"""
A release-automation toolkit.

Don't use this outside of Twisted.

Maintainer: Christopher Armstrong
"""

import os
import re


# errors

class DirectoryExists(OSError):
    """Some directory exists when it shouldn't."""
    pass



class DirectoryDoesntExist(OSError):
    """Some directory doesn't exist when it should."""
    pass



class CommandFailed(OSError):
    pass



# utilities

def sh(command, null=True, prompt=False):
    """
    I'll try to execute `command', and if `prompt' is true, I'll
    ask before running it.  If the command returns something other
    than 0, I'll raise CommandFailed(command).
    """
    print "--$", command

    if prompt:
        if raw_input("run ?? ").startswith('n'):
            return
    if null:
        command = "%s > /dev/null" % command
    if os.system(command) != 0:
        raise CommandFailed(command)



def runChdirSafe(f, *args, **kw):
    origdir = os.path.abspath('.')
    try:
        return f(*args, **kw)
    finally:
        os.chdir(origdir)