working implementation of handler

Cargo.lock

@@ -616,7 +616,7 @@ dependencies = [
 
 [[package]]
 name = "markov"
-version = "0.8.2"
+version = "0.9.0"
 dependencies = [
  "async-compression",
  "bzip2-sys",

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "markov"
-version = "0.8.2"
+version = "0.9.0"
 description = "Generate string of text from Markov chain fed by stdin"
 authors = ["Avril <flanchan@cumallover.me>"]
 edition = "2018"
@@ -36,14 +36,7 @@ split-sentance = []
 # NOTE: This does nothing if `split-newlines` is not enabled
 always-aggregate = []
 
-# Feeds will hog the buffer lock until the whole body has been fed, instead of acquiring lock every time
+# Does nothing, legacy thing.
-# This will make feeds of many lines faster but can potentially cause DoS
-#
-# With:		~169ms
-# Without:	~195ms
-#
-# NOTE:
-# This does nothing if `always-aggregate` is enabled and/or `split-newlines` is not enabled
 hog-buffer = []
 
 # Enable the /api/ route

markov.toml

@@ -7,5 +7,12 @@ trust_x_forwarded_for = false
 feed_bounds = '2..'
 
 [filter]
-inbound = '<>/\\'
+inbound = ''
 outbound = ''
+
+[writer]
+backlog = 32
+internal_backlog = 8
+capacity = 4
+timeout_ms = 5000
+throttle_ms = 50

src/chunking.rs

@@ -215,6 +215,16 @@ where S: Stream<Item=T>,
 	&self.buf[..]
     }
 
+    pub fn get_ref(&self) -> &S
+    {
+	self.stream.get_ref()
+    }
+
+    pub fn get_mut(&mut self)-> &mut S
+    {
+	self.stream.get_mut()
+    }
+
     /// Force the next read to send the buffer even if it's not full.
     ///
     /// # Note
@@ -223,6 +233,18 @@ where S: Stream<Item=T>,
     {
 	self.push_now= true;
     }
+
+    /// Consume into the current held buffer
+    pub fn into_buffer(self) -> Vec<T>
+    {
+	self.buf
+    }
+
+    /// Take the buffer now
+    pub fn take_now(&mut self) -> Into
+    {
+	std::mem::replace(&mut self.buf, Vec::with_capacity(self.cap)).into()
+    }
 }
 
 impl<S, T, Into> Stream for ChunkingStream<S,T, Into>
@@ -246,6 +268,7 @@ where S: Stream<Item=T>,
 		_ => return Poll::Pending,
 	    }
 	}
+	debug!("Sending buffer of {} (cap {})", self.buf.len(), self.cap);
 	// Buffer is full or we reach end of stream
 	Poll::Ready(if self.buf.len() == 0 {
 	    None

src/config.rs

@@ -28,9 +28,11 @@ pub struct Config
     pub save_interval_secs: Option<NonZeroU64>,
     pub trust_x_forwarded_for: bool,
     #[serde(default)]
+    pub feed_bounds: String,
+    #[serde(default)]
     pub filter: FilterConfig,
     #[serde(default)]
-    pub feed_bounds: String,
+    pub writer: WriterConfig,
 }
 
 #[derive(Debug, Default, Clone, PartialEq, Eq, PartialOrd, Hash, Serialize, Deserialize)]
@@ -41,6 +43,49 @@ pub struct FilterConfig
     outbound: String,
 }
 
+#[derive(Debug, Copy,  Clone, PartialEq, Eq, PartialOrd, Hash, Serialize, Deserialize)]
+pub struct WriterConfig
+{
+    pub backlog: usize,
+    pub internal_backlog: usize,
+    pub capacity: usize,
+    pub timeout_ms: Option<u64>,
+    pub throttle_ms: Option<u64>,
+}
+
+impl Default for WriterConfig
+{
+    #[inline]
+    fn default() -> Self
+    {
+	Self {
+	    backlog: 32,
+	    internal_backlog: 8,
+	    capacity: 4,
+	    timeout_ms: None,
+	    throttle_ms: None,
+	}
+    }
+}
+
+impl WriterConfig
+{
+    fn create_settings(self, bounds: range::DynRange<usize>) -> handle::Settings
+    {
+	
+	handle::Settings{
+	    backlog: self.backlog,
+	    internal_backlog: self.internal_backlog,
+	    capacity: self.capacity,
+	    timeout: self.timeout_ms.map(tokio::time::Duration::from_millis).unwrap_or(handle::DEFAULT_TIMEOUT),
+	    throttle: self.throttle_ms.map(tokio::time::Duration::from_millis),
+	    bounds,
+	}
+	
+    }
+}
+
+
 impl FilterConfig
 {
     fn get_inbound_filter(&self) -> sanitise::filter::Filter
@@ -77,6 +122,7 @@ impl Default for Config
 	    trust_x_forwarded_for: false,
 	    filter: Default::default(),
 	    feed_bounds: "2..".to_owned(),
+	    writer: Default::default(),
 	}
     }
 }
@@ -96,12 +142,14 @@ impl Config
 	}
 	use std::ops::RangeBounds;
 
-	Ok(Cache {
+	let feed_bounds = section!("feed_bounds", self.parse_feed_bounds()).and_then(|bounds| if bounds.contains(&0) {
-	    feed_bounds: section!("feed_bounds", self.parse_feed_bounds()).and_then(|bounds| if bounds.contains(&0) {
 		Err(InvalidConfigError("feed_bounds", Box::new(opaque_error!("Bounds not allowed to contains 0 (they were `{}`)", bounds))))
 	    } else {
 		Ok(bounds)
-	    })?,
+	    })?;
+	Ok(Cache {
+	    handler_settings: self.writer.create_settings(feed_bounds.clone()),
+	    feed_bounds,
 	    inbound_filter: self.filter.get_inbound_filter(),
 	    outbound_filter: self.filter.get_outbound_filter(),
 	})
@@ -205,12 +253,13 @@ impl fmt::Display for InvalidConfigError
 
 
 /// Caches some parsed config arguments
-#[derive(Clone, PartialEq, Eq)]
+#[derive(Clone, PartialEq)]
 pub struct Cache
 {
     pub feed_bounds: range::DynRange<usize>,
     pub inbound_filter: sanitise::filter::Filter,
     pub outbound_filter: sanitise::filter::Filter,
+    pub handler_settings: handle::Settings,
 }
 
 impl fmt::Debug for Cache
@@ -221,6 +270,7 @@ impl fmt::Debug for Cache
 	    .field("feed_bounds", &self.feed_bounds)
 	    .field("inbound_filter", &self.inbound_filter.iter().collect::<String>())
 	    .field("outbound_filter", &self.outbound_filter.iter().collect::<String>())
+	    .field("handler_settings", &self.handler_settings)
 	    .finish()
     }
 }

src/feed.rs

@@ -2,7 +2,7 @@
 use super::*;
 #[cfg(any(feature="feed-sentance", feature="split-sentance"))]
 use sanitise::Sentance;
-use std::iter;
+use futures::stream;
 
 
 pub const DEFAULT_FEED_BOUNDS: std::ops::RangeFrom<usize> = 2..;
@@ -58,7 +58,7 @@ pub fn feed(chain: &mut Chain<String>, what: impl AsRef<str>, bounds: impl std::
 	    }
 	    debug_assert!(!bounds.contains(&0), "Cannot allow 0 size feeds");
 	    if bounds.contains(&map.len()) {
-		debug!("Feeding chain {} items", map.len());
+		//debug!("Feeding chain {} items", map.len());
 		chain.feed(map);
 	    }
 	    else {
@@ -80,7 +80,7 @@ pub async fn full(who: &IpAddr, state: State, body: impl Unpin + Stream<Item = R
 	($buffer:expr) => {
 	    {
 		let buffer = $buffer;
-		state.chain_write(buffer.map(ToOwned::to_owned)).await.map_err(|_| FillBodyError)?;
+		state.chain_write(buffer).await.map_err(|_| FillBodyError)?;
 	    }
 	}
     }
@@ -105,38 +105,40 @@ pub async fn full(who: &IpAddr, state: State, body: impl Unpin + Stream<Item = R
 	    info!("{} -> {:?}", who, buffer);
 	    cfg_if! {
 		if #[cfg(feature="split-newlines")] {
-		    feed!(buffer.split('\n').filter(|line| !line.trim().is_empty())) 
+		    feed!(stream::iter(buffer.split('\n').filter(|line| !line.trim().is_empty())
+				       .map(|x| x.to_owned())))
 		} else {
-		    feed!(iter::once(buffer));
+		    feed!(stream::once(async move{buffer.into_owned()}));
 		}
 	    }
 	} else {
 	    use tokio::prelude::*;
 
 	    let reader = chunking::StreamReader::new(body.filter_map(|x| x.map(|mut x| x.to_bytes()).ok()));
-	    let mut lines = reader.lines();
+	    let lines = reader.lines();
 	    
-	    #[cfg(feature="hog-buffer")] 
+	    feed!(lines.filter_map(|x| x.ok().and_then(|line| {
-	    let mut chain = state.chain().write().await;
-	    while let Some(line) = lines.next_line().await.map_err(|_| FillBodyError)? {
 		let line = state.inbound_filter().filter_cow(&line);
 		let line = line.trim();
+		
 		if !line.is_empty() {
 		    //#[cfg(not(feature="hog-buffer"))] 
 		    //let mut chain = state.chain().write().await; // Acquire mutex once per line? Is this right?
 
-		    feed!(iter::once(line));
 		    info!("{} -> {:?}", who, line);
-		}
 		    written+=line.len();
+		    Some(line.to_owned())
+		} else {
+		    None
 		}
+		
+	    })));
 	}
     }
 
-    if_debug!{
+    if_debug! {
 	trace!("Write took {}ms", timer.elapsed().as_millis());
     }
-    state.notify_save();
     Ok(written)
 	
 }

src/handle.rs

@@ -15,6 +15,8 @@ use tokio::{
 	    self,
 	    error::SendError,
 	},
+	watch,
+	Notify,
     },
     task::JoinHandle,
     time::{
@@ -24,11 +26,14 @@ use tokio::{
 };
 use futures::StreamExt;
 
+pub const DEFAULT_TIMEOUT: Duration= Duration::from_secs(5);
+
 /// Settings for chain handler
 #[derive(Debug, Clone, PartialEq)]
 pub struct Settings
 {
     pub backlog: usize,
+    pub internal_backlog: usize,
     pub capacity: usize,
     pub timeout: Duration,
     pub throttle: Option<Duration>,
@@ -38,7 +43,7 @@ pub struct Settings
 impl Settings
 {
     /// Should we keep this string.
-    #[inline] fn matches(&self, s: &str) -> bool
+    #[inline] fn matches(&self, _s: &str) -> bool
     {
 	true
     }
@@ -51,6 +56,7 @@ impl Default for Settings
     {
 	Self {
 	    backlog: 32,
+	    internal_backlog: 8,
 	    capacity: 4,
 	    timeout: Duration::from_secs(5),
 	    throttle: Some(Duration::from_millis(200)),
@@ -64,6 +70,7 @@ impl Default for Settings
 struct HostInner<T>
 {
     input: mpsc::Receiver<Vec<T>>,
+    shutdown: watch::Receiver<bool>,
 }
 
 #[derive(Debug)]
@@ -72,6 +79,9 @@ struct Handle<T: Send+ chain::Chainable>
     chain: RwLock<chain::Chain<T>>,
     input: mpsc::Sender<Vec<T>>,
     opt: Settings,
+    notify_write: Arc<Notify>,
+    push_now: Arc<Notify>,
+    shutdown: watch::Sender<bool>,
     
     /// Data used only for the worker task.
     host: msg::Once<HostInner<T>>,
@@ -80,22 +90,23 @@ struct Handle<T: Send+ chain::Chainable>
 #[derive(Clone, Debug)]
 pub struct ChainHandle<T: Send + chain::Chainable>(Arc<Box<Handle<T>>>);
 
-impl<T: Send+ chain::Chainable> ChainHandle<T>
+impl<T: Send+ chain::Chainable + 'static> ChainHandle<T>
 {
-    #[inline] pub fn new(chain: chain::Chain<T>) -> Self
-    {
-	Self::with_settings(chain, Default::default())
-    }
     pub fn with_settings(chain: chain::Chain<T>, opt: Settings) -> Self
     {
+	let (shutdown_tx, shutdown) = watch::channel(false);
 	let (itx, irx) = mpsc::channel(opt.backlog);
 	Self(Arc::new(Box::new(Handle{
 	    chain: RwLock::new(chain),
 	    input: itx,
 	    opt,
+	    push_now: Arc::new(Notify::new()),
+	    notify_write: Arc::new(Notify::new()),
+	    shutdown: shutdown_tx,
 	    
 	    host: msg::Once::new(HostInner{
 		input: irx,
+		shutdown,
 	    })
 	})))
     }
@@ -122,10 +133,51 @@ impl<T: Send+ chain::Chainable> ChainHandle<T>
     }
 
     /// Send this buffer to the chain
-    pub async fn write(&self, buf: Vec<T>) -> Result<(), SendError<Vec<T>>>
+    pub fn write(&self, buf: Vec<T>) -> impl futures::Future<Output = Result<(), SendError<Vec<T>>>> + 'static
+    {
+	let mut write = self.0.input.clone();
+	async move {
+	    write.send(buf).await
+	}
+    }
+    
+    /// Send this stream buffer to the chain
+    pub fn write_stream<'a, I: Stream<Item=T>>(&self, buf: I) -> impl futures::Future<Output = Result<(), SendError<Vec<T>>>> + 'a
+    where I: 'a
+    {
+	let mut write = self.0.input.clone();
+	async move {
+	    write.send(buf.collect().await).await
+	}
+    }
+    
+    /// Send this buffer to the chain
+    pub async fn write_in_place(&self, buf: Vec<T>) -> Result<(), SendError<Vec<T>>>
     {
 	self.0.input.clone().send(buf).await
     }
+
+    /// A referencer for the notifier
+    pub fn notify_when(&self) -> &Arc<Notify>
+    {
+	&self.0.notify_write
+    }
+
+    /// Force the pending buffers to be written to the chain now
+    pub fn push_now(&self)
+    {
+	self.0.push_now.notify();
+    }
+
+    /// Hang the worker thread, preventing it from taking any more inputs and also flushing it.
+    ///
+    /// # Panics
+    /// If there was no worker thread.
+    pub fn hang(&self)
+    {
+	trace!("Communicating hang request");
+	self.0.shutdown.broadcast(true).expect("Failed to communicate hang");
+    }
 }
 
 impl ChainHandle<String>
@@ -157,13 +209,13 @@ impl ChainHandle<String>
 pub async fn host(from: ChainHandle<String>)
 {
     let opt = from.0.opt.clone();
-    let data = from.0.host.unwrap().await;
+    let mut data = from.0.host.unwrap().await;
 
-    let (mut tx, child) = {
+    let (mut tx, mut child) = {
 	// The `real` input channel.
 	let from = from.clone();
 	let opt = opt.clone();
-	let (tx, rx) = mpsc::channel::<Vec<Vec<_>>>(opt.backlog);
+	let (tx, rx) = mpsc::channel::<Vec<Vec<_>>>(opt.internal_backlog);
 	(tx, tokio::spawn(async move {
 	    let mut rx = if let Some(thr) = opt.throttle {
 		time::throttle(thr, rx).boxed()
@@ -172,6 +224,8 @@ pub async fn host(from: ChainHandle<String>)
 	    };
 	    trace!("child: Begin waiting on parent");
 	    while let Some(item) = rx.next().await {
+		if item.len() > 0 {
+		    info!("Write lock acq");
 		    let mut lock = from.0.chain.write().await;
 		    for item in item.into_iter()
 		    {
@@ -180,6 +234,9 @@ pub async fn host(from: ChainHandle<String>)
 			    feed::feed(lock.deref_mut(), item, &from.0.opt.bounds);
 			}
 		    }
+		    trace!("Signalling write");
+		    from.0.notify_write.notify();
+		}
 	    }
 	    trace!("child: exiting");
 	}))
@@ -187,44 +244,94 @@ pub async fn host(from: ChainHandle<String>)
 
     trace!("Begin polling on child");
     tokio::select!{
-	v = child => {
+	v = &mut child => {
 	    match v  {
 		#[cold] Ok(_) => {warn!("Child exited before we have? This should probably never happen.")},//Should never happen.
 		Err(e) => {error!("Child exited abnormally. Aborting: {}", e)}, //Child panic or cancel.
 	    }
 	},
 	_ = async move {
-	    let mut rx = data.input.chunk(opt.capacity); //we don't even need this tbh
+	    let mut rx = data.input.chunk(opt.capacity); //we don't even need this tbh, oh well.
 	    
+	    if !data.shutdown.recv().await.unwrap_or(true) { //first shutdown we get for free
 		while Arc::strong_count(&from.0) > 2 {
+		    if *data.shutdown.borrow() {
+			break;
+		    }
+		    
 		    tokio::select!{
+			Some(true) = data.shutdown.recv() => {
+			    debug!("Got shutdown (hang) request. Sending now then breaking");
+			    
+			    let mut rest = {
+				let irx = rx.get_mut();
+				irx.close();  //accept no more inputs
+				let mut output = Vec::with_capacity(opt.capacity);
+				while let Ok(item) = irx.try_recv() {
+				    output.push(item);
+				}
+				output
+			    };
+			    rest.extend(rx.take_now());
+			    if rest.len() > 0 {
+				if let Err(err) = tx.send(rest).await {
+				    error!("Failed to force send buffer, exiting now: {}", err);
+				}
+			    }
+			    break;
+			}
 			_ = time::delay_for(opt.timeout) => {
+			    trace!("Setting push now");
+			    rx.push_now();
+			}
+			_ = from.0.push_now.notified() => {
+			    debug!("Got force push signal");
+			    let take =rx.take_now();
 			    rx.push_now();
+			    if take.len() > 0 {
+				if let Err(err) = tx.send(take).await {
+				    error!("Failed to force send buffer: {}", err);
+				    break;
+				}
+			    }
 			}
 			Some(buffer) = rx.next() => {
+			    debug!("Sending {} (cap {})", buffer.len(), buffer.capacity());
 			    if let Err(err) = tx.send(buffer).await {
 				// Receive closed?
 				//
 				// This probably shouldn't happen, as we `select!` for it up there and child never calls `close()` on `rx`.
 				// In any case, it means we should abort.
-			    error!("Failed to send buffer: {}", err);
+				#[cold] error!("Failed to send buffer: {}", err);
 				break;
 			    }
 			}
 		    }
 		}
+	    }
+	    let last = rx.into_buffer();
+	    if last.len() > 0 {
+		if let Err(err) = tx.send(last).await {
+		    error!("Failed to force send last part of buffer: {}", err);
+		} else {
+		    trace!("Sent rest of buffer");
+		}
+	    }
 	} => {
 	    // Normal exit
 	    trace!("Normal exit")
 	},
     }
+    trace!("Waiting on child");
     // No more handles except child, no more possible inputs.
+    child.await.expect("Child panic");
     trace!("Returning");
 }
 
 /// Spawn a new chain handler for this chain.
 pub fn spawn(from: chain::Chain<String>, opt: Settings) -> (JoinHandle<()>, ChainHandle<String>)
 {
+    debug!("Spawning with opt: {:?}", opt);
     let handle = ChainHandle::with_settings(from, opt);
     (tokio::spawn(host(handle.clone())), handle)
 }

src/main.rs

@@ -145,16 +145,15 @@ async fn main() {
 	    trace!("Error: {}", e);
 	    Chain::new()
 	},
-    }, Default::default()/*TODO*/);
+    }, ccache.handler_settings.clone());
     {
 	let mut tasks = Vec::<BoxFuture<'static, ()>>::new();
+	tasks.push(chain_handle.map(|res| res.expect("Chain handle panicked")).boxed());
 	let (state, chain) = {
-	    let save_when = Arc::new(Notify::new());
 	    
 	    let state = State::new(config,
 				   ccache,
-				   chain,
+				   chain);
-				   Arc::clone(&save_when));
 	    let state2 = state.clone();
 	    let saver = tokio::spawn(save::host(Box::new(state.clone())));
 	    let chain = warp::any().map(move || state.clone());

src/save.rs

@@ -77,10 +77,11 @@ pub async fn host(mut state: Box<State>)
 {
     let to = state.config().file.to_owned();
     let interval = state.config().save_interval();
+    let when = Arc::clone(state.when_ref());
     trace!("Setup oke. Waiting on init");
     if state.on_init().await.is_ok() {
 	debug!("Begin save handler");
-	while Arc::strong_count(state.when()) > 1 {
+	while Arc::strong_count(&when) > 1 {
 	    {
 		let chain = state.chain_ref().read().await;
 		use std::ops::Deref;
@@ -97,7 +98,7 @@ pub async fn host(mut state: Box<State>)
 		    break;
 		}
 	    }
-	    state.when().notified().await;
+	    when.notified().await;
 	    if state.has_shutdown() {
 		break;
 	    }

src/signals.rs

@@ -14,6 +14,7 @@ pub async fn handle(mut state: State)
     let mut usr1 = unix::signal(SignalKind::user_defined1()).expect("Failed to hook SIGUSR1");
     let mut usr2 = unix::signal(SignalKind::user_defined2()).expect("Failed to hook SIGUSR2"); 
     let mut quit = unix::signal(SignalKind::quit()).expect("Failed to hook SIGQUIT");
+    let mut io = unix::signal(SignalKind::io()).expect("Failed to hook IO");
 
     trace!("Setup oke. Waiting on init");
     if state.on_init().await.is_ok() {
@@ -24,15 +25,11 @@ pub async fn handle(mut state: State)
 		    break;
 		}
 		_ = usr1.recv() => {
-		    info!("Got SIGUSR1. Saving chain immediately.");
+		    info!("Got SIGUSR1. Causing chain write.");
-		    if let Err(e) = save::save_now(&state).await {
+		    state.push_now();
-			error!("Failed to save chain: {}", e);
-		    } else{
-			trace!("Saved chain okay");
-		    }
 		},
 		_ = usr2.recv() => {
-		    info!("Got SIGUSR1. Loading chain immediately.");
+		    info!("Got SIGUSR2. Loading chain immediately.");
 		    match save::load(&state.config().file).await {
 			Ok(new) => {
 			    {
@@ -46,6 +43,15 @@ pub async fn handle(mut state: State)
 			},
 		    }
 		},
+		
+		_ = io.recv() => {
+		    info!("Got SIGIO. Saving chain immediately.");
+		    if let Err(e) = save::save_now(&state).await {
+			error!("Failed to save chain: {}", e);
+		    } else{
+			trace!("Saved chain okay");
+		    }
+		},
 		_ = quit.recv() => {
 		    warn!("Got SIGQUIT. Saving chain then aborting.");
 		    if let Err(e) = save::save_now(&state).await {

src/state.rs

@@ -27,7 +27,7 @@ pub struct State
 {
     config: Arc<Box<(Config, config::Cache)>>, //to avoid cloning config
     chain: handle::ChainHandle<String>,
-    save: Arc<Notify>,
+    //save: Arc<Notify>,
     begin: Initialiser,
 
     shutdown: Arc<watch::Sender<bool>>,
@@ -79,13 +79,12 @@ impl State
 	&self.config_cache().outbound_filter
     }
     
-    pub fn new(config: Config, cache: config::Cache, chain: handle::ChainHandle<String>, save: Arc<Notify>) -> Self
+    pub fn new(config: Config, cache: config::Cache, chain: handle::ChainHandle<String>) -> Self
     {
 	let (shutdown, shutdown_recv) = watch::channel(false);
 	Self {
 	    config: Arc::new(Box::new((config, cache))),
 	    chain,
-	    save,
 	    begin: Initialiser::new(),
 	    shutdown: Arc::new(shutdown),
 	    shutdown_recv,
@@ -102,10 +101,10 @@ impl State
 	&self.config.as_ref().1
     }
 
-    pub fn notify_save(&self)
+    /*pub fn notify_save(&self)
     {
     self.save.notify();
-    }
+}*/
 
     /*pub fn chain(&self) -> &RwLock<Chain<String>>
     {
@@ -121,20 +120,29 @@ impl State
 	self.chain.read()
     }
 
-    pub async fn chain_write(&self, buffer: impl IntoIterator<Item = String>) -> Result<(), SendError<Vec<String>>>
+    /// Write to this chain
+    pub async fn chain_write<'a, T: Stream<Item = String>>(&'a self, buffer: T) -> Result<(), SendError<Vec<String>>>
     {
-	self.chain.write(buffer.into_iter().collect()).await
+	self.chain.write_stream(buffer).await
     }
 
-    pub fn when(&self) -> &Arc<Notify>
+    
+    pub fn when_ref(&self) -> &Arc<Notify>
     {
-	&self.save
+	&self.chain.notify_when()
+    }
+
+    /// Force the chain to push through now
+    pub fn push_now(&self)
+    {
+	self.chain.push_now()
     }
 
     pub fn shutdown(self)
     {
 	self.shutdown.broadcast(true).expect("Failed to communicate shutdown");
-	self.save.notify();
+	self.chain.hang();
+	self.when_ref().notify();
     }
 
     pub fn has_shutdown(&self) -> bool