aboutsummaryrefslogtreecommitdiff
path: root/src/leveldbwrapper.h
blob: 0effea407acd3e2c112ff183138ddc06f70963f0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
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_LEVELDBWRAPPER_H
#define BITCOIN_LEVELDBWRAPPER_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 leveldb_error : public std::runtime_error
{
public:
    leveldb_error(const std::string& msg) : std::runtime_error(msg) {}
};

void HandleError(const leveldb::Status& status) throw(leveldb_error);

/** Batch of changes queued to be written to a CLevelDBWrapper */
class CLevelDBBatch
{
    friend class CLevelDBWrapper;

private:
    leveldb::WriteBatch batch;
    const std::vector<unsigned char> *obfuscate_key;

public:
    /**
     * @param[in] obfuscate_key    If passed, XOR data with this key.
     */
    CLevelDBBatch(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 CLevelDBIterator
{
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.
     */
    CLevelDBIterator(leveldb::Iterator *piterIn, const std::vector<unsigned char>* obfuscate_key) :
        piter(piterIn), obfuscate_key(obfuscate_key) { };
    ~CLevelDBIterator();

    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 CLevelDBWrapper
{
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.
     */
    CLevelDBWrapper(const boost::filesystem::path& path, size_t nCacheSize, bool fMemory = false, bool fWipe = false, bool obfuscate = false);
    ~CLevelDBWrapper();

    template <typename K, typename V>
    bool Read(const K& key, V& value) const throw(leveldb_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(leveldb_error)
    {
        CLevelDBBatch batch(&obfuscate_key);
        batch.Write(key, value);
        return WriteBatch(batch, fSync);
    }

    template <typename K>
    bool Exists(const K& key) const throw(leveldb_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(leveldb_error)
    {
        CLevelDBBatch batch(&obfuscate_key);
        batch.Erase(key);
        return WriteBatch(batch, fSync);
    }

    bool WriteBatch(CLevelDBBatch& batch, bool fSync = false) throw(leveldb_error);

    // not available for LevelDB; provide for compatibility with BDB
    bool Flush()
    {
        return true;
    }

    bool Sync() throw(leveldb_error)
    {
        CLevelDBBatch batch(&obfuscate_key);
        return WriteBatch(batch, true);
    }

    CLevelDBIterator *NewIterator()
    {
        return new CLevelDBIterator(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_LEVELDBWRAPPER_H