Merge bitcoin/bitcoin#19438: Introduce deploymentstatus

e48826ad87b4f92261f7433e84f48dac9bd9e5c3 tests: remove ComputeBlockVersion shortcut from versionbits tests (Anthony Towns)
c5f36725e877d8eb492383844f8ef7535466b366 [refactor] Move ComputeBlockVersion into VersionBitsCache (Anthony Towns)
4a69b4dbe0d7f504811b67c399da7e6d11e4f805 [move-only] Move ComputeBlockVersion from validation to versionbits (Anthony Towns)
0cfd6c6a8f929d5567ac41f95c21548f115efee5 [refactor] versionbits: make VersionBitsCache a full class (Anthony Towns)
8ee3e0bed5bf2cd3c7a68ca6ba6c65f7b9a72cca [refactor] rpc/blockchain.cpp: SoftForkPushBack (Anthony Towns)
92f48f360da5f425428b761219301f509826bec4 deploymentinfo: Add DeploymentName() (Anthony Towns)
ea68b3a5729f5d240e968388c4f88acffeb27228 [move-only] Rename versionbitsinfo to deploymentinfo (Anthony Towns)
c64b2c6a0f79369624ae96b2e3d579d50aae4de6 scripted-diff: rename versionbitscache (Anthony Towns)
de55304f6e7a8b607e6b3fc7436de50910747b0c [refactor] Add versionbits deployments to deploymentstatus.h (Anthony Towns)
2b0d291da8f479739ff394dd92801da8c40b9f8e [refactor] Add deploymentstatus.h (Anthony Towns)
eccd736f3dc231ac0306ca763c3b72cf8247230a versionbits: Use dedicated lock instead of cs_main (Anthony Towns)
36a4ba0aaaa9b35185d7178994e36bc02cca9887 versionbits: correct doxygen comments (Anthony Towns)

Pull request description:

  Introduces helper functions to make it easy to bury future deployments, along the lines of the suggestion from [11398](https://github.com/bitcoin/bitcoin/pull/11398#issuecomment-335599326) "I would prefer it if a buried deployment wouldn't require all code paths that check the BIP9 status to require changing".

  This provides three functions: `DeploymentEnabled()` which tests if a deployment can ever be active, `DeploymentActiveAt()` which checks if a deployment should be enforced in the given block, and `DeploymentActiveAfter()` which checks if a deployment should be enforced in the block following the given block, and overloads all three to work both with buried deployments and versionbits deployments.

  This adds a dedicated lock for the versionbits cache, which is acquired internally by the versionbits functions, rather than relying on `cs_main`. It also moves moves versionbitscache into deploymentstatus to avoid a circular dependency with validation.

ACKs for top commit:
  jnewbery:
    ACK e48826ad87b4f92261f7433e84f48dac9bd9e5c3
  gruve-p:
    ACK https://github.com/bitcoin/bitcoin/pull/19438/commits/e48826ad87b4f92261f7433e84f48dac9bd9e5c3
  MarcoFalke:
    re-ACK e48826ad87b4f92261f7433e84f48dac9bd9e5c3 🥈

Tree-SHA512: c846ba64436d36f8180046ad551d8b0d9e20509b9bc185aa2639055fc28803dd8ec2d6771ab337e80da0b40009ad959590d5772f84a0bf6199b65190d4155bed

1 files changed, 26 insertions, 7 deletions

diff --git a/src/versionbits.cpp b/src/versionbits.cpp
index df2ec4e056..94c3c9559f 100644
--- a/src/versionbits.cpp
+++ b/src/versionbits.cpp
@@ -190,29 +190,48 @@ public:
 
 } // namespace
 
-ThresholdState VersionBitsState(const CBlockIndex* pindexPrev, const Consensus::Params& params, Consensus::DeploymentPos pos, VersionBitsCache& cache)
+ThresholdState VersionBitsCache::State(const CBlockIndex* pindexPrev, const Consensus::Params& params, Consensus::DeploymentPos pos)
 {
-    return VersionBitsConditionChecker(pos).GetStateFor(pindexPrev, params, cache.caches[pos]);
+    LOCK(m_mutex);
+    return VersionBitsConditionChecker(pos).GetStateFor(pindexPrev, params, m_caches[pos]);
 }
 
-BIP9Stats VersionBitsStatistics(const CBlockIndex* pindexPrev, const Consensus::Params& params, Consensus::DeploymentPos pos)
+BIP9Stats VersionBitsCache::Statistics(const CBlockIndex* pindexPrev, const Consensus::Params& params, Consensus::DeploymentPos pos)
 {
     return VersionBitsConditionChecker(pos).GetStateStatisticsFor(pindexPrev, params);
 }
 
-int VersionBitsStateSinceHeight(const CBlockIndex* pindexPrev, const Consensus::Params& params, Consensus::DeploymentPos pos, VersionBitsCache& cache)
+int VersionBitsCache::StateSinceHeight(const CBlockIndex* pindexPrev, const Consensus::Params& params, Consensus::DeploymentPos pos)
 {
-    return VersionBitsConditionChecker(pos).GetStateSinceHeightFor(pindexPrev, params, cache.caches[pos]);
+    LOCK(m_mutex);
+    return VersionBitsConditionChecker(pos).GetStateSinceHeightFor(pindexPrev, params, m_caches[pos]);
 }
 
-uint32_t VersionBitsMask(const Consensus::Params& params, Consensus::DeploymentPos pos)
+uint32_t VersionBitsCache::Mask(const Consensus::Params& params, Consensus::DeploymentPos pos)
 {
     return VersionBitsConditionChecker(pos).Mask(params);
 }
 
+int32_t VersionBitsCache::ComputeBlockVersion(const CBlockIndex* pindexPrev, const Consensus::Params& params)
+{
+    LOCK(m_mutex);
+    int32_t nVersion = VERSIONBITS_TOP_BITS;
+
+    for (int i = 0; i < (int)Consensus::MAX_VERSION_BITS_DEPLOYMENTS; i++) {
+        Consensus::DeploymentPos pos = static_cast<Consensus::DeploymentPos>(i);
+        ThresholdState state = VersionBitsConditionChecker(pos).GetStateFor(pindexPrev, params, m_caches[pos]);
+        if (state == ThresholdState::LOCKED_IN || state == ThresholdState::STARTED) {
+            nVersion |= Mask(params, pos);
+        }
+    }
+
+    return nVersion;
+}
+
 void VersionBitsCache::Clear()
 {
+    LOCK(m_mutex);
     for (unsigned int d = 0; d < Consensus::MAX_VERSION_BITS_DEPLOYMENTS; d++) {
-        caches[d].clear();
+        m_caches[d].clear();
     }
 }