1 files changed, 241 insertions, 0 deletions
diff --git a/src/wallet/bdb.h b/src/wallet/bdb.h
new file mode 100644
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+++ b/src/wallet/bdb.h
@@ -0,0 +1,241 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-2020 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_WALLET_BDB_H
+#define BITCOIN_WALLET_BDB_H
+
+#include <clientversion.h>
+#include <fs.h>
+#include <serialize.h>
+#include <streams.h>
+#include <util/system.h>
+#include <wallet/db.h>
+
+#include <atomic>
+#include <map>
+#include <memory>
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+#if defined(__GNUC__) && !defined(__clang__)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wsuggest-override"
+#endif
+#include <db_cxx.h>
+#if defined(__GNUC__) && !defined(__clang__)
+#pragma GCC diagnostic pop
+#endif
+
+struct bilingual_str;
+
+static const unsigned int DEFAULT_WALLET_DBLOGSIZE = 100;
+static const bool DEFAULT_WALLET_PRIVDB = true;
+
+struct WalletDatabaseFileId {
+    u_int8_t value[DB_FILE_ID_LEN];
+    bool operator==(const WalletDatabaseFileId& rhs) const;
+};
+
+class BerkeleyDatabase;
+
+class BerkeleyEnvironment
+{
+private:
+    bool fDbEnvInit;
+    bool fMockDb;
+    // Don't change into fs::path, as that can result in
+    // shutdown problems/crashes caused by a static initialized internal pointer.
+    std::string strPath;
+
+public:
+    std::unique_ptr<DbEnv> dbenv;
+    std::map<std::string, int> mapFileUseCount;
+    std::map<std::string, std::reference_wrapper<BerkeleyDatabase>> m_databases;
+    std::unordered_map<std::string, WalletDatabaseFileId> m_fileids;
+    std::condition_variable_any m_db_in_use;
+
+    BerkeleyEnvironment(const fs::path& env_directory);
+    BerkeleyEnvironment();
+    ~BerkeleyEnvironment();
+    void Reset();
+
+    bool IsMock() const { return fMockDb; }
+    bool IsInitialized() const { return fDbEnvInit; }
+    bool IsDatabaseLoaded(const std::string& db_filename) const { return m_databases.find(db_filename) != m_databases.end(); }
+    fs::path Directory() const { return strPath; }
+
+    bool Verify(const std::string& strFile);
+
+    bool Open(bilingual_str& error);
+    void Close();
+    void Flush(bool fShutdown);
+    void CheckpointLSN(const std::string& strFile);
+
+    void CloseDb(const std::string& strFile);
+    void ReloadDbEnv();
+
+    DbTxn* TxnBegin(int flags = DB_TXN_WRITE_NOSYNC)
+    {
+        DbTxn* ptxn = nullptr;
+        int ret = dbenv->txn_begin(nullptr, &ptxn, flags);
+        if (!ptxn || ret != 0)
+            return nullptr;
+        return ptxn;
+    }
+};
+
+/** Get BerkeleyEnvironment and database filename given a wallet path. */
+std::shared_ptr<BerkeleyEnvironment> GetWalletEnv(const fs::path& wallet_path, std::string& database_filename);
+
+/** Return whether a BDB wallet database is currently loaded. */
+bool IsBDBWalletLoaded(const fs::path& wallet_path);
+
+class BerkeleyBatch;
+
+/** An instance of this class represents one database.
+ * For BerkeleyDB this is just a (env, strFile) tuple.
+ **/
+class BerkeleyDatabase : public WalletDatabase
+{
+    friend class BerkeleyBatch;
+public:
+    /** Create dummy DB handle */
+    BerkeleyDatabase() : WalletDatabase(), env(nullptr)
+    {
+    }
+
+    /** Create DB handle to real database */
+    BerkeleyDatabase(std::shared_ptr<BerkeleyEnvironment> env, std::string filename) :
+        WalletDatabase(), env(std::move(env)), strFile(std::move(filename))
+    {
+        auto inserted = this->env->m_databases.emplace(strFile, std::ref(*this));
+        assert(inserted.second);
+    }
+
+    ~BerkeleyDatabase() override;
+
+    /** Open the database if it is not already opened.
+     *  Dummy function, doesn't do anything right now, but is needed for class abstraction */
+    void Open(const char* mode) override;
+
+    /** Rewrite the entire database on disk, with the exception of key pszSkip if non-zero
+     */
+    bool Rewrite(const char* pszSkip=nullptr) override;
+
+    /** Indicate the a new database user has began using the database. */
+    void AddRef() override;
+    /** Indicate that database user has stopped using the database and that it could be flushed or closed. */
+    void RemoveRef() override;
+
+    /** Back up the entire database to a file.
+     */
+    bool Backup(const std::string& strDest) const override;
+
+    /** Make sure all changes are flushed to database file.
+     */
+    void Flush() override;
+    /** Flush to the database file and close the database.
+     *  Also close the environment if no other databases are open in it.
+     */
+    void Close() override;
+    /* flush the wallet passively (TRY_LOCK)
+       ideal to be called periodically */
+    bool PeriodicFlush() override;
+
+    void IncrementUpdateCounter() override;
+
+    void ReloadDbEnv() override;
+
+    /** Verifies the environment and database file */
+    bool Verify(bilingual_str& error) override;
+
+    /**
+     * Pointer to shared database environment.
+     *
+     * Normally there is only one BerkeleyDatabase object per
+     * BerkeleyEnvivonment, but in the special, backwards compatible case where
+     * multiple wallet BDB data files are loaded from the same directory, this
+     * will point to a shared instance that gets freed when the last data file
+     * is closed.
+     */
+    std::shared_ptr<BerkeleyEnvironment> env;
+
+    /** Database pointer. This is initialized lazily and reset during flushes, so it can be null. */
+    std::unique_ptr<Db> m_db;
+
+    /** Make a BerkeleyBatch connected to this database */
+    std::unique_ptr<DatabaseBatch> MakeBatch(const char* mode = "r+", bool flush_on_close = true) override;
+
+private:
+    std::string strFile;
+
+    /** Return whether this database handle is a dummy for testing.
+     * Only to be used at a low level, application should ideally not care
+     * about this.
+     */
+    bool IsDummy() const { return env == nullptr; }
+};
+
+/** RAII class that provides access to a Berkeley database */
+class BerkeleyBatch : public DatabaseBatch
+{
+    /** RAII class that automatically cleanses its data on destruction */
+    class SafeDbt final
+    {
+        Dbt m_dbt;
+
+    public:
+        // construct Dbt with internally-managed data
+        SafeDbt();
+        // construct Dbt with provided data
+        SafeDbt(void* data, size_t size);
+        ~SafeDbt();
+
+        // delegate to Dbt
+        const void* get_data() const;
+        u_int32_t get_size() const;
+
+        // conversion operator to access the underlying Dbt
+        operator Dbt*();
+    };
+
+private:
+    bool ReadKey(CDataStream&& key, CDataStream& value) override;
+    bool WriteKey(CDataStream&& key, CDataStream&& value, bool overwrite = true) override;
+    bool EraseKey(CDataStream&& key) override;
+    bool HasKey(CDataStream&& key) override;
+
+protected:
+    Db* pdb;
+    std::string strFile;
+    DbTxn* activeTxn;
+    Dbc* m_cursor;
+    bool fReadOnly;
+    bool fFlushOnClose;
+    BerkeleyEnvironment *env;
+    BerkeleyDatabase& m_database;
+
+public:
+    explicit BerkeleyBatch(BerkeleyDatabase& database, const char* pszMode = "r+", bool fFlushOnCloseIn=true);
+    ~BerkeleyBatch() override { Close(); }
+
+    BerkeleyBatch(const BerkeleyBatch&) = delete;
+    BerkeleyBatch& operator=(const BerkeleyBatch&) = delete;
+
+    void Flush() override;
+    void Close() override;
+
+    bool StartCursor() override;
+    bool ReadAtCursor(CDataStream& ssKey, CDataStream& ssValue, bool& complete) override;
+    void CloseCursor() override;
+    bool TxnBegin() override;
+    bool TxnCommit() override;
+    bool TxnAbort() override;
+};
+
+std::string BerkeleyDatabaseVersion();
+
+#endif // BITCOIN_WALLET_BDB_H