kicad-developers team mailing list archive

[Wayne Stambaugh <stambaughw@xxxxxxxxx>]

LOL, I just replied to Miles.  Thanks Orson for helping out!

On 3/2/2018 8:36 AM, Maciej Sumiński wrote:
> Hi Miles,
> 
> I suppose the silence in the thread indicates there are not many
> developers knowing the Python scripting interface inside out. Since you
> are both studying the scripting interface and developing own scripts, it
> is quite possible you are the most competent person to give us an advice
> on how to proceed. See some comments below, but I am neither a Python
> script developer nor a scripting interface maintainer, so I might be
> lacking some basic knowledge here.
> 
> On 02/28/2018 05:12 PM, miles mccoo wrote:
>> So I'm plugin-ifying my python scripts (the mechanism is awesome). One of
>> the plugins deletes some stuff and that is causing trouble.
>>
>>
>>
>> I'm not sure how to fix the root cause. Hence this mail.
>>
>>
>>
>> The plugin just deletes Edge.Cuts[1]:
>> for d in board.GetDrawings():
>>             if (d.GetLayerName() == 'Edge.Cuts'):
>>                 board.Remove(d)
>>
>>
>>
>> in board_item_container.i, I see this (with stuff deleted):
>> %rename(RemoveNative)    BOARD_ITEM_CONTAINER::Remove;
>>     def Remove(self,item):
>>         self.RemoveNative(item)
>>         item.thisown=1
>>
>>
>> Setting thisown tells, python "you own it". Delete it when you're done.
>> Which it does.
>>
>>
>> The problem this causes is that the plugin mechanism saves a list of all
>> objects before running the plugin and then checks if any of them has a null
>> list after (ie is it still in the design).
> 
> Is this mechanism implemented to handle memory leaks? If so, would not
> it be sufficient to stick to 'thisown' flag on Remove() calls or is
> there another way objects might be destroyed using Python scripts?
> 
>> Since the object has been deleted by python, the plugin stuff gets confused.
>>
>>
>> *So, the question is how to fix this?*
>>
>>
>> It appears that the plugin infrastructure will delete for you (that's what
>> I'm guessing), so the thisown setting shouldn't be done.
>>
>>
>> On the other hand, if running code from within a standalone script (ie from
>> regular python shell), now thisown'ing it would yield a memory leak.
>>
>>
>>
>> Perhaps the plugin stuff should have some sort of flag indicating "you're
>> in a plugin". Then the thisown setting could be conditional.
> 
> If the object listing mechanism is required for other reasons, then I
> suppose it is second best idea. Generally speaking, I would like to make
> the scripting interface convenient for the users, so they do not need to
> worry about whether their scripts are run standalone or as a plugin.
> Let's hide the dirty magic from them and make the coding process enjoyable.
> 
> Regards,
> Orson
> 
>> But I'm just a spectator. *I'm happy to put in the time to fix this but
>> need guidance on what approach to take.*
>>
>>
>> Miles
>>
>>
>>
>> [1] full plugin text
>> import pcbnew
>>
>> class RemoveBoundaryPlugin(pcbnew.ActionPlugin):
>>     def defaults(self):
>>         self.name = "Remove boundary"
>>         self.category = "A descriptive category name"
>>         self.description = "This plugin reads a dxf file and converts it to
>> a zone"
>>
>>     def Run(self):
>>         board = pcbnew.GetBoard()
>>
>>         for d in board.GetDrawings():
>>             print("{}".format(str(d)))
>>             #print("on layer {} {} {}".format(d.GetLayerName(),
>>             #                                 str(d.GetStart()),
>>             #                                 str(d.GetEnd())))
>>             if (d.GetLayerName() == 'Edge.Cuts'):
>>                 board.Remove(d)
>>
>> RemoveBoundaryPlugin().register()
>>
>>
>>
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> 
> 
> 
> 
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