Define variables more close to its use place in types (#1675)

Co-authored-by: Binbin <[email protected]>

src/types/redis_bitmap.cc

@@ -106,8 +106,6 @@ rocksdb::Status Bitmap::GetString(const Slice &user_key, const uint32_t max_btos
   }
   value->assign(metadata.size, 0);
 
-  std::string fragment;
-  fragment.reserve(kBitmapSegmentBytes * 2);
   std::string prefix_key = InternalKey(ns_key, "", metadata.version, storage_->IsSlotIdEncoded()).Encode();
 
   rocksdb::ReadOptions read_options = storage_->DefaultScanOptions();
@@ -122,7 +120,7 @@ rocksdb::Status Bitmap::GetString(const Slice &user_key, const uint32_t max_btos
       return rocksdb::Status::InvalidArgument(parse_result.Msg());
     }
     uint32_t frag_index = *parse_result;
-    fragment = iter->value().ToString();
+    std::string fragment = iter->value().ToString();
     // To be compatible with data written before the commit d603b0e(#338)
     // and avoid returning extra null char after expansion.
     uint32_t valid_size = std::min(

src/types/redis_list.cc

@@ -294,7 +294,6 @@ rocksdb::Status List::Insert(const Slice &user_key, const Slice &pivot, const Sl
                              {std::to_string(kRedisCmdLInsert), before ? "1" : "0", pivot.ToString(), elem.ToString()});
   batch->PutLogData(log_data.Encode());
 
-  std::string to_update_key;
   uint64_t left_part_len = pivot_index - metadata.head + (before ? 0 : 1);
   uint64_t right_part_len = metadata.tail - 1 - pivot_index + (before ? 1 : 0);
   bool reversed = left_part_len <= right_part_len;
@@ -308,12 +307,12 @@ rocksdb::Status List::Insert(const Slice &user_key, const Slice &pivot, const Sl
   for (; iter->Valid() && iter->key().starts_with(prefix); !reversed ? iter->Next() : iter->Prev()) {
     buf.clear();
     PutFixed64(&buf, reversed ? --pivot_index : ++pivot_index);
-    to_update_key = InternalKey(ns_key, buf, metadata.version, storage_->IsSlotIdEncoded()).Encode();
+    std::string to_update_key = InternalKey(ns_key, buf, metadata.version, storage_->IsSlotIdEncoded()).Encode();
     batch->Put(to_update_key, iter->value());
   }
   buf.clear();
   PutFixed64(&buf, new_elem_index);
-  to_update_key = InternalKey(ns_key, buf, metadata.version, storage_->IsSlotIdEncoded()).Encode();
+  std::string to_update_key = InternalKey(ns_key, buf, metadata.version, storage_->IsSlotIdEncoded()).Encode();
   batch->Put(to_update_key, elem);
 
   if (reversed) {

src/types/redis_string.cc

@@ -285,7 +285,6 @@ rocksdb::Status String::SetRange(const std::string &user_key, size_t offset, con
 }
 
 rocksdb::Status String::IncrBy(const std::string &user_key, int64_t increment, int64_t *new_value) {
-  std::string value;
   std::string ns_key = AppendNamespacePrefix(user_key);
 
   LockGuard guard(storage_->GetLockManager(), ns_key);
@@ -298,7 +297,7 @@ rocksdb::Status String::IncrBy(const std::string &user_key, int64_t increment, i
   }
 
   size_t offset = Metadata::GetOffsetAfterExpire(raw_value[0]);
-  value = raw_value.substr(offset);
+  std::string value = raw_value.substr(offset);
   int64_t n = 0;
   if (!value.empty()) {
     auto parse_result = ParseInt<int64_t>(value, 10);
@@ -323,7 +322,6 @@ rocksdb::Status String::IncrBy(const std::string &user_key, int64_t increment, i
 }
 
 rocksdb::Status String::IncrByFloat(const std::string &user_key, double increment, double *new_value) {
-  std::string value;
   std::string ns_key = AppendNamespacePrefix(user_key);
   LockGuard guard(storage_->GetLockManager(), ns_key);
   std::string raw_value;
@@ -335,7 +333,7 @@ rocksdb::Status String::IncrByFloat(const std::string &user_key, double incremen
     metadata.Encode(&raw_value);
   }
   size_t offset = Metadata::GetOffsetAfterExpire(raw_value[0]);
-  value = raw_value.substr(offset);
+  std::string value = raw_value.substr(offset);
   double n = 0;
   if (!value.empty()) {
     auto n_stat = ParseFloat(value);