michael@0: """By using execfile(this_file, dict(__file__=this_file)) you will
michael@0: activate this virtualenv environment.
michael@0: 
michael@0: This can be used when you must use an existing Python interpreter, not
michael@0: the virtualenv bin/python
michael@0: """
michael@0: 
michael@0: try:
michael@0:     __file__
michael@0: except NameError:
michael@0:     raise AssertionError(
michael@0:         "You must run this like execfile('path/to/activate_this.py', dict(__file__='path/to/activate_this.py'))")
michael@0: import sys
michael@0: import os
michael@0: 
michael@0: old_os_path = os.environ['PATH']
michael@0: os.environ['PATH'] = os.path.dirname(os.path.abspath(__file__)) + os.pathsep + old_os_path
michael@0: base = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
michael@0: if sys.platform == 'win32':
michael@0:     site_packages = os.path.join(base, 'Lib', 'site-packages')
michael@0: else:
michael@0:     site_packages = os.path.join(base, 'lib', 'python%s' % sys.version[:3], 'site-packages')
michael@0: prev_sys_path = list(sys.path)
michael@0: import site
michael@0: site.addsitedir(site_packages)
michael@0: sys.real_prefix = sys.prefix
michael@0: sys.prefix = base
michael@0: # Move the added items to the front of the path:
michael@0: new_sys_path = []
michael@0: for item in list(sys.path):
michael@0:     if item not in prev_sys_path:
michael@0:         new_sys_path.append(item)
michael@0:         sys.path.remove(item)
michael@0: sys.path[:0] = new_sys_path