StateMachine for global photobooth state started to implement. States and Events defined, state actions still missing
This commit is contained in:
Balthasar Reuter
351
photobooth/StateMachine.py
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351
photobooth/StateMachine.py
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#!/usr/bin/env python3
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# -*- coding: utf-8 -*-
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# Photobooth - a flexible photo booth software
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# Copyright (C) 2018 Balthasar Reuter <photobooth at re - web dot eu>
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU Affero General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU Affero General Public License for more details.
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#
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# You should have received a copy of the GNU Affero General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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class Context:
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def __init__(self, initial_state):
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super().__init__()
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self.state = initial_state
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@property
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def state(self):
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return self._state
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@state.setter
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def state(self, new_state):
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if not isinstance(new_state, State):
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raise TypeError('new_state must implement State')
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def handleEvent(self, event):
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if not isinstance(event, Event):
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raise TypeError('event must implement Event')
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if isinstance(event, ErrorEvent):
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self.state = ErrorState(event.exception, self.state)
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elif isinstance(event, TeardownEvent):
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self.state = TeardownState(event.target)
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else:
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self.state.handleEvent(event, self)
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class Event:
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def __init__(self, name):
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super().__init__()
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self.name = name
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def __str__(self):
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return self.name
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@property
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def name(self):
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return self._name
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@name.setter
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def name(self, name):
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if not isinstance(name, str):
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raise TypeError('name must be a str')
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self._name = name
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class ErrorEvent(Event):
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def __init__(self, exception):
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super().__init__('Error')
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self.exception = exception
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def __str__(self):
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return str(self.exception)
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@property
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def exception(self):
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return self._exception
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@exception.setter
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def exception(self, exception):
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if not isinstance(exception, Exception):
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raise TypeError('exception must be derived from Exception')
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self._exception = exception
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class TeardownEvent(Event):
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EXIT = 0
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RESTART = 1
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WELCOME = 2
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def __init__(self, target):
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self._target = target
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super().__init__('Teardown')
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@property
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def target(self):
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return self._target
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class GuiEvent(Event):
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def __init__(self, name):
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super().__init__(name)
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class GpioEvent(Event):
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def __init__(self, name):
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super().__init__(name)
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class CameraEvent(Event):
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def __init__(self, name):
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super().__init__(name)
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class WorkerEvent(Event):
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def __init__(self, name):
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super().__init__(name)
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class State:
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def __init__(self):
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super().__init__()
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self.update()
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def update(self):
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pass
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def handleEvent(self, event, context):
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raise NotImplementedError()
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class ErrorState(State):
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def __init__(self, exception, old_state):
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self.old_state = old_state
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super().__init__()
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@property
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def old_state(self):
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return self._old_state
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@old_state.setter
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def old_state(self, old_state):
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if not isinstance(old_state, State):
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raise TypeError('old_state must be derived from State')
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self._old_state = old_state
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def handleEvent(self, event, context):
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if isinstance(event, GuiEvent) and event.name == 'retry':
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context.state = self.old_state
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context.state.update()
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elif isinstance(event, GuiEvent) and event.name == 'abort':
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context.state = TeardownState()
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else:
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raise TypeError('Unknown Event type "{}"'.format(event))
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class TeardownState(State):
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def __init__(self, target):
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super().__init__()
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class WelcomeState(State):
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def __init__(self):
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super().__init__()
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def handleEvent(self, event, context):
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if isinstance(event, GuiEvent):
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if event.name == 'start':
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context.state = StartupState()
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elif event.name == 'settings':
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context.state = SettingsState()
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elif event.name == 'exit':
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context.state = TeardownState()
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else:
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raise ValueError('Unknown GuiEvent "{}"'.format(event.name))
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else:
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raise TypeError('Unknown Event type "{}"'.format(event))
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class SettingsState(State):
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def __init__(self):
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super().__init__()
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def handleEvent(self, event, context):
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if isinstance(event, GuiEvent) and event.name == 'welcome':
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context.state = WelcomeState()
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else:
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raise TypeError('Unknown Event type "{}"'.format(event))
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class StartupState(State):
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def __init__(self):
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super().__init__()
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def handleEvent(self, event, context):
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if isinstance(event, CameraEvent) and event.name == 'ready':
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context.state = IdleState()
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else:
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raise TypeError('Unknown Event type "{}"'.format(event))
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class IdleState(State):
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def __init__(self):
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super().__init__()
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def handleEvent(self, event, context):
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if ((isinstance(event, GuiEvent) or isinstance(event, GpioEvent)) and
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event.name == 'trigger'):
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context.state = GreeterState()
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else:
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raise TypeError('Unknown Event type "{}"'.format(event))
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class GreeterState(State):
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def __init__(self):
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super().__init__()
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def handleEvent(self, event, context):
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if ((isinstance(event, GuiEvent) or isinstance(event, GpioEvent)) and
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event.name == 'countdown'):
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context.state = CountdownState()
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else:
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raise TypeError('Unknown Event type "{}"'.format(event))
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class CountdownState(State):
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def __init__(self):
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super().__init__()
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def handleEvent(self, event, context):
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if isinstance(event, GuiEvent) and event.name == 'capture':
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context.state == CaptureState()
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else:
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raise TypeError('Unknown Event type "{}"'.format(event))
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class CaptureState(State):
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def __init__(self):
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super().__init__()
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def handleEvent(self, event, context):
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if isinstance(event, CameraEvent) and event.name == 'next':
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context.state = CountdownState()
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elif isinstance(event, CameraEvent) and event.name == 'assemble':
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context.state = AssembleState()
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else:
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raise TypeError('Unknown Event type "{}"'.format(event))
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class AssembleState(State):
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def __init__(self):
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super().__init__()
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def handleEvent(self, event, context):
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if isinstance(event, CameraEvent) and event.name == 'review':
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context.state = ReviewState()
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else:
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raise TypeError('Unknown Event type "{}"'.format(event))
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class ReviewState(State):
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def __init__(self):
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super().__init__()
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def handleEvent(self, event, context):
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if isinstance(event, GuiEvent) and event.name == 'postprocess':
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context.state == PostprocessState()
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else:
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raise TypeError('Unknown Event type "{}"'.format(event))
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class PostprocessState(State):
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def __init__(self):
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super().__init__()
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def handleEvent(self, event, context):
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if ((isinstance(event, GuiEvent) or isinstance(event, GpioEvent)) and
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event.name == 'idle'):
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context.state == IdleState()
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else:
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raise TypeError('Unknown Event type "{}"'.format(event))
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