Simplify old_state handling.

helix-core/src/state.rs

@@ -4,6 +4,7 @@
 use anyhow::Error;
 
 /// A state represents the current editor state of a single buffer.
+#[derive(Clone)]
 pub struct State {
     // TODO: fields should be private but we need to refactor commands.rs first
     pub doc: Rope,

helix-view/src/commands.rs

@@ -411,15 +411,9 @@ fn append_changes_to_history(view: &mut View) {
     // TODO: trigger lsp/documentDidChange with changes
 
     // HAXX: we need to reconstruct the state as it was before the changes..
-    let (doc, selection) = view.doc.old_state.take().unwrap();
-    let mut old_state = State::new(doc);
-    old_state.selection = selection;
-
+    let old_state = std::mem::replace(&mut view.doc.old_state, view.doc.state.clone());
     // TODO: take transaction by value?
     view.doc.history.commit_revision(&transaction, &old_state);
-
-    // HAXX
-    view.doc.old_state = Some((view.doc.text().clone(), view.doc.state.selection.clone()));
 }
 
 pub fn normal_mode(view: &mut View, _count: usize) {

helix-view/src/document.rs

@@ -27,9 +27,9 @@ pub struct Document {
 
     /// Pending changes since last history commit.
     pub changes: ChangeSet,
+    pub old_state: State,
     pub history: History,
     pub version: i64, // should be usize?
-    pub old_state: Option<(Rope, Selection)>,
 
     pub diagnostics: Vec<Diagnostic>,
 }
@@ -55,7 +55,7 @@ fn take_with<T, F>(mut_ref: &mut T, closure: F)
 impl Document {
     fn new(state: State) -> Self {
         let changes = ChangeSet::new(&state.doc);
-        let old_state = Some((state.doc.clone(), Selection::single(0, 0)));
+        let old_state = state.clone();
 
         Self {
             path: None,