michael@0: # This Source Code Form is subject to the terms of the Mozilla Public
michael@0: # License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0: # file, You can obtain one at http://mozilla.org/MPL/2.0/.
michael@0: 
michael@0: import os
michael@0: import errno
michael@0: 
michael@0: def mtime(path):
michael@0:     try:
michael@0:         return os.stat(path).st_mtime
michael@0:     except OSError as e:
michael@0:         if e.errno == errno.ENOENT:
michael@0:             return -1
michael@0:         raise
michael@0: 
michael@0: def rebuild_check(args):
michael@0:     target = args[0]
michael@0:     deps = args[1:]
michael@0:     t = mtime(target)
michael@0:     if t < 0:
michael@0:         print target
michael@0:         return
michael@0: 
michael@0:     newer = []
michael@0:     removed = []
michael@0:     for dep in deps:
michael@0:         deptime = mtime(dep)
michael@0:         if deptime < 0:
michael@0:             removed.append(dep)
michael@0:         elif mtime(dep) > t:
michael@0:             newer.append(dep)
michael@0: 
michael@0:     if newer and removed:
michael@0:         print 'Rebuilding %s because %s changed and %s was removed' % (target, ', '.join(newer), ', '.join(removed))
michael@0:     elif newer:
michael@0:         print 'Rebuilding %s because %s changed' % (target, ', '.join(newer))
michael@0:     elif removed:
michael@0:         print 'Rebuilding %s because %s was removed' % (target, ', '.join(removed))
michael@0:     else:
michael@0:         print 'Rebuilding %s for an unknown reason' % target
michael@0: 
michael@0: if __name__ == '__main__':
michael@0:     import sys
michael@0:     rebuild_check(sys.argv[1:])