Bitcoin ABC  0.26.3
P2P Digital Currency
versionbits.h
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1 // Copyright (c) 2016-2018 The Bitcoin Core developers
2 // Distributed under the MIT software license, see the accompanying
3 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
4 
5 #ifndef BITCOIN_VERSIONBITS_H
6 #define BITCOIN_VERSIONBITS_H
7 
8 #include <chain.h>
9 #include <sync.h>
10 
11 #include <map>
12 
14 static const int32_t VERSIONBITS_LAST_OLD_BLOCK_VERSION = 4;
16 static const int32_t VERSIONBITS_TOP_BITS = 0x20000000UL;
18 static const int32_t VERSIONBITS_TOP_MASK = 0xE0000000UL;
20 static const int32_t VERSIONBITS_NUM_BITS = 29;
21 
28 enum class ThresholdState {
29  DEFINED, // First state that each softfork starts out as. The genesis block
30  // is by definition in this state for each deployment.
31  STARTED, // For blocks past the starttime.
32  LOCKED_IN, // For one retarget period after the first retarget period with
33  // STARTED blocks of which at least threshold have the associated
34  // bit set in nVersion.
35  ACTIVE, // For all blocks after the LOCKED_IN retarget period (final state)
36  FAILED, // For all blocks once the first retarget period after the timeout
37  // time is hit, if LOCKED_IN wasn't already reached (final state)
38 };
39 
40 // A map that gives the state for blocks whose height is a multiple of Period().
41 // The map is indexed by the block's parent, however, so all keys in the map
42 // will either be nullptr or a block with (height + 1) % Period() == 0.
43 typedef std::map<const CBlockIndex *, ThresholdState> ThresholdConditionCache;
44 
46 struct BIP9Stats {
48  int period;
53  int threshold;
57  int elapsed;
62  int count;
67  bool possible;
68 };
69 
75 protected:
76  virtual bool Condition(const CBlockIndex *pindex,
77  const Consensus::Params &params) const = 0;
78  virtual int64_t BeginTime(const Consensus::Params &params) const = 0;
79  virtual int64_t EndTime(const Consensus::Params &params) const = 0;
80  virtual int Period(const Consensus::Params &params) const = 0;
81  virtual int Threshold(const Consensus::Params &params) const = 0;
82 
83 public:
89  const Consensus::Params &params) const;
95  ThresholdState GetStateFor(const CBlockIndex *pindexPrev,
96  const Consensus::Params &params,
97  ThresholdConditionCache &cache) const;
102  int GetStateSinceHeightFor(const CBlockIndex *pindexPrev,
103  const Consensus::Params &params,
104  ThresholdConditionCache &cache) const;
105 };
106 
112 private:
116 
117 public:
122  static BIP9Stats Statistics(const CBlockIndex *pindexPrev,
123  const Consensus::Params &params,
125 
126  static uint32_t Mask(const Consensus::Params &params,
128 
132  ThresholdState State(const CBlockIndex *pindexPrev,
133  const Consensus::Params &params,
135 
140  int StateSinceHeight(const CBlockIndex *pindexPrev,
141  const Consensus::Params &params,
143 
147  int32_t ComputeBlockVersion(const CBlockIndex *pindexPrev,
148  const Consensus::Params &params);
149 
150  void Clear();
151 };
152 
153 #endif // BITCOIN_VERSIONBITS_H
Abstract class that implements BIP9-style threshold logic, and caches results.
Definition: versionbits.h:74
virtual bool Condition(const CBlockIndex *pindex, const Consensus::Params &params) const =0
virtual int Period(const Consensus::Params &params) const =0
BIP9Stats GetStateStatisticsFor(const CBlockIndex *pindex, const Consensus::Params &params) const
Returns the numerical statistics of an in-progress BIP9 softfork in the current period.
ThresholdState GetStateFor(const CBlockIndex *pindexPrev, const Consensus::Params &params, ThresholdConditionCache &cache) const
Returns the state for pindex A based on parent pindexPrev B.
Definition: versionbits.cpp:8
virtual int64_t EndTime(const Consensus::Params &params) const =0
int GetStateSinceHeightFor(const CBlockIndex *pindexPrev, const Consensus::Params &params, ThresholdConditionCache &cache) const
Returns the height since when the ThresholdState has started for pindex.
virtual int64_t BeginTime(const Consensus::Params &params) const =0
virtual int Threshold(const Consensus::Params &params) const =0
The block chain is a tree shaped structure starting with the genesis block at the root,...
Definition: blockindex.h:23
BIP 9 allows multiple softforks to be deployed in parallel.
Definition: versionbits.h:111
static BIP9Stats Statistics(const CBlockIndex *pindexPrev, const Consensus::Params &params, Consensus::DeploymentPos pos)
Get the numerical statistics for a given deployment for the signalling period that includes the block...
ThresholdState State(const CBlockIndex *pindexPrev, const Consensus::Params &params, Consensus::DeploymentPos pos)
Get the BIP9 state for a given deployment for the block after pindexPrev.
int32_t ComputeBlockVersion(const CBlockIndex *pindexPrev, const Consensus::Params &params)
Determine what nVersion a new block should use.
int StateSinceHeight(const CBlockIndex *pindexPrev, const Consensus::Params &params, Consensus::DeploymentPos pos)
Get the block height at which the BIP9 deployment switched into the state for the block after pindexP...
static uint32_t Mask(const Consensus::Params &params, Consensus::DeploymentPos pos)
ThresholdConditionCache m_caches[Consensus::MAX_VERSION_BITS_DEPLOYMENTS] GUARDED_BY(m_mutex)
DeploymentPos
Definition: params.h:30
@ MAX_VERSION_BITS_DEPLOYMENTS
Definition: params.h:34
Display status of an in-progress BIP9 softfork.
Definition: versionbits.h:46
int count
Number of blocks with the version bit set since the beginning of the current period.
Definition: versionbits.h:62
int elapsed
Number of blocks elapsed since the beginning of the current period.
Definition: versionbits.h:57
int threshold
Number of blocks with the version bit set required to activate the softfork.
Definition: versionbits.h:53
bool possible
False if there are not enough blocks left in this period to pass activation threshold.
Definition: versionbits.h:67
int period
Length of blocks of the BIP9 signalling period.
Definition: versionbits.h:48
Parameters that influence chain consensus.
Definition: params.h:76
static const int32_t VERSIONBITS_NUM_BITS
Total bits available for versionbits.
Definition: versionbits.h:20
std::map< const CBlockIndex *, ThresholdState > ThresholdConditionCache
Definition: versionbits.h:43
static const int32_t VERSIONBITS_TOP_BITS
What bits to set in version for versionbits blocks.
Definition: versionbits.h:16
static const int32_t VERSIONBITS_LAST_OLD_BLOCK_VERSION
What block version to use for new blocks (pre versionbits)
Definition: versionbits.h:14
static const int32_t VERSIONBITS_TOP_MASK
What bitmask determines whether versionbits is in use.
Definition: versionbits.h:18
ThresholdState
BIP 9 defines a finite-state-machine to deploy a softfork in multiple stages.
Definition: versionbits.h:28