Generate signals about gir

[gkoz]

I'm still undecided about where exactly the signals belong. If they are generated alongside other functions, perhaps xxxSignals traits are unnecessary, just put them into xxxExt?

Also we should probably fix callback_guard! to not require importing the struct.

[EPashkin]

Currently signals trait implemented with bound IsA<ComboBox> + IsA<Object>.

[gkoz]

Yeah the IsA<Object> is required to get ToGlibPtr<*mut GObject> but it's harmless as a bound because all objects implement it.

[EPashkin]

Other that bound don't see any problem with implementing in xxxExt or in same impl for childless class.

[gkoz]

Generating correct trampoline signatures might require finishing the ffi_ng branch. Eventually I'd like the trampoline signatures to match C exactly (no f: &Box<Fn(...)>, but rather cast user_data: gpointer to &Box<Fn(...)>).

[gkoz]

It's worse than that: signal definitions seem to routinely omit c:type attributes:

      <glib:signal name="accel-activate" detailed="1">
...
        <parameters>
          <parameter name="acceleratable" transfer-ownership="none">
            <doc xml:space="preserve">the object on which the accelerator was activated</doc>
            <type name="GObject.Object"/>
          </parameter>
          <parameter name="keyval" transfer-ownership="none">
            <doc xml:space="preserve">the accelerator keyval</doc>
            <type name="guint" c:type="guint"/>
          </parameter>
          <parameter name="modifier" transfer-ownership="none">
            <doc xml:space="preserve">the modifier combination of the accelerator</doc>
            <type name="Gdk.ModifierType"/>
          </parameter>
        </parameters>
      </glib:signal>

[EPashkin]

If it omit only for glib-related types then its not big problem

[gkoz]

Speaking of signals, I'm yet again considering adding Borrow<T> and BorrowMut<T> wrappers, that forget their contents on destruction, and from_glib_borrow transfer mode so callback parameters could truly be borrowed without touching refcounts or copying boxed types (e.g. GdkEvent).

[EPashkin]

Signals with no-recurse could take FnMut instead of Fn.

[EPashkin]

All child issues was closed, so I also close this