1use crate::{
  2    AsyncWindowContext, Bounds, Pixels, PlatformInputHandler, View, ViewContext, WindowContext,
  3};
  4use std::ops::Range;
  5
  6/// Implement this trait to allow views to handle textual input when implementing an editor, field, etc.
  7///
  8/// Once your view `V` implements this trait, you can use it to construct an [ElementInputHandler<V>].
  9/// This input handler can then be assigned during paint by calling [WindowContext::handle_input].
 10pub trait InputHandler: 'static + Sized {
 11    fn text_for_range(&mut self, range: Range<usize>, cx: &mut ViewContext<Self>)
 12        -> Option<String>;
 13    fn selected_text_range(&mut self, cx: &mut ViewContext<Self>) -> Option<Range<usize>>;
 14    fn marked_text_range(&self, cx: &mut ViewContext<Self>) -> Option<Range<usize>>;
 15    fn unmark_text(&mut self, cx: &mut ViewContext<Self>);
 16    fn replace_text_in_range(
 17        &mut self,
 18        range: Option<Range<usize>>,
 19        text: &str,
 20        cx: &mut ViewContext<Self>,
 21    );
 22    fn replace_and_mark_text_in_range(
 23        &mut self,
 24        range: Option<Range<usize>>,
 25        new_text: &str,
 26        new_selected_range: Option<Range<usize>>,
 27        cx: &mut ViewContext<Self>,
 28    );
 29    fn bounds_for_range(
 30        &mut self,
 31        range_utf16: Range<usize>,
 32        element_bounds: Bounds<Pixels>,
 33        cx: &mut ViewContext<Self>,
 34    ) -> Option<Bounds<Pixels>>;
 35}
 36
 37/// The canonical implementation of `PlatformInputHandler`. Call `WindowContext::handle_input`
 38/// with an instance during your element's paint.
 39pub struct ElementInputHandler<V> {
 40    view: View<V>,
 41    element_bounds: Bounds<Pixels>,
 42    cx: AsyncWindowContext,
 43}
 44
 45impl<V: 'static> ElementInputHandler<V> {
 46    /// Used in [Element::paint] with the element's bounds and a view context for its
 47    /// containing view.
 48    pub fn new(element_bounds: Bounds<Pixels>, view: View<V>, cx: &mut WindowContext) -> Self {
 49        ElementInputHandler {
 50            view,
 51            element_bounds,
 52            cx: cx.to_async(),
 53        }
 54    }
 55}
 56
 57impl<V: InputHandler> PlatformInputHandler for ElementInputHandler<V> {
 58    fn selected_text_range(&mut self) -> Option<Range<usize>> {
 59        self.view
 60            .update(&mut self.cx, |view, cx| view.selected_text_range(cx))
 61            .ok()
 62            .flatten()
 63    }
 64
 65    fn marked_text_range(&mut self) -> Option<Range<usize>> {
 66        self.view
 67            .update(&mut self.cx, |view, cx| view.marked_text_range(cx))
 68            .ok()
 69            .flatten()
 70    }
 71
 72    fn text_for_range(&mut self, range_utf16: Range<usize>) -> Option<String> {
 73        self.view
 74            .update(&mut self.cx, |view, cx| {
 75                view.text_for_range(range_utf16, cx)
 76            })
 77            .ok()
 78            .flatten()
 79    }
 80
 81    fn replace_text_in_range(&mut self, replacement_range: Option<Range<usize>>, text: &str) {
 82        self.view
 83            .update(&mut self.cx, |view, cx| {
 84                view.replace_text_in_range(replacement_range, text, cx)
 85            })
 86            .ok();
 87    }
 88
 89    fn replace_and_mark_text_in_range(
 90        &mut self,
 91        range_utf16: Option<Range<usize>>,
 92        new_text: &str,
 93        new_selected_range: Option<Range<usize>>,
 94    ) {
 95        self.view
 96            .update(&mut self.cx, |view, cx| {
 97                view.replace_and_mark_text_in_range(range_utf16, new_text, new_selected_range, cx)
 98            })
 99            .ok();
100    }
101
102    fn unmark_text(&mut self) {
103        self.view
104            .update(&mut self.cx, |view, cx| view.unmark_text(cx))
105            .ok();
106    }
107
108    fn bounds_for_range(&mut self, range_utf16: Range<usize>) -> Option<Bounds<Pixels>> {
109        self.view
110            .update(&mut self.cx, |view, cx| {
111                view.bounds_for_range(range_utf16, self.element_bounds, cx)
112            })
113            .ok()
114            .flatten()
115    }
116}