add undo-aware dirty tracking for documents

src/views/editor/text.rs

@@ -3,7 +3,7 @@ use std::{borrow::Cow, fmt::Debug, ops::Range, rc::Rc};
 use crate::{
     peniko::Color,
     peniko::color::palette,
-    reactive::{RwSignal, Scope},
+    reactive::{Memo, RwSignal, Scope},
     text::{Attrs, AttrsList, FamilyOwned, FontWeight, FontWidth},
     views::EditorCustomStyle,
 };
@@ -206,6 +206,17 @@ pub trait Document: DocumentPhantom + ::std::any::Any {
     /// ))
     /// ```
     fn edit(&self, iter: &mut dyn Iterator<Item = (Selection, &str)>, edit_type: EditType);
+
+    /// Reactive dirty state for the document.
+    fn dirty(&self) -> Memo<bool>;
+
+    /// Whether the document has been modified since it was last marked pristine.
+    fn is_dirty(&self) -> bool {
+        self.dirty().get_untracked()
+    }
+
+    /// Mark the current state as the pristine (saved) baseline.
+    fn mark_pristine(&self) {}
 }
 
 pub trait DocumentPhantom {
@@ -519,6 +530,18 @@ where
     fn edit(&self, iter: &mut dyn Iterator<Item = (Selection, &str)>, edit_type: EditType) {
         self.doc.edit(iter, edit_type)
     }
+
+    fn dirty(&self) -> Memo<bool> {
+        self.doc.dirty()
+    }
+
+    fn is_dirty(&self) -> bool {
+        self.doc.is_dirty()
+    }
+
+    fn mark_pristine(&self) {
+        self.doc.mark_pristine()
+    }
 }
 impl<D, F> DocumentPhantom for ExtCmdDocument<D, F>
 where

src/views/editor/text_document.rs

@@ -15,7 +15,9 @@ use floem_editor_core::{
     selection::Selection,
     word::WordCursor,
 };
-use floem_reactive::{Effect, RwSignal, Scope, SignalGet, SignalTrack, SignalUpdate, SignalWith};
+use floem_reactive::{
+    Effect, Memo, RwSignal, Scope, SignalGet, SignalTrack, SignalUpdate, SignalWith,
+};
 use lapce_xi_rope::{Rope, RopeDelta};
 use smallvec::{SmallVec, smallvec};
 use ui_events::keyboard::Modifiers;
@@ -58,6 +60,7 @@ impl<'a> OnUpdate<'a> {
 pub struct TextDocument {
     buffer: RwSignal<Buffer>,
     cache_rev: RwSignal<u64>,
+    dirty: Memo<bool>,
     preedit: PreeditData,
 
     /// Whether to keep the indent of the previous line when inserting a new line
@@ -77,7 +80,8 @@ pub struct TextDocument {
 impl TextDocument {
     pub fn new(cx: Scope, text: impl Into<Rope>) -> TextDocument {
         let text = text.into();
-        let buffer = Buffer::new(text);
+        let buffer = cx.create_rw_signal(Buffer::new(text));
+        let dirty = cx.create_memo(move |_| !buffer.with(Buffer::is_pristine));
         let preedit = PreeditData {
             preedit: cx.create_rw_signal(None),
         };
@@ -94,8 +98,9 @@ impl TextDocument {
         });
 
         TextDocument {
-            buffer: cx.create_rw_signal(buffer),
+            buffer,
             cache_rev,
+            dirty,
             preedit,
             keep_indent: Cell::new(true),
             auto_indent: Cell::new(false),
@@ -240,6 +245,14 @@ impl Document for TextDocument {
         self.update_cache_rev();
         self.on_update(None, deltas);
     }
+
+    fn dirty(&self) -> Memo<bool> {
+        self.dirty
+    }
+
+    fn mark_pristine(&self) {
+        self.buffer.update(Buffer::set_pristine);
+    }
 }
 impl DocumentPhantom for TextDocument {
     fn phantom_text(&self, edid: EditorId, styling: &EditorStyle, line: usize) -> PhantomTextLine {
@@ -366,3 +379,44 @@ impl std::fmt::Debug for TextDocument {
         s.finish()
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use floem_editor_core::{cursor::CursorAffinity, editor::EditType, selection::Selection};
+    use floem_reactive::{Scope, SignalGet};
+
+    use super::TextDocument;
+    use crate::views::editor::text::Document;
+
+    #[test]
+    fn dirty_tracking_respects_pristine_baseline() {
+        let cx = Scope::new();
+        let doc = TextDocument::new(cx, "abc");
+        let dirty = doc.dirty();
+
+        assert!(!doc.is_dirty());
+        assert!(!dirty.get_untracked());
+
+        doc.edit_single(
+            Selection::caret(3, CursorAffinity::Backward),
+            "d",
+            EditType::InsertChars,
+        );
+        assert!(doc.is_dirty());
+        assert!(dirty.get_untracked());
+
+        let marked_rev = doc.cache_rev().get_untracked();
+        doc.mark_pristine();
+        assert!(!doc.is_dirty());
+        assert!(!dirty.get_untracked());
+        assert_eq!(doc.cache_rev().get_untracked(), marked_rev);
+
+        doc.edit_single(
+            Selection::caret(4, CursorAffinity::Backward),
+            "e",
+            EditType::InsertChars,
+        );
+        assert!(doc.is_dirty());
+        assert!(dirty.get_untracked());
+    }
+}