fix Move txouts_from_input_prev_txs helper to interactivetxs.rs

Author: optout21

lightning/src/ln/channel.rs

@@ -2241,8 +2241,6 @@ impl<SP: Deref> PendingV2Channel<SP> where SP::Target: SignerProvider {
 			funding_inputs.push(prev_funding_input);
 		}
 
-		let funding_inputs_prev_outputs = DualFundingChannelContext::txouts_from_input_prev_txs(&funding_inputs)?;
-
 		// Add output for funding tx
 		// Note: For the error case when the inputs are insufficient, it will be handled after
 		// the `calculate_change_output_value` call below
@@ -2277,7 +2275,7 @@ impl<SP: Deref> PendingV2Channel<SP> where SP::Target: SignerProvider {
 		};
 		let change_value_opt = calculate_change_output_value(
 			self.funding.is_outbound(), self.dual_funding_context.our_funding_satoshis,
-			&funding_inputs_prev_outputs, &funding_outputs,
+			&funding_inputs, &funding_outputs,
 			self.dual_funding_context.funding_feerate_sat_per_1000_weight,
 			change_script.minimal_non_dust().to_sat(),
 		)?;
@@ -4965,28 +4963,6 @@ pub(super) struct DualFundingChannelContext {
 	pub our_funding_inputs: Vec<(TxIn, TransactionU16LenLimited)>,
 }
 
-impl DualFundingChannelContext {
-	/// Obtain prev outputs for each supplied input and matching transaction.
-	/// Will error when a prev tx does not have an output for the specified vout.
-	/// Also checks for matching of transaction IDs.
-	fn txouts_from_input_prev_txs(inputs: &Vec<(TxIn, TransactionU16LenLimited)>) -> Result<Vec<&TxOut>, AbortReason> {
-		let mut prev_outputs: Vec<&TxOut> = Vec::with_capacity(inputs.len());
-		// Check that vouts exist for each TxIn in provided transactions.
-		for (idx, (txin, tx)) in inputs.iter().enumerate() {
-			let txid = tx.as_transaction().compute_txid();
-			if txin.previous_output.txid != txid {
-				return Err(AbortReason::ProvidedInputsAndPrevtxsTxIdMismatch(idx as u32));
-			}
-			if let Some(output) = tx.as_transaction().output.get(txin.previous_output.vout as usize) {
-				prev_outputs.push(output);
-			} else {
-				return Err(AbortReason::ProvidedInputsAndPrevtxsVoutNotFound(idx as u32));
-			}
-		}
-		Ok(prev_outputs)
-	}
-}
-
 // Holder designates channel data owned for the benefit of the user client.
 // Counterparty designates channel data owned by the another channel participant entity.
 pub(super) struct FundedChannel<SP: Deref> where SP::Target: SignerProvider {

lightning/src/ln/interactivetxs.rs

@@ -1695,6 +1695,22 @@ impl InteractiveTxConstructor {
 ///   `Err(AbortReason::InsufficientFees)`
 #[allow(dead_code)] // TODO(dual_funding): Remove once begin_interactive_funding_tx_construction() is used
 pub(super) fn calculate_change_output_value(
+	is_initiator: bool, our_contribution: u64,
+	funding_inputs: &Vec<(TxIn, TransactionU16LenLimited)>, funding_outputs: &Vec<OutputOwned>,
+	funding_feerate_sat_per_1000_weight: u32, change_output_dust_limit: u64,
+) -> Result<Option<u64>, AbortReason> {
+	let funding_input_prev_outs = txouts_from_input_prev_txs(&funding_inputs)?;
+	calculate_change_output_value_prevout(
+		is_initiator,
+		our_contribution,
+		&funding_input_prev_outs,
+		funding_outputs,
+		funding_feerate_sat_per_1000_weight,
+		change_output_dust_limit,
+	)
+}
+
+fn calculate_change_output_value_prevout(
 	is_initiator: bool, our_contribution: u64, funding_inputs_prev_outputs: &Vec<&TxOut>,
 	funding_outputs: &Vec<OutputOwned>, funding_feerate_sat_per_1000_weight: u32,
 	change_output_dust_limit: u64,
@@ -1734,12 +1750,34 @@ pub(super) fn calculate_change_output_value(
 	}
 }
 
+/// Obtain prev outputs for each supplied input and matching transaction.
+/// Will error when a prev tx does not have an output for the specified vout.
+/// Also checks for matching of transaction IDs.
+fn txouts_from_input_prev_txs(
+	inputs: &Vec<(TxIn, TransactionU16LenLimited)>,
+) -> Result<Vec<&TxOut>, AbortReason> {
+	let mut prev_outputs: Vec<&TxOut> = Vec::with_capacity(inputs.len());
+	// Check that vouts exist for each TxIn in provided transactions.
+	for (idx, (txin, tx)) in inputs.iter().enumerate() {
+		let txid = tx.as_transaction().compute_txid();
+		if txin.previous_output.txid != txid {
+			return Err(AbortReason::ProvidedInputsAndPrevtxsTxIdMismatch(idx as u32));
+		}
+		if let Some(output) = tx.as_transaction().output.get(txin.previous_output.vout as usize) {
+			prev_outputs.push(output);
+		} else {
+			return Err(AbortReason::ProvidedInputsAndPrevtxsVoutNotFound(idx as u32));
+		}
+	}
+	Ok(prev_outputs)
+}
+
 #[cfg(test)]
 mod tests {
 	use crate::chain::chaininterface::{fee_for_weight, FEERATE_FLOOR_SATS_PER_KW};
 	use crate::ln::channel::TOTAL_BITCOIN_SUPPLY_SATOSHIS;
 	use crate::ln::interactivetxs::{
-		calculate_change_output_value, generate_holder_serial_id, AbortReason,
+		calculate_change_output_value_prevout, generate_holder_serial_id, AbortReason,
 		HandleTxCompleteValue, InteractiveTxConstructor, InteractiveTxConstructorArgs,
 		InteractiveTxMessageSend, MAX_INPUTS_OUTPUTS_COUNT, MAX_RECEIVED_TX_ADD_INPUT_COUNT,
 		MAX_RECEIVED_TX_ADD_OUTPUT_COUNT,
@@ -2686,7 +2724,7 @@ mod tests {
 		let common_fees = 126;
 		{
 			// There is leftover for change
-			let res = calculate_change_output_value(
+			let res = calculate_change_output_value_prevout(
 				true,
 				our_contributed,
 				&input_prevouts,
@@ -2698,7 +2736,7 @@ mod tests {
 		}
 		{
 			// There is leftover for change, without common fees
-			let res = calculate_change_output_value(
+			let res = calculate_change_output_value_prevout(
 				false,
 				our_contributed,
 				&input_prevouts,
@@ -2710,7 +2748,7 @@ mod tests {
 		}
 		{
 			// Larger fee, smaller change
-			let res = calculate_change_output_value(
+			let res = calculate_change_output_value_prevout(
 				true,
 				our_contributed,
 				&input_prevouts,
@@ -2722,7 +2760,7 @@ mod tests {
 		}
 		{
 			// Insufficient inputs, no leftover
-			let res = calculate_change_output_value(
+			let res = calculate_change_output_value_prevout(
 				false,
 				130_000,
 				&input_prevouts,
@@ -2734,7 +2772,7 @@ mod tests {
 		}
 		{
 			// Very small leftover
-			let res = calculate_change_output_value(
+			let res = calculate_change_output_value_prevout(
 				false,
 				128_100,
 				&input_prevouts,
@@ -2746,7 +2784,7 @@ mod tests {
 		}
 		{
 			// Small leftover, but not dust
-			let res = calculate_change_output_value(
+			let res = calculate_change_output_value_prevout(
 				false,
 				128_100,
 				&input_prevouts,