Merge branch '1.14-branding'

1 files changed, 292 insertions, 0 deletions

diff --git a/src/dbwrapper.h b/src/dbwrapper.h
new file mode 100644
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--- /dev/null
+++ b/src/dbwrapper.h
@@ -0,0 +1,292 @@
+// Copyright (c) 2012-2016 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>
+
+static const size_t DBWRAPPER_PREALLOC_KEY_SIZE = 64;
+static const size_t DBWRAPPER_PREALLOC_VALUE_SIZE = 1024;
+
+class dbwrapper_error : public std::runtime_error
+{
+public:
+    dbwrapper_error(const std::string& msg) : std::runtime_error(msg) {}
+};
+
+class CDBWrapper;
+
+/** These should be considered an implementation detail of the specific database.
+ */
+namespace dbwrapper_private {
+
+/** Handle database error by throwing dbwrapper_error exception.
+ */
+void HandleError(const leveldb::Status& status);
+
+/** Work around circular dependency, as well as for testing in dbwrapper_tests.
+ * Database obfuscation should be considered an implementation detail of the
+ * specific database.
+ */
+const std::vector<unsigned char>& GetObfuscateKey(const CDBWrapper &w);
+
+};
+
+/** Batch of changes queued to be written to a CDBWrapper */
+class CDBBatch
+{
+    friend class CDBWrapper;
+
+private:
+    const CDBWrapper &parent;
+    leveldb::WriteBatch batch;
+
+    CDataStream ssKey;
+    CDataStream ssValue;
+
+public:
+    /**
+     * @param[in] _parent   CDBWrapper that this batch is to be submitted to
+     */
+    CDBBatch(const CDBWrapper &_parent) : parent(_parent), ssKey(SER_DISK, CLIENT_VERSION), ssValue(SER_DISK, CLIENT_VERSION) { };
+
+    template <typename K, typename V>
+    void Write(const K& key, const V& value)
+    {
+        ssKey.reserve(DBWRAPPER_PREALLOC_KEY_SIZE);
+        ssKey << key;
+        leveldb::Slice slKey(ssKey.data(), ssKey.size());
+
+        ssValue.reserve(DBWRAPPER_PREALLOC_VALUE_SIZE);
+        ssValue << value;
+        ssValue.Xor(dbwrapper_private::GetObfuscateKey(parent));
+        leveldb::Slice slValue(ssValue.data(), ssValue.size());
+
+        batch.Put(slKey, slValue);
+        ssKey.clear();
+        ssValue.clear();
+    }
+
+    template <typename K>
+    void Erase(const K& key)
+    {
+        ssKey.reserve(DBWRAPPER_PREALLOC_KEY_SIZE);
+        ssKey << key;
+        leveldb::Slice slKey(ssKey.data(), ssKey.size());
+
+        batch.Delete(slKey);
+        ssKey.clear();
+    }
+};
+
+class CDBIterator
+{
+private:
+    const CDBWrapper &parent;
+    leveldb::Iterator *piter;
+
+public:
+
+    /**
+     * @param[in] _parent          Parent CDBWrapper instance.
+     * @param[in] _piter           The original leveldb iterator.
+     */
+    CDBIterator(const CDBWrapper &_parent, leveldb::Iterator *_piter) :
+        parent(_parent), piter(_piter) { };
+    ~CDBIterator();
+
+    bool Valid();
+
+    void SeekToFirst();
+
+    template<typename K> void Seek(const K& key) {
+        CDataStream ssKey(SER_DISK, CLIENT_VERSION);
+        ssKey.reserve(DBWRAPPER_PREALLOC_KEY_SIZE);
+        ssKey << key;
+        leveldb::Slice slKey(ssKey.data(), 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 (const std::exception&) {
+            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(dbwrapper_private::GetObfuscateKey(parent));
+            ssValue >> value;
+        } catch (const std::exception&) {
+            return false;
+        }
+        return true;
+    }
+
+    unsigned int GetValueSize() {
+        return piter->value().size();
+    }
+
+};
+
+class CDBWrapper
+{
+    friend const std::vector<unsigned char>& dbwrapper_private::GetObfuscateKey(const CDBWrapper &w);
+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
+    {
+        CDataStream ssKey(SER_DISK, CLIENT_VERSION);
+        ssKey.reserve(DBWRAPPER_PREALLOC_KEY_SIZE);
+        ssKey << key;
+        leveldb::Slice slKey(ssKey.data(), 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());
+            dbwrapper_private::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)
+    {
+        CDBBatch batch(*this);
+        batch.Write(key, value);
+        return WriteBatch(batch, fSync);
+    }
+
+    template <typename K>
+    bool Exists(const K& key) const
+    {
+        CDataStream ssKey(SER_DISK, CLIENT_VERSION);
+        ssKey.reserve(DBWRAPPER_PREALLOC_KEY_SIZE);
+        ssKey << key;
+        leveldb::Slice slKey(ssKey.data(), 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());
+            dbwrapper_private::HandleError(status);
+        }
+        return true;
+    }
+
+    template <typename K>
+    bool Erase(const K& key, bool fSync = false)
+    {
+        CDBBatch batch(*this);
+        batch.Erase(key);
+        return WriteBatch(batch, fSync);
+    }
+
+    bool WriteBatch(CDBBatch& batch, bool fSync = false);
+
+    // not available for LevelDB; provide for compatibility with BDB
+    bool Flush()
+    {
+        return true;
+    }
+
+    bool Sync()
+    {
+        CDBBatch batch(*this);
+        return WriteBatch(batch, true);
+    }
+
+    CDBIterator *NewIterator()
+    {
+        return new CDBIterator(*this, pdb->NewIterator(iteroptions));
+    }
+
+    /**
+     * Return true if the database managed by this class contains no entries.
+     */
+    bool IsEmpty();
+};
+
+#endif // BITCOIN_DBWRAPPER_H
+