Auto merge of #3579 - Eirik0:3577-generate-sprout-zkey, r=bitcartel

Make it clear that CWallet::GenerateNewZKey is Sprout specific

Closes https://github.com/zcash/zcash/issues/3577

When adding sapling support we had considered making the method `GenerateNewZKey` generic, but it ended up making more sense to add a second method `GenerateNewSaplingZKey` for sapling support.

This PR changes the name of `GenerateNewZKey` to `GenerateNewSproutZKey` and changes the return type from `libzcash::PaymentAddress` to `libzcash::SproutPaymentAddress` to make it more clear that this is what the method does.

src/wallet/gtest/test_wallet_zkeys.cpp

@@ -105,7 +105,7 @@ TEST(wallet_zkeys_tests, StoreAndLoadSaplingZkeys) {
 
 /**
  * This test covers methods on CWallet
- * GenerateNewZKey()
+ * GenerateNewSproutZKey()
  * AddSproutZKey()
  * LoadZKey()
  * LoadZKeyMetadata()
@@ -121,9 +121,7 @@ TEST(wallet_zkeys_tests, store_and_load_zkeys) {
     ASSERT_EQ(0, addrs.size());
 
     // wallet should have one key
-    auto address = wallet.GenerateNewZKey();
-    ASSERT_NE(boost::get<libzcash::SproutPaymentAddress>(&address), nullptr);
-    auto addr = boost::get<libzcash::SproutPaymentAddress>(address);
+    auto addr = wallet.GenerateNewSproutZKey();
     wallet.GetSproutPaymentAddresses(addrs);
     ASSERT_EQ(1, addrs.size());
 
@@ -236,7 +234,7 @@ TEST(wallet_zkeys_tests, write_zkey_direct_to_db) {
     ASSERT_EQ(0, addrs.size());
 
     // Add random key to the wallet
-    auto paymentAddress = wallet.GenerateNewZKey();
+    auto paymentAddress = wallet.GenerateNewSproutZKey();
 
     // wallet should have one key
     wallet.GetSproutPaymentAddresses(addrs);
@@ -353,9 +351,7 @@ TEST(wallet_zkeys_tests, write_cryptedzkey_direct_to_db) {
     ASSERT_EQ(0, addrs.size());
 
     // Add random key to the wallet
-    auto address = wallet.GenerateNewZKey();
-    ASSERT_NE(boost::get<libzcash::SproutPaymentAddress>(&address), nullptr);
-    auto paymentAddress = boost::get<libzcash::SproutPaymentAddress>(address);
+    auto paymentAddress = wallet.GenerateNewSproutZKey();
 
     // wallet should have one key
     wallet.GetSproutPaymentAddresses(addrs);
@@ -368,13 +364,11 @@ TEST(wallet_zkeys_tests, write_cryptedzkey_direct_to_db) {
     ASSERT_TRUE(wallet.EncryptWallet(strWalletPass));
     
     // adding a new key will fail as the wallet is locked
-    EXPECT_ANY_THROW(wallet.GenerateNewZKey());
+    EXPECT_ANY_THROW(wallet.GenerateNewSproutZKey());
     
     // unlock wallet and then add
     wallet.Unlock(strWalletPass);
-    auto address2 = wallet.GenerateNewZKey();
-    ASSERT_NE(boost::get<libzcash::SproutPaymentAddress>(&address2), nullptr);
-    auto paymentAddress2 = boost::get<libzcash::SproutPaymentAddress>(address2);
+    auto paymentAddress2 = wallet.GenerateNewSproutZKey();
 
     // Create a new wallet from the existing wallet path
     CWallet wallet2("wallet_crypted.dat");

src/wallet/rpcwallet.cpp

@@ -3166,7 +3166,7 @@ UniValue z_getnewaddress(const UniValue& params, bool fHelp)
     }
 
     if (addrType == ADDR_TYPE_SPROUT) {
-        return EncodePaymentAddress(pwalletMain->GenerateNewZKey());
+        return EncodePaymentAddress(pwalletMain->GenerateNewSproutZKey());
     } else if (addrType == ADDR_TYPE_SAPLING) {
         return EncodePaymentAddress(pwalletMain->GenerateNewSaplingZKey());
     } else {

src/wallet/wallet.cpp

@@ -82,23 +82,23 @@ const CWalletTx* CWallet::GetWalletTx(const uint256& hash) const
 }
 
 // Generate a new spending key and return its public payment address
-libzcash::PaymentAddress CWallet::GenerateNewZKey()
+libzcash::SproutPaymentAddress CWallet::GenerateNewSproutZKey()
 {
     AssertLockHeld(cs_wallet); // mapSproutZKeyMetadata
-    // TODO: Add Sapling support
+
     auto k = SproutSpendingKey::random();
     auto addr = k.address();
 
     // Check for collision, even though it is unlikely to ever occur
     if (CCryptoKeyStore::HaveSproutSpendingKey(addr))
-        throw std::runtime_error("CWallet::GenerateNewZKey(): Collision detected");
+        throw std::runtime_error("CWallet::GenerateNewSproutZKey(): Collision detected");
 
     // Create new metadata
     int64_t nCreationTime = GetTime();
     mapSproutZKeyMetadata[addr] = CKeyMetadata(nCreationTime);
 
     if (!AddSproutZKey(k))
-        throw std::runtime_error("CWallet::GenerateNewZKey(): AddSproutZKey failed");
+        throw std::runtime_error("CWallet::GenerateNewSproutZKey(): AddSproutZKey failed");
     return addr;
 }
 

src/wallet/wallet.h

@@ -1042,10 +1042,10 @@ public:
     void GetKeyBirthTimes(std::map<CKeyID, int64_t> &mapKeyBirth) const;
 
     /**
-      * ZKeys
+      * Sprout ZKeys
       */
-    //! Generates a new zaddr
-    libzcash::PaymentAddress GenerateNewZKey();
+    //! Generates a new Sprout zaddr
+    libzcash::SproutPaymentAddress GenerateNewSproutZKey();
     //! Adds spending key to the store, and saves it to disk
     bool AddSproutZKey(const libzcash::SproutSpendingKey &key);
     //! Adds spending key to the store, without saving it to disk (used by LoadWallet)