Merge #13723: PSBT key path cleanups

917353c8b0 Make SignPSBTInput operate on a private SignatureData object (Pieter Wuille)
cad5dd2368 Pass HD path data through SignatureData (Pieter Wuille)
03a99586a3 Implement key origin lookup in CWallet (Pieter Wuille)
3b01efa0d1 [MOVEONLY] Move ParseHDKeypath to utilstrencodings (Pieter Wuille)
81e1dd5ce1 Generalize PublicOnlySigningProvider into HidingSigningProvider (Pieter Wuille)
84f1f1bfdf Make SigningProvider expose key origin information (Pieter Wuille)
611ab307fb Introduce KeyOriginInfo for fingerprint + path (Pieter Wuille)

Pull request description:

  This PR adds "key origin" (master fingeprint + key path) information to what is exposed from `SigningProvider`s, allowing this information to be used by the generic PSBT code instead of having the RPC pull it directly from the wallet.

  This is also a preparation to having PSBT interact with output descriptors, which can then directly expose key origin information for the scripts they generate.

Tree-SHA512: c718382ba8ba2d6fc9a32c062bd4cff08b6f39b133838aa03115c39aeca0f654c7cc3ec72d87005bf8306e550824cd8eb9d60f0bd41784a3e22e17b2afcfe833

src/wallet/wallet.cpp

@@ -4469,3 +4469,29 @@ std::vector<OutputGroup> CWallet::GroupOutputs(const std::vector<COutput>& outpu
     }
     return groups;
 }
+
+bool CWallet::GetKeyOrigin(const CKeyID& keyID, KeyOriginInfo& info) const
+{
+    CKeyMetadata meta;
+    {
+        LOCK(cs_wallet);
+        auto it = mapKeyMetadata.find(keyID);
+        if (it != mapKeyMetadata.end()) {
+            meta = it->second;
+        }
+    }
+    if (!meta.hdKeypath.empty()) {
+        if (!ParseHDKeypath(meta.hdKeypath, info.path)) return false;
+        // Get the proper master key id
+        CKey key;
+        GetKey(meta.hd_seed_id, key);
+        CExtKey masterKey;
+        masterKey.SetSeed(key.begin(), key.size());
+        // Compute identifier
+        CKeyID masterid = masterKey.key.GetPubKey().GetID();
+        std::copy(masterid.begin(), masterid.begin() + 4, info.fingerprint);
+    } else { // Single pubkeys get the master fingerprint of themselves
+        std::copy(keyID.begin(), keyID.begin() + 4, info.fingerprint);
+    }
+    return true;
+}