feat(wallet): add scan method on blocking esplora client

Author: thunderbiscuit

bdk-ffi/Cargo.lock

@@ -86,36 +86,6 @@ interface Wallet {
 
 interface Update {};
 
-// ------------------------------------------------------------------------
-// bdk crate - bitcoin reexports
-// ------------------------------------------------------------------------
-
-enum Network {
-  "Bitcoin",
-  "Testnet",
-  "Signet",
-  "Regtest",
-};
-
-enum WordCount {
-  "Words12",
-  "Words15",
-  "Words18",
-  "Words21",
-  "Words24",
-};
-
-interface Address {
-  [Throws=BdkError]
-  constructor(string address, Network network);
-
-  Network network();
-
-  string to_qr_uri();
-
-  string as_string();
-};
-
 // ------------------------------------------------------------------------
 // bdk crate - descriptor module
 // ------------------------------------------------------------------------
@@ -208,4 +178,43 @@ interface Descriptor {
 
 interface EsploraClient {
   constructor(string url);
+
+  [Throws=BdkError]
+  Update scan(Wallet wallet, u64 stop_gap, u64 parallel_requests);
+};
+
+// ------------------------------------------------------------------------
+// bdk crate - bitcoin re-exports
+// ------------------------------------------------------------------------
+
+interface Script {
+  constructor(sequence<u8> raw_output_script);
+
+  sequence<u8> to_bytes();
+};
+
+enum Network {
+  "Bitcoin",
+  "Testnet",
+  "Signet",
+  "Regtest",
+};
+
+enum WordCount {
+  "Words12",
+  "Words15",
+  "Words18",
+  "Words21",
+  "Words24",
+};
+
+interface Address {
+  [Throws=BdkError]
+  constructor(string address, Network network);
+
+  Network network();
+
+  string to_qr_uri();
+
+  string as_string();
 };

bdk-ffi/src/bdk.udl

@@ -0,0 +1,22 @@
+use bdk::bitcoin::blockdata::script::ScriptBuf as BdkScriptBuf;
+
+/// A Bitcoin script.
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct Script(pub(crate) BdkScriptBuf);
+
+impl Script {
+    pub fn new(raw_output_script: Vec<u8>) -> Self {
+        let script: BdkScriptBuf = raw_output_script.into();
+        Script(script)
+    }
+
+    pub fn to_bytes(&self) -> Vec<u8> {
+        self.0.to_bytes()
+    }
+}
+
+impl From<BdkScriptBuf> for Script {
+    fn from(script: BdkScriptBuf) -> Self {
+        Script(script)
+    }
+}

bdk-ffi/src/bitcoin.rs

@@ -1,4 +1,9 @@
+use crate::wallet::{Update, Wallet};
+use bdk::wallet::Update as BdkUpdate;
+use bdk::Error as BdkError;
 use bdk_esplora::esplora_client::{BlockingClient, Builder};
+use bdk_esplora::EsploraExt;
+use std::sync::Arc;
 
 pub struct EsploraClient(BlockingClient);
 
@@ -8,7 +13,44 @@ impl EsploraClient {
         Self(client)
     }
 
-    // pub fn scan();
+    // This is a temporary solution for scanning. The long-term solution involves not passing
+    // the wallet to the client at all.
+    pub fn scan(
+        &self,
+        wallet: Arc<Wallet>,
+        stop_gap: u64,
+        parallel_requests: u64,
+    ) -> Result<Arc<Update>, BdkError> {
+        let wallet = wallet.get_wallet();
+
+        let previous_tip = wallet.latest_checkpoint();
+        let keychain_spks = wallet.spks_of_all_keychains().into_iter().collect();
+
+        let (update_graph, last_active_indices) = self
+            .0
+            .scan_txs_with_keychains(
+                keychain_spks,
+                None,
+                None,
+                stop_gap as usize,
+                parallel_requests as usize,
+            )
+            .unwrap();
+
+        let missing_heights = update_graph.missing_heights(wallet.local_chain());
+        let chain_update = self
+            .0
+            .update_local_chain(previous_tip, missing_heights)
+            .unwrap();
+
+        let update = BdkUpdate {
+            last_active_indices,
+            graph: update_graph,
+            chain: Some(chain_update),
+        };
+
+        Ok(Arc::new(Update(update)))
+    }
 
     // pub fn sync();
 

bdk-ffi/src/esplora.rs

@@ -1,3 +1,4 @@
+mod bitcoin;
 mod descriptor;
 mod esplora;
 mod keys;
@@ -15,6 +16,7 @@ use bdk::KeychainKind;
 use std::sync::Arc;
 
 // TODO 6: Why are these imports required?
+use crate::bitcoin::Script;
 use crate::descriptor::Descriptor;
 use crate::esplora::EsploraClient;
 use crate::keys::DerivationPath;
@@ -24,7 +26,6 @@ use crate::keys::Mnemonic;
 use crate::wallet::Update;
 use crate::wallet::Wallet;
 use bdk::keys::bip39::WordCount;
-// use bdk_esplora::EsploraExt;
 
 uniffi::include_scaffolding!("bdk");
 

bdk-ffi/src/lib.rs

@@ -62,7 +62,6 @@ impl Wallet {
     }
 
     pub fn apply_update(&self, update: Arc<Update>) -> Result<(), BdkError> {
-        // self.get_wallet(). .apply_update(update.0).map_err(|e| BdkError::Generic(e.to_string()))
         self.get_wallet()
             .apply_update(update.0.clone())
             .map_err(|e| BdkError::Generic(e.to_string()))
@@ -639,7 +638,7 @@ pub struct Update(pub(crate) BdkUpdate);
 //             .map(Arc::new)
 //     }
 // }
-//
+
 // // The goal of these tests to to ensure `bdk-ffi` intermediate code correctly calls `bdk` APIs.
 // // These tests should not be used to verify `bdk` behavior that is already tested in the `bdk`
 // // crate.