Switch away from exceptions in refactored tx code

After refactoring general-purpose PSBT and transaction code out of RPC code,
for use in the GUI, it's no longer appropriate to throw exceptions. Instead we
now return bools for success, and take an output parameter for an error object.
We still use JSONRPCError() for the error objects, since only RPC callers
actually care about the error codes.

1 files changed, 30 insertions, 2 deletions

diff --git a/src/node/transaction.h b/src/node/transaction.h
index 1916c6db26..83354d9400 100644
--- a/src/node/transaction.h
+++ b/src/node/transaction.h
@@ -8,7 +8,35 @@
 #include <primitives/transaction.h>
 #include <uint256.h>
 
-/** Broadcast a transaction */
-uint256 BroadcastTransaction(CTransactionRef tx, bool allowhighfees = false);
+enum class TransactionError {
+    OK = 0,
+    UNKNOWN_ERROR,
+
+    MISSING_INPUTS,
+    ALREADY_IN_CHAIN,
+    P2P_DISABLED,
+    MEMPOOL_REJECTED,
+    MEMPOOL_ERROR,
+    INVALID_PSBT,
+    SIGHASH_MISMATCH,
+
+    ERROR_COUNT
+};
+
+#define TRANSACTION_ERR_LAST TransactionError::ERROR_COUNT
+
+const char* TransactionErrorString(const TransactionError error);
+
+/**
+ * Broadcast a transaction
+ *
+ * @param[in]  tx the transaction to broadcast
+ * @param[out] &txid the txid of the transaction, if successfully broadcast
+ * @param[out] &error reference to UniValue to fill with error info on failure
+ * @param[out] &err_string reference to std::string to fill with error string if available
+ * @param[in]  allowhighfees whether to allow fees exceeding maxTxFee
+ * return true on success, false on error (and fills in `error`)
+ */
+bool BroadcastTransaction(CTransactionRef tx, uint256& txid, TransactionError& error, std::string& err_string, bool allowhighfees = false);
 
 #endif // BITCOIN_NODE_TRANSACTION_H