Improve capability information and disable old clients.

ethcore/src/client/client.rs

@@ -127,6 +127,7 @@ impl SleepState {
 /// Blockchain database client backed by a persistent database. Owns and manages a blockchain and a block queue.
 /// Call `import_block()` to import a block asynchronously; `flush_queue()` flushes the queue.
 pub struct Client {
+	enabled: AtomicBool,
 	mode: Mutex<Mode>,
 	chain: RwLock<Arc<BlockChain>>,
 	tracedb: RwLock<TraceDB<BlockChain>>,
@@ -164,6 +165,7 @@ impl Client {
 		message_channel: IoChannel<ClientIoMessage>,
 		db_config: &DatabaseConfig,
 	) -> Result<Arc<Client>, ClientError> {
+
 		let path = path.to_path_buf();
 		let gb = spec.genesis_block();
 
@@ -226,6 +228,7 @@ impl Client {
 		};
 
 		let client = Arc::new(Client {
+			enabled: AtomicBool::new(true),
 			sleep_state: Mutex::new(SleepState::new(awake)),
 			liveness: AtomicBool::new(awake),
 			mode: Mutex::new(config.mode.clone()),
@@ -411,6 +414,12 @@ impl Client {
 
 	/// This is triggered by a message coming from a block queue when the block is ready for insertion
 	pub fn import_verified_blocks(&self) -> usize {
+
+		// Shortcut out if we know we're incapable of syncing the chain.
+		if !self.enabled.load(AtomicOrdering::Relaxed) {
+			return 0;
+		}
+
 		let max_blocks_to_import = 4;
 		let (imported_blocks, import_results, invalid_blocks, imported, duration, is_empty) = {
 			let mut imported_blocks = Vec::with_capacity(max_blocks_to_import);
@@ -909,8 +918,16 @@ impl BlockChainClient for Client {
 		r
 	}
 
+	fn disable(&self) {
+		self.set_mode(IpcMode::Off);
+		self.enabled.store(false, AtomicOrdering::Relaxed);
+	}
+
 	fn set_mode(&self, new_mode: IpcMode) {
 		trace!(target: "mode", "Client::set_mode({:?})", new_mode);
+		if !self.enabled.load(AtomicOrdering::Relaxed) {
+			return;
+		}
 		{
 			let mut mode = self.mode.lock();
 			*mode = new_mode.clone().into();

ethcore/src/client/test_client.rs

@@ -677,6 +677,8 @@ impl BlockChainClient for TestBlockChainClient {
 
 	fn set_mode(&self, _: Mode) { unimplemented!(); }
 
+	fn disable(&self) { unimplemented!(); }
+
 	fn pruning_info(&self) -> PruningInfo {
 		PruningInfo {
 			earliest_chain: 1,

ethcore/src/client/traits.rs

@@ -252,6 +252,10 @@ pub trait BlockChainClient : Sync + Send {
 	/// Set the mode.
 	fn set_mode(&self, mode: Mode);
 
+	/// Disable the client from importing blocks. This cannot be undone in this session and indicates
+	/// that a subsystem has reason to believe this executable incapable of syncing the chain.
+	fn disable(&self);
+
 	/// Returns engine-related extra info for `BlockId`.
 	fn block_extra_info(&self, id: BlockId) -> Option<BTreeMap<String, String>>;
 

parity/configuration.rs

@@ -282,7 +282,6 @@ impl Configuration {
 				no_periodic_snapshot: self.args.flag_no_periodic_snapshot,
 				check_seal: !self.args.flag_no_seal_check,
 				download_old_blocks: !self.args.flag_no_ancient_blocks,
-				require_consensus: !self.args.flag_no_consensus,
 				serve_light: self.args.flag_serve_light,
 				verifier_settings: verifier_settings,
 			};
@@ -628,6 +627,7 @@ impl Configuration {
 	fn update_policy(&self) -> Result<UpdatePolicy, String> {
 		Ok(UpdatePolicy {
 			enable_downloading: !self.args.flag_no_download,
+			require_consensus: !self.args.flag_no_consensus,
 			filter: match self.args.flag_auto_update.as_ref() {
 				"none" => UpdateFilter::None,
 				"critical" => UpdateFilter::Critical,
@@ -943,7 +943,7 @@ mod tests {
 			acc_conf: Default::default(),
 			gas_pricer: Default::default(),
 			miner_extras: Default::default(),
-			update_policy: UpdatePolicy { enable_downloading: true, filter: UpdateFilter::Critical },
+			update_policy: UpdatePolicy { enable_downloading: true, require_consensus: true, filter: UpdateFilter::Critical },
 			mode: Default::default(),
 			tracing: Default::default(),
 			compaction: Default::default(),
@@ -961,7 +961,6 @@ mod tests {
 			no_periodic_snapshot: false,
 			check_seal: true,
 			download_old_blocks: true,
-			require_consensus: true,
 			serve_light: false,
 			verifier_settings: Default::default(),
 		}));
@@ -992,14 +991,14 @@ mod tests {
 	fn should_parse_updater_options() {
 		// when
 		let conf0 = parse(&["parity"]);
-		let conf1 = parse(&["parity", "--auto-update", "all"]);
+		let conf1 = parse(&["parity", "--auto-update", "all", "--no-consensus"]);
 		let conf2 = parse(&["parity", "--no-download", "--auto-update=all"]);
 		let conf3 = parse(&["parity", "--auto-update=xxx"]);
 
 		// then
-		assert_eq!(conf0.update_policy().unwrap(), UpdatePolicy{enable_downloading: true, filter: UpdateFilter::Critical});
-		assert_eq!(conf1.update_policy().unwrap(), UpdatePolicy{enable_downloading: true, filter: UpdateFilter::All});
-		assert_eq!(conf2.update_policy().unwrap(), UpdatePolicy{enable_downloading: false, filter: UpdateFilter::All});
+		assert_eq!(conf0.update_policy().unwrap(), UpdatePolicy{enable_downloading: true, require_consensus: true, filter: UpdateFilter::Critical});
+		assert_eq!(conf1.update_policy().unwrap(), UpdatePolicy{enable_downloading: true, require_consensus: false, filter: UpdateFilter::All});
+		assert_eq!(conf2.update_policy().unwrap(), UpdatePolicy{enable_downloading: false, require_consensus: true, filter: UpdateFilter::All});
 		assert!(conf3.update_policy().is_err());
 	}
 

parity/run.rs

@@ -94,7 +94,6 @@ pub struct RunCmd {
 	pub no_periodic_snapshot: bool,
 	pub check_seal: bool,
 	pub download_old_blocks: bool,
-	pub require_consensus: bool,
 	pub serve_light: bool,
 	pub verifier_settings: VerifierSettings,
 }

parity/updater.rs

@@ -40,6 +40,8 @@ pub enum UpdateFilter {
 pub struct UpdatePolicy {
 	/// Download potential updates.
 	pub enable_downloading: bool,
+	/// Disable client if we know we're incapable of syncing.
+	pub require_consensus: bool,
 	/// Which of those downloaded should be automatically installed.
 	pub filter: UpdateFilter,
 }
@@ -48,6 +50,7 @@ impl Default for UpdatePolicy {
 	fn default() -> Self {
 		UpdatePolicy {
 			enable_downloading: false,
+			require_consensus: true,
 			filter: UpdateFilter::None,
 		}
 	}
@@ -81,6 +84,23 @@ pub struct OperationsInfo {
 	pub minor: Option<ReleaseInfo>,
 }
 
+/// Information on the current version's consensus capabililty.
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub enum CapState {
+	/// Unknown.
+	Unknown,
+	/// Capable of consensus indefinitely.
+	Capable,
+	/// Capable of consensus up until a definite block. 
+	CapableUntil(u64),
+	/// Incapable of consensus since a particular block. 
+	IncapableSince(u64),
+}
+
+impl Default for CapState {
+	fn default() -> Self { CapState::Unknown }
+}
+
 #[derive(Debug, Default)]
 struct UpdaterState {
 	latest: Option<OperationsInfo>,
@@ -88,6 +108,8 @@ struct UpdaterState {
 	fetching: Option<ReleaseInfo>,
 	ready: Option<ReleaseInfo>,
 	installed: Option<ReleaseInfo>,
+
+	capability: CapState,
 }
 
 /// Service for checking for updates and determining whether we can achieve consensus.
@@ -135,18 +157,16 @@ impl Updater {
 		let r = Arc::new(u);
 		*r.fetcher.lock() = Some(fetch::Client::new(r.clone()));
 		*r.weak_self.lock() = Arc::downgrade(&r);
+
+		r.poll();
+
 		r
 	}
 
 	/// Is the currently running client capable of supporting the current chain?
-	/// `Some` answer or `None` if information on the running client is not available.
-	pub fn is_capable(&self) -> Option<bool> {
-		self.state.lock().latest.as_ref().and_then(|latest| {
-			latest.this_fork.map(|this_fork| {
-				let current_number = self.client.upgrade().map_or(0, |c| c.block_number(BlockId::Latest).unwrap_or(0));
-				this_fork >= latest.fork || current_number < latest.fork
-			})
-		})
+	/// We default to true if there's no clear information.
+	pub fn capability(&self) -> CapState {
+		self.state.lock().capability
 	}
 
 	/// The release which is ready to be upgraded to, if any. If this returns `Some`, then
@@ -294,6 +314,7 @@ impl Updater {
 
 		let current_number = self.client.upgrade().map_or(0, |c| c.block_number(BlockId::Latest).unwrap_or(0));
 
+		let mut capability = CapState::Unknown; 
 		let latest = self.collect_latest().ok();
 		if let Some(ref latest) = latest {
 			info!(target: "updater", "Latest release in our track is v{} it is {}critical ({} binary is {})",
@@ -321,8 +342,31 @@ impl Updater {
 				}
 			}
 			info!(target: "updater", "Fork: this/current/latest/latest-known: {}/#{}/#{}/#{}", match latest.this_fork { Some(f) => format!("#{}", f), None => "unknown".into(), }, current_number, latest.track.fork, latest.fork);
+
+			if let Some(this_fork) = latest.this_fork {
+				if this_fork < latest.fork {
+					// We're behind the latest fork. Now is the time to be upgrading; perhaps we're too late... 
+					if let Some(c) = self.client.upgrade() {
+						let current_number = c.block_number(BlockId::Latest).unwrap_or(0);
+						if current_number >= latest.fork - 1 {
+							// We're at (or past) the last block we can import. Disable the client.
+							if self.update_policy.require_consensus {
+								c.disable();
+							}
+							capability = CapState::IncapableSince(latest.fork);
+						} else {
+							capability = CapState::CapableUntil(latest.fork);
+						}
+					}
+				} else {
+					capability = CapState::Capable;
+				}
+			}
 		}
-		(*self.state.lock()).latest = latest;
+
+		let mut s = self.state.lock();
+		s.latest = latest;
+		s.capability = capability;
 	}
 }