, and set more of
 them

---
 build_system.py | 35 ++++++++++++++++++++++++++++++-----
 1 file changed, 30 insertions(+), 5 deletions(-)

diff --git a/build_system.py b/build_system.py
index 971cf7b..478503e 100644
--- 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. ')
-- 
2.30.2