sqlite backend with actual pagination

1 files changed, 43 insertions, 0 deletions

diff --git a/include/InMemoryBackend.h b/include/InMemoryBackend.h
new file mode 100644
index 0000000..8f7f50a
--- /dev/null
+++ b/include/InMemoryBackend.h
@@ -0,0 +1,43 @@
+#pragma once
+
+#include "Api.h"
+#include "IStorageBackend.h"
+
+#include <cstdint>
+#include <optional>
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+/**
+ * @file InMemoryBackend.h
+ * @brief In-process KV storage backend backed by unordered_maps.
+ */
+
+namespace nt
+{
+    /**
+     * @interface InMemoryBackend
+     * @brief IStorageBackend implementation that keeps all data in process memory.
+     *
+     * Intended for unit tests where SQLite is not appropriate. Data does not
+     * survive process exit and is not thread-safe.
+     */
+    class NT_API InMemoryBackend : public IStorageBackend
+    {
+    public:
+        std::string Put(std::vector<uint8_t> value) override;
+        std::optional<std::vector<uint8_t>> Get(const std::string& hash) override;
+        void LinkTuple(const std::vector<std::string>& relation_path,
+                       const std::string& tuple_hash) override;
+        std::vector<std::string> TupleHashes(const std::vector<std::string>& relation_path,
+                                             std::size_t offset,
+                                             std::size_t limit) override;
+
+    private:
+        std::unordered_map<std::string, std::vector<uint8_t>> kv_;
+        std::unordered_map<std::string, std::vector<std::string>> index_;
+
+        static std::string PathKey(const std::vector<std::string>& path);
+    };
+}