Add global_xpubs to decodepsbt

Author: achow101

src/rpc/rawtransaction.cpp

@@ -3,6 +3,7 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
+#include <base58.h>
 #include <chain.h>
 #include <coins.h>
 #include <consensus/amount.h>
@@ -1075,6 +1076,15 @@ static RPCHelpMan decodepsbt()
                         {
                             {RPCResult::Type::ELISION, "", "The layout is the same as the output of decoderawtransaction."},
                         }},
+                        {RPCResult::Type::ARR, "global_xpubs", "",
+                        {
+                            {RPCResult::Type::OBJ, "", "",
+                            {
+                                {RPCResult::Type::STR, "xpub", "The extended public key this path corresponds to"},
+                                {RPCResult::Type::STR_HEX, "master_fingerprint", "The fingerprint of the master key"},
+                                {RPCResult::Type::STR, "path", "The path"},
+                            }},
+                        }},
                         {RPCResult::Type::NUM, "psbt_version", "The PSBT version number. Not to be confused with the unsigned transaction version"},
                         {RPCResult::Type::ARR, "proprietary", "The global proprietary map",
                         {
@@ -1225,6 +1235,23 @@ static RPCHelpMan decodepsbt()
     TxToUniv(CTransaction(*psbtx.tx), uint256(), tx_univ, false);
     result.pushKV("tx", tx_univ);
 
+    // Add the global xpubs
+    UniValue global_xpubs(UniValue::VARR);
+    for (std::pair<KeyOriginInfo, std::set<CExtPubKey>> xpub_pair : psbtx.m_xpubs) {
+        for (auto& xpub : xpub_pair.second) {
+            std::vector<unsigned char> ser_xpub;
+            ser_xpub.assign(BIP32_EXTKEY_WITH_VERSION_SIZE, 0);
+            xpub.EncodeWithVersion(ser_xpub.data());
+
+            UniValue keypath(UniValue::VOBJ);
+            keypath.pushKV("xpub", EncodeBase58Check(ser_xpub));
+            keypath.pushKV("master_fingerprint", HexStr(Span<unsigned char>(xpub_pair.first.fingerprint, xpub_pair.first.fingerprint + 4)));
+            keypath.pushKV("path", WriteHDKeypath(xpub_pair.first.path));
+            global_xpubs.push_back(keypath);
+        }
+    }
+    result.pushKV("global_xpubs", global_xpubs);
+
     // PSBT version
     result.pushKV("psbt_version", static_cast<uint64_t>(psbtx.GetVersion()));