Merge bitcoindevkit/bdk#1325: Add map_anchors for TxGraph

5489f905a434ecc06867603c7c421e3e50d993ca feat(chain): add `map_anchors` for `TxGraph` and `ChangeSet` (Antonio Yang)
022d5a21cff6c46fb869f8fd538b4026e531ee57 test(chain) use `Anchor` generic on `init_graph` (Antonio Yang)

Pull request description:

  ### Description
  Fix #1295

  ### Checklists
  #### All Submissions:
  * [X] I've signed all my commits
  * [X] I followed the [contribution guidelines](https://github.com/bitcoindevkit/bdk/blob/master/CONTRIBUTING.md)
  * [X] I ran `cargo fmt` and `cargo clippy` before committing

  #### New Features:

  * [ ] I've added tests for the new feature
  * [ ] I've added docs for the new feature

  #### Bugfixes:

  * [ ] This pull request breaks the existing API
  * [ ] I've added tests to reproduce the issue which are now passing
  * [ ] I'm linking the issue being fixed by this PR

ACKs for top commit:
  evanlinjin:
    ACK 5489f905a434ecc06867603c7c421e3e50d993ca
  LLFourn:
    ACK 5489f905a434ecc06867603c7c421e3e50d993ca

Tree-SHA512: c8327f2e7035a46208eb32c6da1f9f0bc3e8625168450c5b0b39f695268e42b0b9053b6eb97805b116328195d77af7ca9edb1f12206c50513fbe295dded542e7

crates/chain/src/tx_graph.rs

@@ -454,6 +454,21 @@ impl<A> TxGraph<A> {
     }
 }
 
+impl<A: Clone + Ord> TxGraph<A> {
+    /// Transform the [`TxGraph`] to have [`Anchor`]s of another type.
+    ///
+    /// This takes in a closure of signature `FnMut(A) -> A2` which is called for each [`Anchor`] to
+    /// transform it.
+    pub fn map_anchors<A2: Clone + Ord, F>(self, f: F) -> TxGraph<A2>
+    where
+        F: FnMut(A) -> A2,
+    {
+        let mut new_graph = TxGraph::<A2>::default();
+        new_graph.apply_changeset(self.initial_changeset().map_anchors(f));
+        new_graph
+    }
+}
+
 impl<A: Clone + Ord> TxGraph<A> {
     /// Construct a new [`TxGraph`] from a list of transactions.
     pub fn new(txs: impl IntoIterator<Item = Transaction>) -> Self {
@@ -1294,6 +1309,26 @@ impl<A: Ord> Append for ChangeSet<A> {
     }
 }
 
+impl<A: Ord> ChangeSet<A> {
+    /// Transform the [`ChangeSet`] to have [`Anchor`]s of another type.
+    ///
+    /// This takes in a closure of signature `FnMut(A) -> A2` which is called for each [`Anchor`] to
+    /// transform it.
+    pub fn map_anchors<A2: Ord, F>(self, mut f: F) -> ChangeSet<A2>
+    where
+        F: FnMut(A) -> A2,
+    {
+        ChangeSet {
+            txs: self.txs,
+            txouts: self.txouts,
+            anchors: BTreeSet::<(A2, Txid)>::from_iter(
+                self.anchors.into_iter().map(|(a, txid)| (f(a), txid)),
+            ),
+            last_seen: self.last_seen,
+        }
+    }
+}
+
 impl<A> AsRef<TxGraph<A>> for TxGraph<A> {
     fn as_ref(&self) -> &TxGraph<A> {
         self

crates/chain/tests/common/tx_template.rs

@@ -1,7 +1,7 @@
 use rand::distributions::{Alphanumeric, DistString};
 use std::collections::HashMap;
 
-use bdk_chain::{tx_graph::TxGraph, BlockId, SpkTxOutIndex};
+use bdk_chain::{tx_graph::TxGraph, Anchor, SpkTxOutIndex};
 use bitcoin::{
     locktime::absolute::LockTime, secp256k1::Secp256k1, OutPoint, ScriptBuf, Sequence, Transaction,
     TxIn, TxOut, Txid, Witness,
@@ -49,11 +49,11 @@ impl TxOutTemplate {
 }
 
 #[allow(dead_code)]
-pub fn init_graph<'a>(
-    tx_templates: impl IntoIterator<Item = &'a TxTemplate<'a, BlockId>>,
-) -> (TxGraph<BlockId>, SpkTxOutIndex<u32>, HashMap<&'a str, Txid>) {
+pub fn init_graph<'a, A: Anchor + Clone + 'a>(
+    tx_templates: impl IntoIterator<Item = &'a TxTemplate<'a, A>>,
+) -> (TxGraph<A>, SpkTxOutIndex<u32>, HashMap<&'a str, Txid>) {
     let (descriptor, _) = Descriptor::parse_descriptor(&Secp256k1::signing_only(), "tr(tprv8ZgxMBicQKsPd3krDUsBAmtnRsK3rb8u5yi1zhQgMhF1tR8MW7xfE4rnrbbsrbPR52e7rKapu6ztw1jXveJSCGHEriUGZV7mCe88duLp5pj/86'/1'/0'/0/*)").unwrap();
-    let mut graph = TxGraph::<BlockId>::default();
+    let mut graph = TxGraph::<A>::default();
     let mut spk_index = SpkTxOutIndex::default();
     (0..10).for_each(|index| {
         spk_index.insert_spk(
@@ -126,7 +126,7 @@ pub fn init_graph<'a>(
         spk_index.scan(&tx);
         let _ = graph.insert_tx(tx.clone());
         for anchor in tx_tmp.anchors.iter() {
-            let _ = graph.insert_anchor(tx.txid(), *anchor);
+            let _ = graph.insert_anchor(tx.txid(), anchor.clone());
         }
         if let Some(seen_at) = tx_tmp.last_seen {
             let _ = graph.insert_seen_at(tx.txid(), seen_at);

crates/chain/tests/test_tx_graph.rs

@@ -10,7 +10,9 @@ use bdk_chain::{
 use bitcoin::{
     absolute, hashes::Hash, BlockHash, OutPoint, ScriptBuf, Transaction, TxIn, TxOut, Txid,
 };
+use common::*;
 use core::iter;
+use rand::RngCore;
 use std::vec;
 
 #[test]
@@ -1178,3 +1180,86 @@ fn test_missing_blocks() {
         ),
     ]);
 }
+
+#[test]
+/// The `map_anchors` allow a caller to pass a function to reconstruct the [`TxGraph`] with any [`Anchor`],
+/// even though the function is non-deterministic.
+fn call_map_anchors_with_non_deterministic_anchor() {
+    #[derive(Debug, Default, Clone, PartialEq, Eq, Copy, PartialOrd, Ord, core::hash::Hash)]
+    /// A non-deterministic anchor
+    pub struct NonDeterministicAnchor {
+        pub anchor_block: BlockId,
+        pub non_deterministic_field: u32,
+    }
+
+    let template = [
+        TxTemplate {
+            tx_name: "tx1",
+            inputs: &[TxInTemplate::Bogus],
+            outputs: &[TxOutTemplate::new(10000, Some(1))],
+            anchors: &[block_id!(1, "A")],
+            last_seen: None,
+        },
+        TxTemplate {
+            tx_name: "tx2",
+            inputs: &[TxInTemplate::PrevTx("tx1", 0)],
+            outputs: &[TxOutTemplate::new(20000, Some(2))],
+            anchors: &[block_id!(2, "B")],
+            ..Default::default()
+        },
+        TxTemplate {
+            tx_name: "tx3",
+            inputs: &[TxInTemplate::PrevTx("tx2", 0)],
+            outputs: &[TxOutTemplate::new(30000, Some(3))],
+            anchors: &[block_id!(3, "C"), block_id!(4, "D")],
+            ..Default::default()
+        },
+    ];
+    let (graph, _, _) = init_graph(&template);
+    let new_graph = graph.clone().map_anchors(|a| NonDeterministicAnchor {
+        anchor_block: a,
+        // A non-deterministic value
+        non_deterministic_field: rand::thread_rng().next_u32(),
+    });
+
+    // Check all the details in new_graph reconstruct as well
+
+    let mut full_txs_vec: Vec<_> = graph.full_txs().collect();
+    full_txs_vec.sort();
+    let mut new_txs_vec: Vec<_> = new_graph.full_txs().collect();
+    new_txs_vec.sort();
+    let mut new_txs = new_txs_vec.iter();
+
+    for tx_node in full_txs_vec.iter() {
+        let new_txnode = new_txs.next().unwrap();
+        assert_eq!(new_txnode.txid, tx_node.txid);
+        assert_eq!(new_txnode.tx, tx_node.tx);
+        assert_eq!(
+            new_txnode.last_seen_unconfirmed,
+            tx_node.last_seen_unconfirmed
+        );
+        assert_eq!(new_txnode.anchors.len(), tx_node.anchors.len());
+
+        let mut new_anchors: Vec<_> = new_txnode.anchors.iter().map(|a| a.anchor_block).collect();
+        new_anchors.sort();
+        let mut old_anchors: Vec<_> = tx_node.anchors.iter().copied().collect();
+        old_anchors.sort();
+        assert_eq!(new_anchors, old_anchors);
+    }
+    assert!(new_txs.next().is_none());
+
+    let new_graph_anchors: Vec<_> = new_graph
+        .all_anchors()
+        .iter()
+        .map(|i| i.0.anchor_block)
+        .collect();
+    assert_eq!(
+        new_graph_anchors,
+        vec![
+            block_id!(1, "A"),
+            block_id!(2, "B"),
+            block_id!(3, "C"),
+            block_id!(4, "D"),
+        ]
+    );
+}