Ad-hoc patch for libbitcoinconsensus that adds taproot (only for testing)

bitcoinconsensus-adhoc-add-taproot.diff

diff --git a/src/script/bitcoinconsensus.cpp b/src/script/bitcoinconsensus.cpp
index a9aa6a006..e0a79058e 100644
--- a/src/script/bitcoinconsensus.cpp
+++ b/src/script/bitcoinconsensus.cpp
@@ -9,6 +9,7 @@
 #include <pubkey.h>
 #include <script/interpreter.h>
 #include <version.h>
+#include <streams.h>
 
 namespace {
 
@@ -75,6 +76,7 @@ static bool verify_flags(unsigned int flags)
 
 static int verify_script(const unsigned char *scriptPubKey, unsigned int scriptPubKeyLen, CAmount amount,
                                     const unsigned char *txTo        , unsigned int txToLen,
+                                    const unsigned char *spentOutputs        , unsigned int spentOutputsLen,
                                     unsigned int nIn, unsigned int flags, bitcoinconsensus_error* err)
 {
     if (!verify_flags(flags)) {
@@ -88,22 +90,49 @@ static int verify_script(const unsigned char *scriptPubKey, unsigned int scriptP
         if (GetSerializeSize(tx, PROTOCOL_VERSION) != txToLen)
             return set_error(err, bitcoinconsensus_ERR_TX_SIZE_MISMATCH);
 
+        PrecomputedTransactionData txdata;
+
+        if (spentOutputsLen == 0) {
+            txdata.Init(tx, {});
+        }
+        else {
+            int numSpentOutputs = tx.vin.size();
+            std::vector<CTxOut> spent_outputs(numSpentOutputs);
+            std::vector<unsigned char> outs_data(spentOutputs, spentOutputs+spentOutputsLen);
+            CDataStream ss_data(MakeUCharSpan(outs_data), SER_NETWORK, PROTOCOL_VERSION);
+            //TODO catch exception if data is short for the number of outputs provided
+            for(int i = 0; i < numSpentOutputs; i++) {
+                spent_outputs[i].Unserialize(ss_data);
+            }
+            //TODO check that the number of outputs match the length (that all data was consumed)
+
+            txdata.Init(tx, std::move(spent_outputs));
+        }
+
         // Regardless of the verification result, the tx did not error.
         set_error(err, bitcoinconsensus_ERR_OK);
 
-        PrecomputedTransactionData txdata(tx);
         return VerifyScript(tx.vin[nIn].scriptSig, CScript(scriptPubKey, scriptPubKey + scriptPubKeyLen), &tx.vin[nIn].scriptWitness, flags, TransactionSignatureChecker(&tx, nIn, amount, txdata, MissingDataBehavior::FAIL), nullptr);
     } catch (const std::exception&) {
         return set_error(err, bitcoinconsensus_ERR_TX_DESERIALIZE); // Error deserializing
     }
 }
 
+int bitcoinconsensus_verify_script_taproot(const unsigned char *scriptPubKey, unsigned int scriptPubKeyLen, int64_t amount,
+                                    const unsigned char *txTo        , unsigned int txToLen,
+                                    const unsigned char *spentOutputs      , unsigned int spentOutputsLen,
+                                    unsigned int nIn, unsigned int flags, bitcoinconsensus_error* err)
+{
+    CAmount am(amount);
+    return ::verify_script(scriptPubKey, scriptPubKeyLen, am, txTo, txToLen, spentOutputs, spentOutputsLen, nIn, flags, err);
+}
+
 int bitcoinconsensus_verify_script_with_amount(const unsigned char *scriptPubKey, unsigned int scriptPubKeyLen, int64_t amount,
                                     const unsigned char *txTo        , unsigned int txToLen,
                                     unsigned int nIn, unsigned int flags, bitcoinconsensus_error* err)
 {
     CAmount am(amount);
-    return ::verify_script(scriptPubKey, scriptPubKeyLen, am, txTo, txToLen, nIn, flags, err);
+    return ::verify_script(scriptPubKey, scriptPubKeyLen, am, txTo, txToLen, 0, 0, nIn, flags, err);
 }
 
 
@@ -116,7 +145,7 @@ int bitcoinconsensus_verify_script(const unsigned char *scriptPubKey, unsigned i
     }
 
     CAmount am(0);
-    return ::verify_script(scriptPubKey, scriptPubKeyLen, am, txTo, txToLen, nIn, flags, err);
+    return ::verify_script(scriptPubKey, scriptPubKeyLen, am, txTo, txToLen, 0, 0, nIn, flags, err);
 }
 
 unsigned int bitcoinconsensus_version()
diff --git a/src/script/bitcoinconsensus.h b/src/script/bitcoinconsensus.h
index b6939127e..9f9c6f101 100644
--- a/src/script/bitcoinconsensus.h
+++ b/src/script/bitcoinconsensus.h
@@ -53,9 +53,10 @@ enum
     bitcoinconsensus_SCRIPT_FLAGS_VERIFY_CHECKLOCKTIMEVERIFY = (1U << 9), // enable CHECKLOCKTIMEVERIFY (BIP65)
     bitcoinconsensus_SCRIPT_FLAGS_VERIFY_CHECKSEQUENCEVERIFY = (1U << 10), // enable CHECKSEQUENCEVERIFY (BIP112)
     bitcoinconsensus_SCRIPT_FLAGS_VERIFY_WITNESS             = (1U << 11), // enable WITNESS (BIP141)
+    bitcoinconsensus_SCRIPT_VERIFY_TAPROOT = (1U << 17),
     bitcoinconsensus_SCRIPT_FLAGS_VERIFY_ALL                 = bitcoinconsensus_SCRIPT_FLAGS_VERIFY_P2SH | bitcoinconsensus_SCRIPT_FLAGS_VERIFY_DERSIG |
                                                                bitcoinconsensus_SCRIPT_FLAGS_VERIFY_NULLDUMMY | bitcoinconsensus_SCRIPT_FLAGS_VERIFY_CHECKLOCKTIMEVERIFY |
-                                                               bitcoinconsensus_SCRIPT_FLAGS_VERIFY_CHECKSEQUENCEVERIFY | bitcoinconsensus_SCRIPT_FLAGS_VERIFY_WITNESS
+                                                               bitcoinconsensus_SCRIPT_FLAGS_VERIFY_CHECKSEQUENCEVERIFY | bitcoinconsensus_SCRIPT_FLAGS_VERIFY_WITNESS | bitcoinconsensus_SCRIPT_VERIFY_TAPROOT
 };
 
 /// Returns 1 if the input nIn of the serialized transaction pointed to by
@@ -70,6 +71,11 @@ EXPORT_SYMBOL int bitcoinconsensus_verify_script_with_amount(const unsigned char
                                     const unsigned char *txTo        , unsigned int txToLen,
                                     unsigned int nIn, unsigned int flags, bitcoinconsensus_error* err);
 
+EXPORT_SYMBOL int bitcoinconsensus_verify_script_taproot(const unsigned char *scriptPubKey, unsigned int scriptPubKeyLen, int64_t amount,
+                                    const unsigned char *txTo        , unsigned int txToLen,
+                                    const unsigned char *spentOutputs      , unsigned int spentOutputsLen,
+                                    unsigned int nIn, unsigned int flags, bitcoinconsensus_error* err);
+
 EXPORT_SYMBOL unsigned int bitcoinconsensus_version();
 
 #ifdef __cplusplus