Factor out low-level build_closing_transaction

[rust-lightning] / lightning / src / ln / chan_utils.rs

diff --git a/lightning/src/ln/chan_utils.rs b/lightning/src/ln/chan_utils.rs
index 6bdef4307350d17c158ef2fe88dac121532db532..492bf89c70324a9379c8a16dddfca203c157f5a5 100644 (file)
--- a/lightning/src/ln/chan_utils.rs
+++ b/lightning/src/ln/chan_utils.rs
@@ -23,7 +23,7 @@ use bitcoin::hash_types::{Txid, PubkeyHash};
 use ln::{PaymentHash, PaymentPreimage};
 use ln::msgs::DecodeError;
 use util::ser::{Readable, Writeable, Writer};
-use util::byte_utils;
+use util::{byte_utils, transaction_utils};
 
 use bitcoin::hash_types::WPubkeyHash;
 use bitcoin::secp256k1::key::{SecretKey, PublicKey};
@@ -80,6 +80,50 @@ pub fn build_commitment_secret(commitment_seed: &[u8; 32], idx: u64) -> [u8; 32]
        res
 }
 
+/// Build a closing transaction
+pub fn build_closing_transaction(value_to_holder: u64, value_to_counterparty: u64, holder_shutdown_script: Script, counterparty_shutdown_script: Script, funding_outpoint: OutPoint) -> Transaction {
+       let txins = {
+               let mut ins: Vec<TxIn> = Vec::new();
+               ins.push(TxIn {
+                       previous_output: funding_outpoint,
+                       script_sig: Script::new(),
+                       sequence: 0xffffffff,
+                       witness: Vec::new(),
+               });
+               ins
+       };
+
+       let mut txouts: Vec<(TxOut, ())> = Vec::new();
+
+       if value_to_counterparty > 0 {
+               txouts.push((TxOut {
+                       script_pubkey: counterparty_shutdown_script,
+                       value: value_to_counterparty
+               }, ()));
+       }
+
+       if value_to_holder > 0 {
+               txouts.push((TxOut {
+                       script_pubkey: holder_shutdown_script,
+                       value: value_to_holder
+               }, ()));
+       }
+
+       transaction_utils::sort_outputs(&mut txouts, |_, _| { cmp::Ordering::Equal }); // Ordering doesnt matter if they used our pubkey...
+
+       let mut outputs: Vec<TxOut> = Vec::new();
+       for out in txouts.drain(..) {
+               outputs.push(out.0);
+       }
+
+       Transaction {
+               version: 2,
+               lock_time: 0,
+               input: txins,
+               output: outputs,
+       }
+}
+
 /// Implements the per-commitment secret storage scheme from
 /// [BOLT 3](https://github.com/lightningnetwork/lightning-rfc/blob/dcbf8583976df087c79c3ce0b535311212e6812d/03-transactions.md#efficient-per-commitment-secret-storage).
 ///