From 78584ef794f8d6a9af93348c4186d0ad63cacd7b Mon Sep 17 00:00:00 2001
From: Simon <simon@bitcartel.com>
Date: Sat, 28 Jul 2018 10:09:42 -0700
Subject: [PATCH] Create CWallet::FindMySaplingNotes()

---
 src/wallet/wallet.cpp | 52 ++++++++++++++++++++++++++++++++++++++-----
 src/wallet/wallet.h   |  1 +
 2 files changed, 48 insertions(+), 5 deletions(-)

diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index 2e09f5546..d5cbd0885 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -1363,15 +1363,19 @@ bool CWallet::AddToWalletIfInvolvingMe(const CTransaction& tx, const CBlock* pbl
         AssertLockHeld(cs_wallet);
         bool fExisted = mapWallet.count(tx.GetHash()) != 0;
         if (fExisted && !fUpdate) return false;
-        auto noteData = FindMySproutNotes(tx);
-        if (fExisted || IsMine(tx) || IsFromMe(tx) || noteData.size() > 0)
+        auto sproutNoteData = FindMySproutNotes(tx);
+        auto saplingNoteData = FindMySaplingNotes(tx);
+        if (fExisted || IsMine(tx) || IsFromMe(tx) || sproutNoteData.size() > 0 || saplingNoteData.size() > 0)
         {
             CWalletTx wtx(this,tx);
 
-            if (noteData.size() > 0) {
-                wtx.SetSproutNoteData(noteData);
+            if (sproutNoteData.size() > 0) {
+                wtx.SetSproutNoteData(sproutNoteData);
+            }
+
+            if (saplingNoteData.size() > 0) {
+                wtx.SetSaplingNoteData(saplingNoteData);
             }
-            // TODO: Sapling note data
 
             // Get merkle branch if transaction was found in a block
             if (pblock)
@@ -1512,6 +1516,44 @@ mapSproutNoteData_t CWallet::FindMySproutNotes(const CTransaction &tx) const
     return noteData;
 }
 
+
+/**
+ * Finds all output notes in the given transaction that have been sent to
+ * SaplingPaymentAddresses in this wallet.
+ *
+ * It should never be necessary to call this method with a CWalletTx, because
+ * the result of FindMySaplingNotes (for the addresses available at the time) will
+ * already have been cached in CWalletTx.mapSaplingNoteData.
+ */
+mapSaplingNoteData_t CWallet::FindMySaplingNotes(const CTransaction &tx) const
+{
+    LOCK(cs_SpendingKeyStore);
+    uint256 hash = tx.GetHash();
+
+    mapSaplingNoteData_t noteData;
+
+    // Protocol Spec: 4.19 Block Chain Scanning (Sapling)
+    for (uint32_t i = 0; i < tx.vShieldedOutput.size(); ++i) {
+        const OutputDescription output = tx.vShieldedOutput[i];
+        for (auto it = mapSaplingIncomingViewingKeys.begin(); it != mapSaplingIncomingViewingKeys.end(); ++it) {
+            SaplingIncomingViewingKey ivk = it->second;
+            auto result = SaplingNotePlaintext::decrypt(output.encCiphertext, ivk, output.ephemeralKey, output.cm);
+            if (!result) {
+                continue;
+            }
+            // We don't cache the nullifier here as computing it requires knowledge of the note position
+            // in the commitment tree, which can only be determined when the transaction has been mined.
+            SaplingOutPoint op {hash, i};
+            SaplingNoteData nd;
+            nd.ivk = ivk;
+            noteData.insert(std::make_pair(op, nd));
+            break;
+        }
+    }
+
+    return noteData;
+}
+
 bool CWallet::IsFromMe(const uint256& nullifier) const
 {
     {
diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
index 4c0188138..675a4428f 100644
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -1097,6 +1097,7 @@ public:
         const uint256& hSig,
         uint8_t n) const;
     mapSproutNoteData_t FindMySproutNotes(const CTransaction& tx) const;
+    mapSaplingNoteData_t FindMySaplingNotes(const CTransaction& tx) const;
     bool IsFromMe(const uint256& nullifier) const;
     void GetSproutNoteWitnesses(
          std::vector<JSOutPoint> notes,