feat(wallet): add sync_request and full_scan_request functions

crates/bdk/src/wallet/error.rs

@@ -44,9 +44,9 @@ impl fmt::Display for MiniscriptPsbtError {
 impl std::error::Error for MiniscriptPsbtError {}
 
 #[derive(Debug)]
-/// Error returned from [`TxBuilder::finish`]
+/// Error returned by [`TxBuilder::finish`]
 ///
-/// [`TxBuilder::finish`]: crate::wallet::tx_builder::TxBuilder::finish
+/// [`TxBuilder::finish`]: super::tx_builder::TxBuilder::finish
 pub enum CreateTxError<P> {
     /// There was a problem with the descriptors passed in
     Descriptor(DescriptorError),
@@ -246,9 +246,7 @@ impl<P> From<coin_selection::Error> for CreateTxError<P> {
 impl<P: core::fmt::Display + core::fmt::Debug> std::error::Error for CreateTxError<P> {}
 
 #[derive(Debug)]
-/// Error returned from [`Wallet::build_fee_bump`]
-///
-/// [`Wallet::build_fee_bump`]: super::Wallet::build_fee_bump
+/// Error returned by [`Wallet::build_fee_bump`]
 pub enum BuildFeeBumpError {
     /// Happens when trying to spend an UTXO that is not in the internal database
     UnknownUtxo(OutPoint),

crates/bdk/src/wallet/mod.rs

@@ -43,6 +43,7 @@ use core::ops::Deref;
 use descriptor::error::Error as DescriptorError;
 use miniscript::psbt::{PsbtExt, PsbtInputExt, PsbtInputSatisfier};
 
+use bdk_chain::spk_client::{FullScanRequest, SyncRequest};
 use bdk_chain::tx_graph::CalculateFeeError;
 
 pub mod coin_selection;
@@ -2485,6 +2486,70 @@ impl<D> Wallet<D> {
             .batch_insert_relevant_unconfirmed(unconfirmed_txs);
         self.persist.stage(ChangeSet::from(indexed_graph_changeset));
     }
+
+    /// Create a [`SyncRequest`] for this wallet.
+    ///
+    /// This is the first step when performing a spk-based wallet sync, the returned [`SyncRequest`] collects
+    /// the wallet keychain all or unused script pub keys, unconfirmed transaction id, UTXOs and local
+    /// chain checkpoint data needed to start a blockchain sync with a blockchain client. For a faster
+    /// sync set `unused_spks_only` to true to only get updates for unused wallet script pub keys (addresses).
+    pub fn sync_request(&self, unused_spks_only: bool) -> SyncRequest {
+        let local_chain = self.local_chain().clone();
+
+        // Sync only unused SPKs
+        let spks = if unused_spks_only {
+            self.spk_index()
+                .unused_spks()
+                .map(|(_keychain, _index, script)| ScriptBuf::from(script))
+                .collect::<Vec<ScriptBuf>>()
+        }
+        // Sync all SPKs
+        else {
+            self.spk_index()
+                .revealed_spks()
+                .map(|(_keychain, _index, script)| ScriptBuf::from(script))
+                .collect::<Vec<ScriptBuf>>()
+        };
+
+        // Sync UTXOs
+        // We want to search for whether our UTXOs are spent, and spent by which transaction.
+        let outpoints: Vec<OutPoint> = self.list_unspent().map(|utxo| utxo.outpoint).collect();
+
+        // Sync unconfirmed TX
+        // We want to search for whether our unconfirmed transactions are now confirmed.
+        let txids: Vec<Txid> = self
+            .transactions()
+            .filter(|canonical_tx| !canonical_tx.chain_position.is_confirmed())
+            .map(|canonical_tx| canonical_tx.tx_node.txid)
+            .collect();
+
+        SyncRequest {
+            spks,
+            txids,
+            outpoints,
+            local_chain,
+        }
+    }
+
+    /// Create a [`FullScanRequest] for this wallet.
+    ///
+    /// This is the first step when performing a spk-based wallet full scan, the returned [`FullScanRequest]
+    /// collects iterators for the wallet's keychain script pub keys, and local chain checkpoint
+    /// data needed to start a blockchain full scan with a blockchain client.
+    ///
+    /// This operation is generally only used when importing or restoring a previously used wallet
+    /// in which the list of used scripts is not known.
+    pub fn full_scan_request(
+        &self,
+    ) -> FullScanRequest<KeychainKind, impl Iterator<Item = (u32, ScriptBuf)> + Clone> {
+        let spks_by_keychain = self.all_unbounded_spk_iters();
+        let local_chain = self.local_chain().clone();
+
+        FullScanRequest {
+            spks_by_keychain,
+            local_chain,
+        }
+    }
 }
 
 impl<D> AsRef<bdk_chain::tx_graph::TxGraph<ConfirmationTimeHeightAnchor>> for Wallet<D> {