slint/internal/core/properties/ffi.rs

// Copyright © SixtyFPS GmbH <info@slint.dev>
// SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-Slint-Royalty-free-1.0 OR LicenseRef-Slint-commercial

use super::*;
use crate::graphics::{Brush, Color};
use crate::items::PropertyAnimation;
use core::pin::Pin;

#[allow(non_camel_case_types)]
type c_void = ();
#[repr(C)]
/// Has the same layout as PropertyHandle
pub struct PropertyHandleOpaque(PropertyHandle);

/// Initialize the first pointer of the Property. Does not initialize the content.
/// `out` is assumed to be uninitialized
#[no_mangle]
pub unsafe extern "C" fn slint_property_init(out: *mut PropertyHandleOpaque) {
    core::ptr::write(out, PropertyHandleOpaque(PropertyHandle::default()));
}

/// To be called before accessing the value
#[no_mangle]
pub unsafe extern "C" fn slint_property_update(handle: &PropertyHandleOpaque, val: *mut c_void) {
    let handle = Pin::new_unchecked(&handle.0);
    handle.update(val);
    handle.register_as_dependency_to_current_binding();
}

/// Mark the fact that the property was changed and that its binding need to be removed, and
/// the dependencies marked dirty.
/// To be called after the `value` has been changed
#[no_mangle]
pub unsafe extern "C" fn slint_property_set_changed(
    handle: &PropertyHandleOpaque,
    value: *const c_void,
) {
    if !handle.0.access(|b| {
        b.map_or(false, |b| (b.vtable.intercept_set)(&*b as *const BindingHolder, value))
    }) {
        handle.0.remove_binding();
    }
    handle.0.mark_dirty();
}

fn make_c_function_binding(
    binding: extern "C" fn(*mut c_void, *mut c_void),
    user_data: *mut c_void,
    drop_user_data: Option<extern "C" fn(*mut c_void)>,
    intercept_set: Option<
        extern "C" fn(user_data: *mut c_void, pointer_to_value: *const c_void) -> bool,
    >,
    intercept_set_binding: Option<
        extern "C" fn(user_data: *mut c_void, new_binding: *mut c_void) -> bool,
    >,
) -> impl BindingCallable {
    struct CFunctionBinding<T> {
        binding_function: extern "C" fn(*mut c_void, *mut T),
        user_data: *mut c_void,
        drop_user_data: Option<extern "C" fn(*mut c_void)>,
        intercept_set:
            Option<extern "C" fn(user_data: *mut c_void, pointer_to_value: *const c_void) -> bool>,
        intercept_set_binding:
            Option<extern "C" fn(user_data: *mut c_void, new_binding: *mut c_void) -> bool>,
    }

    impl<T> Drop for CFunctionBinding<T> {
        fn drop(&mut self) {
            if let Some(x) = self.drop_user_data {
                x(self.user_data)
            }
        }
    }

    unsafe impl<T> BindingCallable for CFunctionBinding<T> {
        unsafe fn evaluate(self: Pin<&Self>, value: *mut ()) -> BindingResult {
            (self.binding_function)(self.user_data, value as *mut T);
            BindingResult::KeepBinding
        }
        unsafe fn intercept_set(self: Pin<&Self>, value: *const ()) -> bool {
            match self.intercept_set {
                None => false,
                Some(intercept_set) => intercept_set(self.user_data, value),
            }
        }
        unsafe fn intercept_set_binding(self: Pin<&Self>, new_binding: *mut BindingHolder) -> bool {
            match self.intercept_set_binding {
                None => false,
                Some(intercept_set_b) => intercept_set_b(self.user_data, new_binding.cast()),
            }
        }
    }

    CFunctionBinding {
        binding_function: binding,
        user_data,
        drop_user_data,
        intercept_set,
        intercept_set_binding,
    }
}

/// Set a binding
///
/// The current implementation will do usually two memory allocation:
///  1. the allocation from the calling code to allocate user_data
///  2. the box allocation within this binding
/// It might be possible to reduce that by passing something with a
/// vtable, so there is the need for less memory allocation.
#[no_mangle]
pub unsafe extern "C" fn slint_property_set_binding(
    handle: &PropertyHandleOpaque,
    binding: extern "C" fn(user_data: *mut c_void, pointer_to_value: *mut c_void),
    user_data: *mut c_void,
    drop_user_data: Option<extern "C" fn(*mut c_void)>,
    intercept_set: Option<
        extern "C" fn(user_data: *mut c_void, pointer_to_Value: *const c_void) -> bool,
    >,
    intercept_set_binding: Option<
        extern "C" fn(user_data: *mut c_void, new_binding: *mut c_void) -> bool,
    >,
) {
    let binding = make_c_function_binding(
        binding,
        user_data,
        drop_user_data,
        intercept_set,
        intercept_set_binding,
    );
    handle.0.set_binding(binding);
}

/// Set a binding using an already allocated building holder
///
//// (take ownership of the binding)
#[no_mangle]
pub unsafe extern "C" fn slint_property_set_binding_internal(
    handle: &PropertyHandleOpaque,
    binding: *mut c_void,
) {
    handle.0.set_binding_impl(binding.cast());
}

/// Returns whether the property behind this handle is marked as dirty
#[no_mangle]
pub extern "C" fn slint_property_is_dirty(handle: &PropertyHandleOpaque) -> bool {
    handle.0.access(|binding| binding.map_or(false, |b| b.dirty.get()))
}

/// Marks the property as dirty and notifies dependencies.
#[no_mangle]
pub extern "C" fn slint_property_mark_dirty(handle: &PropertyHandleOpaque) {
    handle.0.mark_dirty()
}

/// Destroy handle
#[no_mangle]
pub unsafe extern "C" fn slint_property_drop(handle: *mut PropertyHandleOpaque) {
    core::ptr::drop_in_place(handle);
}

fn c_set_animated_value<T: InterpolatedPropertyValue + Clone>(
    handle: &PropertyHandleOpaque,
    from: T,
    to: T,
    animation_data: &PropertyAnimation,
) {
    let d = RefCell::new(properties_animations::PropertyValueAnimationData::new(
        from,
        to,
        animation_data.clone(),
    ));
    // Safety: The BindingCallable is for type T
    unsafe {
        handle.0.set_binding(move |val: *mut ()| {
            let (value, finished) = d.borrow_mut().compute_interpolated_value();
            *(val as *mut T) = value;
            if finished {
                BindingResult::RemoveBinding
            } else {
                crate::animations::CURRENT_ANIMATION_DRIVER
                    .with(|driver| driver.set_has_active_animations());
                BindingResult::KeepBinding
            }
        })
    };
    handle.0.mark_dirty();
}

/// Internal function to set up a property animation to the specified target value for an integer property.
#[no_mangle]
pub unsafe extern "C" fn slint_property_set_animated_value_int(
    handle: &PropertyHandleOpaque,
    from: i32,
    to: i32,
    animation_data: &PropertyAnimation,
) {
    c_set_animated_value(handle, from, to, animation_data)
}

/// Internal function to set up a property animation to the specified target value for a float property.
#[no_mangle]
pub unsafe extern "C" fn slint_property_set_animated_value_float(
    handle: &PropertyHandleOpaque,
    from: f32,
    to: f32,
    animation_data: &PropertyAnimation,
) {
    c_set_animated_value(handle, from, to, animation_data)
}

/// Internal function to set up a property animation to the specified target value for a color property.
#[no_mangle]
pub unsafe extern "C" fn slint_property_set_animated_value_color(
    handle: &PropertyHandleOpaque,
    from: Color,
    to: Color,
    animation_data: &PropertyAnimation,
) {
    c_set_animated_value(handle, from, to, animation_data);
}

unsafe fn c_set_animated_binding<T: InterpolatedPropertyValue + Clone>(
    handle: &PropertyHandleOpaque,
    binding: extern "C" fn(*mut c_void, *mut T),
    user_data: *mut c_void,
    drop_user_data: Option<extern "C" fn(*mut c_void)>,
    animation_data: Option<&PropertyAnimation>,
    transition_data: Option<
        extern "C" fn(user_data: *mut c_void, start_instant: &mut u64) -> PropertyAnimation,
    >,
) {
    let binding = core::mem::transmute::<
        extern "C" fn(*mut c_void, *mut T),
        extern "C" fn(*mut c_void, *mut ()),
    >(binding);
    let original_binding = PropertyHandle {
        handle: Cell::new(
            (alloc_binding_holder(make_c_function_binding(
                binding,
                user_data,
                drop_user_data,
                None,
                None,
            )) as usize)
                | 0b10,
        ),
    };
    let animation_data = RefCell::new(properties_animations::PropertyValueAnimationData::new(
        T::default(),
        T::default(),
        animation_data.cloned().unwrap_or_default(),
    ));
    if let Some(transition_data) = transition_data {
        handle.0.set_binding(properties_animations::AnimatedBindingCallable::<T, _> {
            original_binding,
            state: Cell::new(properties_animations::AnimatedBindingState::NotAnimating),
            animation_data,
            compute_animation_details: move || -> properties_animations::AnimationDetail {
                let mut start_instant = 0;
                let anim = transition_data(user_data, &mut start_instant);
                Some((anim, crate::animations::Instant(start_instant)))
            },
        });
    } else {
        handle.0.set_binding(properties_animations::AnimatedBindingCallable::<T, _> {
            original_binding,
            state: Cell::new(properties_animations::AnimatedBindingState::NotAnimating),
            animation_data,
            compute_animation_details: || -> properties_animations::AnimationDetail { None },
        });
    }
    handle.0.mark_dirty();
}

/// Internal function to set up a property animation between values produced by the specified binding for an integer property.
#[no_mangle]
pub unsafe extern "C" fn slint_property_set_animated_binding_int(
    handle: &PropertyHandleOpaque,
    binding: extern "C" fn(*mut c_void, *mut i32),
    user_data: *mut c_void,
    drop_user_data: Option<extern "C" fn(*mut c_void)>,
    animation_data: Option<&PropertyAnimation>,
    transition_data: Option<
        extern "C" fn(user_data: *mut c_void, start_instant: &mut u64) -> PropertyAnimation,
    >,
) {
    c_set_animated_binding(
        handle,
        binding,
        user_data,
        drop_user_data,
        animation_data,
        transition_data,
    );
}

/// Internal function to set up a property animation between values produced by the specified binding for a float property.
#[no_mangle]
pub unsafe extern "C" fn slint_property_set_animated_binding_float(
    handle: &PropertyHandleOpaque,
    binding: extern "C" fn(*mut c_void, *mut f32),
    user_data: *mut c_void,
    drop_user_data: Option<extern "C" fn(*mut c_void)>,
    animation_data: Option<&PropertyAnimation>,
    transition_data: Option<
        extern "C" fn(user_data: *mut c_void, start_instant: &mut u64) -> PropertyAnimation,
    >,
) {
    c_set_animated_binding(
        handle,
        binding,
        user_data,
        drop_user_data,
        animation_data,
        transition_data,
    );
}

/// Internal function to set up a property animation between values produced by the specified binding for a color property.
#[no_mangle]
pub unsafe extern "C" fn slint_property_set_animated_binding_color(
    handle: &PropertyHandleOpaque,
    binding: extern "C" fn(*mut c_void, *mut Color),
    user_data: *mut c_void,
    drop_user_data: Option<extern "C" fn(*mut c_void)>,
    animation_data: Option<&PropertyAnimation>,
    transition_data: Option<
        extern "C" fn(user_data: *mut c_void, start_instant: &mut u64) -> PropertyAnimation,
    >,
) {
    c_set_animated_binding(
        handle,
        binding,
        user_data,
        drop_user_data,
        animation_data,
        transition_data,
    );
}

/// Internal function to set up a property animation between values produced by the specified binding for a brush property.
#[no_mangle]
pub unsafe extern "C" fn slint_property_set_animated_binding_brush(
    handle: &PropertyHandleOpaque,
    binding: extern "C" fn(*mut c_void, *mut Brush),
    user_data: *mut c_void,
    drop_user_data: Option<extern "C" fn(*mut c_void)>,
    animation_data: Option<&PropertyAnimation>,
    transition_data: Option<
        extern "C" fn(user_data: *mut c_void, start_instant: &mut u64) -> PropertyAnimation,
    >,
) {
    c_set_animated_binding(
        handle,
        binding,
        user_data,
        drop_user_data,
        animation_data,
        transition_data,
    );
}

/// Internal function to set up a state binding on a Property<StateInfo>.
#[no_mangle]
pub unsafe extern "C" fn slint_property_set_state_binding(
    handle: &PropertyHandleOpaque,
    binding: extern "C" fn(*mut c_void) -> i32,
    user_data: *mut c_void,
    drop_user_data: Option<extern "C" fn(*mut c_void)>,
) {
    struct CStateBinding {
        binding: extern "C" fn(*mut c_void) -> i32,
        user_data: *mut c_void,
        drop_user_data: Option<extern "C" fn(*mut c_void)>,
    }

    impl Drop for CStateBinding {
        fn drop(&mut self) {
            if let Some(x) = self.drop_user_data {
                x(self.user_data)
            }
        }
    }

    impl CStateBinding {
        fn call(&self) -> i32 {
            (self.binding)(self.user_data)
        }
    }

    let c_state_binding = CStateBinding { binding, user_data, drop_user_data };
    let bind_callable =
        StateInfoBinding { dirty_time: Cell::new(None), binding: move || c_state_binding.call() };
    handle.0.set_binding(bind_callable)
}

#[repr(C)]
/// Opaque type representing the PropertyTracker
pub struct PropertyTrackerOpaque {
    dependencies: usize,
    dep_nodes: usize,
    vtable: usize,
    dirty: bool,
}

static_assertions::assert_eq_align!(PropertyTrackerOpaque, PropertyTracker);
static_assertions::assert_eq_size!(PropertyTrackerOpaque, PropertyTracker);

/// Initialize the first pointer of the PropertyTracker.
/// `out` is assumed to be uninitialized
/// slint_property_tracker_drop need to be called after that
#[no_mangle]
pub unsafe extern "C" fn slint_property_tracker_init(out: *mut PropertyTrackerOpaque) {
    core::ptr::write(out as *mut PropertyTracker, PropertyTracker::default());
}

/// Call the callback with the user data. Any properties access within the callback will be registered.
/// Any currently evaluated bindings or property trackers will be notified if accessed properties are changed.
#[no_mangle]
pub unsafe extern "C" fn slint_property_tracker_evaluate(
    handle: *const PropertyTrackerOpaque,
    callback: extern "C" fn(user_data: *mut c_void),
    user_data: *mut c_void,
) {
    Pin::new_unchecked(&*(handle as *const PropertyTracker)).evaluate(|| callback(user_data))
}

/// Call the callback with the user data. Any properties access within the callback will be registered.
/// Any currently evaluated bindings or property trackers will be not notified if accessed properties are changed.
#[no_mangle]
pub unsafe extern "C" fn slint_property_tracker_evaluate_as_dependency_root(
    handle: *const PropertyTrackerOpaque,
    callback: extern "C" fn(user_data: *mut c_void),
    user_data: *mut c_void,
) {
    Pin::new_unchecked(&*(handle as *const PropertyTracker))
        .evaluate_as_dependency_root(|| callback(user_data))
}
/// Query if the property tracker is dirty
#[no_mangle]
pub unsafe extern "C" fn slint_property_tracker_is_dirty(
    handle: *const PropertyTrackerOpaque,
) -> bool {
    (*(handle as *const PropertyTracker)).is_dirty()
}

/// Destroy handle
#[no_mangle]
pub unsafe extern "C" fn slint_property_tracker_drop(handle: *mut PropertyTrackerOpaque) {
    core::ptr::drop_in_place(handle as *mut PropertyTracker);
}

/// return the current animation tick for the `animation-tick` function
#[no_mangle]
pub extern "C" fn slint_animation_tick() -> u64 {
    crate::animations::animation_tick()
}