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
|
// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
// vim: ts=8 sw=2 smarttab
#ifndef LEVEL_DB_STORE_H
#define LEVEL_DB_STORE_H
#include "include/types.h"
#include <boost/scoped_ptr.hpp>
#include "include/buffer.h"
#include "leveldb/db.h"
#include "leveldb/write_batch.h"
#include "leveldb/slice.h"
#include "KeyValueDB.h"
/**
* Uses LevelDB to implement the KeyValueDB interface
*/
class LevelDBStore : public KeyValueDB {
string path;
boost::scoped_ptr<leveldb::DB> db;
public:
LevelDBStore(const string &path) : path(path) {}
/// Opens underlying db
int init(ostream &out);
class LevelDBTransactionImpl : public KeyValueDB::TransactionImpl {
public:
leveldb::WriteBatch bat;
list<bufferlist> buffers;
list<string> keys;
LevelDBStore *db;
LevelDBTransactionImpl(LevelDBStore *db) : db(db) {}
void set(
const string &prefix,
const string &k,
const bufferlist &bl);
void rmkey(
const string &prefix,
const string &k);
void rmkeys_by_prefix(
const string &prefix
);
};
KeyValueDB::Transaction get_transaction() {
return std::tr1::shared_ptr< LevelDBTransactionImpl >(
new LevelDBTransactionImpl(this));
}
int submit_transaction(KeyValueDB::Transaction t) {
LevelDBTransactionImpl * _t =
static_cast<LevelDBTransactionImpl *>(t.get());
leveldb::Status s = db->Write(leveldb::WriteOptions(), &(_t->bat));
return s.ok() ? 0 : -1;
}
int submit_transaction_sync(KeyValueDB::Transaction t) {
LevelDBTransactionImpl * _t =
static_cast<LevelDBTransactionImpl *>(t.get());
leveldb::WriteOptions options;
options.sync = true;
leveldb::Status s = db->Write(options, &(_t->bat));
return s.ok() ? 0 : -1;
}
int get(
const string &prefix,
const std::set<string> &key,
std::map<string, bufferlist> *out
);
class LevelDBWholeSpaceIteratorImpl :
public KeyValueDB::WholeSpaceIteratorImpl {
protected:
boost::scoped_ptr<leveldb::Iterator> dbiter;
public:
LevelDBWholeSpaceIteratorImpl(leveldb::Iterator *iter) :
dbiter(iter) { }
virtual ~LevelDBWholeSpaceIteratorImpl() { }
int seek_to_first() {
dbiter->SeekToFirst();
return dbiter->status().ok() ? 0 : -1;
}
int seek_to_first(const string &prefix) {
leveldb::Slice slice_prefix(prefix);
dbiter->Seek(slice_prefix);
return dbiter->status().ok() ? 0 : -1;
}
int seek_to_last() {
dbiter->SeekToLast();
return dbiter->status().ok() ? 0 : -1;
}
int seek_to_last(const string &prefix) {
string limit = past_prefix(prefix);
leveldb::Slice slice_limit(limit);
dbiter->Seek(slice_limit);
if (!dbiter->Valid()) {
dbiter->SeekToLast();
} else {
dbiter->Prev();
}
return dbiter->status().ok() ? 0 : -1;
}
int upper_bound(const string &prefix, const string &after) {
lower_bound(prefix, after);
if (valid()) {
pair<string,string> key = raw_key();
if (key.first == prefix && key.second == after)
next();
}
return dbiter->status().ok() ? 0 : -1;
}
int lower_bound(const string &prefix, const string &to) {
string bound = combine_strings(prefix, to);
leveldb::Slice slice_bound(bound);
dbiter->Seek(slice_bound);
return dbiter->status().ok() ? 0 : -1;
}
bool valid() {
return dbiter->Valid();
}
int next() {
if (valid())
dbiter->Next();
return dbiter->status().ok() ? 0 : -1;
}
int prev() {
if (valid())
dbiter->Prev();
return dbiter->status().ok() ? 0 : -1;
}
string key() {
string out_key;
split_key(dbiter->key(), 0, &out_key);
return out_key;
}
pair<string,string> raw_key() {
string prefix, key;
split_key(dbiter->key(), &prefix, &key);
return make_pair(prefix, key);
}
bufferlist value() {
return to_bufferlist(dbiter->value());
}
int status() {
return dbiter->status().ok() ? 0 : -1;
}
};
class LevelDBSnapshotIteratorImpl : public LevelDBWholeSpaceIteratorImpl {
leveldb::DB *db;
const leveldb::Snapshot *snapshot;
public:
LevelDBSnapshotIteratorImpl(leveldb::DB *db, const leveldb::Snapshot *s,
leveldb::Iterator *iter) :
LevelDBWholeSpaceIteratorImpl(iter), db(db), snapshot(s) { }
~LevelDBSnapshotIteratorImpl() {
assert(snapshot != NULL);
db->ReleaseSnapshot(snapshot);
}
};
/// Utility
static string combine_strings(const string &prefix, const string &value);
static int split_key(leveldb::Slice in, string *prefix, string *key);
static bufferlist to_bufferlist(leveldb::Slice in);
static bool in_prefix(const string &prefix, leveldb::Slice key) {
return (key.compare(leveldb::Slice(past_prefix(prefix))) < 0) &&
(key.compare(leveldb::Slice(prefix)) > 0);
}
static string past_prefix(const string prefix) {
string limit = prefix;
limit.push_back(1);
return limit;
}
protected:
WholeSpaceIterator _get_iterator() {
return std::tr1::shared_ptr<KeyValueDB::WholeSpaceIteratorImpl>(
new LevelDBWholeSpaceIteratorImpl(
db->NewIterator(leveldb::ReadOptions())
)
);
}
WholeSpaceIterator _get_snapshot_iterator() {
const leveldb::Snapshot *snapshot;
leveldb::ReadOptions options;
snapshot = db->GetSnapshot();
options.snapshot = snapshot;
return std::tr1::shared_ptr<KeyValueDB::WholeSpaceIteratorImpl>(
new LevelDBSnapshotIteratorImpl(db.get(), snapshot,
db->NewIterator(options))
);
}
};
#endif
|
