feat(chain)!: wrap TxGraph txs with Arc

Wrapping transactions as `Arc<Transaction>` allows us to share
transactions cheaply between the chain-source and receiving structures.
Therefore the chain-source can keep already-fetched transactions (save
bandwidth) and have a shared pointer to the transactions (save memory).

This is better than the current way we do things, which is to refer back
to the receiving structures mid-sync.

Documentation for `TxGraph` is also updated.

crates/bdk/src/wallet/mod.rs

@@ -942,7 +942,7 @@ impl<D> Wallet<D> {
     /// # let mut wallet: Wallet<()> = todo!();
     /// # let txid:Txid = todo!();
     /// let tx = wallet.get_tx(txid).expect("transaction").tx_node.tx;
-    /// let fee = wallet.calculate_fee(tx).expect("fee");
+    /// let fee = wallet.calculate_fee(&tx).expect("fee");
     /// ```
     ///
     /// ```rust, no_run
@@ -973,7 +973,7 @@ impl<D> Wallet<D> {
     /// # let mut wallet: Wallet<()> = todo!();
     /// # let txid:Txid = todo!();
     /// let tx = wallet.get_tx(txid).expect("transaction").tx_node.tx;
-    /// let fee_rate = wallet.calculate_fee_rate(tx).expect("fee rate");
+    /// let fee_rate = wallet.calculate_fee_rate(&tx).expect("fee rate");
     /// ```
     ///
     /// ```rust, no_run
@@ -982,7 +982,7 @@ impl<D> Wallet<D> {
     /// # let mut wallet: Wallet<()> = todo!();
     /// # let mut psbt: PartiallySignedTransaction = todo!();
     /// let tx = &psbt.clone().extract_tx();
-    /// let fee_rate = wallet.calculate_fee_rate(tx).expect("fee rate");
+    /// let fee_rate = wallet.calculate_fee_rate(&tx).expect("fee rate");
     /// ```
     /// [`insert_txout`]: Self::insert_txout
     pub fn calculate_fee_rate(&self, tx: &Transaction) -> Result<FeeRate, CalculateFeeError> {
@@ -1006,7 +1006,7 @@ impl<D> Wallet<D> {
     /// # let mut wallet: Wallet<()> = todo!();
     /// # let txid:Txid = todo!();
     /// let tx = wallet.get_tx(txid).expect("transaction").tx_node.tx;
-    /// let (sent, received) = wallet.sent_and_received(tx);
+    /// let (sent, received) = wallet.sent_and_received(&tx);
     /// ```
     ///
     /// ```rust, no_run
@@ -1067,7 +1067,7 @@ impl<D> Wallet<D> {
     pub fn get_tx(
         &self,
         txid: Txid,
-    ) -> Option<CanonicalTx<'_, Transaction, ConfirmationTimeHeightAnchor>> {
+    ) -> Option<CanonicalTx<'_, Arc<Transaction>, ConfirmationTimeHeightAnchor>> {
         let graph = self.indexed_graph.graph();
 
         Some(CanonicalTx {
@@ -1169,7 +1169,8 @@ impl<D> Wallet<D> {
     /// Iterate over the transactions in the wallet.
     pub fn transactions(
         &self,
-    ) -> impl Iterator<Item = CanonicalTx<'_, Transaction, ConfirmationTimeHeightAnchor>> + '_ {
+    ) -> impl Iterator<Item = CanonicalTx<'_, Arc<Transaction>, ConfirmationTimeHeightAnchor>> + '_
+    {
         self.indexed_graph
             .graph()
             .list_chain_txs(&self.chain, self.chain.tip().block_id())
@@ -1673,6 +1674,7 @@ impl<D> Wallet<D> {
         let mut tx = graph
             .get_tx(txid)
             .ok_or(BuildFeeBumpError::TransactionNotFound(txid))?
+            .as_ref()
             .clone();
 
         let pos = graph
@@ -1742,7 +1744,7 @@ impl<D> Wallet<D> {
                                 sequence: Some(txin.sequence),
                                 psbt_input: Box::new(psbt::Input {
                                     witness_utxo: Some(txout.clone()),
-                                    non_witness_utxo: Some(prev_tx.clone()),
+                                    non_witness_utxo: Some(prev_tx.as_ref().clone()),
                                     ..Default::default()
                                 }),
                             },
@@ -2283,7 +2285,7 @@ impl<D> Wallet<D> {
                 psbt_input.witness_utxo = Some(prev_tx.output[prev_output.vout as usize].clone());
             }
             if !desc.is_taproot() && (!desc.is_witness() || !only_witness_utxo) {
-                psbt_input.non_witness_utxo = Some(prev_tx.clone());
+                psbt_input.non_witness_utxo = Some(prev_tx.as_ref().clone());
             }
         }
         Ok(psbt_input)

crates/bdk/tests/wallet.rs

@@ -208,12 +208,12 @@ fn test_get_funded_wallet_sent_and_received() {
 
     let mut tx_amounts: Vec<(Txid, (u64, u64))> = wallet
         .transactions()
-        .map(|ct| (ct.tx_node.txid, wallet.sent_and_received(ct.tx_node.tx)))
+        .map(|ct| (ct.tx_node.txid, wallet.sent_and_received(&ct.tx_node)))
         .collect();
     tx_amounts.sort_by(|a1, a2| a1.0.cmp(&a2.0));
 
     let tx = wallet.get_tx(txid).expect("transaction").tx_node.tx;
-    let (sent, received) = wallet.sent_and_received(tx);
+    let (sent, received) = wallet.sent_and_received(&tx);
 
     // The funded wallet contains a tx with a 76_000 sats input and two outputs, one spending 25_000
     // to a foreign address and one returning 50_000 back to the wallet as change. The remaining 1000
@@ -227,7 +227,7 @@ fn test_get_funded_wallet_tx_fees() {
     let (wallet, txid) = get_funded_wallet(get_test_wpkh());
 
     let tx = wallet.get_tx(txid).expect("transaction").tx_node.tx;
-    let tx_fee = wallet.calculate_fee(tx).expect("transaction fee");
+    let tx_fee = wallet.calculate_fee(&tx).expect("transaction fee");
 
     // The funded wallet contains a tx with a 76_000 sats input and two outputs, one spending 25_000
     // to a foreign address and one returning 50_000 back to the wallet as change. The remaining 1000
@@ -240,7 +240,9 @@ fn test_get_funded_wallet_tx_fee_rate() {
     let (wallet, txid) = get_funded_wallet(get_test_wpkh());
 
     let tx = wallet.get_tx(txid).expect("transaction").tx_node.tx;
-    let tx_fee_rate = wallet.calculate_fee_rate(tx).expect("transaction fee rate");
+    let tx_fee_rate = wallet
+        .calculate_fee_rate(&tx)
+        .expect("transaction fee rate");
 
     // The funded wallet contains a tx with a 76_000 sats input and two outputs, one spending 25_000
     // to a foreign address and one returning 50_000 back to the wallet as change. The remaining 1000
@@ -1301,7 +1303,7 @@ fn test_add_foreign_utxo_where_outpoint_doesnt_match_psbt_input() {
             .add_foreign_utxo(
                 utxo2.outpoint,
                 psbt::Input {
-                    non_witness_utxo: Some(tx1),
+                    non_witness_utxo: Some(tx1.as_ref().clone()),
                     ..Default::default()
                 },
                 satisfaction_weight
@@ -1314,7 +1316,7 @@ fn test_add_foreign_utxo_where_outpoint_doesnt_match_psbt_input() {
             .add_foreign_utxo(
                 utxo2.outpoint,
                 psbt::Input {
-                    non_witness_utxo: Some(tx2),
+                    non_witness_utxo: Some(tx2.as_ref().clone()),
                     ..Default::default()
                 },
                 satisfaction_weight
@@ -1378,7 +1380,7 @@ fn test_add_foreign_utxo_only_witness_utxo() {
         let mut builder = builder.clone();
         let tx2 = wallet2.get_tx(txid2).unwrap().tx_node.tx;
         let psbt_input = psbt::Input {
-            non_witness_utxo: Some(tx2.clone()),
+            non_witness_utxo: Some(tx2.as_ref().clone()),
             ..Default::default()
         };
         builder
@@ -3006,7 +3008,8 @@ fn test_taproot_sign_using_non_witness_utxo() {
     let mut psbt = builder.finish().unwrap();
 
     psbt.inputs[0].witness_utxo = None;
-    psbt.inputs[0].non_witness_utxo = Some(wallet.get_tx(prev_txid).unwrap().tx_node.tx.clone());
+    psbt.inputs[0].non_witness_utxo =
+        Some(wallet.get_tx(prev_txid).unwrap().tx_node.as_ref().clone());
     assert!(
         psbt.inputs[0].non_witness_utxo.is_some(),
         "Previous tx should be present in the database"

crates/chain/Cargo.toml

@@ -15,7 +15,7 @@ readme = "README.md"
 [dependencies]
 # For no-std, remember to enable the bitcoin/no-std feature
 bitcoin = { version = "0.30.0", default-features = false }
-serde_crate = { package = "serde", version = "1", optional = true, features = ["derive"] }
+serde_crate = { package = "serde", version = "1", optional = true, features = ["derive", "rc"] }
 
 # Use hashbrown as a feature flag to have HashSet and HashMap from it.
 hashbrown = { version = "0.9.1", optional = true, features = ["serde"] }