Rename xsk to expsk

xsk will be used for ZIP 32 extended spending keys, so renaming here to
reduce confusion.

src/gtest/test_transaction_builder.cpp

@@ -28,7 +28,7 @@ TEST(TransactionBuilder, Invoke)
     auto fvk_from = sk_from.full_viewing_key();
 
     auto sk = libzcash::SaplingSpendingKey::random();
-    auto xsk = sk.expanded_spending_key();
+    auto expsk = sk.expanded_spending_key();
     auto fvk = sk.full_viewing_key();
     auto ivk = fvk.in_viewing_key();
     libzcash::diversifier_t d = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
@@ -69,9 +69,9 @@ TEST(TransactionBuilder, Invoke)
     // Create a Sapling-only transaction
     // 0.0004 z-ZEC in, 0.00025 z-ZEC out, 0.0001 t-ZEC fee, 0.00005 z-ZEC change
     auto builder2 = TransactionBuilder(consensusParams, 2);
-    ASSERT_TRUE(builder2.AddSaplingSpend(xsk, note, anchor, witness));
+    ASSERT_TRUE(builder2.AddSaplingSpend(expsk, note, anchor, witness));
     // Check that trying to add a different anchor fails
-    ASSERT_FALSE(builder2.AddSaplingSpend(xsk, note, uint256(), witness));
+    ASSERT_FALSE(builder2.AddSaplingSpend(expsk, note, uint256(), witness));
 
     builder2.AddSaplingOutput(fvk, pk, 25000, {});
     auto maybe_tx2 = builder2.Build();
@@ -130,7 +130,7 @@ TEST(TransactionBuilder, FailsWithNegativeChange)
 
     // Generate dummy Sapling address
     auto sk = libzcash::SaplingSpendingKey::random();
-    auto xsk = sk.expanded_spending_key();
+    auto expsk = sk.expanded_spending_key();
     auto fvk = sk.full_viewing_key();
     auto pk = sk.default_address();
 
@@ -164,7 +164,7 @@ TEST(TransactionBuilder, FailsWithNegativeChange)
 
     // Fails if there is insufficient input
     // 0.0005 t-ZEC out, 0.0001 t-ZEC fee, 0.00059999 z-ZEC in
-    EXPECT_TRUE(builder.AddSaplingSpend(xsk, note, anchor, witness));
+    EXPECT_TRUE(builder.AddSaplingSpend(expsk, note, anchor, witness));
     EXPECT_FALSE(static_cast<bool>(builder.Build()));
 
     // Succeeds if there is sufficient input
@@ -185,7 +185,7 @@ TEST(TransactionBuilder, ChangeOutput)
 
     // Generate dummy Sapling address
     auto sk = libzcash::SaplingSpendingKey::random();
-    auto xsk = sk.expanded_spending_key();
+    auto expsk = sk.expanded_spending_key();
     auto pk = sk.default_address();
 
     // Generate dummy Sapling note
@@ -220,7 +220,7 @@ TEST(TransactionBuilder, ChangeOutput)
     {
         auto builder = TransactionBuilder(consensusParams, 1, &keystore);
         builder.AddTransparentInput(COutPoint(), scriptPubKey, 25000);
-        ASSERT_TRUE(builder.AddSaplingSpend(xsk, note, anchor, witness));
+        ASSERT_TRUE(builder.AddSaplingSpend(expsk, note, anchor, witness));
         auto maybe_tx = builder.Build();
         ASSERT_EQ(static_cast<bool>(maybe_tx), true);
         auto tx = maybe_tx.get();
@@ -282,7 +282,7 @@ TEST(TransactionBuilder, SetFee)
 
     // Generate dummy Sapling address
     auto sk = libzcash::SaplingSpendingKey::random();
-    auto xsk = sk.expanded_spending_key();
+    auto expsk = sk.expanded_spending_key();
     auto fvk = sk.full_viewing_key();
     auto pk = sk.default_address();
 
@@ -297,7 +297,7 @@ TEST(TransactionBuilder, SetFee)
     // Default fee
     {
         auto builder = TransactionBuilder(consensusParams, 1);
-        ASSERT_TRUE(builder.AddSaplingSpend(xsk, note, anchor, witness));
+        ASSERT_TRUE(builder.AddSaplingSpend(expsk, note, anchor, witness));
         builder.AddSaplingOutput(fvk, pk, 25000, {});
         auto maybe_tx = builder.Build();
         ASSERT_EQ(static_cast<bool>(maybe_tx), true);
@@ -314,7 +314,7 @@ TEST(TransactionBuilder, SetFee)
     // Configured fee
     {
         auto builder = TransactionBuilder(consensusParams, 1);
-        ASSERT_TRUE(builder.AddSaplingSpend(xsk, note, anchor, witness));
+        ASSERT_TRUE(builder.AddSaplingSpend(expsk, note, anchor, witness));
         builder.AddSaplingOutput(fvk, pk, 25000, {});
         builder.SetFee(20000);
         auto maybe_tx = builder.Build();

src/transaction_builder.cpp

@@ -12,10 +12,10 @@
 #include <librustzcash.h>
 
 SpendDescriptionInfo::SpendDescriptionInfo(
-    libzcash::SaplingExpandedSpendingKey xsk,
+    libzcash::SaplingExpandedSpendingKey expsk,
     libzcash::SaplingNote note,
     uint256 anchor,
-    ZCSaplingIncrementalWitness witness) : xsk(xsk), note(note), anchor(anchor), witness(witness)
+    ZCSaplingIncrementalWitness witness) : expsk(expsk), note(note), anchor(anchor), witness(witness)
 {
     librustzcash_sapling_generate_r(alpha.begin());
 }
@@ -29,7 +29,7 @@ TransactionBuilder::TransactionBuilder(
 }
 
 bool TransactionBuilder::AddSaplingSpend(
-    libzcash::SaplingExpandedSpendingKey xsk,
+    libzcash::SaplingExpandedSpendingKey expsk,
     libzcash::SaplingNote note,
     uint256 anchor,
     ZCSaplingIncrementalWitness witness)
@@ -41,7 +41,7 @@ bool TransactionBuilder::AddSaplingSpend(
         }
     }
 
-    spends.emplace_back(xsk, note, anchor, witness);
+    spends.emplace_back(expsk, note, anchor, witness);
     mtx.valueBalance += note.value();
     return true;
 }
@@ -131,7 +131,7 @@ boost::optional<CTransaction> TransactionBuilder::Build()
             // tChangeAddr has already been validated.
             assert(AddTransparentOutput(tChangeAddr.value(), change));
         } else if (!spends.empty()) {
-            auto fvk = spends[0].xsk.full_viewing_key();
+            auto fvk = spends[0].expsk.full_viewing_key();
             auto note = spends[0].note;
             libzcash::SaplingPaymentAddress changeAddr(note.d, note.pk_d);
             AddSaplingOutput(fvk, changeAddr, change, {});
@@ -150,7 +150,7 @@ boost::optional<CTransaction> TransactionBuilder::Build()
     for (auto spend : spends) {
         auto cm = spend.note.cm();
         auto nf = spend.note.nullifier(
-            spend.xsk.full_viewing_key(), spend.witness.position());
+            spend.expsk.full_viewing_key(), spend.witness.position());
         if (!(cm && nf)) {
             librustzcash_sapling_proving_ctx_free(ctx);
             return boost::none;
@@ -163,8 +163,8 @@ boost::optional<CTransaction> TransactionBuilder::Build()
         SpendDescription sdesc;
         if (!librustzcash_sapling_spend_proof(
                 ctx,
-                spend.xsk.full_viewing_key().ak.begin(),
-                spend.xsk.nsk.begin(),
+                spend.expsk.full_viewing_key().ak.begin(),
+                spend.expsk.nsk.begin(),
                 spend.note.d.data(),
                 spend.note.r.begin(),
                 spend.alpha.begin(),
@@ -247,7 +247,7 @@ boost::optional<CTransaction> TransactionBuilder::Build()
     // Create Sapling spendAuth and binding signatures
     for (size_t i = 0; i < spends.size(); i++) {
         librustzcash_sapling_spend_sig(
-            spends[i].xsk.ask.begin(),
+            spends[i].expsk.ask.begin(),
             spends[i].alpha.begin(),
             dataToBeSigned.begin(),
             mtx.vShieldedSpend[i].spendAuthSig.data());

src/transaction_builder.h

@@ -19,14 +19,14 @@
 #include <boost/optional.hpp>
 
 struct SpendDescriptionInfo {
-    libzcash::SaplingExpandedSpendingKey xsk;
+    libzcash::SaplingExpandedSpendingKey expsk;
     libzcash::SaplingNote note;
     uint256 alpha;
     uint256 anchor;
     ZCSaplingIncrementalWitness witness;
 
     SpendDescriptionInfo(
-        libzcash::SaplingExpandedSpendingKey xsk,
+        libzcash::SaplingExpandedSpendingKey expsk,
         libzcash::SaplingNote note,
         uint256 anchor,
         ZCSaplingIncrementalWitness witness);
@@ -76,7 +76,7 @@ public:
     // Returns false if the anchor does not match the anchor used by
     // previously-added Sapling spends.
     bool AddSaplingSpend(
-        libzcash::SaplingExpandedSpendingKey xsk,
+        libzcash::SaplingExpandedSpendingKey expsk,
         libzcash::SaplingNote note,
         uint256 anchor,
         ZCSaplingIncrementalWitness witness);