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from . import VPNStateChange
from enum import Enum
from typing import Callable
from .state import StateType
EDUVPN_CALLBACK_PROPERTY = "_eduvpn_property_callback"
# A state transition decorator for classes
# To use this, make sure to register the class with `register_class_callbacks`
def class_state_transition(state: int, state_type: StateType) -> Callable:
def wrapper(func):
setattr(func, EDUVPN_CALLBACK_PROPERTY, (state, state_type))
return func
return wrapper
class EventHandler(object):
def __init__(self):
self.handlers = {}
def change_class_callbacks(self, cls, add=True) -> None:
# Loop over method names
for method_name in dir(cls):
try:
# Get the method
method = getattr(cls, method_name)
except:
# Unable to get a value, go to the next
continue
# If it has a callback defined, add it to the events
method_value = getattr(method, EDUVPN_CALLBACK_PROPERTY, None)
if method_value:
state, state_type = method_value
if add:
self.add_event(state, state_type, method)
else:
self.remove_event(state, state_type, method)
def remove_event(self, state: int, state_type: StateType, func: Callable):
for key, values in self.handlers.copy().items():
if key == (state, state_type):
values.remove(func)
if not values:
del self.handlers[key]
else:
self.handlers[key] = values
def add_event(self, state: int, state_type: StateType, func: Callable):
if (state, state_type) not in self.handlers:
self.handlers[(state, state_type)] = []
self.handlers[(state, state_type)].append(func)
# A decorator for standalone functions
def on(self, state: int, state_type: StateType) -> Callable:
def wrapped_f(func):
self.add_event(state, state_type, func)
return func
return wrapped_f
def run_state(
self, state: int, other_state: int, state_type: StateType, data: str
) -> None:
if (state, state_type) not in self.handlers:
return
for func in self.handlers[(state, state_type)]:
func(other_state, data)
def run(self, old_state: int, new_state: int, data: str) -> None:
if old_state == new_state:
return
# First run leave transitions, then enter
# The state is done when the wait event finishes
self.run_state(old_state, new_state, StateType.Leave, data)
self.run_state(new_state, old_state, StateType.Enter, data)
self.run_state(new_state, old_state, StateType.Wait, data)
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