feat: add simple electrum client

bdk-ffi/Cargo.toml

@@ -20,6 +20,7 @@ default = ["uniffi/cli"]
 [dependencies]
 bdk = { version = "1.0.0-alpha.11", features = ["all-keys", "keys-bip39"] }
 bdk_esplora = { version = "0.13.0", default-features = false, features = ["std", "blocking", "blocking-https-rustls"] }
+bdk_electrum = { version = "0.13.0" }
 bdk_file_store = { version = "0.11.0" }
 
 uniffi = { version = "=0.26.1" }

bdk-ffi/src/bdk.udl

@@ -101,6 +101,27 @@ interface DescriptorKeyError {
   Bip32(string error_message);
 };
 
+[Error]
+interface ElectrumError {
+  IOError(string error_message);
+  Json(string error_message);
+  Hex(string error_message);
+  Protocol(string error_message);
+  Bitcoin(string error_message);
+  AlreadySubscribed();
+  NotSubscribed();
+  InvalidResponse(string error_message);
+  Message(string error_message);
+  InvalidDNSNameError(string domain);
+  MissingDomain();
+  AllAttemptsErrored();
+  SharedIOError(string error_message);
+  CouldntLockReader();
+  Mpsc();
+  CouldNotCreateConnection(string error_message);
+  RequestAlreadyConsumed();
+};
+
 [Error]
 interface EsploraError {
   Minreq(string error_message);
@@ -271,6 +292,9 @@ interface Wallet {
   [Throws=WalletCreationError]
   constructor(Descriptor descriptor, Descriptor? change_descriptor, string persistence_backend_path, Network network);
 
+  [Name=new_no_persist, Throws=DescriptorError]
+  constructor(Descriptor descriptor, Descriptor? change_descriptor, Network network);
+
   [Throws=PersistenceError]
   AddressInfo reveal_next_address(KeychainKind keychain);
 
@@ -464,6 +488,24 @@ interface EsploraClient {
   void broadcast([ByRef] Transaction transaction);
 };
 
+// ------------------------------------------------------------------------
+// bdk_electrum crate
+// ------------------------------------------------------------------------
+
+interface ElectrumClient {
+  [Throws=ElectrumError]
+  constructor(string url);
+
+  [Throws=ElectrumError]
+  Update full_scan(FullScanRequest full_scan_request, u64 stop_gap, u64 batch_size, boolean fetch_prev_txouts);
+
+  [Throws=ElectrumError]
+  Update sync(SyncRequest sync_request, u64 batch_size, boolean fetch_prev_txouts);
+
+  [Throws=ElectrumError]
+  string broadcast([ByRef] Transaction transaction);
+};
+
 // ------------------------------------------------------------------------
 // bdk-ffi-defined types
 // ------------------------------------------------------------------------

bdk-ffi/src/electrum.rs

@@ -0,0 +1,95 @@
+use crate::bitcoin::Transaction;
+use crate::error::ElectrumError;
+use crate::types::{FullScanRequest, SyncRequest};
+use crate::wallet::Update;
+
+use bdk::bitcoin::Transaction as BdkTransaction;
+use bdk::chain::spk_client::FullScanRequest as BdkFullScanRequest;
+use bdk::chain::spk_client::FullScanResult as BdkFullScanResult;
+use bdk::chain::spk_client::SyncRequest as BdkSyncRequest;
+use bdk::chain::spk_client::SyncResult as BdkSyncResult;
+use bdk::KeychainKind;
+use bdk_electrum::electrum_client::{Client as BdkBlockingClient, ElectrumApi};
+use bdk_electrum::{ElectrumExt, ElectrumFullScanResult, ElectrumSyncResult};
+
+use std::collections::BTreeMap;
+use std::sync::Arc;
+
+pub struct ElectrumClient(BdkBlockingClient);
+
+impl ElectrumClient {
+    pub fn new(url: String) -> Result<Self, ElectrumError> {
+        let client = BdkBlockingClient::new(url.as_str())?;
+        Ok(Self(client))
+    }
+
+    pub fn full_scan(
+        &self,
+        request: Arc<FullScanRequest>,
+        stop_gap: u64,
+        batch_size: u64,
+        fetch_prev_txouts: bool,
+    ) -> Result<Arc<Update>, ElectrumError> {
+        // using option and take is not ideal but the only way to take full ownership of the request
+        let request: BdkFullScanRequest<KeychainKind> = request
+            .0
+            .lock()
+            .unwrap()
+            .take()
+            .ok_or(ElectrumError::RequestAlreadyConsumed)?;
+
+        let electrum_result: ElectrumFullScanResult<KeychainKind> = self.0.full_scan(
+            request,
+            stop_gap as usize,
+            batch_size as usize,
+            fetch_prev_txouts,
+        )?;
+        let full_scan_result: BdkFullScanResult<KeychainKind> =
+            electrum_result.with_confirmation_time_height_anchor(&self.0)?;
+
+        let update = bdk::wallet::Update {
+            last_active_indices: full_scan_result.last_active_indices,
+            graph: full_scan_result.graph_update,
+            chain: Some(full_scan_result.chain_update),
+        };
+
+        Ok(Arc::new(Update(update)))
+    }
+
+    pub fn sync(
+        &self,
+        request: Arc<SyncRequest>,
+        batch_size: u64,
+        fetch_prev_txouts: bool,
+    ) -> Result<Arc<Update>, ElectrumError> {
+        // using option and take is not ideal but the only way to take full ownership of the request
+        let request: BdkSyncRequest = request
+            .0
+            .lock()
+            .unwrap()
+            .take()
+            .ok_or(ElectrumError::RequestAlreadyConsumed)?;
+
+        let electrum_result: ElectrumSyncResult =
+            self.0
+                .sync(request, batch_size as usize, fetch_prev_txouts)?;
+        let sync_result: BdkSyncResult =
+            electrum_result.with_confirmation_time_height_anchor(&self.0)?;
+
+        let update = bdk::wallet::Update {
+            last_active_indices: BTreeMap::default(),
+            graph: sync_result.graph_update,
+            chain: Some(sync_result.chain_update),
+        };
+
+        Ok(Arc::new(Update(update)))
+    }
+
+    pub fn broadcast(&self, transaction: &Transaction) -> Result<String, ElectrumError> {
+        let bdk_transaction: BdkTransaction = transaction.into();
+        self.0
+            .transaction_broadcast(&bdk_transaction)
+            .map_err(ElectrumError::from)
+            .map(|txid| txid.to_string())
+    }
+}