Implement an InputHandler trait for gpui2

Co-Authored-By: Marshall <marshall@zed.dev>
Co-Authored-By: Max <max@zed.dev>
Co-Authored-By: Julia <julia@zed.dev>

crates/gpui2/src/window_input_handler.rs

@@ -0,0 +1,89 @@
+use crate::{AnyWindowHandle, AppCell, Context, PlatformInputHandler, ViewContext, WeakView};
+use std::{ops::Range, rc::Weak};
+
+pub struct WindowInputHandler<V>
+where
+    V: InputHandler,
+{
+    pub cx: Weak<AppCell>,
+    pub window: AnyWindowHandle,
+    pub handler: WeakView<V>,
+}
+
+impl<V: InputHandler + 'static> PlatformInputHandler for WindowInputHandler<V> {
+    fn selected_text_range(&self) -> Option<std::ops::Range<usize>> {
+        self.update(|view, cx| view.selected_text_range(cx))
+            .flatten()
+    }
+
+    fn marked_text_range(&self) -> Option<std::ops::Range<usize>> {
+        self.update(|view, cx| view.marked_text_range(cx)).flatten()
+    }
+
+    fn text_for_range(&self, range_utf16: std::ops::Range<usize>) -> Option<String> {
+        self.update(|view, cx| view.text_for_range(range_utf16, cx))
+            .flatten()
+    }
+
+    fn replace_text_in_range(
+        &mut self,
+        replacement_range: Option<std::ops::Range<usize>>,
+        text: &str,
+    ) {
+        self.update(|view, cx| view.replace_text_in_range(replacement_range, text, cx));
+    }
+
+    fn replace_and_mark_text_in_range(
+        &mut self,
+        range_utf16: Option<std::ops::Range<usize>>,
+        new_text: &str,
+        new_selected_range: Option<std::ops::Range<usize>>,
+    ) {
+        self.update(|view, cx| {
+            view.replace_and_mark_text_in_range(range_utf16, new_text, new_selected_range, cx)
+        });
+    }
+
+    fn unmark_text(&mut self) {
+        self.update(|view, cx| view.unmark_text(cx));
+    }
+
+    fn bounds_for_range(&self, range_utf16: std::ops::Range<usize>) -> Option<crate::Bounds<f32>> {
+        self.update(|view, cx| view.bounds_for_range(range_utf16, cx))
+            .flatten()
+    }
+}
+
+impl<V: InputHandler + 'static> WindowInputHandler<V> {
+    fn update<T>(&self, f: impl FnOnce(&mut V, &mut ViewContext<V>) -> T) -> Option<T> {
+        let cx = self.cx.upgrade()?;
+        let mut cx = cx.borrow_mut();
+        cx.update_window(self.window, |_, cx| self.handler.update(cx, f).ok())
+            .ok()?
+    }
+}
+
+pub trait InputHandler: Sized {
+    fn text_for_range(&self, range: Range<usize>, cx: &mut ViewContext<Self>) -> Option<String>;
+    fn selected_text_range(&self, cx: &mut ViewContext<Self>) -> Option<Range<usize>>;
+    fn marked_text_range(&self, cx: &mut ViewContext<Self>) -> Option<Range<usize>>;
+    fn unmark_text(&mut self, cx: &mut ViewContext<Self>);
+    fn replace_text_in_range(
+        &mut self,
+        range: Option<Range<usize>>,
+        text: &str,
+        cx: &mut ViewContext<Self>,
+    );
+    fn replace_and_mark_text_in_range(
+        &mut self,
+        range: Option<Range<usize>>,
+        new_text: &str,
+        new_selected_range: Option<Range<usize>>,
+        cx: &mut ViewContext<Self>,
+    );
+    fn bounds_for_range(
+        &self,
+        range_utf16: std::ops::Range<usize>,
+        cx: &mut ViewContext<Self>,
+    ) -> Option<crate::Bounds<f32>>;
+}