dbus - hal 属性什么时候更新

我在 PropertyNotified 信号期间从我的处理程序调用 org.freedesktop.Hal.Device 上的 GetProperty。我只在已添加或更改的属性上调用 GetProperty。

当我在属性添加期间调用 GetProperty 时，我收到 org.freedesktop.Hal.NoSuchProperty 异常。我还担心在更改期间，我会得到旧值。

我应该什么时候调用 GetProperty？涉及哪些竞争条件？

最佳答案

DeviceExists 方法如何(如 here ):

    if device.PropertyExists('info.product'):
        return device.GetProperty('info.product')
    return "unknown"

和 PropertyModified 信号，( ex from real world ):

 #
 # _CBHalDeviceConnected
 #
 # INTERNAL
 #
 # Callback triggered when a device is connected through Hal.
 #

 def _CBHalDeviceConnected(self, obj_path):
...
 self.device.connect_to_signal("PropertyModified",
   self._CBHalDeviceAuthStateChanged)
...

#
# _CBHalDeviceAuthStateChanged
#
# INTERNAL
#
# Callback triggered when a Hal device property is changed,
# for checking authorization state changes
#

def _CBHalDeviceAuthStateChanged(self,num_changes,properties):
 for property in properties:
 property_name, added, removed = property
 if property_name == "pda.pocketpc.password":
 self.logger.info("_CBHalDeviceAuthStateChanged:
     device authorization state changed: reauthorizing")
 self._ProcessAuth()

HAL 0.5.10 Specification
D-Bus Specification
D-Bus Tutorial

关于dbus - hal 属性什么时候更新，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/69744/