refactor: refine parent info register

crates/loro-internal/src/arena.rs

@@ -222,7 +222,7 @@ impl SharedArena {
             .unwrap()
             .get(&child)
             .copied()
-            .flatten()
+            .expect("InternalError: Parent is not registered")
     }
 
     /// Call `f` on each ancestor of `container`, including `container` itself.
@@ -234,7 +234,7 @@ impl SharedArena {
         while let Some(c) = container {
             f(c, is_first);
             is_first = false;
-            container = self.get_parent(c);
+            container = self.get_parent(c)
         }
     }
 

crates/loro-internal/src/container.rs

@@ -21,9 +21,12 @@ pub mod idx {
     ///
     /// TODO: make this type private in this crate only
     ///
+    ///
     // During a transaction, we may create some containers which are deleted later. And these containers also need a unique ContainerIdx.
     // So when we encode snapshot, we need to sort the containers by ContainerIdx and change the `container` of ops to the index of containers.
     // An empty store decodes the snapshot, it will create these containers in a sequence of natural numbers so that containers and ops can correspond one-to-one
+    //
+    // TODO: PERF: use NonZeroU32 to save memory
     #[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Copy, Hash)]
     pub struct ContainerIdx(u32);
 

crates/loro-internal/src/oplog.rs

@@ -3,7 +3,6 @@ mod iter;
 pub(crate) mod loro_dag;
 mod pending_changes;
 
-use once_cell::sync::OnceCell;
 use std::borrow::Cow;
 use std::cell::RefCell;
 use std::cmp::Ordering;
@@ -21,13 +20,13 @@ use crate::encoding::{decode_oplog, encode_oplog, EncodeMode};
 use crate::history_cache::ContainerHistoryCache;
 use crate::id::{Counter, PeerID, ID};
 use crate::op::{FutureInnerContent, ListSlice, RawOpContent, RemoteOp, RichOp};
-use crate::span::{HasCounterSpan, HasIdSpan, HasLamportSpan};
+use crate::span::{HasCounterSpan, HasLamportSpan};
 use crate::version::{Frontiers, VersionVector};
 use crate::LoroError;
 use change_store::BlockOpRef;
 pub use change_store::{BlockChangeRef, ChangeStore};
-use loro_common::{HasId, IdLp, IdSpan};
-use rle::{HasLength, Mergable, RleVec, Sliceable};
+use loro_common::{IdLp, IdSpan};
+use rle::{HasLength, RleVec, Sliceable};
 use smallvec::SmallVec;
 
 use self::iter::MergedChangeIter;

crates/loro-internal/src/state.rs

@@ -892,10 +892,6 @@ impl DocState {
         F: FnOnce(&State) -> R,
     {
         let depth = self.arena.get_depth(idx).unwrap().get() as usize;
-        let parent = self
-            .arena
-            .get_parent(idx)
-            .and_then(|a| self.arena.get_container_id(a));
         let state = self
             .store
             .get_or_create(idx, || {