Full scan up to derivation index

lwk_bindings/src/electrum_client.rs

@@ -36,8 +36,19 @@ impl ElectrumClient {
     }
 
     pub fn full_scan(&self, wollet: &Wollet) -> Result<Option<Arc<Update>>, LwkError> {
+        self.full_scan_to_index(wollet, 0)
+    }
+
+    pub fn full_scan_to_index(
+        &self,
+        wollet: &Wollet,
+        index: u32,
+    ) -> Result<Option<Arc<Update>>, LwkError> {
         let wollet = wollet.inner_wollet()?;
-        let update: Option<lwk_wollet::Update> = self.inner.lock()?.full_scan(&wollet.state())?;
+        let update: Option<lwk_wollet::Update> = self
+            .inner
+            .lock()?
+            .full_scan_to_index(&wollet.state(), index)?;
         Ok(update.map(Into::into).map(Arc::new))
     }
 }

lwk_bindings/src/esplora_client.rs

@@ -35,8 +35,19 @@ impl EsploraClient {
     }
 
     pub fn full_scan(&self, wollet: &Wollet) -> Result<Option<Arc<Update>>, LwkError> {
+        self.full_scan_to_index(wollet, 0)
+    }
+
+    pub fn full_scan_to_index(
+        &self,
+        wollet: &Wollet,
+        index: u32,
+    ) -> Result<Option<Arc<Update>>, LwkError> {
         let wollet = wollet.inner_wollet()?;
-        let update: Option<lwk_wollet::Update> = self.inner.lock()?.full_scan(&wollet.state())?;
+        let update: Option<lwk_wollet::Update> = self
+            .inner
+            .lock()?
+            .full_scan_to_index(&wollet.state(), index)?;
         Ok(update.map(Into::into).map(Arc::new))
     }
 }

lwk_wollet/src/clients/blocking/mod.rs

@@ -58,6 +58,7 @@ pub trait BlockchainBackend {
         &mut self,
         descriptor: &WolletDescriptor,
         state: &S,
+        index: u32,
     ) -> Result<Data, Error> {
         let mut data = Data::default();
 
@@ -91,7 +92,7 @@ pub trait BlockchainBackend {
 
                 let flattened: Vec<History> = result.into_iter().flatten().collect();
 
-                if flattened.is_empty() {
+                if flattened.is_empty() && index <= 1 + batch_count * BATCH_SIZE {
                     break;
                 }
 
@@ -127,6 +128,18 @@ pub trait BlockchainBackend {
 
     /// Scan the blockchain for the scripts generated by a watch-only wallet
     fn full_scan<S: WolletState>(&mut self, state: &S) -> Result<Option<Update>, Error> {
+        self.full_scan_to_index(state, 0)
+    }
+
+    /// Scan the blockchain for the scripts generated by a watch-only wallet
+    ///
+    /// Will scan up to a specified derivation index before stopping to prevent gap limit issues
+    /// if the number of addresses derived is already known
+    fn full_scan_to_index<S: WolletState>(
+        &mut self,
+        state: &S,
+        index: u32,
+    ) -> Result<Option<Update>, Error> {
         let descriptor = state.descriptor();
 
         let Data {
@@ -139,11 +152,13 @@ pub trait BlockchainBackend {
         } = if self.capabilities().contains(&Capability::Waterfalls) {
             match self.get_history_waterfalls(&descriptor, state) {
                 Ok(d) => d,
-                Err(Error::UsingWaterfallsWithElip151) => self.get_history(&descriptor, state)?,
+                Err(Error::UsingWaterfallsWithElip151) => {
+                    self.get_history(&descriptor, state, index)?
+                }
                 Err(e) => return Err(e),
             }
         } else {
-            self.get_history(&descriptor, state)?
+            self.get_history(&descriptor, state, index)?
         };
 
         let tip = self.tip()?;

lwk_wollet/src/lib.rs

@@ -119,6 +119,8 @@ pub use crate::wollet::{Tip, Wollet};
 #[cfg(feature = "electrum")]
 pub use crate::wollet::full_scan_with_electrum_client;
 #[cfg(feature = "electrum")]
+pub use crate::wollet::full_scan_to_index_with_electrum_client;
+#[cfg(feature = "electrum")]
 pub use clients::blocking::electrum_client::{ElectrumClient, ElectrumOptions, ElectrumUrl};
 
 #[cfg(feature = "esplora")]

lwk_wollet/src/wollet.rs

@@ -784,10 +784,19 @@ fn tx_balance(
 pub fn full_scan_with_electrum_client(
     wollet: &mut Wollet,
     electrum_client: &mut crate::ElectrumClient,
+) -> Result<(), Error> {
+    full_scan_to_index_with_electrum_client(wollet, 0, electrum_client)
+}
+
+#[cfg(feature = "electrum")]
+pub fn full_scan_to_index_with_electrum_client(
+    wollet: &mut Wollet,
+    index: u32,
+    electrum_client: &mut crate::ElectrumClient,
 ) -> Result<(), Error> {
     use crate::clients::blocking::BlockchainBackend;
 
-    let update = electrum_client.full_scan(wollet)?;
+    let update = electrum_client.full_scan_to_index(wollet, index)?;
     if let Some(update) = update {
         wollet.apply_update(update)?
     }