platform_build_soong/reverse_path.py
Dan Willemsen 6ac18ecb84 Improve BUILDDIR handling with symlinks
If BUILDDIR is a local symlink to another directory in the same parent
directory (out -> out.angler), then using out and .. as relative paths
to get back and forth work.

But if BUILDDIR is a symlink to another directory altogether (out ->
/mnt/sdd/out.master), then we shouldn't be relying on relative paths (so
that the source directory can still be moved).

Change-Id: I946c8116090410ab2b935eafba9b6e96f5f2f1dd
2016-03-22 19:53:36 -07:00

40 lines
1.3 KiB
Python
Executable file

#!/usr/bin/env python
from __future__ import print_function
import os
import sys
# Find the best reverse path to reference the current directory from another
# directory. We use this to find relative paths to and from the source and build
# directories.
#
# If the directory is given as an absolute path, return an absolute path to the
# current directory.
#
# If there's a symlink involved, and the same relative path would not work if
# the symlink was replace with a regular directory, then return an absolute
# path. This handles paths like out -> /mnt/ssd/out
#
# For symlinks that can use the same relative path (out -> out.1), just return
# the relative path. That way out.1 can be renamed as long as the symlink is
# updated.
#
# For everything else, just return the relative path. That allows the source and
# output directories to be moved as long as they stay in the same position
# relative to each other.
def reverse_path(path):
if path.startswith("/"):
return os.path.abspath('.')
realpath = os.path.relpath(os.path.realpath('.'), os.path.realpath(path))
relpath = os.path.relpath('.', path)
if realpath != relpath:
return os.path.abspath('.')
return relpath
if __name__ == '__main__':
print(reverse_path(sys.argv[1]))