chore: RdbSerializer::SaveListObject supports QList

Now, `./rdb_test --list_experimental_v2` passes.

Signed-off-by: Roman Gershman <roman@dragonflydb.io>

Author: romange

src/core/qlist.h

@@ -109,12 +109,16 @@ class QList {
   // Requires calling subsequent Next() to initialize the iterator.
   Iterator GetIterator(long idx) const;
 
-  uint32_t noded_count() const {
+  uint32_t node_count() const {
     return len_;
   }
 
   Iterator Erase(Iterator it);
 
+  const quicklistNode* Head() const {
+    return head_;
+  }
+
  private:
   bool AllowCompression() const {
     return compress_ != 0;

src/server/rdb_save.cc

@@ -29,6 +29,7 @@ extern "C" {
 #include "base/logging.h"
 #include "core/bloom.h"
 #include "core/json/json_object.h"
+#include "core/qlist.h"
 #include "core/size_tracking_channel.h"
 #include "core/sorted_map.h"
 #include "core/string_map.h"
@@ -168,12 +169,10 @@ uint8_t RdbObjectType(const PrimeValue& pv) {
     case OBJ_STRING:
       return RDB_TYPE_STRING;
     case OBJ_LIST:
-      if (compact_enc == OBJ_ENCODING_QUICKLIST) {
-        if (absl::GetFlag(FLAGS_list_rdb_encode_v2))
-          return RDB_TYPE_LIST_QUICKLIST_2;
-        return RDB_TYPE_LIST_QUICKLIST;
+      if (compact_enc == OBJ_ENCODING_QUICKLIST || compact_enc == kEncodingQL2) {
+        return absl::GetFlag(FLAGS_list_rdb_encode_v2) ? RDB_TYPE_LIST_QUICKLIST_2
+                                                       : RDB_TYPE_LIST_QUICKLIST;
       }
-
       break;
     case OBJ_SET:
       if (compact_enc == kEncodingIntSet)
@@ -436,12 +435,21 @@ error_code RdbSerializer::SaveObject(const PrimeValue& pv) {
 
 error_code RdbSerializer::SaveListObject(const PrimeValue& pv) {
   /* Save a list value */
-  DCHECK_EQ(OBJ_ENCODING_QUICKLIST, pv.Encoding());
-  const quicklist* ql = reinterpret_cast<const quicklist*>(pv.RObjPtr());
-  quicklistNode* node = ql->head;
-  DVLOG(2) << "Saving list of length " << ql->len;
-
-  RETURN_ON_ERR(SaveLen(ql->len));
+  size_t len = 0;
+  const quicklistNode* node = nullptr;
+
+  if (pv.Encoding() == OBJ_ENCODING_QUICKLIST) {
+    const quicklist* ql = reinterpret_cast<const quicklist*>(pv.RObjPtr());
+    node = ql->head;
+    DVLOG(2) << "Saving list of length " << ql->len;
+    len = ql->len;
+  } else {
+    DCHECK_EQ(pv.Encoding(), kEncodingQL2);
+    QList* ql = reinterpret_cast<QList*>(pv.RObjPtr());
+    node = ql->Head();
+    len = ql->noded_count();
+  }
+  RETURN_ON_ERR(SaveLen(len));
 
   while (node) {
     DVLOG(3) << "QL node (encoding/container/sz): " << node->encoding << "/" << node->container
@@ -759,7 +767,7 @@ error_code RdbSerializer::SaveListPackAsZiplist(uint8_t* lp) {
   return ec;
 }
 
-error_code RdbSerializer::SavePlainNodeAsZiplist(quicklistNode* node) {
+error_code RdbSerializer::SavePlainNodeAsZiplist(const quicklistNode* node) {
   uint8_t* zl = ziplistNew();
   zl = ziplistPush(zl, node->entry, node->sz, ZIPLIST_TAIL);
 

src/server/rdb_save.h

@@ -255,7 +255,7 @@ class RdbSerializer : public SerializerBase {
   std::error_code SaveListPackAsZiplist(uint8_t* lp);
   std::error_code SaveStreamPEL(rax* pel, bool nacks);
   std::error_code SaveStreamConsumers(streamCG* cg);
-  std::error_code SavePlainNodeAsZiplist(quicklistNode* node);
+  std::error_code SavePlainNodeAsZiplist(const quicklistNode* node);
 
   // Might preempt
   void FlushIfNeeded(FlushState flush_state);