chore: ClearInternal now can clear partially

src/core/dense_set.cc

@@ -179,16 +179,17 @@ void* DenseSet::PopDataFront(DenseSet::ChainVectorIterator it) {
   return ret;
 }
 
-void DenseSet::ClearInternal() {
+uint32_t DenseSet::ClearInternal(uint32_t start, uint32_t count) {
   constexpr unsigned kArrLen = 32;
   ClearItem arr[kArrLen];
   unsigned len = 0;
 
-  for (auto it = entries_.begin(); it != entries_.end(); ++it) {
-    if (it->IsEmpty())
+  size_t end = min<size_t>(entries_.size(), start + count);
+  for (size_t i = start; i < end; ++i) {
+    DensePtr ptr = entries_[i];
+    if (ptr.IsEmpty())
       continue;
 
-    DensePtr ptr = *it;
     auto& dest = arr[len++];
     dest.has_ttl = ptr.HasTtl();
 
@@ -208,11 +209,13 @@ void DenseSet::ClearInternal() {
 
   ClearBatch(len, arr);
 
-  entries_.clear();
-  num_used_buckets_ = 0;
-  num_links_ = 0;
-  size_ = 0;
-  expiration_used_ = false;
+  if (size_ == 0) {
+    entries_.clear();
+    num_used_buckets_ = 0;
+    num_links_ = 0;
+    expiration_used_ = false;
+  }
+  return end;
 }
 
 bool DenseSet::Equal(DensePtr dptr, const void* ptr, uint32_t cookie) const {
@@ -277,6 +280,7 @@ void DenseSet::ClearBatch(unsigned len, ClearItem* items) {
       auto& src = items[i];
       if (src.obj) {
         ObjDelete(src.obj, src.has_ttl);
+        --size_;
         src.obj = nullptr;
       }
 
@@ -285,6 +289,7 @@ void DenseSet::ClearBatch(unsigned len, ClearItem* items) {
 
       if (src.ptr.IsObject()) {
         ObjDelete(src.ptr.Raw(), src.has_ttl);
+        --size_;
       } else {
         auto& dest = items[dest_id++];
         DenseLinkKey* link = src.ptr.AsLink();

src/core/dense_set.h

@@ -212,6 +212,10 @@ class DenseSet {
   explicit DenseSet(MemoryResource* mr = PMR_NS::get_default_resource());
   virtual ~DenseSet();
 
+  void Clear() {
+    ClearInternal(0, entries_.size());
+  }
+
   // Returns the number of elements in the map. Note that it might be that some of these elements
   // have expired and can't be accessed.
   size_t UpperBoundSize() const {
@@ -300,7 +304,7 @@ class DenseSet {
   // Note this does not free any dynamic allocations done by derived classes, that a DensePtr
   // in the set may point to. This function only frees the allocated DenseLinkKeys created by
   // DenseSet. All data allocated by a derived class should be freed before calling this
-  void ClearInternal();
+  uint32_t ClearInternal(uint32_t start, uint32_t count);
 
   void IncreaseMallocUsed(size_t delta) {
     obj_malloc_used_ += delta;

src/core/score_map.h

@@ -105,10 +105,6 @@ class ScoreMap : public DenseSet {
     return FindInternal(ele, Hash(ele, 0), 0);
   }
 
-  void Clear() {
-    ClearInternal();
-  }
-
   iterator begin() {
     return iterator{this, false};
   }

src/core/string_map.cc

@@ -62,7 +62,7 @@ pair<sds, uint64_t> CreateEntry(string_view field, string_view value, uint32_t t
 }  // namespace
 
 StringMap::~StringMap() {
-  ClearInternal();
+  Clear();
 }
 
 bool StringMap::AddOrUpdate(string_view field, string_view value, uint32_t ttl_sec) {
@@ -101,10 +101,6 @@ bool StringMap::Contains(string_view field) const {
   return FindInternal(&field, hashcode, 1) != nullptr;
 }
 
-void StringMap::Clear() {
-  ClearInternal();
-}
-
 optional<pair<sds, sds>> StringMap::RandomPair() {
   // Iteration may remove elements, and so we need to loop if we happen to reach the end
   while (true) {

src/core/string_map.h

@@ -121,8 +121,6 @@ class StringMap : public DenseSet {
     return iterator{FindIt(&member, 1)};
   }
 
-  void Clear();
-
   iterator begin() {
     return iterator{this};
   }

src/core/string_set.h

@@ -36,10 +36,6 @@ class StringSet : public DenseSet {
     return FindInternal(&s1, Hash(&s1, 1), 1) != nullptr;
   }
 
-  void Clear() {
-    ClearInternal();
-  }
-
   std::optional<std::string> Pop();
 
   class iterator : private IteratorBase {