device.py 文件源码

def _prependToEnvVar(self, newVal, envVar):
        path = self._getEnvVarAsList(envVar)
        foundValue = False
        for entry in path:
            # Search to determine if the new value is already in the path
            try:
                if os.path.samefile(entry, newVal):
                    # The value is already in the path
                    foundValue = True
                    break
            except OSError:
                # If we can't find concrete files to compare, fall back to string compare
                if entry == newVal:
                    # The value is already in the path
                    foundValue = True
                    break

        if not foundValue:
            # The value does not already exist
            if os.environ.has_key(envVar):
                newpath = newVal+os.path.pathsep + os.getenv(envVar)+os.path.pathsep
            else:
                newpath = newVal+os.path.pathsep
            os.putenv(envVar, newpath)
            os.environ[envVar] = newpath