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
|
// Copyright (c) 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.
#include "versionbits.h"
#include "consensus/params.h"
const struct BIP9DeploymentInfo VersionBitsDeploymentInfo[Consensus::MAX_VERSION_BITS_DEPLOYMENTS] = {
{
/*.name =*/ "testdummy",
},
{
/*.name =*/ "csv",
}
};
ThresholdState AbstractThresholdConditionChecker::GetStateFor(const CBlockIndex* pindexPrev, const Consensus::Params& params, ThresholdConditionCache& cache) const
{
int nPeriod = Period(params);
int nThreshold = Threshold(params);
int64_t nTimeStart = BeginTime(params);
int64_t nTimeTimeout = EndTime(params);
// A block's state is always the same as that of the first of its period, so it is computed based on a pindexPrev whose height equals a multiple of nPeriod - 1.
if (pindexPrev != NULL) {
pindexPrev = pindexPrev->GetAncestor(pindexPrev->nHeight - ((pindexPrev->nHeight + 1) % nPeriod));
}
// Walk backwards in steps of nPeriod to find a pindexPrev whose information is known
std::vector<const CBlockIndex*> vToCompute;
while (cache.count(pindexPrev) == 0) {
if (pindexPrev == NULL) {
// The genesis block is by definition defined.
cache[pindexPrev] = THRESHOLD_DEFINED;
break;
}
if (pindexPrev->GetMedianTimePast() < nTimeStart) {
// Optimizaton: don't recompute down further, as we know every earlier block will be before the start time
cache[pindexPrev] = THRESHOLD_DEFINED;
break;
}
vToCompute.push_back(pindexPrev);
pindexPrev = pindexPrev->GetAncestor(pindexPrev->nHeight - nPeriod);
}
// At this point, cache[pindexPrev] is known
assert(cache.count(pindexPrev));
ThresholdState state = cache[pindexPrev];
// Now walk forward and compute the state of descendants of pindexPrev
while (!vToCompute.empty()) {
ThresholdState stateNext = state;
pindexPrev = vToCompute.back();
vToCompute.pop_back();
switch (state) {
case THRESHOLD_DEFINED: {
if (pindexPrev->GetMedianTimePast() >= nTimeTimeout) {
stateNext = THRESHOLD_FAILED;
} else if (pindexPrev->GetMedianTimePast() >= nTimeStart) {
stateNext = THRESHOLD_STARTED;
}
break;
}
case THRESHOLD_STARTED: {
if (pindexPrev->GetMedianTimePast() >= nTimeTimeout) {
stateNext = THRESHOLD_FAILED;
break;
}
// We need to count
const CBlockIndex* pindexCount = pindexPrev;
int count = 0;
for (int i = 0; i < nPeriod; i++) {
if (Condition(pindexCount, params)) {
count++;
}
pindexCount = pindexCount->pprev;
}
if (count >= nThreshold) {
stateNext = THRESHOLD_LOCKED_IN;
}
break;
}
case THRESHOLD_LOCKED_IN: {
// Always progresses into ACTIVE.
stateNext = THRESHOLD_ACTIVE;
break;
}
case THRESHOLD_FAILED:
case THRESHOLD_ACTIVE: {
// Nothing happens, these are terminal states.
break;
}
}
cache[pindexPrev] = state = stateNext;
}
return state;
}
namespace
{
/**
* Class to implement versionbits logic.
*/
class VersionBitsConditionChecker : public AbstractThresholdConditionChecker {
private:
const Consensus::DeploymentPos id;
protected:
int64_t BeginTime(const Consensus::Params& params) const { return params.vDeployments[id].nStartTime; }
int64_t EndTime(const Consensus::Params& params) const { return params.vDeployments[id].nTimeout; }
int Period(const Consensus::Params& params) const { return params.nMinerConfirmationWindow; }
int Threshold(const Consensus::Params& params) const { return params.nRuleChangeActivationThreshold; }
bool Condition(const CBlockIndex* pindex, const Consensus::Params& params) const
{
return (((pindex->nVersion & VERSIONBITS_TOP_MASK) == VERSIONBITS_TOP_BITS) && (pindex->nVersion & Mask(params)) != 0);
}
public:
VersionBitsConditionChecker(Consensus::DeploymentPos id_) : id(id_) {}
uint32_t Mask(const Consensus::Params& params) const { return ((uint32_t)1) << params.vDeployments[id].bit; }
};
}
ThresholdState VersionBitsState(const CBlockIndex* pindexPrev, const Consensus::Params& params, Consensus::DeploymentPos pos, VersionBitsCache& cache)
{
return VersionBitsConditionChecker(pos).GetStateFor(pindexPrev, params, cache.caches[pos]);
}
uint32_t VersionBitsMask(const Consensus::Params& params, Consensus::DeploymentPos pos)
{
return VersionBitsConditionChecker(pos).Mask(params);
}
void VersionBitsCache::Clear()
{
for (unsigned int d = 0; d < Consensus::MAX_VERSION_BITS_DEPLOYMENTS; d++) {
caches[d].clear();
}
}
|
