1 #!/usr/bin/env python 2 3 from __future__ import print_function 4 5 import os 6 import sys 7 8 # Find the best reverse path to reference the current directory from another 9 # directory. We use this to find relative paths to and from the source and build 10 # directories. 11 # 12 # If the directory is given as an absolute path, return an absolute path to the 13 # current directory. 14 # 15 # If there's a symlink involved, and the same relative path would not work if 16 # the symlink was replace with a regular directory, then return an absolute 17 # path. This handles paths like out -> /mnt/ssd/out 18 # 19 # For symlinks that can use the same relative path (out -> out.1), just return 20 # the relative path. That way out.1 can be renamed as long as the symlink is 21 # updated. 22 # 23 # For everything else, just return the relative path. That allows the source and 24 # output directories to be moved as long as they stay in the same position 25 # relative to each other. 26 def reverse_path(path): 27 if path.startswith("/"): 28 return os.path.abspath('.') 29 30 realpath = os.path.relpath(os.path.realpath('.'), os.path.realpath(path)) 31 relpath = os.path.relpath('.', path) 32 33 if realpath != relpath: 34 return os.path.abspath('.') 35 36 return relpath 37 38 39 if __name__ == '__main__': 40 print(reverse_path(sys.argv[1])) 41
