try:
    import _dbapi
except ImportError:
    import _nullapi as _dbapi

__all__ = [
    "hooknames",
    "addHook",
    "debugHooks",
]

hooknames = _dbapi._hooks.keys()

def addHook(state, func):
    """addHook("stats", funcion)
    Add callable to IOC start sequence.
    
    Callables are run in the reverse of the order in
    which they were added.
    
    >>> def show():
    ...     print 'State Occurred'
    >>> addHook("AfterIocRunning", show)
    
    An additional special hook 'AtIocExit' may be used
    for cleanup actions during IOC shutdown.
    """
    sid = _dbapi._hooks[state]
    try:
        slist = _dbapi._hooktable[sid]
    except KeyError:
        slist = []
        _dbapi._hooktable[sid] = slist

    slist.append(func)


def debugHooks():
    """Install debugging print to hooks
    """
    for h in hooknames:
        def _showstate(state=h):
            print 'Reached state',state
        addHook(h, _showstate)