* fix: should transform checkout event
* chore: update fuzz dep
* chore: add pos to error info
* fix: clear undo/redo stack when checkingout
* test: update fuzz dep
* test: a new failed test case
* fix: tree transform
* chore: fuzz
* chore: add log
* chore: add more logs
* fix: compose err
* chore: fuzz test dep
* test: a failed tree case
* fix: undo tree event
* fix: do not compare tree position in fuzz
* fix: fuzz rev
* test: a failed tree case
* fix: add tree compose
* chore: add comment
* chore: fuzz
* fix: test
* fix: tree transform
* fix: tree transform index
* fix: sort tree index
* chore: fuzz
* fix: undo/redo remote change effect compose
* bk
* fix: tree undo redo (#385)
* fix: event hint none
* chore: fuzz version
* ci: fuzz
* bk: weird err
* fix: type err
* fix: fractional index between
* fix: wasm counter feature
* test: a new failed case
* fix: recursively create child nodes
* fix: filter empty event
* bk
* bk
* fix: tree undo redo remap
* chore: clean
* bk
* fix: tree need remap first
* fix: tree undo effect
* fix: tree diff calc
* fix: tree fuzz check eq func
* fix: remove EventHint None
* chore: cargo fix
* fix: tree uncreate
* fix: fuzz tree assert only structure
* refactor: rename methods
* fix: movable tree apply delta
* fix: another movable list issue
* chore: fuzz only check 1 actor's history
---------
Co-authored-by: Leon Zhao <leeeon233@gmail.com>
This PR introduces support for retrieving and querying cursors.
## Motivation
Using "index" to denote cursor positions can be unstable, as positions may shift with document edits. To reliably represent a position or range within a document, it is more effective to leverage the unique ID of each item/character in a List CRDT or Text CRDT.
## Updating Cursors
Loro optimizes State metadata by not storing the IDs of deleted elements. This approach, while efficient, complicates tracking cursor positions since they rely on these IDs for precise locations within the document. The solution recalculates position by replaying relevant history to update stable positions accurately. To minimize the performance impact of history replay, the system updates cursor info to reference only the IDs of currently present elements, thereby reducing the need for replay.
Each position has a "Side" information, indicating the actual cursor position is on the left, right, or directly in the center of the target ID.
Note: In JavaScript, the offset returned when querying a Stable Position is based on the UTF-16 index.
# Example
```ts
const loro = new Loro();
const list = loro.getList("list");
list.insert(0, "a");
const pos0 = list.getStablePos(0);
list.insert(1, "b");
{
const ans = loro.queryStablePos(pos0!);
expect(ans.offset).toEqual(0);
expect(ans.side).toEqual(0);
expect(ans.update).toBeUndefined();
}
list.insert(0, "c");
{
const ans = loro.queryStablePos(pos0!);
expect(ans.offset).toEqual(1);
expect(ans.side).toEqual(0);
expect(ans.update).toBeUndefined();
}
list.delete(1, 1);
{
const ans = loro.queryStablePos(pos0!);
expect(ans.offset).toEqual(1);
expect(ans.side).toEqual(-1);
expect(ans.update).toBeDefined();
}
```
