Merge pull request #863 from valentinewallace/expose-read-chanmons-from-disk

persister: Expose method to read ChannelMonitors from disk

Author: TheBlueMatt

lightning-persister/src/lib.rs

@@ -12,7 +12,8 @@ extern crate lightning;
 extern crate bitcoin;
 extern crate libc;
 
-use bitcoin::hashes::hex::ToHex;
+use bitcoin::{BlockHash, Txid};
+use bitcoin::hashes::hex::{FromHex, ToHex};
 use crate::util::DiskWriteable;
 use lightning::chain;
 use lightning::chain::chaininterface::{BroadcasterInterface, FeeEstimator};
@@ -22,21 +23,14 @@ use lightning::chain::keysinterface::{Sign, KeysInterface};
 use lightning::chain::transaction::OutPoint;
 use lightning::ln::channelmanager::ChannelManager;
 use lightning::util::logger::Logger;
-use lightning::util::ser::Writeable;
+use lightning::util::ser::{ReadableArgs, Writeable};
+use std::collections::HashMap;
 use std::fs;
-use std::io::Error;
-use std::path::PathBuf;
+use std::io::{Cursor, Error};
+use std::ops::Deref;
+use std::path::{Path, PathBuf};
 use std::sync::Arc;
 
-#[cfg(test)]
-use {
-	lightning::util::ser::ReadableArgs,
-	bitcoin::{BlockHash, Txid},
-	bitcoin::hashes::hex::FromHex,
-	std::collections::HashMap,
-	std::io::Cursor
-};
-
 /// FilesystemPersister persists channel data on disk, where each channel's
 /// data is stored in a file named after its funding outpoint.
 ///
@@ -108,39 +102,61 @@ impl FilesystemPersister {
 		util::write_to_file(path, "manager".to_string(), manager)
 	}
 
-	#[cfg(test)]
-	fn load_channel_data<Keys: KeysInterface>(&self, keys: &Keys) ->
-		Result<HashMap<OutPoint, ChannelMonitor<Keys::Signer>>, ChannelMonitorUpdateErr> {
-			if let Err(_) = fs::create_dir_all(self.path_to_monitor_data()) {
-				return Err(ChannelMonitorUpdateErr::PermanentFailure);
+	/// Read `ChannelMonitor`s from disk.
+	pub fn read_channelmonitors<Signer: Sign, K: Deref> (
+		&self, keys_manager: K
+	) -> Result<HashMap<OutPoint, (BlockHash, ChannelMonitor<Signer>)>, std::io::Error>
+	     where K::Target: KeysInterface<Signer=Signer> + Sized
+	{
+		let path = self.path_to_monitor_data();
+		if !Path::new(&path).exists() {
+			return Ok(HashMap::new());
+		}
+		let mut outpoint_to_channelmonitor = HashMap::new();
+		for file_option in fs::read_dir(path).unwrap() {
+			let file = file_option.unwrap();
+			let owned_file_name = file.file_name();
+			let filename = owned_file_name.to_str();
+			if !filename.is_some() || !filename.unwrap().is_ascii() || filename.unwrap().len() < 65 {
+				return Err(std::io::Error::new(
+					std::io::ErrorKind::InvalidData,
+					"Invalid ChannelMonitor file name",
+				));
 			}
-			let mut res = HashMap::new();
-			for file_option in fs::read_dir(self.path_to_monitor_data()).unwrap() {
-				let file = file_option.unwrap();
-				let owned_file_name = file.file_name();
-				let filename = owned_file_name.to_str();
-				if !filename.is_some() || !filename.unwrap().is_ascii() || filename.unwrap().len() < 65 {
-					return Err(ChannelMonitorUpdateErr::PermanentFailure);
-				}
 
-				let txid = Txid::from_hex(filename.unwrap().split_at(64).0);
-				if txid.is_err() { return Err(ChannelMonitorUpdateErr::PermanentFailure); }
-
-				let index = filename.unwrap().split_at(65).1.split('.').next().unwrap().parse();
-				if index.is_err() { return Err(ChannelMonitorUpdateErr::PermanentFailure); }
+			let txid = Txid::from_hex(filename.unwrap().split_at(64).0);
+			if txid.is_err() {
+				return Err(std::io::Error::new(
+					std::io::ErrorKind::InvalidData,
+					"Invalid tx ID in filename",
+				));
+			}
 
-				let contents = fs::read(&file.path());
-				if contents.is_err() { return Err(ChannelMonitorUpdateErr::PermanentFailure); }
+			let index = filename.unwrap().split_at(65).1.parse();
+			if index.is_err() {
+				return Err(std::io::Error::new(
+					std::io::ErrorKind::InvalidData,
+					"Invalid tx index in filename",
+				));
+			}
 
-				if let Ok((_, loaded_monitor)) =
-					<(BlockHash, ChannelMonitor<Keys::Signer>)>::read(&mut Cursor::new(&contents.unwrap()), keys) {
-						res.insert(OutPoint { txid: txid.unwrap(), index: index.unwrap() }, loaded_monitor);
-					} else {
-						return Err(ChannelMonitorUpdateErr::PermanentFailure);
-					}
+			let contents = fs::read(&file.path())?;
+			let mut buffer = Cursor::new(&contents);
+			match <(BlockHash, ChannelMonitor<Signer>)>::read(&mut buffer, &*keys_manager) {
+				Ok((blockhash, channel_monitor)) => {
+					outpoint_to_channelmonitor.insert(
+						OutPoint { txid: txid.unwrap(), index: index.unwrap() },
+						(blockhash, channel_monitor),
+					);
+				}
+				Err(e) => return Err(std::io::Error::new(
+					std::io::ErrorKind::InvalidData,
+					format!("Failed to deserialize ChannelMonitor: {}", e),
+				))
 			}
-			Ok(res)
 		}
+		Ok(outpoint_to_channelmonitor)
+	}
 }
 
 impl<ChannelSigner: Sign + Send + Sync> channelmonitor::Persist<ChannelSigner> for FilesystemPersister {
@@ -210,22 +226,22 @@ mod tests {
 
 		// Check that the persisted channel data is empty before any channels are
 		// open.
-		let mut persisted_chan_data_0 = persister_0.load_channel_data(nodes[0].keys_manager).unwrap();
+		let mut persisted_chan_data_0 = persister_0.read_channelmonitors(nodes[0].keys_manager).unwrap();
 		assert_eq!(persisted_chan_data_0.keys().len(), 0);
-		let mut persisted_chan_data_1 = persister_1.load_channel_data(nodes[1].keys_manager).unwrap();
+		let mut persisted_chan_data_1 = persister_1.read_channelmonitors(nodes[1].keys_manager).unwrap();
 		assert_eq!(persisted_chan_data_1.keys().len(), 0);
 
 		// Helper to make sure the channel is on the expected update ID.
 		macro_rules! check_persisted_data {
 			($expected_update_id: expr) => {
-				persisted_chan_data_0 = persister_0.load_channel_data(nodes[0].keys_manager).unwrap();
+				persisted_chan_data_0 = persister_0.read_channelmonitors(nodes[0].keys_manager).unwrap();
 				assert_eq!(persisted_chan_data_0.keys().len(), 1);
-				for mon in persisted_chan_data_0.values() {
+				for (_, mon) in persisted_chan_data_0.values() {
 					assert_eq!(mon.get_latest_update_id(), $expected_update_id);
 				}
-				persisted_chan_data_1 = persister_1.load_channel_data(nodes[1].keys_manager).unwrap();
+				persisted_chan_data_1 = persister_1.read_channelmonitors(nodes[1].keys_manager).unwrap();
 				assert_eq!(persisted_chan_data_1.keys().len(), 1);
-				for mon in persisted_chan_data_1.values() {
+				for (_, mon) in persisted_chan_data_1.values() {
 					assert_eq!(mon.get_latest_update_id(), $expected_update_id);
 				}
 			}