Create text_input::Editor to hold editing logic

native/src/widget/text_input/editor.rs

@@ -0,0 +1,80 @@
+use crate::text_input::{Cursor, Value};
+
+pub struct Editor<'a> {
+    value: &'a mut Value,
+    cursor: &'a mut Cursor,
+}
+
+impl<'a> Editor<'a> {
+    pub fn new(value: &'a mut Value, cursor: &'a mut Cursor) -> Editor<'a> {
+        Editor { value, cursor }
+    }
+
+    pub fn contents(&self) -> String {
+        self.value.to_string()
+    }
+
+    pub fn insert(&mut self, character: char) {
+        match self.cursor.selection() {
+            Some((left, right)) => {
+                self.value.remove_many(left, right);
+                self.cursor.move_left(&self.value);
+            }
+            _ => (),
+        }
+
+        self.value.insert(self.cursor.end(&self.value), character);
+        self.cursor.move_right(&self.value);
+    }
+
+    pub fn paste(&mut self, content: Value) {
+        let length = content.len();
+
+        match self.cursor.selection() {
+            Some((left, right)) => {
+                self.value.remove_many(left, right);
+                self.cursor.move_left(&self.value);
+            }
+            _ => (),
+        }
+
+        self.value
+            .insert_many(self.cursor.end(&self.value), content);
+
+        self.cursor.move_right_by_amount(&self.value, length);
+    }
+
+    pub fn backspace(&mut self) {
+        match self.cursor.selection() {
+            Some((start, end)) => {
+                self.value.remove_many(start, end);
+                self.cursor.move_left(&self.value);
+            }
+            None => {
+                let start = self.cursor.start(&self.value);
+
+                if start > 0 {
+                    self.cursor.move_left(&self.value);
+
+                    let _ = self.value.remove(start - 1);
+                }
+            }
+        }
+    }
+
+    pub fn delete(&mut self) {
+        match self.cursor.selection() {
+            Some((start, end)) => {
+                self.value.remove_many(start, end);
+                self.cursor.move_left(&self.value);
+            }
+            None => {
+                let end = self.cursor.end(&self.value);
+
+                if end < self.value.len() {
+                    let _ = self.value.remove(end);
+                }
+            }
+        }
+    }
+}