73 lines
1.9 KiB
Python
73 lines
1.9 KiB
Python
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class BarcodeReader(DeviceBase):
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def doInitialize(self):
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self.disable()
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self.readout = None
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self.processing = False
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self.task_callable=None
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def enable(self):
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microscan_cmd.write("<H>")
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self.setState(State.Ready)
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def disable(self):
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microscan_cmd.write("<I>")
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self.setState(State.Disabled)
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def get(self,timeout=1.0):
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self.state.assertReady()
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try:
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self.setState(State.Busy)
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microscan.flush()
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ret = microscan.waitString(int(timeout * 1000))
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self.setCache(ret, None)
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return ret
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except:
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self.setCache(None, None)
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return None
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finally:
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self.setState(State.Ready)
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def doUpdate(self):
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self.get()
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def read(self,timeout=1.0):
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if self.processing:
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raise Exception("Ongoing read operation")
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self.processing = True
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try:
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initial = self.state
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if initial == State.Disabled:
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self.enable()
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try:
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return self.get(timeout)
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finally:
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if initial == State.Disabled:
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self.disable()
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finally:
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self.processing = False
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def _read_task(self, timeout):
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global readout
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self.readout = self.read(timeout)
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return self.readout
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def start_read(self, timeout=1.0):
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self.readout = None
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self.task_callable = fork((self._read_task, (timeout,)))
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def get_readout(self):
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return self.readout
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def wait_readout(self):
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if self.task_callable is not None:
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join(self.task_callable)
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self.task_callable = None
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return self.readout
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add_device(BarcodeReader("barcode_reader"), force = True)
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