gtk4/subclass/
scrollable.rs

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// Take a look at the license at the top of the repository in the LICENSE file.

// rustdoc-stripper-ignore-next
//! Traits intended for implementing the [`Scrollable`](crate::Scrollable)
//! interface.

use glib::translate::*;

use crate::{ffi, prelude::*, subclass::prelude::*, Border, Scrollable};

pub trait ScrollableImpl: WidgetImpl {
    #[doc(alias = "get_border")]
    fn border(&self) -> Option<Border> {
        self.parent_border()
    }
}

mod sealed {
    pub trait Sealed {}
    impl<T: super::ScrollableImplExt> Sealed for T {}
}

pub trait ScrollableImplExt: sealed::Sealed + ObjectSubclass {
    fn parent_border(&self) -> Option<Border> {
        unsafe {
            let type_data = Self::type_data();
            let parent_iface = type_data.as_ref().parent_interface::<Scrollable>()
                as *const ffi::GtkScrollableInterface;

            if let Some(func) = (*parent_iface).get_border {
                let border = std::ptr::null_mut();
                if from_glib(func(
                    self.obj().unsafe_cast_ref::<Scrollable>().to_glib_none().0,
                    border,
                )) {
                    return Some(from_glib_none(border));
                }
            }
            None
        }
    }
}

impl<T: ScrollableImpl> ScrollableImplExt for T {}

unsafe impl<T: ScrollableImpl> IsImplementable<T> for Scrollable {
    fn interface_init(iface: &mut glib::Interface<Self>) {
        let iface = iface.as_mut();

        iface.get_border = Some(scrollable_get_border::<T>);
    }
}

unsafe extern "C" fn scrollable_get_border<T: ScrollableImpl>(
    scrollable: *mut ffi::GtkScrollable,
    borderptr: *mut ffi::GtkBorder,
) -> glib::ffi::gboolean {
    let instance = &*(scrollable as *mut T::Instance);
    let imp = instance.imp();

    if let Some(border) = imp.border() {
        *borderptr = *IntoGlibPtr::<*mut _>::into_glib_ptr(border);
        true.into_glib()
    } else {
        *borderptr = ffi::GtkBorder {
            top: 0,
            right: 0,
            left: 0,
            bottom: 0,
        };
        false.into_glib()
    }
}