swiftui_native/views/

accessibility.rs

//! Accessibility, focus, lifecycle, gestures, geometry.
//!
//! * Accessibility attributes, traits, and focus

use super::*;
use crate::abi;
use crate::resolve;
use core::ffi::c_void;
use crate::mangle::{self, swift_type};

// ── Accessibility, focus, lifecycle, gestures, geometry ──

mangle::result_types! {
    /// `GeometryReader<AnyView>`
    pub(crate) GEOMETRY_T = ty("GeometryReader").of(vec![ty("AnyView")]);
}
mangle::modifier_types! {
    /// `ModifiedContent<AnyView, AccessibilityAttachmentModifier>`
    pub(crate) A11Y_T = ty("AccessibilityAttachmentModifier");
    /// `ModifiedContent<AnyView, _FocusableModifier>`
    pub(crate) FOCUSABLE_T = ty("_FocusableModifier");
    /// `ModifiedContent<AnyView, AddGestureModifier<LongPressGesture, DefaultGestureCombiner>>`
    pub(crate) LONG_PRESS_T = ty("AddGestureModifier").of(vec![ty("LongPressGesture"), ty("DefaultGestureCombiner")]);
}




/// Apply `.accessibilityLabel(_:)`.
pub fn accessibility_label(view: &ViewHandle, label: &str) -> ViewHandle {
    unsafe {
        let ss = abi::swift_string(label);
        let s0 = u64::from_le_bytes(ss[..8].try_into().unwrap());
        let s1 = u64::from_le_bytes(ss[8..].try_into().unwrap());
        let (k0, k1, k2, k3) = localized_string_key(s0, s1);
        let (_, _, size) = A11Y_T.applied_to(view.meta);
        let r = abi::call_modifier(resolve::a11y_label_fn(), view.value_ptr(), view.meta, view.wt, &[k0, k1, k2, k3], [0.0; 4], size);
        wrap_modified(r, &A11Y_T, view)
    }
}

/// Apply `.accessibilityHidden(_:)`.
pub fn accessibility_hidden(view: &ViewHandle, hidden: bool) -> ViewHandle {
    unsafe {
        let (_, _, size) = A11Y_T.applied_to(view.meta);
        let r =
            abi::call_modifier(resolve::a11y_hidden_fn(), view.value_ptr(), view.meta, view.wt, &[u64::from(hidden)], [0.0; 4], size);
        wrap_modified(r, &A11Y_T, view)
    }
}

/// Apply `.focusable(_:)`.
pub fn focusable(view: &ViewHandle, value: bool) -> ViewHandle {
    unsafe {
        let (_, _, size) = FOCUSABLE_T.applied_to(view.meta);
        let r =
            abi::call_modifier(resolve::focusable_fn(), view.value_ptr(), view.meta, view.wt, &[u64::from(value)], [0.0; 4], size);
        wrap_modified(r, &FOCUSABLE_T, view)
    }
}

/// Apply `.onDisappear(perform:)`.
pub fn on_disappear(view: &ViewHandle, action: impl Fn() + 'static) -> ViewHandle {
    unsafe {
        let ctx = Box::leak(Box::new(abi::ClosureCtx::new(
            invoke_action,
            boxed_ctx(Box::new(action) as Box<dyn Fn()>),
        ))) as *mut abi::ClosureCtx;
        let (_, _, size) = ON_APPEAR_T.applied_to(view.meta);
        let r = abi::call_modifier(resolve::on_disappear_fn(), view.value_ptr(), view.meta, view.wt,
            &[abi::swift_closure_thunk as *const () as u64, ctx as u64],
            [0.0; 4],
            size,
        );
        wrap_modified(r, &ON_APPEAR_T, view)
    }
}

/// Attach a `LongPressGesture` with `.gesture(_:including:)`.
pub fn long_press_gesture(view: &ViewHandle, duration: f64, max_distance: f64) -> ViewHandle {
    unsafe {
        let g_meta = abi::metadata0(resolve::long_press_ma());
        let mut gesture = vec![0u8; abi::type_bytes(g_meta)];
        // LongPressGesture.init(minimumDuration:maximumDistance:)
        core::arch::asm!("blr {f}", f = in(reg) resolve::long_press_init(),
            in("d0") duration, in("d1") max_distance,
            in("x8") gesture.as_mut_ptr(),
            in("x20") g_meta,
            lateout("x0") _, lateout("x1") _, lateout("x2") _, lateout("x3") _,
            lateout("x4") _, lateout("x5") _, lateout("x6") _, lateout("x7") _,
            lateout("x9") _, lateout("x10") _, lateout("x11") _, lateout("x12") _,
            lateout("x13") _, lateout("x14") _, lateout("x15") _, lateout("x16") _,
            lateout("x17") _, lateout("lr") _, lateout("x21") _, clobber_abi("C"),
        );

        let g_wt = abi::get_view_wt_for_proto(g_meta, resolve::gesture_proto());
        assert!(!g_wt.is_null(), "LongPressGesture: Gesture");

        let (_, _, size) = LONG_PRESS_T.applied_to(view.meta);
        let mut result = vec![0u8; size];
        let this = view.value_ptr();
        // gesture<G: Gesture>(_: G, including: GestureMask)
        //   x0 = @in gesture, x1 = GestureMask (.all == 3),
        //   x2 = Self.Type, x3 = G.Type, x4 = Self: View WT, x5 = G: Gesture WT
        core::arch::asm!("blr {f}", f = in(reg) resolve::gesture_fn(),
            in("x0") gesture.as_mut_ptr(),
            in("x1") 3u64,
            in("x2") view.meta,
            in("x3") g_meta,
            in("x4") view.wt,
            in("x5") g_wt,
            in("x8") result.as_mut_ptr(),
            in("x20") this,
            lateout("x6") _, lateout("x7") _,
            lateout("x9") _, lateout("x10") _, lateout("x11") _, lateout("x12") _,
            lateout("x13") _, lateout("x14") _, lateout("x15") _, lateout("x16") _,
            lateout("x17") _, lateout("lr") _, lateout("x21") _, clobber_abi("C"),
        );
        wrap_modified(result, &LONG_PRESS_T, view)
    }
}

/// The Rust side of a `GeometryReader` content closure, given the measured size.
pub(crate) type GeometryBuilder = Box<dyn Fn(f64, f64) -> ViewHandle>;

/// Read `GeometryProxy.size`.
///
/// `GeometryProxy` is 52 bytes and address-only, so it arrives by pointer; the
/// getter returns a `CGSize`, which is two doubles in d0/d1.
pub(crate) unsafe fn geometry_proxy_size(proxy: *const u8) -> (f64, f64) {
    let (w, h): (f64, f64);
    unsafe {
        core::arch::asm!("blr {f}", f = in(reg) resolve::geometry_proxy_size(),
            in("x20") proxy,
            lateout("d0") w, lateout("d1") h,
            lateout("x0") _, lateout("x1") _, lateout("x2") _, lateout("x3") _,
            lateout("x4") _, lateout("x5") _, lateout("x6") _, lateout("x7") _,
            lateout("x8") _, lateout("x9") _, lateout("x10") _, lateout("x11") _,
            lateout("x12") _, lateout("x13") _, lateout("x14") _, lateout("x15") _,
            lateout("x16") _, lateout("x17") _, lateout("lr") _, lateout("x21") _,
            clobber_abi("C"),
        );
    }
    (w, h)
}

/// A builder together with the content type it was found to produce.
///
/// Swift knows a `GeometryReader`'s content type at compile time — the IR shows
/// the closure lowered to `(@out Text, @in GeometryProxy)`, with `Text` written
/// straight into the result — which is why the instantiation is
/// `GeometryReader<Text>` and not `GeometryReader<AnyView>`. A Rust closure
/// returning `ViewHandle` has no such type to read off, so it is *asked*: the
/// builder is run once while constructing, and whatever it produced fixes the
/// instantiation.
pub(crate) struct TypedBuilder {
    pub(crate) builder: GeometryBuilder,
    /// What the probe produced. Every later call has to agree.
    pub(crate) meta: *const c_void,
}

/// `(GeometryProxy) -> Content` — measure the proxy, then build from Rust.
pub(crate) unsafe extern "C" fn emit_geometry_view(out: *mut u8, proxy: i64, payload: *mut c_void) {
    let typed = unsafe { &*(payload as *const TypedBuilder) };
    let (w, h) = unsafe { geometry_proxy_size(proxy as *const u8) };
    let view = (typed.builder)(w, h);
    unsafe {
        if typed.meta.is_null() {
            // No type was promised, so the content is an `AnyView` and the box
            // is the value.
            *(out as *mut u64) = view.into_anyview_word();
            return;
        }
        // A type *was* promised, and SwiftUI has sized its storage for it.
        // Writing anything else would scribble past that, so this is checked
        // rather than assumed — the same rule Swift enforces at compile time by
        // making the closure's return type `some View`, i.e. exactly one type.
        assert_eq!(
            view.meta, typed.meta,
            "a GeometryReader's builder returned {} after returning {} — SwiftUI \
             sized the reader for the first. Use `view_if!` for a branch, which \
             builds a `_ConditionalContent` and so stays one type.",
            crate::diag::type_name(view.meta),
            crate::diag::type_name(typed.meta),
        );
        let vwt = &*swift_runtime_sys::SwiftABI::get_value_witness_table(view.meta);
        if vwt.size > 0 {
            (vwt.initialize_with_copy)(out as *mut c_void, view.value_ptr() as *mut c_void, view.meta);
        }
    }
}

/// `GeometryReader { size in … }`.
///
/// The builder receives the measured width and height, which is the whole point
/// of a `GeometryReader` — a version that discarded the proxy would just be a
/// container. The closure escapes, since SwiftUI re-runs it whenever the
/// geometry changes, so its context is leaked.
pub fn geometry_reader(builder: impl Fn(f64, f64) -> ViewHandle + 'static) -> ViewHandle {
    unsafe {
        let boxed: GeometryBuilder = Box::new(builder);
        // Ask the builder what it makes. A zero-sized proxy is what a reader is
        // handed before it has been laid out, so this is a call it will see
        // anyway — but it *is* an extra call, and a builder with side effects
        // will notice.
        let probe = boxed(0.0, 0.0);
        let (known_meta, known_wt, _) = result_type(&GEOMETRY_T);
        let typed = abi::generic_metadata_from(known_meta, &[probe.meta, probe.wt]);
        let typed_wt = if typed.is_null() { core::ptr::null() } else { abi::get_view_wt(typed) };
        let promised = if typed_wt.is_null() { core::ptr::null() } else { probe.meta };
        let (meta, wt) = if promised.is_null() {
            (known_meta, known_wt)
        } else {
            (typed, typed_wt)
        };
        let content_meta = if promised.is_null() { resolve::anyview_meta() } else { probe.meta };
        let content_wt = if promised.is_null() { resolve::anyview_wt() } else { probe.wt };
        drop(probe);

        let payload =
            Box::into_raw(Box::new(TypedBuilder { builder: boxed, meta: promised })) as *mut c_void;
        let ctx = Box::leak(Box::new(abi::IndexClosureCtx::new(emit_geometry_view, payload)))
            as *mut abi::IndexClosureCtx;

        // `GeometryReader<AnyView>` is sixteen bytes, so it comes back *in
        // registers* rather than through an indirect `x8` result. Supplying an
        // out-pointer here leaves the buffer untouched.
        let (r0, r1): (u64, u64);
        core::arch::asm!("blr {f}", f = in(reg) resolve::geometry_reader_init(),
            inout("x0") abi::index_closure_thunk as *const () as u64 => r0,
            inout("x1") ctx as u64 => r1,
            in("x2") content_meta,
            in("x3") content_wt,
            lateout("x4") _, lateout("x5") _, lateout("x6") _, lateout("x7") _,
            lateout("x8") _, lateout("x9") _, lateout("x10") _, lateout("x11") _,
            lateout("x12") _, lateout("x13") _, lateout("x14") _, lateout("x15") _,
            lateout("x16") _, lateout("x17") _, lateout("lr") _, lateout("x20") _,
            lateout("x21") _, clobber_abi("C"),
        );
        let mut result = [0u8; 16];
        result[..8].copy_from_slice(&r0.to_le_bytes());
        result[8..].copy_from_slice(&r1.to_le_bytes());
        // An array on the stack, not a buffer the callee filled: this one has
        // to be copied into the handle.
        wrap_buf(&result, meta, wt)
    }
}

/// Apply `.confirmationDialog(_:isPresented:titleVisibility:actions:)`.
///
/// Like `alert`, the actions builder escapes, and the generic arguments spill:
/// the title, binding and visibility fill all eight registers.
/// Shared tail of `confirmation_dialog` and `confirmation_dialog_bound`.
///
/// # Safety
/// `binding` must be a `Binding<Bool>`.
pub(crate) unsafe fn confirmation_dialog_with_binding(
    view: &ViewHandle,
    title: &str, actions: &ViewHandle,
    binding: &[u8],
) -> ViewHandle {
    unsafe {
        let ss = abi::swift_string(title);
        let s0 = u64::from_le_bytes(ss[..8].try_into().unwrap());
        let s1 = u64::from_le_bytes(ss[8..].try_into().unwrap());
        let (k0, k1, k2, k3) = localized_string_key(s0, s1);
        let b0 = u64::from_le_bytes(binding[0..8].try_into().unwrap());
        let b1 = u64::from_le_bytes(binding[8..16].try_into().unwrap());
        let b2 = binding[16] as u64;

        let ctx = Box::leak(Box::new(abi::ClosureCtx::new(
            emit_tuple,
            Child::leak(actions, Content::Concrete),
        ))) as *mut abi::ClosureCtx;

        let subst = [
            view.meta,                        // Self.Type — the concrete receiver
            actions.meta,          // content — the closure emits AnyView
            view.wt,                          // Self: View
            actions.wt,            // content: View
        ];
        let (meta, wt, size) = opaque_result_type(resolve::confirm_oret(), &subst);
        let mut result = vec![0u8; size];
        let this = view.value_ptr();
        // confirmationDialog(_:isPresented:titleVisibility:actions:)
        //   x0-x3 = key, x4-x6 = Binding<Bool>, x7 = Visibility (.automatic == 0),
        //   [sp] = actions fn, [sp+8] = actions ctx, [sp+16] = Self.Type,
        //   [sp+24] = A.Type, [sp+32] = Self: View WT, [sp+40] = A: View WT
        core::arch::asm!(
            "sub sp, sp, #48",
            "stp {fnp}, {cx}, [sp]",
            "stp {sm}, {am}, [sp, #16]",
            "stp {sw}, {aw}, [sp, #32]",
            "blr {f}",
            "add sp, sp, #48",
            f = in(reg) resolve::confirm_fn(),
            fnp = in(reg) abi::swift_closure_thunk as *const c_void,
            cx = in(reg) ctx,
            sm = in(reg) view.meta,
            am = in(reg) actions.meta,
            sw = in(reg) view.wt,
            aw = in(reg) actions.wt,
            in("x0") k0, in("x1") k1, in("x2") k2, in("x3") k3,
            in("x4") b0, in("x5") b1, in("x6") b2,
            in("x7") 0u64,
            in("x8") result.as_mut_ptr(),
            in("x20") this,
            lateout("x9") _, lateout("x10") _, lateout("x11") _, lateout("x12") _,
            lateout("x13") _, lateout("x14") _, lateout("x15") _, lateout("x16") _,
            lateout("x17") _, lateout("lr") _, lateout("x21") _, clobber_abi("C"),
        );
        wrap_owned(result, meta, wt)
    }
}

/// `confirmationDialog(_:isPresented:titleVisibility:actions:message:)`.
///
/// The message is the explanatory line under the title, and on a sheet-style
/// dialog it is often the only place the consequence is stated — "This will
/// delete 12 items" under a bare "Delete". Only the title-and-buttons overload
/// was bound.
///
/// # Safety
/// `binding` must be a live `Binding<Bool>`.
pub(crate) unsafe fn confirmation_message_with_binding(
    view: &ViewHandle,
    title: &str,
    actions: &ViewHandle,
    message: &ViewHandle,
    binding: &[u8],
) -> ViewHandle {
    unsafe {
        let ss = abi::swift_string(title);
        let s0 = u64::from_le_bytes(ss[..8].try_into().expect("title lo"));
        let s1 = u64::from_le_bytes(ss[8..].try_into().expect("title hi"));
        let (k0, k1, k2, k3) = super::primitives::localized_string_key(s0, s1);
        let b0 = u64::from_le_bytes(binding[0..8].try_into().expect("binding 0"));
        let b1 = u64::from_le_bytes(binding[8..16].try_into().expect("binding 1"));
        let b2 = binding[16] as u64;

        let actions_ctx = Box::leak(Box::new(abi::ClosureCtx::new(
            emit_tuple,
            Child::leak(actions, Content::Concrete),
        ))) as *mut abi::ClosureCtx;
        let message_ctx = Box::leak(Box::new(abi::ClosureCtx::new(
            emit_tuple,
            Child::leak(message, Content::Concrete),
        ))) as *mut abi::ClosureCtx;

        let subst = [view.meta, actions.meta, message.meta, view.wt, actions.wt, message.wt];
        let (meta, wt, size) = opaque_result_type(resolve::confirm_msg_oret(), &subst);
        let mut result = vec![0u8; size];
        let this = view.value_ptr();
        // confirmationDialog(_:isPresented:titleVisibility:actions:message:)
        //   x0-x3 = key, x4-x6 = Binding<Bool>, x7 = Visibility (.automatic),
        //   [sp]    = actions fn,  [sp+8]  = actions ctx,
        //   [sp+16] = message fn,  [sp+24] = message ctx,
        //   [sp+32] = Self.Type,   [sp+40] = A.Type,    [sp+48] = B.Type,
        //   [sp+56] = Self: View,  [sp+64] = A: View,   [sp+72] = B: View
        core::arch::asm!(
            "sub sp, sp, #80",
            "stp {af}, {ac}, [sp]",
            "stp {mf}, {mc}, [sp, #16]",
            "stp {sm}, {am}, [sp, #32]",
            "stp {mm}, {sw}, [sp, #48]",
            "stp {aw}, {mw}, [sp, #64]",
            "blr {f}",
            "add sp, sp, #80",
            f = in(reg) resolve::confirm_msg_fn(),
            af = in(reg) abi::swift_closure_thunk as *const c_void,
            ac = in(reg) actions_ctx,
            mf = in(reg) abi::swift_closure_thunk as *const c_void,
            mc = in(reg) message_ctx,
            sm = in(reg) subst[0],
            am = in(reg) subst[1],
            mm = in(reg) subst[2],
            sw = in(reg) subst[3],
            aw = in(reg) subst[4],
            mw = in(reg) subst[5],
            in("x0") k0, in("x1") k1, in("x2") k2, in("x3") k3,
            in("x4") b0, in("x5") b1, in("x6") b2,
            in("x7") 0u64,
            in("x8") result.as_mut_ptr(),
            in("x20") this,
            lateout("x9") _, lateout("x10") _, lateout("x11") _, lateout("x12") _,
            lateout("x13") _, lateout("x14") _, lateout("x15") _, lateout("x16") _,
            lateout("x17") _, lateout("lr") _, lateout("x21") _, clobber_abi("C"),
        );
        wrap_owned(result, meta, wt)
    }
}

/// `confirmationDialog(…actions:message:)` with a fixed flag, which cannot be
/// dismissed — see [`confirmation_dialog`].
pub fn confirmation_message(
    view: &ViewHandle,
    title: &str,
    actions: &ViewHandle,
    message: &ViewHandle,
    presented: bool,
) -> ViewHandle {
    unsafe {
        let binding = constant_binding(
            &[u8::from(presented)],
            resolve::bool_meta(),
            mangle::bound(&swift_type!(SwiftUI.Binding), &[mangle::BOOL]).as_bytes(),
        );
        confirmation_message_with_binding(view, title, actions, message, &binding)
    }
}

/// `confirmationDialog(…actions:message:)` bound to Rust state.
pub fn confirmation_message_bound(
    view: &ViewHandle,
    title: &str,
    actions: &ViewHandle,
    message: &ViewHandle,
    state: &BoundState<bool>,
) -> ViewHandle {
    unsafe {
        let binding = bool_binding_of(state);
        confirmation_message_with_binding(view, title, actions, message, &binding)
    }
}

/// `confirmation_dialog` with a fixed flag. It cannot be dismissed: SwiftUI treats a
/// `Binding.constant` as read-only, so the presentation has no way to write
/// `false` back. Use [`confirmation_dialog_bound`] for one the user can close.
pub fn confirmation_dialog(view: &ViewHandle, title: &str, actions: &ViewHandle, presented: bool) -> ViewHandle {
    unsafe {
        let binding = constant_binding(
            &[u8::from(presented)],
            resolve::bool_meta(),
            mangle::bound(&swift_type!(SwiftUI.Binding), &[mangle::BOOL]).as_bytes(),
        );
        confirmation_dialog_with_binding(view, title, actions, &binding)
    }
}

/// `confirmation_dialog` bound to Rust state, so dismissing it writes `false` back.
pub fn confirmation_dialog_bound(view: &ViewHandle, title: &str, actions: &ViewHandle, state: &BoundState<bool>) -> ViewHandle {
    unsafe {
        let binding = bool_binding_of(state);
        confirmation_dialog_with_binding(view, title, actions, &binding)
    }
}


// ── Accessibility attributes, traits, and focus ──

//
// This family returns `ModifiedContent<Self, AccessibilityAttachmentModifier>`
// outright rather than `some View`, so there is no opaque descriptor to consult
// and the result type is the same for all of them: [`&A11Y_T`].

/// Apply an accessibility modifier, whose result type never varies.
pub(crate) unsafe fn a11y_modifier(
    f: *const c_void,
    v: &ViewHandle,
    ints: &[u64],
    floats: [f64; 4],
) -> ViewHandle {
    unsafe {
        let (_, _, size) = A11Y_T.applied_to(v.meta);
        let r = abi::call_modifier(f, v.value_ptr(), v.meta, v.wt, ints, floats, size);
        wrap_modified(r, &A11Y_T, v)
    }
}

/// Read a resilient type's `static var`, which returns through x8.
///
/// `AccessibilityTraits` and its neighbours are public but not `@frozen`, so
/// their size is not known to a caller compiled against the SDK and every one
/// of them travels by address. That applies to the static members as much as to
/// the arguments: the getter takes the metatype in x20 and writes the value
/// into the buffer x8 points at.
pub(crate) unsafe fn resilient_static(meta: *const c_void, getter: &'static core::ffi::CStr) -> Vec<u8> {
    unsafe {
        let f = resolve::sym(getter);
        assert!(!f.is_null(), "missing static: {}", crate::diag::symbol_name(getter));
        abi::static_out(f, meta, abi::type_bytes(meta))
    }
}

/// A member of `SwiftUI.AccessibilityTraits`.
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum AccessibilityTrait {
    IsButton,
    IsHeader,
    IsLink,
    IsImage,
    IsModal,
    IsSwitch,
    IsTabBar,
    IsToggle,
    IsSelected,
    PlaysSound,
    IsTabButton,
    IsBackButton,
    IsStaticText,
    IsKeyboardKey,
    IsSearchField,
    CausesPageTurn,
    IsMathEquation,
    IsSummaryElement,
    UpdatesFrequently,
    StartsMediaSession,
    AllowsDirectInteraction,
}

impl AccessibilityTrait {
    /// The static property getter that produces this trait.
    pub(crate) fn getter(self) -> &'static core::ffi::CStr {
        match self {
            Self::IsButton => c"$s7SwiftUI19AccessibilityTraitsV8isButtonACvgZ",
            Self::IsHeader => c"$s7SwiftUI19AccessibilityTraitsV8isHeaderACvgZ",
            Self::IsLink => c"$s7SwiftUI19AccessibilityTraitsV6isLinkACvgZ",
            Self::IsImage => c"$s7SwiftUI19AccessibilityTraitsV7isImageACvgZ",
            Self::IsModal => c"$s7SwiftUI19AccessibilityTraitsV7isModalACvgZ",
            Self::IsSwitch => c"$s7SwiftUI19AccessibilityTraitsV8isSwitchACvgZ",
            Self::IsTabBar => c"$s7SwiftUI19AccessibilityTraitsV8isTabBarACvgZ",
            Self::IsToggle => c"$s7SwiftUI19AccessibilityTraitsV8isToggleACvgZ",
            Self::IsSelected => c"$s7SwiftUI19AccessibilityTraitsV10isSelectedACvgZ",
            Self::PlaysSound => c"$s7SwiftUI19AccessibilityTraitsV10playsSoundACvgZ",
            Self::IsTabButton => c"$s7SwiftUI19AccessibilityTraitsV11isTabButtonACvgZ",
            Self::IsBackButton => c"$s7SwiftUI19AccessibilityTraitsV12isBackButtonACvgZ",
            Self::IsStaticText => c"$s7SwiftUI19AccessibilityTraitsV12isStaticTextACvgZ",
            Self::IsKeyboardKey => c"$s7SwiftUI19AccessibilityTraitsV13isKeyboardKeyACvgZ",
            Self::IsSearchField => c"$s7SwiftUI19AccessibilityTraitsV13isSearchFieldACvgZ",
            Self::CausesPageTurn => c"$s7SwiftUI19AccessibilityTraitsV14causesPageTurnACvgZ",
            Self::IsMathEquation => c"$s7SwiftUI19AccessibilityTraitsV14isMathEquationACvgZ",
            Self::IsSummaryElement => c"$s7SwiftUI19AccessibilityTraitsV16isSummaryElementACvgZ",
            Self::UpdatesFrequently => c"$s7SwiftUI19AccessibilityTraitsV17updatesFrequentlyACvgZ",
            Self::StartsMediaSession => c"$s7SwiftUI19AccessibilityTraitsV18startsMediaSessionACvgZ",
            Self::AllowsDirectInteraction => {
                c"$s7SwiftUI19AccessibilityTraitsV23allowsDirectInteractionACvgZ"
            }
        }
    }
}

/// Build an `AccessibilityTraits` set from its members.
///
/// The all-zero pattern is the empty set, so an empty slice needs no call and
/// each trait is folded in with `formUnion` — a mutating method, which takes
/// the receiver by address in x20 like any other resilient `self`.
pub(crate) unsafe fn traits_value(traits: &[AccessibilityTrait]) -> Vec<u8> {
    unsafe {
        let meta = abi::metadata0(resolve::a11y_traits_ma());
        let mut acc = vec![0u8; abi::type_bytes(meta)];
        let union = resolve::a11y_traits_form_union();
        for t in traits {
            let one = resilient_static(meta, t.getter());
            abi::call_out(
                union,
                abi::ints(&[one.as_ptr() as u64]),
                [0.0; 4],
                acc.as_mut_ptr() as u64,
                core::ptr::null_mut(),
            );
        }
        acc
    }
}

swift_cases! {
    /// `SwiftUI.AccessibilityHeadingLevel`, a frozen enum that fits in a register.
    pub enum HeadingLevel {
        Unspecified = 0,
        H1 = 1,
        H2 = 2,
        H3 = 3,
        H4 = 4,
        H5 = 5,
        H6 = 6,
    }
}

swift_statics! {
    /// A member of `SwiftUI.AccessibilityTextContentType`.
    pub enum TextContentType {
        Plain = c"$s7SwiftUI28AccessibilityTextContentTypeV5plainACvgZ",
        Console = c"$s7SwiftUI28AccessibilityTextContentTypeV7consoleACvgZ",
        FileSystem = c"$s7SwiftUI28AccessibilityTextContentTypeV10fileSystemACvgZ",
        Messaging = c"$s7SwiftUI28AccessibilityTextContentTypeV9messagingACvgZ",
        Narrative = c"$s7SwiftUI28AccessibilityTextContentTypeV9narrativeACvgZ",
        SourceCode = c"$s7SwiftUI28AccessibilityTextContentTypeV10sourceCodeACvgZ",
        Spreadsheet = c"$s7SwiftUI28AccessibilityTextContentTypeV11spreadsheetACvgZ",
        WordProcessing = c"$s7SwiftUI28AccessibilityTextContentTypeV14wordProcessingACvgZ",
    }
}

swift_statics! {
    /// A member of `SwiftUI.AccessibilityDirectTouchOptions`.
    pub enum DirectTouchOption {
        SilentOnTouch = c"$s7SwiftUI31AccessibilityDirectTouchOptionsV08silentOnE0ACvgZ",
        RequiresActivation = c"$s7SwiftUI31AccessibilityDirectTouchOptionsV18requiresActivationACvgZ",
    }
}

/// Apply `.accessibility(identifier:)`, the pre-`accessibilityIdentifier` name.
pub fn accessibility_deprecated_identifier(view: &ViewHandle, id: &str) -> ViewHandle {
    unsafe {
        let s = abi::swift_string(id);
        let w0 = u64::from_le_bytes(s[..8].try_into().expect("string lo"));
        let w1 = u64::from_le_bytes(s[8..].try_into().expect("string hi"));
        a11y_modifier(resolve::a11y_deprecated_identifier_fn(), view, &[w0, w1], [0.0; 4])
    }
}

/// Apply `.accessibilityIdentifier(_:)`.
pub fn accessibility_identifier(view: &ViewHandle, id: &str) -> ViewHandle {
    unsafe {
        let s = abi::swift_string(id);
        let w0 = u64::from_le_bytes(s[..8].try_into().expect("string lo"));
        let w1 = u64::from_le_bytes(s[8..].try_into().expect("string hi"));
        a11y_modifier(resolve::a11y_identifier_fn(), view, &[w0, w1], [0.0; 4])
    }
}

/// Apply `.accessibilitySortPriority(_:)`.
pub fn accessibility_sort_priority(view: &ViewHandle, priority: f64) -> ViewHandle {
    unsafe { a11y_modifier(resolve::a11y_sort_priority_fn(), view, &[], [priority, 0.0, 0.0, 0.0]) }
}

/// Apply `.accessibilityValue(_:isEnabled:)`.
pub fn accessibility_value(view: &ViewHandle, value: &str, enabled: bool) -> ViewHandle {
    unsafe {
        let (k0, k1, k2, k3) = lsk_words(value);
        a11y_modifier(resolve::a11y_value_fn(), view, &[k0, k1, k2, k3, u64::from(enabled)], [0.0; 4])
    }
}

/// Apply `.accessibilityRespondsToUserInteraction(_:)`.
pub fn accessibility_responds_to_user_interaction(view: &ViewHandle, responds: bool) -> ViewHandle {
    unsafe {
        a11y_modifier(resolve::a11y_responds_fn(), view, &[u64::from(responds)], [0.0; 4])
    }
}

/// Apply `.accessibilityHint(_:)`.
pub fn accessibility_hint(view: &ViewHandle, hint: &str) -> ViewHandle {
    unsafe {
        let (k0, k1, k2, k3) = lsk_words(hint);
        a11y_modifier(resolve::a11y_hint_fn(), view, &[k0, k1, k2, k3], [0.0; 4])
    }
}

/// Apply `.accessibilityScrollStatus(_:isEnabled:)`.
pub fn accessibility_scroll_status(view: &ViewHandle, status: &str, enabled: bool) -> ViewHandle {
    unsafe {
        let (k0, k1, k2, k3) = lsk_words(status);
        a11y_modifier(
            resolve::a11y_scroll_status_fn(),
            view,
            &[k0, k1, k2, k3, u64::from(enabled)],
            [0.0; 4],
        )
    }
}

/// Apply `.accessibilityActivationPoint(_:)`.
///
/// A `UnitPoint` is two `CGFloat`s and frozen, so it arrives in d0 and d1
/// rather than by address.
pub fn accessibility_activation_point(view: &ViewHandle, x: f64, y: f64) -> ViewHandle {
    unsafe { a11y_modifier(resolve::a11y_activation_point_fn(), view, &[], [x, y, 0.0, 0.0]) }
}

/// Apply `.accessibilityDragPoint(_:description:isEnabled:)`.
pub fn accessibility_drag_point(
    view: &ViewHandle,
    x: f64,
    y: f64,
    description: &str,
    enabled: bool,
) -> ViewHandle {
    unsafe {
        let (k0, k1, k2, k3) = lsk_words(description);
        a11y_modifier(
            resolve::a11y_drag_point_fn(),
            view,
            &[k0, k1, k2, k3, u64::from(enabled)],
            [x, y, 0.0, 0.0],
        )
    }
}

/// Apply `.accessibilityDropPoint(_:description:isEnabled:)`.
pub fn accessibility_drop_point(
    view: &ViewHandle,
    x: f64,
    y: f64,
    description: &str,
    enabled: bool,
) -> ViewHandle {
    unsafe {
        let (k0, k1, k2, k3) = lsk_words(description);
        a11y_modifier(
            resolve::a11y_drop_point_fn(),
            view,
            &[k0, k1, k2, k3, u64::from(enabled)],
            [x, y, 0.0, 0.0],
        )
    }
}

/// Apply `.accessibilityAddTraits(_:)`.
pub fn accessibility_add_traits(view: &ViewHandle, traits: &[AccessibilityTrait]) -> ViewHandle {
    unsafe {
        let v = traits_value(traits);
        a11y_modifier(resolve::a11y_add_traits_fn(), view, &[v.as_ptr() as u64], [0.0; 4])
    }
}

/// Apply `.accessibilityRemoveTraits(_:)`.
pub fn accessibility_remove_traits(view: &ViewHandle, traits: &[AccessibilityTrait]) -> ViewHandle {
    unsafe {
        let v = traits_value(traits);
        a11y_modifier(resolve::a11y_remove_traits_fn(), view, &[v.as_ptr() as u64], [0.0; 4])
    }
}

/// Apply `.accessibilityHeading(_:)`.
pub fn accessibility_heading(view: &ViewHandle, level: HeadingLevel) -> ViewHandle {
    unsafe {
        let meta = abi::metadata0(resolve::a11y_heading_level_ma());
        let arg = abi::enum_argument(meta, level.tag());
        a11y_modifier(resolve::a11y_heading_fn(), view, &[arg], [0.0; 4])
    }
}

/// Apply `.accessibilityTextContentType(_:)`.
pub fn accessibility_text_content_type(view: &ViewHandle, kind: TextContentType) -> ViewHandle {
    unsafe {
        let meta = abi::metadata0(resolve::a11y_text_content_type_ma());
        let v = resilient_static(meta, kind.getter());
        a11y_modifier(
            resolve::a11y_text_content_type_fn(),
            view,
            &[v.as_ptr() as u64],
            [0.0; 4],
        )
    }
}

/// Apply `.accessibilityInputLabels(_:isEnabled:)`.
/// Box a `Hashable` value into a `Swift.AnyHashable`.
///
/// Forty bytes, written through x8; the value goes in by address with its
/// metadata and `Hashable` witness beside it. `AnyHashable` is not something
/// this crate can lay out by hand — the box stores a copy made through the
/// value's own witness table, which is what `_convertToAnyHashable` is for.
///
/// # Safety
/// `bytes` must be a live value of type `meta`, conforming through `wt`.
pub(crate) unsafe fn any_hashable(
    bytes: &[u8],
    meta: *const c_void,
    wt: *const c_void,
) -> Vec<u8> {
    unsafe {
        let any_meta = abi::metadata0(resolve::any_hashable_ma());
        assert!(!any_meta.is_null(), "AnyHashable metadata");
        let mut out = vec![0u8; abi::type_bytes(any_meta)];
        core::arch::asm!("blr {f}", f = in(reg) resolve::convert_to_any_hashable(),
            in("x0") bytes.as_ptr(),
            in("x1") meta,
            in("x2") wt,
            in("x8") out.as_mut_ptr(),
            lateout("x3") _, lateout("x4") _, lateout("x5") _, lateout("x6") _,
            lateout("x7") _, lateout("x9") _, lateout("x10") _, lateout("x11") _,
            lateout("x12") _, lateout("x13") _, lateout("x14") _, lateout("x15") _,
            lateout("x16") _, lateout("x17") _, lateout("lr") _, lateout("x20") _,
            lateout("x21") _, clobber_abi("C"),
        );
        out
    }
}

/// `.accessibility(selectionIdentifier:)` — which item of a selectable group
/// this is, for assistive technologies.
///
/// Deprecated in Swift, with no modern replacement — `accessibilityIdentifier`
/// is a different thing (a test hook). Bound because it is the one member of
/// that family the crate could not otherwise reach.
///
/// The argument is `AnyHashable`, which is three words: the boxed value, its
/// metadata and its `Hashable` witness.
pub fn accessibility_selection_identifier(
    view: &ViewHandle,
    id: super::HashableValue<'_>,
) -> ViewHandle {
    unsafe {
        let (bytes, meta, wt) = id.parts();
        let any = any_hashable(&bytes, meta, wt);
        a11y_modifier(resolve::a11y_selection_identifier_fn(), view, &[any.as_ptr() as u64], [0.0; 4])
    }
}

pub fn accessibility_input_labels(
    view: &ViewHandle,
    labels: &[&str],
    enabled: bool,
) -> ViewHandle {
    unsafe {
        let meta = resolve::lsk_meta();
        let stride = abi::type_bytes(meta);
        let mut bytes = vec![0u8; stride * labels.len()];
        for (i, l) in labels.iter().enumerate() {
            let (k0, k1, k2, k3) = lsk_words(l);
            let at = &mut bytes[i * stride..];
            at[..8].copy_from_slice(&k0.to_le_bytes());
            at[8..16].copy_from_slice(&k1.to_le_bytes());
            at[16..24].copy_from_slice(&k2.to_le_bytes());
            at[24..32].copy_from_slice(&k3.to_le_bytes());
        }
        let array = abi::swift_array(meta, labels.len(), &bytes);
        a11y_modifier(
            resolve::a11y_input_labels_fn(),
            view,
            &[array, u64::from(enabled)],
            [0.0; 4],
        )
    }
}

/// Apply `.accessibilityDirectTouch(_:options:)`.
pub fn accessibility_direct_touch(
    view: &ViewHandle,
    enabled: bool,
    options: &[DirectTouchOption],
) -> ViewHandle {
    unsafe {
        let meta = abi::metadata0(resolve::a11y_direct_touch_options_ma());
        let mut v = vec![0u8; abi::type_bytes(meta)];
        // An `OptionSet` is its `rawValue`, so members combine by bitwise or
        // without going through `formUnion`.
        for o in options {
            let one = resilient_static(meta, o.getter());
            for (dst, src) in v.iter_mut().zip(one.iter()) {
                *dst |= *src;
            }
        }
        a11y_modifier(
            resolve::a11y_direct_touch_fn(),
            view,
            &[u64::from(enabled), v.as_ptr() as u64],
            [0.0; 4],
        )
    }
}

/// A `LocalizedStringKey`'s four words.
pub(crate) unsafe fn lsk_words(s: &str) -> (u64, u64, u64, u64) {
    unsafe {
        let ss = abi::swift_string(s);
        localized_string_key(
            u64::from_le_bytes(ss[..8].try_into().expect("string lo")),
            u64::from_le_bytes(ss[8..].try_into().expect("string hi")),
        )
    }
}

/// How prominent a piece of custom accessibility content is.
///
/// An imported Objective-C `NS_ENUM`, so it is a plain integer in a register
/// rather than a Swift enum with a witness table.
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum CustomContentImportance {
    Default = 0,
    High = 1,
}

/// Apply `.accessibilityCustomContent(_:_:importance:)`.
///
/// The key is built first, through `AccessibilityCustomContentKey.init(_:id:)`
/// — four words of `LocalizedStringKey` and two of `String`, returning the key
/// through x8 because it is resilient. The modifier then takes that key by
/// address, its own label as another `LocalizedStringKey`, and the importance
/// in a register.
pub fn accessibility_custom_content(
    view: &ViewHandle,
    key_label: &str,
    id: &str,
    value: &str,
    importance: CustomContentImportance,
) -> ViewHandle {
    unsafe {
        let (kk0, kk1, kk2, kk3) = lsk_words(key_label);
        let ids = abi::swift_string(id);
        let i0 = u64::from_le_bytes(ids[..8].try_into().expect("id lo"));
        let i1 = u64::from_le_bytes(ids[8..].try_into().expect("id hi"));
        let key_meta = abi::metadata0(resolve::a11y_custom_content_key_ma());
        let mut key = vec![0u8; abi::type_bytes(key_meta)];
        core::arch::asm!("blr {f}", f = in(reg) resolve::a11y_custom_content_key_init(),
            in("x0") kk0, in("x1") kk1, in("x2") kk2, in("x3") kk3,
            in("x4") i0, in("x5") i1,
            in("x8") key.as_mut_ptr(), in("x20") key_meta,
            lateout("x6") _, lateout("x7") _, lateout("x9") _, lateout("x10") _,
            lateout("x11") _, lateout("x12") _, lateout("x13") _, lateout("x14") _,
            lateout("x15") _, lateout("x16") _, lateout("x17") _, lateout("lr") _,
            lateout("x21") _, clobber_abi("C"),
        );
        let (v0, v1, v2, v3) = lsk_words(value);
        let (_, _, size) = A11Y_T.applied_to(view.meta);
        let r = abi::call_modifier(resolve::a11y_custom_content_fn(), view.value_ptr(), view.meta, view.wt,
            &[key.as_ptr() as u64, v0, v1, v2, v3, importance as u64],
            [0.0; 4],
            size,
        );
        wrap_modified(r, &A11Y_T, view)
    }
}

/// One end of a `String`, as a `String.Index`.
///
/// A `String` is sixteen bytes, which is more than the one register Swift pins
/// `self` to — so a method on it takes `self` *indirectly*, with the address in
/// x20. The index itself is one word and comes back in x0.
unsafe fn string_bound(text: &str, getter: *const c_void) -> u64 {
    unsafe {
        let s = abi::swift_string(text);
        let index: u64;
        core::arch::asm!("blr {f}", f = in(reg) getter,
            in("x20") s.as_ptr(),
            lateout("x0") index,
            lateout("x1") _, lateout("x2") _, lateout("x3") _, lateout("x4") _,
            lateout("x5") _, lateout("x6") _, lateout("x7") _, lateout("x8") _,
            lateout("x9") _, lateout("x10") _, lateout("x11") _, lateout("x12") _,
            lateout("x13") _, lateout("x14") _, lateout("x15") _, lateout("x16") _,
            lateout("x17") _, lateout("lr") _, lateout("x21") _, clobber_abi("C"),
        );
        index
    }
}

/// Apply `.accessibilityRotor(_:textRanges:)`.
///
/// The ranges are real `Range<String.Index>` values taken from `text` — one
/// spanning the whole string. `Range` is frozen and its two bounds are stored
/// back to back, so the array elements are built directly rather than through an
/// initialiser.
pub fn accessibility_rotor(view: &ViewHandle, label: &str, text: &str) -> ViewHandle {
    unsafe {
        let lower = string_bound(text, resolve::string_start_index());
        let upper = string_bound(text, resolve::string_end_index());
        let range = abi::resolve_type_by_mangled_name(mangle::range(&mangle::nested(mangle::STRING, "Index", mangle::Kind::Struct)).as_bytes());
        assert!(!range.is_null(), "Range<String.Index>");
        let stride = abi::type_bytes(range);
        let mut bytes = vec![0u8; stride];
        bytes[..8].copy_from_slice(&lower.to_le_bytes());
        bytes[8..16].copy_from_slice(&upper.to_le_bytes());
        let array = abi::swift_array(range, 1, &bytes);
        let (k0, k1, k2, k3) = lsk_words(label);
        let subst = [view.meta, view.wt];
        let (m, wt, size) = opaque_result_type(resolve::a11y_rotor_oret(), &subst);
        let r = abi::call_modifier(resolve::a11y_rotor_fn(), view.value_ptr(), view.meta, view.wt,
            &[k0, k1, k2, k3, array],
            [0.0; 4],
            size,
        );
        wrap_owned(r, m, wt)
    }
}

/// Apply `.accessibilityChartDescriptor(_:)` with a synthesized representable.
///
/// No public SwiftUI type conforms to `AXChartDescriptorRepresentable` — the
/// protocol exists for applications to adopt — so the conformance is built at
/// run time and hung on `EdgeInsets`, which the reference can name too.
pub fn accessibility_chart_descriptor(view: &ViewHandle) -> ViewHandle {
    unsafe {
        let meta = abi::metadata0(resolve::edge_insets_ma());
        let wt = crate::conformance::chart_descriptor_representable().witness_table();
        let value = vec![0u8; abi::type_bytes(meta)];
        generic1_modifier_ints(
            resolve::a11y_chart_descriptor_fn(),
            resolve::a11y_chart_descriptor_oret(),
            view,
            meta,
            wt,
            &[value.as_ptr() as u64],
            [0.0; 4],
        )
    }
}