feat: cursor mut

crates/loro-core/src/container/text/tracker/content_map.rs

@@ -1,5 +1,33 @@
-use rle::RleTree;
+use std::ops::{Deref, DerefMut};
 
-use super::y_span::{YSpan, YSpanTreeTrait};
+use rle::{rle_tree::SafeCursorMut, Rle, RleTree, RleTreeTrait};
 
-pub(super) type ContentMap = RleTree<YSpan, YSpanTreeTrait>;
+use super::y_span::{StatusChange, YSpan, YSpanTreeTrait};
+
+#[repr(transparent)]
+#[derive(Debug)]
+pub(super) struct ContentMap(RleTree<YSpan, YSpanTreeTrait>);
+
+impl Deref for ContentMap {
+    type Target = RleTree<YSpan, YSpanTreeTrait>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl DerefMut for ContentMap {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.0
+    }
+}
+
+pub(super) fn change_status(
+    cursor: &mut SafeCursorMut<'_, '_, YSpan, YSpanTreeTrait>,
+    change: StatusChange,
+) {
+    let value = cursor.as_mut();
+    if value.status.apply(change) {
+        cursor.update_cache_recursively();
+    }
+}

crates/loro-core/src/container/text/tracker/y_span.rs

@@ -8,6 +8,29 @@ pub(super) struct Status {
     undo_times: usize,
 }
 
+impl Status {
+    #[inline]
+    pub fn is_activated(&self) -> bool {
+        !self.unapplied && self.delete_times == 0 && self.undo_times == 0
+    }
+
+    /// Return whether the activation changed
+    #[inline]
+    pub fn apply(&mut self, change: StatusChange) -> bool {
+        let activated = self.is_activated();
+        match change {
+            StatusChange::Apply => self.unapplied = false,
+            StatusChange::PreApply => self.unapplied = true,
+            StatusChange::Redo => self.undo_times -= 1,
+            StatusChange::Undo => self.undo_times += 1,
+            StatusChange::Delete => self.delete_times += 1,
+            StatusChange::UndoDelete => self.delete_times -= 1,
+        }
+
+        self.is_activated() != activated
+    }
+}
+
 #[derive(Debug, Clone)]
 pub(super) struct YSpan {
     pub origin_left: ID,
@@ -17,6 +40,16 @@ pub(super) struct YSpan {
     pub status: Status,
 }
 
+#[derive(Clone, Copy, Debug)]
+pub(super) enum StatusChange {
+    Apply,
+    PreApply,
+    Redo,
+    Undo,
+    Delete,
+    UndoDelete,
+}
+
 pub(super) type YSpanTreeTrait = CumulateTreeTrait<YSpan, 10>;
 
 impl Mergable for YSpan {
@@ -71,7 +104,11 @@ impl InsertContent for YSpan {
 
 impl HasLength for YSpan {
     fn len(&self) -> usize {
-        self.len
+        if self.status.is_activated() {
+            self.len
+        } else {
+            0
+        }
     }
 }
 

crates/rle/src/rle_tree.rs

@@ -1,10 +1,8 @@
-use self::{
-    cursor::SafeCursor,
-    node::{InternalNode, Node},
-};
+use self::node::{InternalNode, Node};
 use crate::Rle;
 pub(self) use bumpalo::collections::vec::Vec as BumpVec;
 use bumpalo::Bump;
+pub use cursor::{SafeCursor, SafeCursorMut};
 use ouroboros::self_referencing;
 use std::marker::{PhantomData, PhantomPinned};
 use tree_trait::RleTreeTrait;
@@ -61,6 +59,7 @@ impl<'a, T: Rle, A: RleTreeTrait<T>> RleTreeRaw<'a, T, A> {
     }
 
     /// return a cursor to the tree
+    #[inline]
     pub fn get<'b>(&'b self, mut index: A::Int) -> SafeCursor<'a, 'b, T, A> {
         let mut node = &self.node;
         loop {
@@ -79,8 +78,9 @@ impl<'a, T: Rle, A: RleTreeTrait<T>> RleTreeRaw<'a, T, A> {
     }
 
     #[inline]
-    pub fn get_mut<'b>(&'b mut self, index: A::Int) -> SafeCursor<'a, 'b, T, A> {
-        self.get(index)
+    pub fn get_mut<'b>(&'b mut self, index: A::Int) -> SafeCursorMut<'a, 'b, T, A> {
+        let cursor = self.get(index);
+        SafeCursorMut(cursor.0)
     }
 
     pub fn iter(&self) -> iter::Iter<'_, 'a, T, A> {

crates/rle/src/rle_tree/cursor.rs

@@ -11,7 +11,11 @@ pub struct UnsafeCursor<'a, Tree, T: Rle, A: RleTreeTrait<T>> {
 }
 
 pub struct SafeCursor<'a, 'b, T: Rle, A: RleTreeTrait<T>>(
-    UnsafeCursor<'a, &'b RleTreeRaw<'a, T, A>, T, A>,
+    pub(crate) UnsafeCursor<'a, &'b RleTreeRaw<'a, T, A>, T, A>,
+);
+
+pub struct SafeCursorMut<'a, 'b, T: Rle, A: RleTreeTrait<T>>(
+    pub(crate) UnsafeCursor<'a, &'b RleTreeRaw<'a, T, A>, T, A>,
 );
 
 impl<'a, Tree, T: Rle, A: RleTreeTrait<T>> UnsafeCursor<'a, Tree, T, A> {
@@ -61,9 +65,41 @@ impl<'a, 'b, T: Rle, A: RleTreeTrait<T>> SafeCursor<'a, 'b, T, A> {
     pub(crate) fn new(leaf: NonNull<LeafNode<'a, T, A>>, index: usize) -> Self {
         Self(UnsafeCursor::new(leaf, index))
     }
+}
 
+impl<'a, 'b, T: Rle, A: RleTreeTrait<T>> AsRef<T> for SafeCursorMut<'a, 'b, T, A> {
+    #[inline]
+    fn as_ref(&self) -> &T {
+        unsafe { self.0.as_ref() }
+    }
+}
+
+impl<'a, 'b, T: Rle, A: RleTreeTrait<T>> SafeCursorMut<'a, 'b, T, A> {
+    #[inline]
+    pub(crate) fn new(leaf: NonNull<LeafNode<'a, T, A>>, index: usize) -> Self {
+        Self(UnsafeCursor::new(leaf, index))
+    }
+}
+
+impl<'a, 'b, T: Rle, A: RleTreeTrait<T>> AsMut<T> for SafeCursorMut<'a, 'b, T, A> {
     #[inline]
     fn as_mut(&mut self) -> &mut T {
         unsafe { self.0.as_mut() }
     }
 }
+
+impl<'a, 'b, T: Rle, A: RleTreeTrait<T>> SafeCursorMut<'a, 'b, T, A> {
+    #[inline]
+    pub fn update_cache_recursively(&mut self) {
+        let leaf = unsafe { self.0.leaf.as_mut() };
+        A::update_cache_leaf(leaf);
+        let mut node = unsafe { leaf.parent.as_mut() };
+        loop {
+            A::update_cache_internal(node);
+            match node.parent {
+                Some(mut parent) => node = unsafe { parent.as_mut() },
+                None => return,
+            }
+        }
+    }
+}

crates/rle/src/rle_tree/node.rs

@@ -6,7 +6,7 @@ use std::{
 
 use crate::Rle;
 
-use super::{tree_trait::RleTreeTrait, BumpVec};
+use super::{cursor::SafeCursor, tree_trait::RleTreeTrait, BumpVec};
 use bumpalo::Bump;
 use enum_as_inner::EnumAsInner;
 mod internal_impl;

crates/rle/src/rle_tree/node/leaf_impl.rs

@@ -1,4 +1,4 @@
-use crate::rle_tree::tree_trait::Position;
+use crate::rle_tree::{cursor::SafeCursorMut, tree_trait::Position};
 use std::fmt::{Debug, Error, Formatter};
 
 use super::*;
@@ -37,6 +37,18 @@ impl<'a, T: Rle, A: RleTreeTrait<T>> LeafNode<'a, T, A> {
         ans
     }
 
+    #[inline]
+    pub fn get_cursor<'b>(&'b self, pos: A::Int) -> SafeCursor<'a, 'b, T, A> {
+        let index = A::find_pos_leaf(self, pos).0;
+        SafeCursor::new(self.into(), index)
+    }
+
+    #[inline]
+    pub fn get_cursor_mut<'b>(&'b mut self, pos: A::Int) -> SafeCursorMut<'a, 'b, T, A> {
+        let index = A::find_pos_leaf(self, pos).0;
+        SafeCursorMut::new(self.into(), index)
+    }
+
     pub fn push_child(&mut self, value: T) -> Result<(), &'a mut Node<'a, T, A>> {
         if !self.children.is_empty() {
             let last = self.children.last_mut().unwrap();