Factor out combine / finalize / extract PSBT helpers

Refactor the new CombinePSBT, FinalizePSBT, and FinalizeAndExtractPSBT
general-purpose functions out of the combinepsbt and finalizepsbt RPCs,
for use in the GUI code.

1 files changed, 27 insertions, 0 deletions

diff --git a/src/psbt.h b/src/psbt.h
index 4b7ea4383..e18790322 100644
--- a/src/psbt.h
+++ b/src/psbt.h
@@ -544,4 +544,31 @@ bool PSBTInputSigned(PSBTInput& input);
 /** Signs a PSBTInput, verifying that all provided data matches what is being signed. */
 bool SignPSBTInput(const SigningProvider& provider, PartiallySignedTransaction& psbt, int index, int sighash = SIGHASH_ALL);
 
+/**
+ * Finalizes a PSBT if possible, combining partial signatures.
+ *
+ * @param[in,out] &psbtx reference to PartiallySignedTransaction to finalize
+ * return True if the PSBT is now complete, false otherwise
+ */
+bool FinalizePSBT(PartiallySignedTransaction& psbtx);
+
+/**
+ * Finalizes a PSBT if possible, and extracts it to a CMutableTransaction if it could be finalized.
+ *
+ * @param[in]  &psbtx reference to PartiallySignedTransaction
+ * @param[out] result CMutableTransaction representing the complete transaction, if successful
+ * @return True if we successfully extracted the transaction, false otherwise
+ */
+bool FinalizeAndExtractPSBT(PartiallySignedTransaction& psbtx, CMutableTransaction& result);
+
+/**
+ * Combines PSBTs with the same underlying transaction, resulting in a single PSBT with all partial signatures from each input.
+ *
+ * @param[out] &out   the combined PSBT, if successful
+ * @param[out] &error reference to TransactionError to fill with error info on failure
+ * @param[in]  psbtxs the PSBTs to combine
+ * @return True if we successfully combined the transactions, false if they were not compatible
+ */
+bool CombinePSBTs(PartiallySignedTransaction& out, TransactionError& error, const std::vector<PartiallySignedTransaction>& psbtxs);
+
 #endif // BITCOIN_PSBT_H