Merge pull request #6873

1 files changed, 280 insertions, 0 deletions

diff --git a/src/dbwrapper.h b/src/dbwrapper.h
new file mode 100644
index 0000000000..aa28767508
--- /dev/null
+++ b/src/dbwrapper.h
@@ -0,0 +1,280 @@
+// Copyright (c) 2012-2014 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_DBWRAPPER_H
+#define BITCOIN_DBWRAPPER_H
+
+#include "clientversion.h"
+#include "serialize.h"
+#include "streams.h"
+#include "util.h"
+#include "utilstrencodings.h"
+#include "version.h"
+
+#include <boost/filesystem/path.hpp>
+
+#include <leveldb/db.h>
+#include <leveldb/write_batch.h>
+
+class dbwrapper_error : public std::runtime_error
+{
+public:
+    dbwrapper_error(const std::string& msg) : std::runtime_error(msg) {}
+};
+
+void HandleError(const leveldb::Status& status) throw(dbwrapper_error);
+
+/** Batch of changes queued to be written to a CDBWrapper */
+class CDBBatch
+{
+    friend class CDBWrapper;
+
+private:
+    leveldb::WriteBatch batch;
+    const std::vector<unsigned char> *obfuscate_key;
+
+public:
+    /**
+     * @param[in] obfuscate_key    If passed, XOR data with this key.
+     */
+    CDBBatch(const std::vector<unsigned char> *obfuscate_key) : obfuscate_key(obfuscate_key) { };
+
+    template <typename K, typename V>
+    void Write(const K& key, const V& value)
+    {
+        CDataStream ssKey(SER_DISK, CLIENT_VERSION);
+        ssKey.reserve(ssKey.GetSerializeSize(key));
+        ssKey << key;
+        leveldb::Slice slKey(&ssKey[0], ssKey.size());
+
+        CDataStream ssValue(SER_DISK, CLIENT_VERSION);
+        ssValue.reserve(ssValue.GetSerializeSize(value));
+        ssValue << value;
+        ssValue.Xor(*obfuscate_key);
+        leveldb::Slice slValue(&ssValue[0], ssValue.size());
+
+        batch.Put(slKey, slValue);
+    }
+
+    template <typename K>
+    void Erase(const K& key)
+    {
+        CDataStream ssKey(SER_DISK, CLIENT_VERSION);
+        ssKey.reserve(ssKey.GetSerializeSize(key));
+        ssKey << key;
+        leveldb::Slice slKey(&ssKey[0], ssKey.size());
+
+        batch.Delete(slKey);
+    }
+};
+
+class CDBIterator
+{
+private:
+    leveldb::Iterator *piter;
+    const std::vector<unsigned char> *obfuscate_key;
+
+public:
+
+    /**
+     * @param[in] piterIn          The original leveldb iterator.
+     * @param[in] obfuscate_key    If passed, XOR data with this key.
+     */
+    CDBIterator(leveldb::Iterator *piterIn, const std::vector<unsigned char>* obfuscate_key) :
+        piter(piterIn), obfuscate_key(obfuscate_key) { };
+    ~CDBIterator();
+
+    bool Valid();
+
+    void SeekToFirst();
+
+    template<typename K> void Seek(const K& key) {
+        CDataStream ssKey(SER_DISK, CLIENT_VERSION);
+        ssKey.reserve(ssKey.GetSerializeSize(key));
+        ssKey << key;
+        leveldb::Slice slKey(&ssKey[0], ssKey.size());
+        piter->Seek(slKey);
+    }
+
+    void Next();
+
+    template<typename K> bool GetKey(K& key) {
+        leveldb::Slice slKey = piter->key();
+        try {
+            CDataStream ssKey(slKey.data(), slKey.data() + slKey.size(), SER_DISK, CLIENT_VERSION);
+            ssKey >> key;
+        } catch(std::exception &e) {
+            return false;
+        }
+        return true;
+    }
+
+    unsigned int GetKeySize() {
+        return piter->key().size();
+    }
+
+    template<typename V> bool GetValue(V& value) {
+        leveldb::Slice slValue = piter->value();
+        try {
+            CDataStream ssValue(slValue.data(), slValue.data() + slValue.size(), SER_DISK, CLIENT_VERSION);
+            ssValue.Xor(*obfuscate_key);
+            ssValue >> value;
+        } catch(std::exception &e) {
+            return false;
+        }
+        return true;
+    }
+
+    unsigned int GetValueSize() {
+        return piter->value().size();
+    }
+
+};
+
+class CDBWrapper
+{
+private:
+    //! custom environment this database is using (may be NULL in case of default environment)
+    leveldb::Env* penv;
+
+    //! database options used
+    leveldb::Options options;
+
+    //! options used when reading from the database
+    leveldb::ReadOptions readoptions;
+
+    //! options used when iterating over values of the database
+    leveldb::ReadOptions iteroptions;
+
+    //! options used when writing to the database
+    leveldb::WriteOptions writeoptions;
+
+    //! options used when sync writing to the database
+    leveldb::WriteOptions syncoptions;
+
+    //! the database itself
+    leveldb::DB* pdb;
+
+    //! a key used for optional XOR-obfuscation of the database
+    std::vector<unsigned char> obfuscate_key;
+
+    //! the key under which the obfuscation key is stored
+    static const std::string OBFUSCATE_KEY_KEY;
+
+    //! the length of the obfuscate key in number of bytes
+    static const unsigned int OBFUSCATE_KEY_NUM_BYTES;
+
+    std::vector<unsigned char> CreateObfuscateKey() const;
+
+public:
+    /**
+     * @param[in] path        Location in the filesystem where leveldb data will be stored.
+     * @param[in] nCacheSize  Configures various leveldb cache settings.
+     * @param[in] fMemory     If true, use leveldb's memory environment.
+     * @param[in] fWipe       If true, remove all existing data.
+     * @param[in] obfuscate   If true, store data obfuscated via simple XOR. If false, XOR
+     *                        with a zero'd byte array.
+     */
+    CDBWrapper(const boost::filesystem::path& path, size_t nCacheSize, bool fMemory = false, bool fWipe = false, bool obfuscate = false);
+    ~CDBWrapper();
+
+    template <typename K, typename V>
+    bool Read(const K& key, V& value) const throw(dbwrapper_error)
+    {
+        CDataStream ssKey(SER_DISK, CLIENT_VERSION);
+        ssKey.reserve(ssKey.GetSerializeSize(key));
+        ssKey << key;
+        leveldb::Slice slKey(&ssKey[0], ssKey.size());
+
+        std::string strValue;
+        leveldb::Status status = pdb->Get(readoptions, slKey, &strValue);
+        if (!status.ok()) {
+            if (status.IsNotFound())
+                return false;
+            LogPrintf("LevelDB read failure: %s\n", status.ToString());
+            HandleError(status);
+        }
+        try {
+            CDataStream ssValue(strValue.data(), strValue.data() + strValue.size(), SER_DISK, CLIENT_VERSION);
+            ssValue.Xor(obfuscate_key);
+            ssValue >> value;
+        } catch (const std::exception&) {
+            return false;
+        }
+        return true;
+    }
+
+    template <typename K, typename V>
+    bool Write(const K& key, const V& value, bool fSync = false) throw(dbwrapper_error)
+    {
+        CDBBatch batch(&obfuscate_key);
+        batch.Write(key, value);
+        return WriteBatch(batch, fSync);
+    }
+
+    template <typename K>
+    bool Exists(const K& key) const throw(dbwrapper_error)
+    {
+        CDataStream ssKey(SER_DISK, CLIENT_VERSION);
+        ssKey.reserve(ssKey.GetSerializeSize(key));
+        ssKey << key;
+        leveldb::Slice slKey(&ssKey[0], ssKey.size());
+
+        std::string strValue;
+        leveldb::Status status = pdb->Get(readoptions, slKey, &strValue);
+        if (!status.ok()) {
+            if (status.IsNotFound())
+                return false;
+            LogPrintf("LevelDB read failure: %s\n", status.ToString());
+            HandleError(status);
+        }
+        return true;
+    }
+
+    template <typename K>
+    bool Erase(const K& key, bool fSync = false) throw(dbwrapper_error)
+    {
+        CDBBatch batch(&obfuscate_key);
+        batch.Erase(key);
+        return WriteBatch(batch, fSync);
+    }
+
+    bool WriteBatch(CDBBatch& batch, bool fSync = false) throw(dbwrapper_error);
+
+    // not available for LevelDB; provide for compatibility with BDB
+    bool Flush()
+    {
+        return true;
+    }
+
+    bool Sync() throw(dbwrapper_error)
+    {
+        CDBBatch batch(&obfuscate_key);
+        return WriteBatch(batch, true);
+    }
+
+    CDBIterator *NewIterator()
+    {
+        return new CDBIterator(pdb->NewIterator(iteroptions), &obfuscate_key);
+    }
+
+    /**
+     * Return true if the database managed by this class contains no entries.
+     */
+    bool IsEmpty();
+
+    /**
+     * Accessor for obfuscate_key.
+     */
+    const std::vector<unsigned char>& GetObfuscateKey() const;
+
+    /**
+     * Return the obfuscate_key as a hex-formatted string.
+     */
+    std::string GetObfuscateKeyHex() const;
+
+};
+
+#endif // BITCOIN_DBWRAPPER_H
+