import os

import util

class TPException(Exception):
    def __str__(self):
        return "%s: %s" % (self.__class__.__name__, Exception.__str__(self))


class InvalidReference     (TPException): pass
class AccessDenied         (TPException): pass
class UnavailableResource  (TPException): pass


class IncompleteSubject    (TPException):
    def __init__(self): pass

class NoSuchDomain         (TPException): pass
class NoSuchMethod         (TPException): pass
class InspectorNotFound    (TPException): pass
class UnavailableInspector (TPException): pass
class SkinNotFound         (TPException): pass

class MissingDependency    (TPException): pass

class InternalError        (TPException): pass


class InterfaceViolation   (TPException): pass


def check_file_dependency(dname, fname, msg):
    fpath = os.path.join(dname, fname)
    if not os.path.exists(fpath):
        raise MissingDependency(msg)

def check_installed_application(name, msg=''):
    if os.system('type %s > /dev/null 2> /dev/null' % name) != 0:
        raise MissingDependency(msg)