74 lines
2.1 KiB
Python
74 lines
2.1 KiB
Python
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# -*- coding: utf-8 -*-
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from threading import Thread, Lock
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import traceback
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import functools
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try:
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from queue import Queue
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except ImportError:
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from Queue import Queue
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class GenericListener(object):
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lock = Lock()
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def __init__(self):
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self.handlers = []
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self.listening = False
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self.queue = Queue()
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def invoke_handlers(self, event):
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for handler in self.handlers:
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try:
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if handler(event):
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# Stop processing this hotkey.
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return 1
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except Exception as e:
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traceback.print_exc()
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def start_if_necessary(self):
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"""
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Starts the listening thread if it wans't already.
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"""
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self.lock.acquire()
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try:
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if not self.listening:
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self.init()
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self.listening = True
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self.listening_thread = Thread(target=self.listen)
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self.listening_thread.daemon = True
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self.listening_thread.start()
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self.processing_thread = Thread(target=self.process)
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self.processing_thread.daemon = True
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self.processing_thread.start()
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finally:
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self.lock.release()
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def pre_process_event(self, event):
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raise NotImplementedError('This method should be implemented in the child class.')
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def process(self):
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"""
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Loops over the underlying queue of events and processes them in order.
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"""
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assert self.queue is not None
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while True:
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event = self.queue.get()
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if self.pre_process_event(event):
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self.invoke_handlers(event)
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self.queue.task_done()
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def add_handler(self, handler):
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"""
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Adds a function to receive each event captured, starting the capturing
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process if necessary.
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"""
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self.start_if_necessary()
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self.handlers.append(handler)
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def remove_handler(self, handler):
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""" Removes a previously added event handler. """
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while handler in self.handlers:
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self.handlers.remove(handler)
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