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`][element_paint] with the element's bounds and a view context for its
 47    /// containing view.
 48    ///
 49    /// [element_paint]: crate::Element::paint
 50    pub fn new(element_bounds: Bounds<Pixels>, view: View<V>, cx: &mut WindowContext) -> Self {
 51        ElementInputHandler {
 52            view,
 53            element_bounds,
 54            cx: cx.to_async(),
 55        }
 56    }
 57}
 58
 59impl<V: InputHandler> PlatformInputHandler for ElementInputHandler<V> {
 60    fn selected_text_range(&mut self) -> Option<Range<usize>> {
 61        self.view
 62            .update(&mut self.cx, |view, cx| view.selected_text_range(cx))
 63            .ok()
 64            .flatten()
 65    }
 66
 67    fn marked_text_range(&mut self) -> Option<Range<usize>> {
 68        self.view
 69            .update(&mut self.cx, |view, cx| view.marked_text_range(cx))
 70            .ok()
 71            .flatten()
 72    }
 73
 74    fn text_for_range(&mut self, range_utf16: Range<usize>) -> Option<String> {
 75        self.view
 76            .update(&mut self.cx, |view, cx| {
 77                view.text_for_range(range_utf16, cx)
 78            })
 79            .ok()
 80            .flatten()
 81    }
 82
 83    fn replace_text_in_range(&mut self, replacement_range: Option<Range<usize>>, text: &str) {
 84        self.view
 85            .update(&mut self.cx, |view, cx| {
 86                view.replace_text_in_range(replacement_range, text, cx)
 87            })
 88            .ok();
 89    }
 90
 91    fn replace_and_mark_text_in_range(
 92        &mut self,
 93        range_utf16: Option<Range<usize>>,
 94        new_text: &str,
 95        new_selected_range: Option<Range<usize>>,
 96    ) {
 97        self.view
 98            .update(&mut self.cx, |view, cx| {
 99                view.replace_and_mark_text_in_range(range_utf16, new_text, new_selected_range, cx)
100            })
101            .ok();
102    }
103
104    fn unmark_text(&mut self) {
105        self.view
106            .update(&mut self.cx, |view, cx| view.unmark_text(cx))
107            .ok();
108    }
109
110    fn bounds_for_range(&mut self, range_utf16: Range<usize>) -> Option<Bounds<Pixels>> {
111        self.view
112            .update(&mut self.cx, |view, cx| {
113                view.bounds_for_range(range_utf16, self.element_bounds, cx)
114            })
115            .ok()
116            .flatten()
117    }
118}