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7565563bc7
Test `VersionBitsConditionChecker` behaviour directly, rather than reimplementing it, thus slightly improving fuzz test coverage of the real code.
86 lines
3.8 KiB
C++
86 lines
3.8 KiB
C++
// Copyright (c) 2016-2022 The Bitcoin Core developers
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// Distributed under the MIT software license, see the accompanying
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// file COPYING or http://www.opensource.org/licenses/mit-license.php.
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#ifndef BITCOIN_VERSIONBITS_IMPL_H
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#define BITCOIN_VERSIONBITS_IMPL_H
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#include <chain.h>
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#include <sync.h>
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#include <versionbits.h>
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/** BIP 9 defines a finite-state-machine to deploy a softfork in multiple stages.
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* State transitions happen during retarget period if conditions are met
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* In case of reorg, transitions can go backward. Without transition, state is
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* inherited between periods. All blocks of a period share the same state.
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*/
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enum class ThresholdState : uint8_t {
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DEFINED, // First state that each softfork starts out as. The genesis block is by definition in this state for each deployment.
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STARTED, // For blocks past the starttime.
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LOCKED_IN, // For at least one retarget period after the first retarget period with STARTED blocks of which at least threshold have the associated bit set in nVersion, until min_activation_height is reached.
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ACTIVE, // For all blocks after the LOCKED_IN retarget period (final state)
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FAILED, // For all blocks once the first retarget period after the timeout time is hit, if LOCKED_IN wasn't already reached (final state)
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};
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/** Get a string with the state name */
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std::string StateName(ThresholdState state);
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/**
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* Abstract class that implements BIP9-style threshold logic, and caches results.
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*/
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class AbstractThresholdConditionChecker {
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protected:
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virtual bool Condition(const CBlockIndex* pindex) const =0;
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virtual int64_t BeginTime() const =0;
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virtual int64_t EndTime() const =0;
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virtual int MinActivationHeight() const { return 0; }
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virtual int Period() const =0;
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virtual int Threshold() const =0;
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public:
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virtual ~AbstractThresholdConditionChecker() = default;
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/** Returns the numerical statistics of an in-progress BIP9 softfork in the period including pindex
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* If provided, signalling_blocks is set to true/false based on whether each block in the period signalled
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*/
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BIP9Stats GetStateStatisticsFor(const CBlockIndex* pindex, std::vector<bool>* signalling_blocks = nullptr) const;
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/** Returns the state for pindex A based on parent pindexPrev B. Applies any state transition if conditions are present.
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* Caches state from first block of period. */
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ThresholdState GetStateFor(const CBlockIndex* pindexPrev, ThresholdConditionCache& cache) const;
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/** Returns the height since when the ThresholdState has started for pindex A based on parent pindexPrev B, all blocks of a period share the same */
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int GetStateSinceHeightFor(const CBlockIndex* pindexPrev, ThresholdConditionCache& cache) const;
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};
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/**
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* Class to implement versionbits logic.
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*/
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class VersionBitsConditionChecker : public AbstractThresholdConditionChecker {
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private:
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const Consensus::BIP9Deployment& dep;
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protected:
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int64_t BeginTime() const override { return dep.nStartTime; }
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int64_t EndTime() const override { return dep.nTimeout; }
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int MinActivationHeight() const override { return dep.min_activation_height; }
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int Period() const override { return dep.period; }
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int Threshold() const override { return dep.threshold; }
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bool Condition(const CBlockIndex* pindex) const override
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{
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return Condition(pindex->nVersion);
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}
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public:
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explicit VersionBitsConditionChecker(const Consensus::BIP9Deployment& dep) : dep{dep} {}
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explicit VersionBitsConditionChecker(const Consensus::Params& params, Consensus::DeploymentPos id) : VersionBitsConditionChecker{params.vDeployments[id]} {}
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uint32_t Mask() const { return (uint32_t{1}) << dep.bit; }
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bool Condition(int32_t nVersion) const
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{
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return (((nVersion & VERSIONBITS_TOP_MASK) == VERSIONBITS_TOP_BITS) && (nVersion & Mask()) != 0);
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}
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};
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#endif // BITCOIN_VERSIONBITS_IMPL_H
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