chore: Lazy initialize SNARK_KEYS (#18709)

Signed-off-by: Neeharika-Sompalli <[email protected]>

Author: Neeharika-Sompalli

hedera-node/hedera-app/src/main/java/com/hedera/node/app/history/impl/HistoryLibraryImpl.java

@@ -3,6 +3,8 @@
 
 import static java.util.Objects.requireNonNull;
 
+import com.google.common.base.Supplier;
+import com.google.common.base.Suppliers;
 import com.hedera.cryptography.rpm.HistoryLibraryBridge;
 import com.hedera.cryptography.rpm.ProvingAndVerifyingSnarkKeys;
 import com.hedera.cryptography.rpm.SigningAndVerifyingSchnorrKeys;
@@ -23,11 +25,18 @@ public class HistoryLibraryImpl implements HistoryLibrary {
 
     private static final SplittableRandom RANDOM = new SplittableRandom();
     private static final HistoryLibraryBridge BRIDGE = HistoryLibraryBridge.getInstance();
-    private static ProvingAndVerifyingSnarkKeys SNARK_KEYS;
+    private static final Supplier<ProvingAndVerifyingSnarkKeys> SNARK_KEYS = Suppliers.memoize(() -> {
+        try {
+            var elf = HistoryLibraryBridge.loadAddressBookRotationProgram();
+            return BRIDGE.snarkVerificationKey(elf);
+        } catch (IOException e) {
+            throw new IllegalStateException("Could not load HistoryLibrary ELF", e);
+        }
+    });
 
     @Override
     public Bytes snarkVerificationKey() {
-        return Bytes.wrap(snarkKeys().verifyingKey());
+        return Bytes.wrap(SNARK_KEYS.get().verifyingKey());
     }
 
     @Override
@@ -94,8 +103,8 @@ public Bytes proveChainOfTrust(
             throw new IllegalArgumentException("The number of weights and verifying keys must be the same");
         }
         final var proof = BRIDGE.proveChainOfTrust(
-                snarkKeys().provingKey(),
-                snarkKeys().verifyingKey(),
+                SNARK_KEYS.get().provingKey(),
+                SNARK_KEYS.get().verifyingKey(),
                 genesisAddressBookHash.toByteArray(),
                 currentAddressBookVerifyingKeys,
                 currentAddressBookWeights,
@@ -111,18 +120,6 @@ public Bytes proveChainOfTrust(
     @Override
     public boolean verifyChainOfTrust(@NonNull final Bytes proof) {
         requireNonNull(proof);
-        return BRIDGE.verifyChainOfTrust(snarkKeys().verifyingKey(), proof.toByteArray());
-    }
-
-    private ProvingAndVerifyingSnarkKeys snarkKeys() {
-        try {
-            if (SNARK_KEYS == null) {
-                final var elf = HistoryLibraryBridge.loadAddressBookRotationProgram();
-                SNARK_KEYS = BRIDGE.snarkVerificationKey(elf);
-            }
-            return SNARK_KEYS;
-        } catch (IOException e) {
-            throw new IllegalStateException("Could not load HistoryLibrary ELF", e);
-        }
+        return BRIDGE.verifyChainOfTrust(SNARK_KEYS.get().verifyingKey(), proof.toByteArray());
     }
 }