Break builder pattern and expose setters via bindings

Unfortunately there is no good way of exposing the builder pattern via
Uniffi bindings currenlty. We therefore resort to internal mutability
and using setters on the `Builder` object.

Author: tnull

README.md

@@ -11,14 +11,15 @@ The primary abstraction of the library is the `Node`, which can be retrieved by
 use ldk_node::{Builder, NetAddress};
 use ldk_node::lightning_invoice::Invoice;
 use ldk_node::bitcoin::secp256k1::PublicKey;
+use ldk_node::bitcoin::Network;
 use std::str::FromStr;
 
 fn main() {
-	let node = Builder::new()
-		.set_network("testnet")
-		.set_esplora_server_url("https://blockstream.info/testnet/api".to_string())
-		.build();
+	let mut builder = Builder::new();
+	builder.set_network(Network::Testnet);
+	builder.set_esplora_server_url("https://blockstream.info/testnet/api".to_string());
 
+	let node = builder.build();
 	node.start().unwrap();
 
 	let _funding_address = node.new_funding_address();

bindings/ldk_node.udl

@@ -13,6 +13,15 @@ interface Builder {
 	constructor();
 	[Name=from_config]
 	constructor(Config config);
+	void set_entropy_seed_path(string seed_path);
+	void set_entropy_seed_bytes(sequence<u8> seed_bytes);
+	void set_entropy_bip39_mnemonic(Mnemonic mnemonic, string? passphrase);
+	void set_gossip_source_p2p();
+	void set_gossip_source_rgs(string rgs_server_url);
+	void set_storage_dir_path(string storage_dir_path);
+	void set_esplora_server_url(string esplora_server_url);
+	void set_network(Network network);
+	void set_listening_address(NetAddress listening_address);
 	Node build();
 };
 
@@ -85,6 +94,7 @@ enum NodeError {
 	"InvalidAddress",
 	"InvalidNetAddress",
 	"InvalidPublicKey",
+	"InvalidSecretKey",
 	"InvalidPaymentHash",
 	"InvalidPaymentPreimage",
 	"InvalidPaymentSecret",
@@ -188,3 +198,6 @@ typedef string UserChannelId;
 
 [Custom]
 typedef string Network;
+
+[Custom]
+typedef string Mnemonic;

src/error.rs

@@ -37,6 +37,8 @@ pub enum Error {
 	InvalidNetAddress,
 	/// The given public key is invalid.
 	InvalidPublicKey,
+	/// The given secret key is invalid.
+	InvalidSecretKey,
 	/// The given payment hash is invalid.
 	InvalidPaymentHash,
 	/// The given payment preimage is invalid.
@@ -79,6 +81,7 @@ impl fmt::Display for Error {
 			Self::InvalidAddress => write!(f, "The given address is invalid."),
 			Self::InvalidNetAddress => write!(f, "The given network address is invalid."),
 			Self::InvalidPublicKey => write!(f, "The given public key is invalid."),
+			Self::InvalidSecretKey => write!(f, "The given secret key is invalid."),
 			Self::InvalidPaymentHash => write!(f, "The given payment hash is invalid."),
 			Self::InvalidPaymentPreimage => write!(f, "The given payment preimage is invalid."),
 			Self::InvalidPaymentSecret => write!(f, "The given payment secret is invalid."),

src/lib.rs

@@ -29,14 +29,15 @@
 //! use ldk_node::{Builder, NetAddress};
 //! use ldk_node::lightning_invoice::Invoice;
 //! use ldk_node::bitcoin::secp256k1::PublicKey;
+//! use ldk_node::bitcoin::Network;
 //! use std::str::FromStr;
 //!
 //! fn main() {
-//! 	let node = Builder::new()
-//! 		.set_network("testnet")
-//! 		.set_esplora_server_url("https://blockstream.info/testnet/api".to_string())
-//! 		.build();
+//! 	let mut builder = Builder::new();
+//! 	builder.set_network(Network::Testnet);
+//! 	builder.set_esplora_server_url("https://blockstream.info/testnet/api".to_string());
 //!
+//! 	let node = builder.build();
 //! 	node.start().unwrap();
 //!
 //! 	let _funding_address = node.new_funding_address();
@@ -144,6 +145,8 @@ use bitcoin::hashes::Hash;
 use bitcoin::secp256k1::PublicKey;
 use bitcoin::Network;
 
+use bip39::Mnemonic;
+
 use bitcoin::{Address, BlockHash, OutPoint, Txid};
 
 use rand::Rng;
@@ -199,7 +202,7 @@ impl Default for Config {
 			storage_dir_path: "/tmp/ldk_node/".to_string(),
 			esplora_server_url: "http://localhost:3002".to_string(),
 			network: Network::Regtest,
-			listening_address: Some("0.0.0.0:9735".parse().unwrap()),
+			listening_address: Some(NetAddress::from_str("0.0.0.0:9735").unwrap()),
 			default_cltv_expiry_delta: 144,
 		}
 	}
@@ -209,7 +212,7 @@ impl Default for Config {
 enum EntropySourceConfig {
 	SeedFile(String),
 	SeedBytes([u8; WALLET_KEYS_SEED_LEN]),
-	Bip39Mnemonic { mnemonic: bip39::Mnemonic, passphrase: Option<String> },
+	Bip39Mnemonic { mnemonic: Mnemonic, passphrase: Option<String> },
 }
 
 #[derive(Debug, Clone)]
@@ -220,106 +223,105 @@ enum GossipSourceConfig {
 
 /// A builder for an [`Node`] instance, allowing to set some configuration and module choices from
 /// the getgo.
-#[derive(Debug, Clone)]
+#[derive(Debug)]
 pub struct Builder {
-	config: Config,
-	entropy_source_config: Option<EntropySourceConfig>,
-	gossip_source_config: Option<GossipSourceConfig>,
+	config: Mutex<Config>,
+	entropy_source_config: Mutex<Option<EntropySourceConfig>>,
+	gossip_source_config: Mutex<Option<GossipSourceConfig>>,
 }
 
 impl Builder {
 	/// Creates a new builder instance with the default configuration.
 	pub fn new() -> Self {
-		let config = Config::default();
-		let entropy_source_config = None;
-		let gossip_source_config = None;
+		let config = Mutex::new(Config::default());
+		let entropy_source_config = Mutex::new(None);
+		let gossip_source_config = Mutex::new(None);
 		Self { config, entropy_source_config, gossip_source_config }
 	}
 
 	/// Creates a new builder instance from an [`Config`].
 	pub fn from_config(config: Config) -> Self {
-		let entropy_source_config = None;
-		let gossip_source_config = None;
+		let config = Mutex::new(config);
+		let entropy_source_config = Mutex::new(None);
+		let gossip_source_config = Mutex::new(None);
 		Self { config, entropy_source_config, gossip_source_config }
 	}
 
 	/// Configures the [`Node`] instance to source its wallet entropy from a seed file on disk.
 	///
 	/// If the given file does not exist a new random seed file will be generated and
 	/// stored at the given location.
-	pub fn set_entropy_seed_path(&mut self, seed_path: String) -> &mut Self {
-		self.entropy_source_config = Some(EntropySourceConfig::SeedFile(seed_path));
-		self
+	pub fn set_entropy_seed_path(&self, seed_path: String) {
+		*self.entropy_source_config.lock().unwrap() =
+			Some(EntropySourceConfig::SeedFile(seed_path));
+	}
+
+	/// Configures the [`Node`] instance to source its wallet entropy from the given 64 seed bytes.
+	///
+	/// **Note:** Panics if the length of the given `seed_bytes` differs from 64.
+	pub fn set_entropy_seed_bytes(&self, seed_bytes: Vec<u8>) {
+		if seed_bytes.len() != WALLET_KEYS_SEED_LEN {
+			panic!("Failed to set seed due to invalid length.");
+		}
+		let mut bytes = [0u8; WALLET_KEYS_SEED_LEN];
+		bytes.copy_from_slice(&seed_bytes);
+		*self.entropy_source_config.lock().unwrap() = Some(EntropySourceConfig::SeedBytes(bytes));
 	}
 
-	/// Configures the [`Node`] instance to source its wallet entropy from the given seed bytes.
-	pub fn set_entropy_seed_bytes(&mut self, seed_bytes: [u8; WALLET_KEYS_SEED_LEN]) -> &mut Self {
-		self.entropy_source_config = Some(EntropySourceConfig::SeedBytes(seed_bytes));
-		self
+	/// Configures the [`Node`] instance to source its wallet entropy from a [BIP 39] mnemonic.
+	///
+	/// [BIP 39]: https://github.com/bitcoin/bips/blob/master/bip-0039.mediawiki
+	pub fn set_entropy_bip39_mnemonic(&self, mnemonic: Mnemonic, passphrase: Option<String>) {
+		*self.entropy_source_config.lock().unwrap() =
+			Some(EntropySourceConfig::Bip39Mnemonic { mnemonic, passphrase });
 	}
 
 	/// Configures the [`Node`] instance to source its gossip data from the Lightning peer-to-peer
 	/// network.
-	pub fn set_gossip_source_p2p(&mut self) -> &mut Self {
-		self.gossip_source_config = Some(GossipSourceConfig::P2PNetwork);
-		self
+	pub fn set_gossip_source_p2p(&self) {
+		*self.gossip_source_config.lock().unwrap() = Some(GossipSourceConfig::P2PNetwork);
 	}
 
 	/// Configures the [`Node`] instance to source its gossip data from the given RapidGossipSync
 	/// server.
-	pub fn set_gossip_source_rgs(&mut self, rgs_server_url: String) -> &mut Self {
-		self.gossip_source_config = Some(GossipSourceConfig::RapidGossipSync(rgs_server_url));
-		self
-	}
-
-	/// Configures the [`Node`] instance to source its wallet entropy from a [BIP 39] mnemonic.
-	///
-	/// [BIP 39]: https://github.com/bitcoin/bips/blob/master/bip-0039.mediawiki
-	pub fn set_entropy_bip39_mnemonic(
-		&mut self, mnemonic: bip39::Mnemonic, passphrase: Option<String>,
-	) -> &mut Self {
-		self.entropy_source_config =
-			Some(EntropySourceConfig::Bip39Mnemonic { mnemonic, passphrase });
-		self
+	pub fn set_gossip_source_rgs(&self, rgs_server_url: String) {
+		*self.gossip_source_config.lock().unwrap() =
+			Some(GossipSourceConfig::RapidGossipSync(rgs_server_url));
 	}
 
 	/// Sets the used storage directory path.
 	///
 	/// Default: `/tmp/ldk_node/`
-	pub fn set_storage_dir_path(&mut self, storage_dir_path: String) -> &mut Self {
-		self.config.storage_dir_path = storage_dir_path;
-		self
+	pub fn set_storage_dir_path(&self, storage_dir_path: String) {
+		let mut config = self.config.lock().unwrap();
+		config.storage_dir_path = storage_dir_path;
 	}
 
 	/// Sets the Esplora server URL.
 	///
 	/// Default: `https://blockstream.info/api`
-	pub fn set_esplora_server_url(&mut self, esplora_server_url: String) -> &mut Self {
-		self.config.esplora_server_url = esplora_server_url;
-		self
+	pub fn set_esplora_server_url(&self, esplora_server_url: String) {
+		let mut config = self.config.lock().unwrap();
+		config.esplora_server_url = esplora_server_url;
 	}
 
 	/// Sets the Bitcoin network used.
-	///
-	/// Options: `mainnet`/`bitcoin`, `testnet`, `regtest`, `signet`
-	///
-	/// Default: `regtest`
-	pub fn set_network(&mut self, network: &str) -> &mut Self {
-		self.config.network = Network::from_str(network).unwrap_or(Network::Regtest);
-		self
+	pub fn set_network(&self, network: Network) {
+		let mut config = self.config.lock().unwrap();
+		config.network = network;
 	}
 
 	/// Sets the IP address and TCP port on which [`Node`] will listen for incoming network connections.
 	///
 	/// Default: `0.0.0.0:9735`
-	pub fn set_listening_address(&mut self, listening_address: NetAddress) -> &mut Self {
-		self.config.listening_address = Some(listening_address);
-		self
+	pub fn set_listening_address(&self, listening_address: NetAddress) {
+		let mut config = self.config.lock().unwrap();
+		config.listening_address = Some(listening_address);
 	}
 
 	/// Builds a [`Node`] instance according to the options previously configured.
 	pub fn build(&self) -> Arc<Node> {
-		let config = Arc::new(self.config.clone());
+		let config = Arc::new(self.config.lock().unwrap().clone());
 
 		let ldk_data_dir = format!("{}/ldk", config.storage_dir_path);
 		fs::create_dir_all(ldk_data_dir.clone()).expect("Failed to create LDK data directory");
@@ -332,7 +334,9 @@ impl Builder {
 		let logger = Arc::new(FilesystemLogger::new(log_file_path));
 
 		// Initialize the on-chain wallet and chain access
-		let seed_bytes = if let Some(entropy_source_config) = &self.entropy_source_config {
+		let seed_bytes = if let Some(entropy_source_config) =
+			&*self.entropy_source_config.lock().unwrap()
+		{
 			// Use the configured entropy source, if the user set one.
 			match entropy_source_config {
 				EntropySourceConfig::SeedBytes(bytes) => bytes.clone(),
@@ -539,8 +543,9 @@ impl Builder {
 
 		// Initialize the GossipSource
 		// Use the configured gossip source, if the user set one, otherwise default to P2PNetwork.
+		let gossip_source_config_lock = self.gossip_source_config.lock().unwrap();
 		let gossip_source_config =
-			self.gossip_source_config.as_ref().unwrap_or(&GossipSourceConfig::P2PNetwork);
+			gossip_source_config_lock.as_ref().unwrap_or(&GossipSourceConfig::P2PNetwork);
 
 		let gossip_source = match gossip_source_config {
 			GossipSourceConfig::P2PNetwork => {

src/types.rs

@@ -25,7 +25,9 @@ use bitcoin::hashes::Hash;
 use bitcoin::secp256k1::PublicKey;
 use bitcoin::{Address, Network, OutPoint, Txid};
 
+use bip39::Mnemonic;
 use core::convert::TryFrom;
+
 use std::convert::TryInto;
 use std::fmt::Display;
 use std::net::{Ipv4Addr, Ipv6Addr, SocketAddr, SocketAddrV4, SocketAddrV6, ToSocketAddrs};
@@ -437,6 +439,17 @@ impl Display for NetAddress {
 	}
 }
 
+impl UniffiCustomTypeConverter for Mnemonic {
+	type Builtin = String;
+	fn into_custom(val: Self::Builtin) -> uniffi::Result<Self> {
+		Ok(Mnemonic::from_str(&val).map_err(|_| Error::InvalidSecretKey)?)
+	}
+
+	fn from_custom(obj: Self) -> Self::Builtin {
+		obj.to_string()
+	}
+}
+
 impl UniffiCustomTypeConverter for NetAddress {
 	type Builtin = String;
 	fn into_custom(val: Self::Builtin) -> uniffi::Result<Self> {