Add method for fetching the next activation height after a given block height

src/consensus/upgrades.cpp

@@ -102,3 +102,21 @@ bool IsActivationHeightForAnyUpgrade(
 
     return false;
 }
+
+boost::optional<int> NextActivationHeight(
+    int nHeight,
+    const Consensus::Params& params)
+{
+    if (nHeight < 0) {
+        return boost::none;
+    }
+
+    // Don't count Sprout as an activation height
+    for (auto idx = Consensus::BASE_SPROUT + 1; idx < Consensus::MAX_NETWORK_UPGRADES; idx++) {
+        if (NetworkUpgradeState(nHeight, params, Consensus::UpgradeIndex(idx)) == UPGRADE_PENDING) {
+            return params.vUpgrades[idx].nActivationHeight;
+        }
+    }
+
+    return boost::none;
+}