lib/python/Components/GUISkin.py

   1 from GUIComponent import *
   2
   3 class GUISkin:
   4         def __init__(self):
   5                 pass
   6
   7         def createGUIScreen(self, parent):
   8                 for (name, val) in self.items():
   9                         if isinstance(val, GUIComponent):
  10                                 val.GUIcreate(parent, None)
  11
  12         def deleteGUIScreen(self):
  13                 for (name, val) in self.items():
  14                         if isinstance(val, GUIComponent):
  15                                 val.GUIdelete()
  16                         try:
  17                                 val.fix()
  18                         except:
  19                                 pass
  20
  21                         # DIESER KOMMENTAR IST NUTZLOS UND MITTLERWEILE VERALTET! (glaub ich)
  22                         # BITTE NICHT LESEN!
  23                         # note: you'll probably run into this assert. if this happens, don't panic!
  24                         # yes, it's evil. I told you that programming in python is just fun, and
  25                         # suddently, you have to care about things you don't even know.
  26                         #
  27                         # but calm down, the solution is easy, at least on paper:
  28                         #
  29                         # Each Component, which is a GUIComponent, owns references to each
  30                         # instantiated eWidget (namely in screen.data[name]["instance"], in case
  31                         # you care.)
  32                         # on deleteGUIscreen, all eWidget *must* (!) be deleted (otherwise,
  33                         # well, problems appear. I don't want to go into details too much,
  34                         # but this would be a memory leak anyway.)
  35                         # The assert beyond checks for that. It asserts that the corresponding
  36                         # eWidget is about to be removed (i.e., that the refcount becomes 0 after
  37                         # running deleteGUIscreen).
  38                         # (You might wonder why the refcount is checked for 2 and not for 1 or 0 -
  39                         # one reference is still hold by the local variable 'w', another one is
  40                         # hold be the function argument to sys.getrefcount itself. So only if it's
  41                         # 2 at this point, the object will be destroyed after leaving deleteGUIscreen.)
  42                         #
  43                         # Now, how to fix this problem? You're holding a reference somewhere. (References
  44                         # can only be hold from Python, as eWidget itself isn't related to the c++
  45                         # way of having refcounted objects. So it must be in python.)
  46                         #
  47                         # It could be possible that you're calling deleteGUIscreen trough a call of
  48                         # a PSignal. For example, you could try to call screen.doClose() in response
  49                         # to a Button::click. This will fail. (It wouldn't work anyway, as you would
  50                         # remove a dialog while running it. It never worked - enigma1 just set a
  51                         # per-mainloop variable on eWidget::close() to leave the exec()...)
  52                         # That's why Session supports delayed closes. Just call Session.close() and
  53                         # it will work.
  54                         #
  55                         # Another reason is that you just stored the data["instance"] somewhere. or
  56                         # added it into a notifier list and didn't removed it.
  57                         #
  58                         # If you can't help yourself, just ask me. I'll be glad to help you out.
  59                         # Sorry for not keeping this code foolproof. I really wanted to archive
  60                         # that, but here I failed miserably. All I could do was to add this assert.
  61 #                       assert sys.getrefcount(w) == 2, "too many refs hold to " + str(w)
  62
  63         def close(self):
  64                 self.deleteGUIScreen()
  65