Implement KVStoreUnpersister

Author: tnull

Cargo.toml

@@ -51,6 +51,7 @@ chrono = "0.4"
 futures = "0.3"
 serde_json = { version = "1.0" }
 tokio = { version = "1", default-features = false, features = [ "rt-multi-thread", "time", "sync" ] }
+libc = "0.2"
 
 [dev-dependencies]
 electrsd = { version = "0.22.0", features = ["legacy", "esplora_a33e97e1", "bitcoind_23_0"] }

src/event.rs

@@ -3,6 +3,7 @@ use crate::{
 	PaymentInfo, PaymentInfoStorage, PaymentStatus, Wallet,
 };
 
+use crate::io_utils::KVStoreUnpersister;
 use crate::logger::{log_error, log_info, Logger};
 
 use lightning::chain::chaininterface::{BroadcasterInterface, ConfirmationTarget, FeeEstimator};
@@ -183,7 +184,7 @@ impl Writeable for EventQueueSerWrapper<'_> {
 
 pub(crate) struct EventHandler<K: Deref, L: Deref>
 where
-	K::Target: KVStorePersister,
+	K::Target: KVStorePersister + KVStoreUnpersister,
 	L::Target: Logger,
 {
 	wallet: Arc<Wallet<bdk::database::SqliteDatabase>>,
@@ -199,7 +200,7 @@ where
 
 impl<K: Deref, L: Deref> EventHandler<K, L>
 where
-	K::Target: KVStorePersister,
+	K::Target: KVStorePersister + KVStoreUnpersister,
 	L::Target: Logger,
 {
 	pub fn new(
@@ -224,7 +225,7 @@ where
 
 impl<K: Deref, L: Deref> LdkEventHandler for EventHandler<K, L>
 where
-	K::Target: KVStorePersister,
+	K::Target: KVStorePersister + KVStoreUnpersister,
 	L::Target: Logger,
 {
 	fn handle_event(&self, event: LdkEvent) {

src/io_utils.rs

@@ -3,12 +3,15 @@ use crate::{Config, Error, FilesystemLogger, NetworkGraph, Scorer};
 
 use lightning::routing::scoring::{ProbabilisticScorer, ProbabilisticScoringParameters};
 use lightning::util::ser::{Readable, ReadableArgs};
+use lightning_persister::FilesystemPersister;
 
 use rand::{thread_rng, RngCore};
 
 use std::fs;
 use std::io::{BufReader, Write};
+use std::os::unix::io::AsRawFd;
 use std::path::Path;
+use std::path::PathBuf;
 use std::sync::Arc;
 
 pub(crate) fn read_or_generate_seed_file(config: &Config) -> [u8; 32] {
@@ -82,3 +85,37 @@ pub(crate) fn read_payment_info(config: &Config) -> Vec<PaymentInfo> {
 
 	payments
 }
+
+/// Provides an interface that allows a previously persisted key to be unpersisted.
+pub trait KVStoreUnpersister {
+	/// Unpersist (i.e., remove) the writeable previously persisted under the provided key.
+	/// Returns `true` if the key was present, and `false` otherwise.
+	fn unpersist(&self, key: &str) -> std::io::Result<bool>;
+}
+
+impl KVStoreUnpersister for FilesystemPersister {
+	fn unpersist(&self, key: &str) -> std::io::Result<bool> {
+		let mut dest_file = PathBuf::from(self.get_data_dir());
+		dest_file.push(key);
+
+		if !dest_file.is_file() {
+			return Ok(false);
+		}
+
+		fs::remove_file(&dest_file)?;
+		let parent_directory = dest_file.parent().unwrap();
+		let dir_file = fs::OpenOptions::new().read(true).open(parent_directory)?;
+		#[cfg(not(target_os = "windows"))]
+		{
+			unsafe {
+				libc::fsync(dir_file.as_raw_fd());
+			}
+		}
+
+		if dest_file.is_file() {
+			return Err(std::io::Error::new(std::io::ErrorKind::Other, "Unpersisting key failed"));
+		}
+
+		return Ok(true);
+	}
+}

src/payment_store.rs

@@ -1,4 +1,5 @@
 use crate::hex_utils;
+use crate::io_utils::KVStoreUnpersister;
 use crate::Error;
 
 use lightning::ln::{PaymentHash, PaymentPreimage, PaymentSecret};
@@ -72,15 +73,15 @@ pub(crate) const PAYMENT_INFO_PERSISTENCE_PREFIX: &str = "payments";
 
 pub(crate) struct PaymentInfoStorage<K: Deref>
 where
-	K::Target: KVStorePersister,
+	K::Target: KVStorePersister + KVStoreUnpersister,
 {
 	payments: Mutex<HashMap<PaymentHash, PaymentInfo>>,
 	persister: K,
 }
 
 impl<K: Deref> PaymentInfoStorage<K>
 where
-	K::Target: KVStorePersister,
+	K::Target: KVStorePersister + KVStoreUnpersister,
 {
 	pub(crate) fn from_payments(mut payments: Vec<PaymentInfo>, persister: K) -> Self {
 		let payments = Mutex::new(HashMap::from_iter(
@@ -106,9 +107,15 @@ where
 		return Ok(());
 	}
 
-	// TODO: Need an `unpersist` method for this?
-	//pub(crate) fn remove_payment(&self, payment_hash: &PaymentHash) -> Result<(), Error> {
-	//}
+	pub(crate) fn remove_payment(&self, payment_hash: &PaymentHash) -> Result<(), Error> {
+		let key = format!(
+			"{}/{}",
+			PAYMENT_INFO_PERSISTENCE_PREFIX,
+			hex_utils::to_string(&payment_hash.0)
+		);
+		self.persister.unpersist(&key).map_err(|_| Error::PersistenceFailed)?;
+		Ok(())
+	}
 
 	pub(crate) fn get(&self, payment_hash: &PaymentHash) -> Option<PaymentInfo> {
 		self.payments.lock().unwrap().get(payment_hash).cloned()