From: hanmac@...
Date: 2014-12-24T10:26:30+00:00
Subject: [ruby-core:67101] [ruby-trunk - Bug #10621] no parent in	rb_data_type_t

Issue #10621 has been updated by Hans Mackowiak.


Koichi Sasada wrote:
> > No does not work because its about rb_check_typeddata, how else should a function know if the object i have can be turned to the given type? it cant be done nicely with the data field because i need to do all checks the rb_check_typeddata function does by my self before too
> 
> Why does not it work?
> 

it might be able to work, but with that i need to write the rb_typeddata_is_kind_of function by myself and might not work so well might also be to much complicated

> > And thats a good point for me, because i have objects of the class that should not always be deleted because it might cause segfaults, thats why i have two data_type for the same class (i dont know of a better way to do that)
> 
> Could you explain more? I can't understand your sitation. Sample code are very welcome.
> 
i wrap T* arg objects into my ruby objects, but sometimes i get a const T* arg, not wanting to waste extra memory, i wrap them too, but them because objects of that class should be freed from ruby it does try to free that one too, and that causes a double free because the library does delete them too (links below)

> > as Eric did said that the old API with unchecked is getting deprecated, the new one should be added to the README.ext, same for the scan_kargs function
> 
> To make official API, we remove `parent` filed because it is ad-hoc, not considered field.
> 
> At first, original T_DATA structure is not deprecate. Most of case it is enough, I think.
> And I agree that it is not enough for some case and it is good to become deprecate.
> 
> So let's start to discuss about it.

> Your case will be nice example to discuss to make it official API.

my binding: https://github.com/Hanmac/rwx
the binded lib: https://github.com/wxWidgets/wxWidgets

where that const pointer does come from: https://github.com/wxWidgets/wxWidgets/blob/master/include/wx/gdicmn.h#L1020
and there i register the data types: https://github.com/Hanmac/rwx/blob/master/ext/main.cpp#L47

i hope you guys understand my code and how i try to get the datatype from/for a ruby class and other stuff

for some classes (that does inherit from wxWindow and some EventHandler) i also added a GC protection that prevent ruby from removing the objects as long as the C++ objects does survive (might not be one of my best coding parts but its better than nothing)

i dont have a problem if you guys can find ways to make my code better, for faster typing i am accessible on irc.freenode.net as hanmac too (mostly in #ruby)

----------------------------------------
Bug #10621: no parent in rb_data_type_t
https://bugs.ruby-lang.org/issues/10621#change-50613

* Author: Hans Mackowiak
* Status: Closed
* Priority: Immediate
* Assignee: Nobuyoshi Nakada
* Category: core
* Target version: current: 2.2.0
* ruby -v: ruby 2.2.0dev (2014-12-19 trunk 48891) [x86_64-linux]
* Backport: 2.0.0: DONTNEED, 2.1: DONTNEED
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`rb_data_type_t` does need to have a parent type otherwise it cant bind objects anymore that have a tree style ClassTree like in C++ or simulated with gtk

in C++ like Class B and Class C does inherit both Class A, cant be ported with ruby anymore because with that Class A cant have its own datatype anymore because the datatype check does break the inheritence. (id did worked before because it did had parent



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