history .vi key

silkworm/db/datastore/snapshots/common/raw_codec.hpp

@@ -35,4 +35,16 @@ struct RawDecoder : public Decoder {
 static_assert(DecoderConcept<RawDecoder<Bytes>>);
 static_assert(DecoderConcept<RawDecoder<ByteView>>);
 
+template <BytesOrByteView TBytes>
+struct RawEncoder : public Encoder {
+    TBytes value;
+    ~RawEncoder() override = default;
+    ByteView encode_word() override {
+        return value;
+    }
+};
+
+static_assert(EncoderConcept<RawEncoder<Bytes>>);
+static_assert(EncoderConcept<RawEncoder<ByteView>>);
+
 }  // namespace silkworm::snapshots

silkworm/db/datastore/snapshots/history.hpp

@@ -16,6 +16,7 @@
 
 #pragma once
 
+#include "history_accessor_index.hpp"
 #include "inverted_index.hpp"
 #include "rec_split/accessor_index.hpp"
 #include "segment/segment_reader.hpp"
@@ -26,6 +27,11 @@ struct History {
     const segment::SegmentFileReader& segment;
     const rec_split::AccessorIndex& accessor_index;
     InvertedIndex inverted_index;
+
+    template <EncoderConcept TIIKeyEncoder>
+    static HistoryAccessorIndexKeyEncoder<TIIKeyEncoder> make_accessor_index_key_encoder() {
+        return HistoryAccessorIndexKeyEncoder<TIIKeyEncoder>{};
+    }
 };
 
 }  // namespace silkworm::snapshots

silkworm/db/datastore/snapshots/history_accessor_index.hpp

@@ -0,0 +1,51 @@
+/*
+   Copyright 2024 The Silkworm Authors
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+#pragma once
+
+#include <silkworm/core/common/endian.hpp>
+
+#include "common/codec.hpp"
+#include "common/raw_codec.hpp"
+
+namespace silkworm::snapshots {
+
+template <EncoderConcept TIIKeyEncoder>
+struct HistoryAccessorIndexKeyEncoder : public snapshots::Encoder {
+    struct {
+        TxnId txn_id{};
+        TIIKeyEncoder inverted_index_key;
+    } value;
+
+    Bytes word;
+
+    ~HistoryAccessorIndexKeyEncoder() override = default;
+
+    ByteView encode_word() override {
+        word.clear();
+
+        word.append(sizeof(TxnId), 0);
+        endian::store_big_u64(word.data(), value.txn_id);
+
+        word += value.inverted_index_key.encode_word();
+
+        return word;
+    }
+};
+
+static_assert(snapshots::EncoderConcept<HistoryAccessorIndexKeyEncoder<RawEncoder<ByteView>>>);
+
+}  // namespace silkworm::snapshots