Add benchmark for incrementing note witnesses

src/zcbenchmarks.cpp

@@ -17,6 +17,7 @@
 #include "script/sign.h"
 #include "sodium.h"
 #include "streams.h"
+#include "utiltest.h"
 #include "wallet/wallet.h"
 
 #include "zcbenchmarks.h"
@@ -243,3 +244,45 @@ double benchmark_try_decrypt_notes(const JSDescription &joinsplit)
     return timer_stop(tv_start);
 }
 
+double benchmark_increment_note_witnesses(size_t nTxs)
+{
+    CWallet wallet;
+    ZCIncrementalMerkleTree tree;
+
+    auto sk = libzcash::SpendingKey::random();
+    wallet.AddSpendingKey(sk);
+
+    // First block
+    CBlock block1;
+    for (int i = 0; i < nTxs; i++) {
+        auto wtx = GetValidReceive(*pzcashParams, sk, 10, true);
+        auto note = GetNote(*pzcashParams, sk, wtx, 0, 1);
+        auto nullifier = note.nullifier(sk);
+
+        mapNoteData_t noteData;
+        JSOutPoint jsoutpt {wtx.GetHash(), 0, 1};
+        CNoteData nd {sk.address(), nullifier};
+        noteData[jsoutpt] = nd;
+
+        wtx.SetNoteData(noteData);
+        wallet.AddToWallet(wtx, true, NULL);
+        block1.vtx.push_back(wtx);
+    }
+    CBlockIndex index1(block1);
+    index1.nHeight = 1;
+
+    // Increment to get transactions witnessed
+    wallet.ChainTip(&index1, &block1, tree, true);
+
+    // Second block
+    CBlock block2;
+    block2.hashPrevBlock = block1.GetHash();
+    CBlockIndex index2(block2);
+    index2.nHeight = 2;
+
+    struct timeval tv_start;
+    timer_start(tv_start);
+    wallet.ChainTip(&index2, &block2, tree, true);
+    return timer_stop(tv_start);
+}
+