[refactor] Add deploymentstatus.h

Provides DeploymentEnabled, DeploymentActiveAt, and DeploymentActiveAfter
helpers for checking the status of buried deployments. Can be overloaded
so the same syntax works for non-buried deployments, allowing future
soft forks to be changed from signalled to buried deployments without
having to touch the implementation code.

Replaces IsWitnessEnabled and IsScriptWitnessEnabled.

1 files changed, 29 insertions, 0 deletions

diff --git a/src/consensus/params.h b/src/consensus/params.h
index 28c95e0884..9b4139d76c 100644
--- a/src/consensus/params.h
+++ b/src/consensus/params.h
@@ -11,6 +11,17 @@
 
 namespace Consensus {
 
+enum BuriedDeployment : int16_t
+{
+    // buried deployments get negative values to avoid overlap with DeploymentPos
+    DEPLOYMENT_HEIGHTINCB = std::numeric_limits<int16_t>::min(),
+    DEPLOYMENT_CLTV,
+    DEPLOYMENT_DERSIG,
+    DEPLOYMENT_CSV,
+    DEPLOYMENT_SEGWIT,
+};
+constexpr bool ValidDeployment(BuriedDeployment dep) { return DEPLOYMENT_HEIGHTINCB <= dep && dep <= DEPLOYMENT_SEGWIT; }
+
 enum DeploymentPos
 {
     DEPLOYMENT_TESTDUMMY,
@@ -100,7 +111,25 @@ struct Params {
      */
     bool signet_blocks{false};
     std::vector<uint8_t> signet_challenge;
+
+    int DeploymentHeight(BuriedDeployment dep) const
+    {
+        switch (dep) {
+        case DEPLOYMENT_HEIGHTINCB:
+            return BIP34Height;
+        case DEPLOYMENT_CLTV:
+            return BIP65Height;
+        case DEPLOYMENT_DERSIG:
+            return BIP66Height;
+        case DEPLOYMENT_CSV:
+            return CSVHeight;
+        case DEPLOYMENT_SEGWIT:
+            return SegwitHeight;
+        } // no default case, so the compiler can warn about missing cases
+        return std::numeric_limits<int>::max();
+    }
 };
+
 } // namespace Consensus
 
 #endif // BITCOIN_CONSENSUS_PARAMS_H