mvz/ruby-gir-ffi

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TODO.md

Summary

Maintainability
Test Coverage
# TODO

## Memory managment

GirFFI does not ~~attempt to free any memory at the moment, or~~ lower the
reference count of any objects it gets from GObject. This task therefore involves two parts:

- Free non-GObject pointers as needed (at garbage-collection time)
- [Done!] Lower reference count of GObjects (at garbage-collection time)

**Use memory_profiler to check memory use (https://github.com/SamSaffron/memory_profiler)**

## Refactorings

These in the order they occured to me, and may therefore be fixed in any order.

- Create Type objects for all FFI types, including the ones currently
  represented by a single symbol, so we can always do stuff like

  > `GirFFI::Types::UInt8.get_value_from_pointer(ptr)`

  rather than having awkward dynamic method dispatch inside GirFFI::InOutPointer.

- Move to a single Pointer class, rather than InPointer, InOutPointer and
  Pointer monkeypatching.

## Derived types

Derived classes are now registered like so:

    class Derived < Base
      install_property GObject.param_spec_int("foo", "foo bar",
                                              "The Foo Bar Property",
                                               10, 20, 15, 3)

      # assume Base defines a virtual function called 'some_vfunc'
      install_vfunc_implementation :some_vfunc, proc {|obj|
        # implementation goes here
      }

      def other_vfunc
        # implementation
      end

      # assume Base defines a virtual function called 'other_vfunc'
      install_vfunc_implementation :other_vfunc
    end

    GirFFI.define_type Derived

Potential improvements:

* Allow `define_type` to be called in the class definition
* Perhaps auto-register types, like Gtk# does
* Perhaps automagically find vfunc implementations, like PyGObject and
  Ruby-GNOME do
* What about properties?

NOTE: When adding an interface module to a derived class, its prerequisites
should be checked.

## Persistent Ruby GObject identity

GirFFI should make sure that if it gets a pointer to a GObject for which a Ruby
object already exists, the existing object is returned. This involves the use
of WeakRef, no doubt.

## Handle fundamental objects that are not GObject.

This is a big one. See commit 1e9822c7817062a9b853269b9418fd78782090b5 in
gobject-introspection, and TestFundamentalObject in Regress.

The tests for TestFundamentalObject accidentally pass, but there may be
hidden issues.

## Check binding of GObject:

    (11:37:03 PM) walters: the basic story is that GObject should be manually bound
    (11:47:02 PM) ebassi: the really necessary bits are: GObject/GInitiallyUnowned memory management; properties accessors; GSignal connection API
    (11:47:15 PM) ebassi: the rest is "nice to have"
    (11:47:37 PM) ebassi: oh, and probably GBinding - but that's just because I wrote it ;-)

## Use FFI::DataConverter to automatically convert GObject types

GirFFI now generates loads of Something.wrap(ptr) calls; Perhaps these can be
replace by implementing to_native and from_native in ClassBase and including
FFI::DataConverter.

## Handle Variants more nicely

Currently, GirFFI requires the user to create GVariant objects by hand, and
retrieve values from them by hand as well. Ideally, we would have `.from_ruby` and
`#to_ruby` methods or somesuch that do this for us. Some classes, like GAction,
require a specifice VariantType to be used consistently. Special logic will have
to be put in place for that.

## Handle ownership-transfer correctly

For how to handle objects, see https://bugzilla.gnome.org/show_bug.cgi?id=657202#c1

## Miscellaneous

* Move GObjectIntrospection to GIRepository, and allow generating its own
  members.
* Do something useful with the versioning info in the GIR

## External dependencies

Things that I think GirFFI cannot fix:

* gobject-introspection should correctly mark private fields as not readable.
* gobject-introspection should ignore functions that are only defined but not
  implemented, or implement those cases in GIMarshallingTests.

## See Also

  dnote