grep across the repo confirms zero external callers of bintrie.NodeStore,
NewNodeStore, NodeFlushFn, or NodeResolverFn. The arena is purely an
implementation detail of BinaryTrie; unexport the top-level names so
the package's external surface stays confined to BinaryTrie plus the
EIP-7864 helpers (ChunkifyCode, GetBinaryTreeKey*).
Methods on *nodeStore remain capitalized for now — with nodeStore
itself unexported, external code has no way to hold a *nodeStore
pointer, so the methods are effectively internal despite their case.
Method case is a cosmetic follow-up.
Comparing against emptyRef (the single value makeRef(kindEmpty, 0))
only works because no other nodeRef with kindEmpty is ever constructed.
That invariant is easy to break if future code ever produces a
kindEmpty ref with nonzero index. Test the kind directly so any
kindEmpty ref reads as empty regardless of index.
Silently masking the index with indexMask would let an oversized idx
collide with emptyRef (makeRef(kindEmpty, 0)): e.g. makeRef(kindEmpty,
1<<30) returned emptyRef, which IsEmpty would accept as absent even
though the caller meant to reference a real node. Panic instead.
allocInternal/allocStem/allocHashed already panic on pool overflow,
so this is a belt-and-suspenders guard for any direct callers.
Gballet asked on PR #34055 to unexport nodeRef, nodeKind, and makeRef
(comments 3099846639, 3099847640, 3100717855) — none are used outside
trie/bintrie. Cascade to the internal-only support symbols and methods:
NodeKind → nodeKind
KindEmpty/... → kindEmpty/...
NodeRef → nodeRef
EmptyRef → emptyRef
MakeRef → makeRef
NodeStore.Root → deleted; inlined to s.root field access (same pkg)
NodeStore.SetRoot → deleted; inlined to s.root = ref
NodeStore.ComputeHash/SerializeNode/DeserializeNode(WithHash)/
CollectNodes/ToDot/GetHeight → lowercased
All 9 method signatures took or returned nodeRef so their export would
have tripped revive:unexported-return after the type rename. Zero
external callers means no API break. The private deserializeNode helper
was renamed to decodeNode to free the name for the newly-private
deserializeNode public function.
Pure rename; no behaviour change.
Replace the BinaryNode interface (which uses Go interface pointers that
the GC must scan) with NodeRef uint32 indices into typed arena pools.
NodeRef packs a 2-bit kind tag and 30-bit pool index into a single
uint32, making it invisible to the garbage collector.
NodeStore manages chunked typed pools per node kind:
- InternalNode pool: ZERO Go pointers (children are NodeRef, hash is
[32]byte) → allocated in noscan spans, GC skips entirely
- HashedNode pool: ZERO Go pointers → noscan spans
- StemNode pool: ONE pointer per node (valueData []byte) → minimal GC
For a trie with 25K InternalNodes, this reduces GC-scanned pointer-words
from ~125K to ~10K (85% reduction). CPU profiling showed 44% of time
in GC; this refactor directly addresses that bottleneck.
Serialization format is unchanged — the on-disk representation is
fully compatible. All existing tests pass.
