Initial Vexta Core v0.1.0 release

src/wallet/db.h

@@ -0,0 +1,236 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-2020 The Bitcoin Core developers
+// Copyright (c) 2014-2020 The DigiByte Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef DIGIBYTE_WALLET_DB_H
+#define DIGIBYTE_WALLET_DB_H
+
+#include <clientversion.h>
+#include <fs.h>
+#include <streams.h>
+#include <support/allocators/secure.h>
+
+#include <atomic>
+#include <memory>
+#include <optional>
+#include <string>
+
+struct bilingual_str;
+
+void SplitWalletPath(const fs::path& wallet_path, fs::path& env_directory, std::string& database_filename);
+
+/** RAII class that provides access to a WalletDatabase */
+class DatabaseBatch
+{
+private:
+    virtual bool ReadKey(CDataStream&& key, CDataStream& value) = 0;
+    virtual bool WriteKey(CDataStream&& key, CDataStream&& value, bool overwrite=true) = 0;
+    virtual bool EraseKey(CDataStream&& key) = 0;
+    virtual bool HasKey(CDataStream&& key) = 0;
+
+public:
+    explicit DatabaseBatch() {}
+    virtual ~DatabaseBatch() {}
+
+    DatabaseBatch(const DatabaseBatch&) = delete;
+    DatabaseBatch& operator=(const DatabaseBatch&) = delete;
+
+    virtual void Flush() = 0;
+    virtual void Close() = 0;
+
+    template <typename K, typename T>
+    bool Read(const K& key, T& value)
+    {
+        CDataStream ssKey(SER_DISK, CLIENT_VERSION);
+        ssKey.reserve(1000);
+        ssKey << key;
+
+        CDataStream ssValue(SER_DISK, CLIENT_VERSION);
+        if (!ReadKey(std::move(ssKey), ssValue)) return false;
+        try {
+            ssValue >> value;
+            return true;
+        } catch (const std::exception&) {
+            return false;
+        }
+    }
+
+    template <typename K, typename T>
+    bool Write(const K& key, const T& value, bool fOverwrite = true)
+    {
+        CDataStream ssKey(SER_DISK, CLIENT_VERSION);
+        ssKey.reserve(1000);
+        ssKey << key;
+
+        CDataStream ssValue(SER_DISK, CLIENT_VERSION);
+        ssValue.reserve(10000);
+        ssValue << value;
+
+        return WriteKey(std::move(ssKey), std::move(ssValue), fOverwrite);
+    }
+
+    template <typename K>
+    bool Erase(const K& key)
+    {
+        CDataStream ssKey(SER_DISK, CLIENT_VERSION);
+        ssKey.reserve(1000);
+        ssKey << key;
+
+        return EraseKey(std::move(ssKey));
+    }
+
+    template <typename K>
+    bool Exists(const K& key)
+    {
+        CDataStream ssKey(SER_DISK, CLIENT_VERSION);
+        ssKey.reserve(1000);
+        ssKey << key;
+
+        return HasKey(std::move(ssKey));
+    }
+
+    virtual bool StartCursor() = 0;
+    virtual bool ReadAtCursor(CDataStream& ssKey, CDataStream& ssValue, bool& complete) = 0;
+    virtual void CloseCursor() = 0;
+    virtual bool TxnBegin() = 0;
+    virtual bool TxnCommit() = 0;
+    virtual bool TxnAbort() = 0;
+};
+
+/** An instance of this class represents one database.
+ **/
+class WalletDatabase
+{
+public:
+    /** Create dummy DB handle */
+    WalletDatabase() : nUpdateCounter(0), nLastSeen(0), nLastFlushed(0), nLastWalletUpdate(0) {}
+    virtual ~WalletDatabase() {};
+
+    /** Open the database if it is not already opened. */
+    virtual void Open() = 0;
+
+    //! Counts the number of active database users to be sure that the database is not closed while someone is using it
+    std::atomic<int> m_refcount{0};
+    /** Indicate the a new database user has began using the database. Increments m_refcount */
+    virtual void AddRef() = 0;
+    /** Indicate that database user has stopped using the database and that it could be flushed or closed. Decrement m_refcount */
+    virtual void RemoveRef() = 0;
+
+    /** Rewrite the entire database on disk, with the exception of key pszSkip if non-zero
+     */
+    virtual bool Rewrite(const char* pszSkip=nullptr) = 0;
+
+    /** Back up the entire database to a file.
+     */
+    virtual bool Backup(const std::string& strDest) const = 0;
+
+    /** Make sure all changes are flushed to database file.
+     */
+    virtual void Flush() = 0;
+    /** Flush to the database file and close the database.
+     *  Also close the environment if no other databases are open in it.
+     */
+    virtual void Close() = 0;
+    /* flush the wallet passively (TRY_LOCK)
+       ideal to be called periodically */
+    virtual bool PeriodicFlush() = 0;
+
+    virtual void IncrementUpdateCounter() = 0;
+
+    virtual void ReloadDbEnv() = 0;
+
+    /** Return path to main database file for logs and error messages. */
+    virtual std::string Filename() = 0;
+
+    virtual std::string Format() = 0;
+
+    std::atomic<unsigned int> nUpdateCounter;
+    unsigned int nLastSeen;
+    unsigned int nLastFlushed;
+    int64_t nLastWalletUpdate;
+
+    /** Make a DatabaseBatch connected to this database */
+    virtual std::unique_ptr<DatabaseBatch> MakeBatch(bool flush_on_close = true) = 0;
+};
+
+/** RAII class that provides access to a DummyDatabase. Never fails. */
+class DummyBatch : public DatabaseBatch
+{
+private:
+    bool ReadKey(CDataStream&& key, CDataStream& value) override { return true; }
+    bool WriteKey(CDataStream&& key, CDataStream&& value, bool overwrite=true) override { return true; }
+    bool EraseKey(CDataStream&& key) override { return true; }
+    bool HasKey(CDataStream&& key) override { return true; }
+
+public:
+    void Flush() override {}
+    void Close() override {}
+
+    bool StartCursor() override { return true; }
+    bool ReadAtCursor(CDataStream& ssKey, CDataStream& ssValue, bool& complete) override { return true; }
+    void CloseCursor() override {}
+    bool TxnBegin() override { return true; }
+    bool TxnCommit() override { return true; }
+    bool TxnAbort() override { return true; }
+};
+
+/** A dummy WalletDatabase that does nothing and never fails. Only used by unit tests.
+ **/
+class DummyDatabase : public WalletDatabase
+{
+public:
+    void Open() override {};
+    void AddRef() override {}
+    void RemoveRef() override {}
+    bool Rewrite(const char* pszSkip=nullptr) override { return true; }
+    bool Backup(const std::string& strDest) const override { return true; }
+    void Close() override {}
+    void Flush() override {}
+    bool PeriodicFlush() override { return true; }
+    void IncrementUpdateCounter() override { ++nUpdateCounter; }
+    void ReloadDbEnv() override {}
+    std::string Filename() override { return "dummy"; }
+    std::string Format() override { return "dummy"; }
+    std::unique_ptr<DatabaseBatch> MakeBatch(bool flush_on_close = true) override { return std::make_unique<DummyBatch>(); }
+};
+
+enum class DatabaseFormat {
+    BERKELEY,
+    SQLITE,
+};
+
+struct DatabaseOptions {
+    bool require_existing = false;
+    bool require_create = false;
+    std::optional<DatabaseFormat> require_format;
+    uint64_t create_flags = 0;
+    SecureString create_passphrase;
+    bool verify = true;
+};
+
+enum class DatabaseStatus {
+    SUCCESS,
+    FAILED_BAD_PATH,
+    FAILED_BAD_FORMAT,
+    FAILED_ALREADY_LOADED,
+    FAILED_ALREADY_EXISTS,
+    FAILED_NOT_FOUND,
+    FAILED_CREATE,
+    FAILED_LOAD,
+    FAILED_VERIFY,
+    FAILED_ENCRYPT,
+};
+
+/** Recursively list database paths in directory. */
+std::vector<fs::path> ListDatabases(const fs::path& path);
+
+std::unique_ptr<WalletDatabase> MakeDatabase(const fs::path& path, const DatabaseOptions& options, DatabaseStatus& status, bilingual_str& error);
+
+fs::path BDBDataFile(const fs::path& path);
+fs::path SQLiteDataFile(const fs::path& path);
+bool IsBDBFile(const fs::path& path);
+bool IsSQLiteFile(const fs::path& path);
+
+#endif // DIGIBYTE_WALLET_DB_H