keep snapshot watcher alive

ethcore/src/snapshot/service.rs

@@ -275,6 +275,13 @@ impl Service {
 			}
 		}
 
+		// delete the temporary snapshot dir if it does exist.
+		if let Err(e) = fs::remove_dir_all(service.temp_snapshot_dir()) {
+			if e.kind() != ErrorKind {
+				return Err(e.into())
+			}
+		}
+
 		Ok(service)
 	}
 

ethcore/src/snapshot/watcher.rs

@@ -49,6 +49,8 @@ impl Broadcast for IoChannel<ClientIoMessage> {
 			None => return,
 		};
 
+		trace!(target: "snapshot_watcher", "broadcast: {}", num);
+
 		if let Err(e) = self.send(ClientIoMessage::TakeSnapshot(num)) {
 			warn!("Snapshot watcher disconnected from IoService: {}", e);
 		}
@@ -88,6 +90,8 @@ impl ChainNotify for Watcher {
 		_: Vec<H256>,
 		_duration: u64)
 	{
+		trace!(target: "snapshot_watcher", "{} imported", imported.len());
+
 		let highest = imported.into_iter()
 			.filter_map(|h| self.oracle.to_number(h))
 			.filter(|&num| num >= self.period + self.history)

parity/run.rs

@@ -257,6 +257,22 @@ pub fn execute(cmd: RunCmd) -> Result<(), String> {
 	});
 	service.register_io_handler(io_handler).expect("Error registering IO handler");
 
+	// the watcher must be kept alive.
+	let _watcher = match cmd.no_periodic_snapshot {
+		true => None,
+		false => {
+			let watcher = Arc::new(snapshot::Watcher::new(
+				service.client(),
+				service.io().channel(),
+				SNAPSHOT_PERIOD,
+				SNAPSHOT_HISTORY,
+			));
+
+			service.add_notify(watcher.clone());
+			Some(watcher)
+		},
+	};
+
 	if !cmd.no_periodic_snapshot {
 		let watcher = snapshot::Watcher::new(
 			service.client(),