Handle paste events in editor

Only on non-windows platforms though, since crossterm doesn't support
pasting on windows.

CHANGELOG.md

@@ -17,6 +17,7 @@ Procedure when bumping the version number:
 ### Added
 - New messages are now marked as unseen
 - Sub-trees can now be folded
+- Support for pasting text into editors
 - More readline-esque editor key bindings
 - Key bindings to move to prev/next sibling
 - Key binding to center cursor on screen

src/ui/util.rs

@@ -78,6 +78,7 @@ pub fn handle_editor_event(
 
         // Editing
         key!(Char ch) if char_filter(*ch) => editor.insert_char(terminal.frame(), *ch),
+        key!(Paste str) if str.chars().all(char_filter) => editor.insert_str(terminal.frame(), str),
         key!(Ctrl + 'h') | key!(Backspace) => editor.backspace(terminal.frame()),
         key!(Ctrl + 'd') | key!(Delete) => editor.delete(),
         key!(Ctrl + 'l') => editor.clear(),

src/ui/widgets/editor.rs

@@ -182,8 +182,15 @@ impl InnerEditorState {
     /// accordingly.
     fn insert_char(&mut self, frame: &mut Frame, ch: char) {
         self.text.insert(self.idx, ch);
-        self.idx += 1;
+        self.idx += ch.len_utf8();
-        self.move_cursor_to_grapheme_boundary();
+        self.record_cursor_col(frame);
+    }
+
+    /// Insert a string at the current cursor position and move the cursor
+    /// accordingly.
+    fn insert_str(&mut self, frame: &mut Frame, str: &str) {
+        self.text.insert_str(self.idx, str);
+        self.idx += str.len();
         self.record_cursor_col(frame);
     }
 
@@ -347,6 +354,10 @@ impl EditorState {
         self.0.lock().insert_char(frame, ch);
     }
 
+    pub fn insert_str(&self, frame: &mut Frame, str: &str) {
+        self.0.lock().insert_str(frame, str);
+    }
+
     /// Delete the grapheme before the cursor position.
     pub fn backspace(&self, frame: &mut Frame) {
         self.0.lock().backspace(frame);