use std::optional instead of std::unique_ptr

erigontech · Sep 20, 2024 · 9205e8f · 9205e8f
1 parent f77791f
commit 9205e8f
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Showing 2 changed files with 14 additions and 25 deletions.
diff --git a/silkworm/db/snapshots/index/btree_index.cpp b/silkworm/db/snapshots/index/btree_index.cpp
@@ -66,12 +66,12 @@ BTreeIndex::BTreeIndex(seg::Decompressor& kv_decompressor,
 BTreeIndex::Cursor::Cursor(BTreeIndex* index, ByteView key, ByteView value, DataIndex data_index, DataIterator data_it)
     : index_(index), key_(key), value_(value), data_index_(data_index), data_it_(std::move(data_it)) {}
 
-std::unique_ptr<BTreeIndex::Cursor> BTreeIndex::seek(ByteView seek_key, DataIterator data_it) {
+std::optional<BTreeIndex::Cursor> BTreeIndex::seek(ByteView seek_key, DataIterator data_it) {
     const auto [found, key, value, data_index] = btree_->seek(seek_key, data_it);
     if (key.compare(seek_key) >= 0) {
         return new_cursor(key, value, data_index, data_it);
     }
-    return nullptr;
+    return std::nullopt;
 }
 
 std::optional<Bytes> BTreeIndex::get(ByteView key, DataIterator data_it) {
@@ -123,8 +123,8 @@ BTree::CompareResult BTreeIndex::compare_key(ByteView key, DataIndex data_index,
     return {data_key.compare(key), data_key};
 }
 
-std::unique_ptr<BTreeIndex::Cursor> BTreeIndex::new_cursor(ByteView key, ByteView value, DataIndex data_index, DataIterator data_it) {
-    return std::unique_ptr<BTreeIndex::Cursor>{new BTreeIndex::Cursor{this, key, value, data_index, std::move(data_it)}};
+BTreeIndex::Cursor BTreeIndex::new_cursor(ByteView key, ByteView value, DataIndex data_index, DataIterator data_it) {
+    return BTreeIndex::Cursor{this, key, value, data_index, std::move(data_it)};
 }
 
 bool BTreeIndex::Cursor::next() {

diff --git a/silkworm/db/snapshots/index/btree_index.hpp b/silkworm/db/snapshots/index/btree_index.hpp
@@ -40,20 +40,6 @@ class BTreeIndex {
 
     class Cursor {
       public:
-        using iterator_category [[maybe_unused]] = std::input_iterator_tag;
-        using difference_type = std::ptrdiff_t;
-        using value_type = std::tuple<ByteView, ByteView, DataIndex>;
-        using pointer = value_type*;
-        using reference = value_type&;
-
-        // reference operator*() { return key_value_index_; }
-        // pointer operator->() { return &key_value_index_; }
-
-        Cursor& operator++() {
-            next();
-            return *this;
-        }
-
         ByteView key() const noexcept { return key_; }
         ByteView value() const noexcept { return value_; }
         DataIndex data_index() const noexcept { return data_index_; }
@@ -70,7 +56,6 @@ class BTreeIndex {
         Bytes key_;
         Bytes value_;
         DataIndex data_index_;
-        // value_type key_value_index_;
         DataIterator data_it_;
     };
 
@@ -88,18 +73,22 @@ class BTreeIndex {
     //! Return the number of keys included into this index
     size_t key_count() const { return data_offsets_ ? data_offsets_->sequence_length() : 0; };
 
-    //! Seek and return cursor at position where key >= \p seek_key
-    //! \param seek_key the given key to seek cursor at
-    //! \return a cursor positioned at key >= \p seek_key
+    //! Seek and return a cursor at position where key >= \p seek_key
+    //! \param seek_key the given key at which the cursor must be seeked
+    //! \param data_it an iterator to the key-value data sequence
+    //! \return a cursor positioned at key >= \p seek_key or nullptr
     //! \details if \p seek_key is empty, first key is returned
-    //! \details if \p seek_key greater than any other key, nullptr is returned
-    std::unique_ptr<Cursor> seek(ByteView seek_key, DataIterator data_it);
+    //! \details if \p seek_key is greater than any other key, std::nullopt is returned
+    std::optional<Cursor> seek(ByteView seek_key, DataIterator data_it);
 
     //! Get the value associated to the given key with exact match
+    //! \param key the data key to match exactly
+    //! \param data_it an iterator to the key-value data sequence
+    //! \return the value associated at \p key or std::nullopt if not found
     std::optional<Bytes> get(ByteView key, DataIterator data_it);
 
   private:
-    std::unique_ptr<Cursor> new_cursor(ByteView key, ByteView value, DataIndex data_index, DataIterator data_it);
+    Cursor new_cursor(ByteView key, ByteView value, DataIndex data_index, DataIterator data_it);
 
     BTree::LookupResult lookup_data(DataIndex data_index, DataIterator data_it);
     BTree::CompareResult compare_key(ByteView key, DataIndex data_index, DataIterator data_it);