Sapling operation: implemented spending from different shielded addresses.

furszy · furszy · commit 9639f8b3401b · 2020-11-10T14:43:26.000-03:00
diff --git a/src/sapling/address.hpp b/src/sapling/address.hpp
@@ -193,6 +193,7 @@ class SaplingExpandedSpendingKey {
     }
 
     SaplingFullViewingKey full_viewing_key() const;
+    bool IsNull() { return ask.IsNull() && nsk.IsNull() && ovk.IsNull(); }
 
     friend inline bool operator==(const SaplingExpandedSpendingKey& a, const SaplingExpandedSpendingKey& b) {
         return a.ask == b.ask && a.nsk == b.nsk && a.ovk == b.ovk;
diff --git a/src/sapling/sapling_operation.cpp b/src/sapling/sapling_operation.cpp
@@ -35,15 +35,56 @@ OperationResult SaplingOperation::checkTxValues(TxValues& txValues, bool isFromt
     return OperationResult(true);
 }
 
+OperationResult loadKeysFromShieldedFrom(const libzcash::SaplingPaymentAddress &addr,
+                                         libzcash::SaplingExpandedSpendingKey& expskOut,
+                                         uint256& ovkOut)
+{
+    // Get spending key for address
+    libzcash::SaplingExtendedSpendingKey sk;
+    if (!pwalletMain->GetSaplingExtendedSpendingKey(addr, sk)) {
+        return errorOut("Spending key not in the wallet");
+    }
+    expskOut = sk.expsk;
+    ovkOut = expskOut.full_viewing_key().ovk;
+    return OperationResult(true);
+}
+
+TxValues calculateTarget(std::vector<SendManyRecipient>& taddrRecipients,
+                         std::vector<SendManyRecipient>& shieldedAddrRecipients,
+                         CAmount fee)
+{
+    TxValues txValues;
+    for (SendManyRecipient &t : taddrRecipients) {
+        txValues.transOutTotal += t.amount;
+    }
+
+    // Add shielded outputs
+    for (const SendManyRecipient &t : shieldedAddrRecipients) {
+        txValues.shieldedOutTotal += t.amount;
+    }
+    txValues.target = txValues.shieldedOutTotal + txValues.transOutTotal + fee;
+    return txValues;
+}
+
 OperationResult SaplingOperation::build()
 {
 
-    bool isFromtAddress = fromAddress.isFromTAddress() || selectFromtaddrs;
+    bool isFromtAddress = fromAddress.isFromTAddress();
     bool isFromShielded = fromAddress.isFromSapAddress();
 
-    // It needs to have a from (for now at least)
     if (!isFromtAddress && !isFromShielded) {
-        return errorOut("From address parameter missing");
+        isFromtAddress = selectFromtaddrs;
+        isFromShielded = selectFromShield;
+
+        // It needs to have a from.
+        if (!isFromtAddress && !isFromShielded) {
+            return errorOut("From address parameter missing");
+        }
+
+        // Cannot be from both
+        if (isFromtAddress && isFromShielded) {
+            return errorOut("From address type cannot be shielded and transparent");
+        }
     }
 
     if (taddrRecipients.empty() && shieldedAddrRecipients.empty()) {
@@ -54,17 +95,25 @@ OperationResult SaplingOperation::build()
         return errorOut("Minconf cannot be zero when sending from shielded address");
     }
 
-    // Get necessary keys
+    // First calculate target values
+    TxValues txValues = calculateTarget(taddrRecipients, shieldedAddrRecipients, fee);
+    OperationResult result(false);
+    // Necessary keys
     libzcash::SaplingExpandedSpendingKey expsk;
     uint256 ovk;
     if (isFromShielded) {
-        // Get spending key for address
-        libzcash::SaplingExtendedSpendingKey sk;
-        if (!pwalletMain->GetSaplingExtendedSpendingKey(fromAddress.fromSapAddr.get(), sk)) {
-            return errorOut("Spending key not in the wallet");
+        // Try to get the sk and ovk if we know the address from, if we don't know it then this will be loaded in loadUnspentNotes
+        // using the sk of the first note input of the transaction.
+        if (fromAddress.isFromSapAddress()) {
+            // Get spending key for address
+            auto loadKeyRes = loadKeysFromShieldedFrom(fromAddress.fromSapAddr.get(), expsk, ovk);
+            if (!loadKeyRes) return loadKeyRes;
+        }
+
+        // Load and select notes to spend
+        if (!(result = loadUnspentNotes(txValues, expsk, ovk))) {
+            return result;
         }
-        expsk = sk.expsk;
-        ovk = expsk.full_viewing_key().ovk;
     } else {
         // Sending from a t-address, which we don't have an ovk for. Instead,
         // generate a common one from the HD seed. This ensures the data is
@@ -73,17 +122,13 @@ OperationResult SaplingOperation::build()
         ovk = pwalletMain->GetSaplingScriptPubKeyMan()->getCommonOVKFromSeed();
     }
 
-    // Results
-    TxValues txValues;
     // Add transparent outputs
     for (SendManyRecipient &t : taddrRecipients) {
-        txValues.transOutTotal += t.amount;
         txBuilder.AddTransparentOutput(DecodeDestination(t.address), t.amount);
     }
 
     // Add shielded outputs
     for (const SendManyRecipient &t : shieldedAddrRecipients) {
-        txValues.shieldedOutTotal += t.amount;
         auto addr = KeyIO::DecodePaymentAddress(t.address);
         assert(IsValidPaymentAddress(addr));
         auto to = boost::get<libzcash::SaplingPaymentAddress>(addr);
@@ -94,25 +139,13 @@ OperationResult SaplingOperation::build()
         txBuilder.AddSaplingOutput(ovk, to, t.amount, memo);
     }
 
-    // Load total
-    txValues.target = txValues.shieldedOutTotal + txValues.transOutTotal + fee;
-    OperationResult result(false);
-
     // If from address is a taddr, select UTXOs to spend
     // note: when spending coinbase utxos, you can only specify a single shielded addr as the change must go somewhere
     // and if there are multiple shielded addrs, we don't know where to send it.
     if (isFromtAddress && !(result = loadUtxos(txValues))) {
         return result;
     }
 
-    // If from a shielded addr, select notes to spend
-    if (isFromShielded) {
-        // Load notes
-        if (!(result = loadUnspentNotes(txValues, expsk))) {
-            return result;
-        }
-    }
-
     const auto& retCalc = checkTxValues(txValues, isFromtAddress, isFromShielded);
     if (!retCalc) return retCalc;
 
@@ -245,11 +278,12 @@ OperationResult SaplingOperation::loadUtxos(TxValues& txValues)
     return OperationResult(true);
 }
 
-OperationResult SaplingOperation::loadUnspentNotes(TxValues& txValues, const libzcash::SaplingExpandedSpendingKey& expsk)
+OperationResult SaplingOperation::loadUnspentNotes(TxValues& txValues,
+                                                   libzcash::SaplingExpandedSpendingKey& expsk,
+                                                   uint256& ovk)
 {
     std::vector<SaplingNoteEntry> saplingEntries;
-    libzcash::PaymentAddress paymentAddress(fromAddress.fromSapAddr.get());
-    pwalletMain->GetSaplingScriptPubKeyMan()->GetFilteredNotes(saplingEntries, paymentAddress, mindepth);
+    pwalletMain->GetSaplingScriptPubKeyMan()->GetFilteredNotes(saplingEntries, fromAddress.fromSapAddr, mindepth);
 
     for (const auto& entry : saplingEntries) {
         shieldedInputs.emplace_back(entry);
@@ -277,6 +311,11 @@ OperationResult SaplingOperation::loadUnspentNotes(TxValues& txValues, const lib
     std::vector<libzcash::SaplingNote> notes;
     CAmount sum = 0;
     for (const auto& t : shieldedInputs) {
+        // if null, load the first input sk
+        if (expsk.IsNull()) {
+            auto resLoadKeys = loadKeysFromShieldedFrom(t.address, expsk, ovk);
+            if (!resLoadKeys) return resLoadKeys;
+        }
         ops.emplace_back(t.op);
         notes.emplace_back(t.note);
         sum += t.note.value();
diff --git a/src/sapling/sapling_operation.h b/src/sapling/sapling_operation.h
@@ -51,6 +51,7 @@ class SaplingOperation {
     void setFromAddress(const libzcash::SaplingPaymentAddress&);
     // In case of no addressFrom filter selected, it will accept any utxo in the wallet as input.
     SaplingOperation* setSelectTransparentCoins(const bool select) { selectFromtaddrs = select; return this; };
+    SaplingOperation* setSelectShieldedCoins(const bool select) { selectFromShield = select; return this; };
     SaplingOperation* setTransparentRecipients(std::vector<SendManyRecipient>& vec) { taddrRecipients = std::move(vec); return this; };
     SaplingOperation* setShieldedRecipients(std::vector<SendManyRecipient>& vec) { shieldedAddrRecipients = std::move(vec); return this; } ;
     SaplingOperation* setFee(CAmount _fee) { fee = _fee; return this; }
@@ -70,6 +71,7 @@ class SaplingOperation {
     FromAddress fromAddress;
     // In case of no addressFrom filter selected, it will accept any utxo in the wallet as input.
     bool selectFromtaddrs{false};
+    bool selectFromShield{false};
     std::vector<SendManyRecipient> taddrRecipients;
     std::vector<SendManyRecipient> shieldedAddrRecipients;
     std::vector<COutput> transInputs;
@@ -85,7 +87,9 @@ class SaplingOperation {
     CTransaction finalTx;
 
     OperationResult loadUtxos(TxValues& values);
-    OperationResult loadUnspentNotes(TxValues& txValues, const libzcash::SaplingExpandedSpendingKey& expsk);
+    OperationResult loadUnspentNotes(TxValues& txValues,
+                                     libzcash::SaplingExpandedSpendingKey& expsk,
+                                     uint256& ovk);
     OperationResult checkTxValues(TxValues& txValues, bool isFromtAddress, bool isFromShielded);
 };
 

Original file line number	Diff line number	Diff line change
`@@ -193,6 +193,7 @@ class SaplingExpandedSpendingKey {`
`193`	`193`	`}`
`194`	`194`
`195`	`195`	`SaplingFullViewingKey full_viewing_key() const;`
	`196`	`+ bool IsNull() { return ask.IsNull() && nsk.IsNull() && ovk.IsNull(); }`
`196`	`197`
`197`	`198`	`friend inline bool operator==(const SaplingExpandedSpendingKey& a, const SaplingExpandedSpendingKey& b) {`
`198`	`199`	`return a.ask == b.ask && a.nsk == b.nsk && a.ovk == b.ovk;`