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1 : : // Copyright (c) 2016-2022 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 <array>
12 : : #include <map>
13 : : #include <optional>
14 : : #include <vector>
15 : :
16 : : class CChainParams;
17 : :
18 : : /** What block version to use for new blocks (pre versionbits) */
19 : : static const int32_t VERSIONBITS_LAST_OLD_BLOCK_VERSION = 4;
20 : : /** What bits to set in version for versionbits blocks */
21 : : static const int32_t VERSIONBITS_TOP_BITS = 0x20000000UL;
22 : : /** What bitmask determines whether versionbits is in use */
23 : : static const int32_t VERSIONBITS_TOP_MASK = 0xE0000000UL;
24 : : /** Total bits available for versionbits */
25 : : static const int32_t VERSIONBITS_NUM_BITS = 29;
26 : :
27 : : /** Opaque type for BIP9 state. See versionbits_impl.h for details. */
28 : : enum class ThresholdState : uint8_t;
29 : :
30 : : // A map that gives the state for blocks whose height is a multiple of Period().
31 : : // The map is indexed by the block's parent, however, so all keys in the map
32 : : // will either be nullptr or a block with (height + 1) % Period() == 0.
33 : : typedef std::map<const CBlockIndex*, ThresholdState> ThresholdConditionCache;
34 : :
35 : : /** Display status of an in-progress BIP9 softfork */
36 : : struct BIP9Stats {
37 : : /** Length of blocks of the BIP9 signalling period */
38 : : uint32_t period{0};
39 : : /** Number of blocks with the version bit set required to activate the softfork */
40 : : uint32_t threshold{0};
41 : : /** Number of blocks elapsed since the beginning of the current period */
42 : : uint32_t elapsed{0};
43 : : /** Number of blocks with the version bit set since the beginning of the current period */
44 : : uint32_t count{0};
45 : : /** False if there are not enough blocks left in this period to pass activation threshold */
46 : : bool possible{false};
47 : : };
48 : :
49 : : /** Detailed status of an enabled BIP9 deployment */
50 [ # # ]: 0 : struct BIP9Info {
51 : : /** Height at which current_state started */
52 : : int since{0};
53 : : /** String representing the current state */
54 : : std::string current_state{};
55 : : /** String representing the next block's state */
56 : : std::string next_state{};
57 : : /** For states where signalling is applicable, information about the signalling */
58 : : std::optional<BIP9Stats> stats;
59 : : /** Which blocks signalled; empty if signalling is not applicable */
60 : : std::vector<bool> signalling_blocks;
61 : : /** Height at which the deployment is active, if known. May be in the future. */
62 : : std::optional<int> active_since;
63 : : };
64 : :
65 [ # # ]: 0 : struct BIP9GBTStatus {
66 : : struct Info {
67 : : int bit;
68 : : uint32_t mask;
69 : : bool gbt_force;
70 : : };
71 : : std::map<std::string, const Info, std::less<>> signalling, locked_in, active;
72 : : };
73 : :
74 : : /** BIP 9 allows multiple softforks to be deployed in parallel. We cache
75 : : * per-period state for every one of them. */
76 : 179 : class VersionBitsCache
77 : : {
78 : : private:
79 : : Mutex m_mutex;
80 : : std::array<ThresholdConditionCache,VERSIONBITS_NUM_BITS> m_warning_caches GUARDED_BY(m_mutex);
81 : : std::array<ThresholdConditionCache,Consensus::MAX_VERSION_BITS_DEPLOYMENTS> m_caches GUARDED_BY(m_mutex);
82 : :
83 : : public:
84 : : BIP9Info Info(const CBlockIndex& block_index, const Consensus::Params& params, Consensus::DeploymentPos id) EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);
85 : :
86 : : BIP9GBTStatus GBTStatus(const CBlockIndex& block_index, const Consensus::Params& params) EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);
87 : :
88 : : /** Get the BIP9 state for a given deployment for the block after pindexPrev. */
89 : : bool IsActiveAfter(const CBlockIndex* pindexPrev, const Consensus::Params& params, Consensus::DeploymentPos pos) EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);
90 : :
91 : : /** Determine what nVersion a new block should use */
92 : : int32_t ComputeBlockVersion(const CBlockIndex* pindexPrev, const Consensus::Params& params) EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);
93 : :
94 : : /** Check for unknown activations
95 : : * Returns a vector containing the bit number used for signalling and a bool
96 : : * indicating the deployment is likely to be ACTIVE, rather than merely LOCKED_IN. */
97 : : std::vector<std::pair<int,bool>> CheckUnknownActivations(const CBlockIndex* pindex, const CChainParams& chainparams) EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);
98 : :
99 : : void Clear() EXCLUSIVE_LOCKS_REQUIRED(!m_mutex);
100 : : };
101 : :
102 : : #endif // BITCOIN_VERSIONBITS_H
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