Cache successful verRctNonSemanticsSimple calls

src/ringct/rctSigs.cpp

@@ -30,6 +30,7 @@
 
 #include "misc_log_ex.h"
 #include "misc_language.h"
+#include "common/data_cache.h"
 #include "common/perf_timer.h"
 #include "common/threadpool.h"
 #include "common/util.h"
@@ -1578,6 +1579,42 @@ namespace rct {
       }
     }
 
+    bool verRctNonSemanticsSimpleCached(const rctSig & rv)
+    {
+      // Hello future Monero dev! If you got this assert, read the following carefully:
+      //
+      // RCT cache assumes that this function will serialize and hash all rv's fields used for RingCT verification
+      // If you're about to add a new RCTType here, first you must check that binary_archive serialization writes all rv's fields to the binary blob
+      // If it's not the case, rewrite this function to serialize everything, even some "temporary" fields which are not serialized normally
+      CHECK_AND_ASSERT_MES_L1(rv.type <= RCTTypeBulletproofPlus, false, "Unknown RCT type. Make sure RCT cache works correctly with this type and then enable it in the code here.");
+
+      // Don't cache older (or newer) rctSig types
+      // This cache only makes sense when it caches data from mempool first,
+      // so only "current fork version-enabled" RCT types need to be cached
+      if (rv.type != RCTTypeBulletproofPlus)
+        return verRctNonSemanticsSimple(rv);
+
+      // Get the hash of rv
+      std::stringstream ss;
+      binary_archive<true> ar(ss);
+
+      ::do_serialize(ar, const_cast<rctSig&>(rv));
+
+      crypto::hash h;
+      cryptonote::get_blob_hash(ss.str(), h);
+
+      static tools::data_cache<crypto::hash, 8192> cache;
+
+      if (cache.has(h))
+        return true;
+
+      const bool res = verRctNonSemanticsSimple(rv);
+      if (res)
+        cache.add(h);
+
+      return res;
+    }
+
     //RingCT protocol
     //genRct: 
     //   creates an rctSig with all data necessary to verify the rangeProofs and that the signer owns one of the