feat: expose Wallet::derivation_of_spk method

bdk-ffi/src/bdk.udl

@@ -376,11 +376,13 @@ interface Wallet {
   constructor(Descriptor descriptor, Descriptor change_descriptor, Connection connection);
 
   void cancel_tx([ByRef] Transaction tx);
-  
+
   u32? derivation_index(KeychainKind keychain);
 
   LocalOutput? get_utxo(OutPoint op);
-
+
+  KeychainAndIndex? derivation_of_spk(Script spk);
+
   AddressInfo reveal_next_address(KeychainKind keychain);
 
   AddressInfo peek_address(KeychainKind keychain, u32 index);
@@ -633,6 +635,11 @@ dictionary SentAndReceivedValues {
     Amount received;
 };
 
+dictionary KeychainAndIndex {
+    KeychainKind keychain;
+    u32 index;
+};
+
 // ------------------------------------------------------------------------
 // bdk_wallet crate - bitcoin re-exports
 // ------------------------------------------------------------------------

bdk-ffi/src/lib.rs

@@ -55,6 +55,7 @@ use crate::types::ConfirmationBlockTime;
 use crate::types::FullScanRequest;
 use crate::types::FullScanRequestBuilder;
 use crate::types::FullScanScriptInspector;
+use crate::types::KeychainAndIndex;
 use crate::types::LocalOutput;
 use crate::types::ScriptAmount;
 use crate::types::SentAndReceivedValues;

bdk-ffi/src/types.rs

@@ -232,3 +232,8 @@ pub struct SentAndReceivedValues {
     pub sent: Arc<Amount>,
     pub received: Arc<Amount>,
 }
+
+pub struct KeychainAndIndex {
+    pub keychain: KeychainKind,
+    pub index: u32,
+}

bdk-ffi/src/wallet.rs

@@ -6,8 +6,8 @@ use crate::error::{
 };
 use crate::store::Connection;
 use crate::types::{
-    AddressInfo, Balance, CanonicalTx, FullScanRequestBuilder, LocalOutput, SentAndReceivedValues,
-    SyncRequestBuilder, Update,
+    AddressInfo, Balance, CanonicalTx, FullScanRequestBuilder, KeychainAndIndex, LocalOutput,
+    SentAndReceivedValues, SyncRequestBuilder, Update,
 };
 
 use bitcoin_ffi::{Amount, FeeRate, OutPoint, Script};
@@ -72,6 +72,15 @@ impl Wallet {
         self.inner_mutex.lock().expect("wallet")
     }
 
+    pub fn derivation_of_spk(&self, spk: Arc<Script>) -> Option<KeychainAndIndex> {
+        self.get_wallet()
+            .derivation_of_spk(spk.0.clone())
+            .map(|(k, i)| KeychainAndIndex {
+                keychain: k,
+                index: i,
+            })
+    }
+
     pub fn cancel_tx(&self, tx: &Transaction) {
         self.get_wallet().cancel_tx(&tx.into())
     }