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
|
// Copyright 2014 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package filters
import (
"math"
"time"
"math/big"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/ethdb"
"github.com/ethereum/go-ethereum/event"
"github.com/ethereum/go-ethereum/rpc"
"golang.org/x/net/context"
)
type Backend interface {
ChainDb() ethdb.Database
EventMux() *event.TypeMux
HeaderByNumber(ctx context.Context, blockNr rpc.BlockNumber) (*types.Header, error)
GetReceipts(ctx context.Context, blockHash common.Hash) (types.Receipts, error)
}
// Filter can be used to retrieve and filter logs
type Filter struct {
backend Backend
useMipMap bool
created time.Time
db ethdb.Database
begin, end int64
addresses []common.Address
topics [][]common.Hash
}
// New creates a new filter which uses a bloom filter on blocks to figure out whether
// a particular block is interesting or not.
func New(backend Backend, useMipMap bool) *Filter {
return &Filter{
backend: backend,
useMipMap: useMipMap,
db: backend.ChainDb(),
}
}
// SetBeginBlock sets the earliest block for filtering.
// -1 = latest block (i.e., the current block)
// hash = particular hash from-to
func (f *Filter) SetBeginBlock(begin int64) {
f.begin = begin
}
// SetEndBlock sets the latest block for filtering.
func (f *Filter) SetEndBlock(end int64) {
f.end = end
}
// SetAddresses matches only logs that are generated from addresses that are included
// in the given addresses.
func (f *Filter) SetAddresses(addr []common.Address) {
f.addresses = addr
}
// SetTopics matches only logs that have topics matching the given topics.
func (f *Filter) SetTopics(topics [][]common.Hash) {
f.topics = topics
}
// Run filters logs with the current parameters set
func (f *Filter) Find(ctx context.Context) ([]Log, error) {
head, _ := f.backend.HeaderByNumber(ctx, rpc.LatestBlockNumber)
if head == nil {
return nil, nil
}
headBlockNumber := head.Number.Uint64()
var beginBlockNo uint64 = uint64(f.begin)
if f.begin == -1 {
beginBlockNo = headBlockNumber
}
var endBlockNo uint64 = uint64(f.end)
if f.end == -1 {
endBlockNo = headBlockNumber
}
// if no addresses are present we can't make use of fast search which
// uses the mipmap bloom filters to check for fast inclusion and uses
// higher range probability in order to ensure at least a false positive
if !f.useMipMap || len(f.addresses) == 0 {
return f.getLogs(ctx, beginBlockNo, endBlockNo)
}
return f.mipFind(beginBlockNo, endBlockNo, 0), nil
}
func (f *Filter) mipFind(start, end uint64, depth int) (logs []Log) {
level := core.MIPMapLevels[depth]
// normalise numerator so we can work in level specific batches and
// work with the proper range checks
for num := start / level * level; num <= end; num += level {
// find addresses in bloom filters
bloom := core.GetMipmapBloom(f.db, num, level)
for _, addr := range f.addresses {
if bloom.TestBytes(addr[:]) {
// range check normalised values and make sure that
// we're resolving the correct range instead of the
// normalised values.
start := uint64(math.Max(float64(num), float64(start)))
end := uint64(math.Min(float64(num+level-1), float64(end)))
if depth+1 == len(core.MIPMapLevels) {
l, _ := f.getLogs(context.Background(), start, end)
logs = append(logs, l...)
} else {
logs = append(logs, f.mipFind(start, end, depth+1)...)
}
// break so we don't check the same range for each
// possible address. Checks on multiple addresses
// are handled further down the stack.
break
}
}
}
return logs
}
func (f *Filter) getLogs(ctx context.Context, start, end uint64) (logs []Log, err error) {
for i := start; i <= end; i++ {
header, err := f.backend.HeaderByNumber(ctx, rpc.BlockNumber(i))
if header == nil || err != nil {
return logs, err
}
// Use bloom filtering to see if this block is interesting given the
// current parameters
if f.bloomFilter(header.Bloom) {
// Get the logs of the block
receipts, err := f.backend.GetReceipts(ctx, header.Hash())
if err != nil {
return nil, err
}
var unfiltered []Log
for _, receipt := range receipts {
rl := make([]Log, len(receipt.Logs))
for i, l := range receipt.Logs {
rl[i] = Log{l, false}
}
unfiltered = append(unfiltered, rl...)
}
logs = append(logs, filterLogs(unfiltered, nil, nil, f.addresses, f.topics)...)
}
}
return logs, nil
}
func includes(addresses []common.Address, a common.Address) bool {
for _, addr := range addresses {
if addr == a {
return true
}
}
return false
}
func filterLogs(logs []Log, fromBlock, toBlock *big.Int, addresses []common.Address, topics [][]common.Hash) []Log {
var ret []Log
// Filter the logs for interesting stuff
Logs:
for _, log := range logs {
if fromBlock != nil && fromBlock.Int64() >= 0 && uint64(fromBlock.Int64()) > log.BlockNumber {
continue
}
if toBlock != nil && toBlock.Int64() >= 0 && uint64(toBlock.Int64()) < log.BlockNumber {
continue
}
if len(addresses) > 0 && !includes(addresses, log.Address) {
continue
}
logTopics := make([]common.Hash, len(topics))
copy(logTopics, log.Topics)
// If the to filtered topics is greater than the amount of topics in logs, skip.
if len(topics) > len(log.Topics) {
continue Logs
}
for i, topics := range topics {
var match bool
for _, topic := range topics {
// common.Hash{} is a match all (wildcard)
if (topic == common.Hash{}) || log.Topics[i] == topic {
match = true
break
}
}
if !match {
continue Logs
}
}
ret = append(ret, log)
}
return ret
}
func (f *Filter) bloomFilter(bloom types.Bloom) bool {
return bloomFilter(bloom, f.addresses, f.topics)
}
func bloomFilter(bloom types.Bloom, addresses []common.Address, topics [][]common.Hash) bool {
if len(addresses) > 0 {
var included bool
for _, addr := range addresses {
if types.BloomLookup(bloom, addr) {
included = true
break
}
}
if !included {
return false
}
}
for _, sub := range topics {
var included bool
for _, topic := range sub {
if (topic == common.Hash{}) || types.BloomLookup(bloom, topic) {
included = true
break
}
}
if !included {
return false
}
}
return true
}
|