Implement parity_versionInfo & parity_setChain on LC; fix parity_setChain (#10312)

* Light client: implement parity_versionInfo RPC

* Light client: implement set_exit_handler & parity_setChain RPC

* parity_setChain RPC: return an error if failed (instead of `true`)

* Implement eth_subscribe('syncing') RPC for full node & light node

* Fix indentation

* Revert commit: Implement eth_subscribe('syncing')

* Revert change to Cr callback function

ethcore/light/src/client/mod.rs

@@ -116,6 +116,9 @@ pub trait LightChainClient: Send + Sync {
 	/// Query whether a block is known.
 	fn is_known(&self, hash: &H256) -> bool;
 
+	/// Set the chain via a spec name.
+	fn set_spec_name(&self, new_spec_name: String) -> Result<(), ()>;
+
 	/// Clear the queue.
 	fn clear_queue(&self);
 
@@ -164,6 +167,8 @@ pub struct Client<T> {
 	listeners: RwLock<Vec<Weak<LightChainNotify>>>,
 	fetcher: T,
 	verify_full: bool,
+	/// A closure to call when we want to restart the client
+	exit_handler: Mutex<Option<Box<Fn(String) + 'static + Send>>>,
 }
 
 impl<T: ChainDataFetcher> Client<T> {
@@ -190,6 +195,7 @@ impl<T: ChainDataFetcher> Client<T> {
 			listeners: RwLock::new(vec![]),
 			fetcher,
 			verify_full: config.verify_full,
+			exit_handler: Mutex::new(None),
 		})
 	}
 
@@ -360,6 +366,14 @@ impl<T: ChainDataFetcher> Client<T> {
 		self.chain.heap_size_of_children()
 	}
 
+	/// Set a closure to call when the client wants to be restarted.
+	///
+	/// The parameter passed to the callback is the name of the new chain spec to use after
+	/// the restart.
+	pub fn set_exit_handler<F>(&self, f: F) where F: Fn(String) + 'static + Send {
+		*self.exit_handler.lock() = Some(Box::new(f));
+	}
+
 	/// Get a handle to the verification engine.
 	pub fn engine(&self) -> &Arc<EthEngine> {
 		&self.engine
@@ -563,6 +577,17 @@ impl<T: ChainDataFetcher> LightChainClient for Client<T> {
 		Client::engine(self)
 	}
 
+	fn set_spec_name(&self, new_spec_name: String) -> Result<(), ()> {
+		trace!(target: "mode", "Client::set_spec_name({:?})", new_spec_name);
+		if let Some(ref h) = *self.exit_handler.lock() {
+			(*h)(new_spec_name);
+			Ok(())
+		} else {
+			warn!("Not hypervised; cannot change chain.");
+			Err(())
+		}
+	}
+
 	fn is_known(&self, hash: &H256) -> bool {
 		self.status(hash) == BlockStatus::InChain
 	}

ethcore/src/client/client.rs

@@ -1706,15 +1706,17 @@ impl BlockChainClient for Client {
 		self.config.spec_name.clone()
 	}
 
-	fn set_spec_name(&self, new_spec_name: String) {
+	fn set_spec_name(&self, new_spec_name: String) -> Result<(), ()> {
 		trace!(target: "mode", "Client::set_spec_name({:?})", new_spec_name);
 		if !self.enabled.load(AtomicOrdering::Relaxed) {
-			return;
+			return Err(());
 		}
 		if let Some(ref h) = *self.exit_handler.lock() {
 			(*h)(new_spec_name);
+			Ok(())
 		} else {
 			warn!("Not hypervised; cannot change chain.");
+			Err(())
 		}
 	}
 

ethcore/src/client/test_client.rs

@@ -863,7 +863,7 @@ impl BlockChainClient for TestBlockChainClient {
 
 	fn spec_name(&self) -> String { "foundation".into() }
 
-	fn set_spec_name(&self, _: String) { unimplemented!(); }
+	fn set_spec_name(&self, _: String) -> Result<(), ()> { unimplemented!(); }
 
 	fn disable(&self) { self.disabled.store(true, AtomicOrder::Relaxed); }
 

ethcore/src/client/traits.rs

@@ -360,7 +360,7 @@ pub trait BlockChainClient : Sync + Send + AccountData + BlockChain + CallContra
 	fn spec_name(&self) -> String;
 
 	/// Set the chain via a spec name.
-	fn set_spec_name(&self, spec_name: String);
+	fn set_spec_name(&self, spec_name: String) -> Result<(), ()>;
 
 	/// 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.

parity/rpc_apis.rs

@@ -634,7 +634,7 @@ impl<C: LightChainClient + 'static> LightDependencies<C> {
 					handler.extend_with(ParityAccounts::to_delegate(ParityAccountsClient::new(&self.accounts)));
 				}
 				Api::ParitySet => handler.extend_with(
-					light::ParitySetClient::new(self.sync.clone(), self.fetch.clone())
+					light::ParitySetClient::new(self.client.clone(), self.sync.clone(), self.fetch.clone())
 						.to_delegate(),
 				),
 				Api::Traces => handler.extend_with(light::TracesClient.to_delegate()),

parity/run.rs

@@ -165,7 +165,9 @@ impl ::local_store::NodeInfo for FullNodeInfo {
 type LightClient = ::light::client::Client<::light_helpers::EpochFetch>;
 
 // helper for light execution.
-fn execute_light_impl(cmd: RunCmd, logger: Arc<RotatingLogger>) -> Result<RunningClient, String> {
+fn execute_light_impl<Cr>(cmd: RunCmd, logger: Arc<RotatingLogger>, on_client_rq: Cr) -> Result<RunningClient, String>
+	where Cr: Fn(String) + 'static + Send
+{
 	use light::client as light_client;
 	use sync::{LightSyncParams, LightSync, ManageNetwork};
 	use parking_lot::{Mutex, RwLock};
@@ -367,6 +369,8 @@ fn execute_light_impl(cmd: RunCmd, logger: Arc<RotatingLogger>) -> Result<Runnin
 	service.add_notify(informant.clone());
 	service.register_handler(informant.clone()).map_err(|_| "Unable to register informant handler".to_owned())?;
 
+	client.set_exit_handler(on_client_rq);
+
 	Ok(RunningClient {
 		inner: RunningClientInner::Light {
 			rpc: rpc_direct,
@@ -930,7 +934,7 @@ pub fn execute<Cr, Rr>(cmd: RunCmd, logger: Arc<RotatingLogger>,
 		Rr: Fn() + 'static + Send
 {
 	if cmd.light {
-		execute_light_impl(cmd, logger)
+		execute_light_impl(cmd, logger, on_client_rq)
 	} else {
 		execute_impl(cmd, logger, on_client_rq, on_updater_rq)
 	}

rpc/src/v1/helpers/errors.rs

@@ -59,6 +59,7 @@ mod codes {
 	pub const NO_PEERS: i64 = -32066;
 	pub const DEPRECATED: i64 = -32070;
 	pub const EXPERIMENTAL_RPC: i64 = -32071;
+	pub const CANNOT_RESTART: i64 = -32080;
 }
 
 pub fn unimplemented(details: Option<String>) -> Error {
@@ -125,6 +126,14 @@ pub fn account<T: fmt::Debug>(error: &str, details: T) -> Error {
 	}
 }
 
+pub fn cannot_restart() -> Error {
+	Error {
+		code: ErrorCode::ServerError(codes::CANNOT_RESTART),
+		message: "Parity could not be restarted. This feature is disabled in development mode and if the binary name isn't parity.".into(),
+		data: None,
+	}
+}
+
 /// Internal error signifying a logic error in code.
 /// Should not be used when function can just fail
 /// because of invalid parameters or incomplete node state.

rpc/src/v1/impls/light/parity.rs

@@ -24,6 +24,7 @@ use crypto::DEFAULT_MAC;
 use ethkey::{crypto::ecies, Brain, Generator};
 use ethstore::random_phrase;
 use sync::{LightSyncInfo, LightSyncProvider, LightNetworkDispatcher, ManageNetwork};
+use updater::VersionInfo as UpdaterVersionInfo;
 use ethereum_types::{H64, H160, H256, H512, U64, U256};
 use ethcore_logger::RotatingLogger;
 
@@ -299,7 +300,7 @@ where
 	}
 
 	fn version_info(&self) -> Result<VersionInfo> {
-		Err(errors::light_unimplemented(None))
+		Ok(UpdaterVersionInfo::this().into())
 	}
 
 	fn releases_info(&self) -> Result<Option<OperationsInfo>> {

rpc/src/v1/impls/light/parity_set.rs

@@ -23,6 +23,7 @@ use std::sync::Arc;
 use ethereum_types::{H160, H256, U256};
 use fetch::{self, Fetch};
 use hash::keccak_buffer;
+use light::client::LightChainClient;
 use sync::ManageNetwork;
 
 use jsonrpc_core::{Result, BoxFuture};
@@ -33,14 +34,16 @@ use v1::types::{Bytes, ReleaseInfo, Transaction};
 
 /// Parity-specific rpc interface for operations altering the settings.
 pub struct ParitySetClient<F> {
+	client: Arc<LightChainClient>,
 	net: Arc<ManageNetwork>,
 	fetch: F,
 }
 
 impl<F: Fetch> ParitySetClient<F> {
 	/// Creates new `ParitySetClient` with given `Fetch`.
-	pub fn new(net: Arc<ManageNetwork>, fetch: F) -> Self {
+	pub fn new(client: Arc<LightChainClient>, net: Arc<ManageNetwork>, fetch: F) -> Self {
 		ParitySetClient {
+			client: client,
 			net: net,
 			fetch: fetch,
 		}
@@ -118,8 +121,8 @@ impl<F: Fetch> ParitySet for ParitySetClient<F> {
 		Err(errors::light_unimplemented(None))
 	}
 
-	fn set_spec_name(&self, _spec_name: String) -> Result<bool> {
+	fn set_spec_name(&self, spec_name: String) -> Result<bool> {
-		Err(errors::light_unimplemented(None))
+		self.client.set_spec_name(spec_name).map(|_| true).map_err(|()| errors::cannot_restart())
 	}
 
 	fn hash_content(&self, url: String) -> BoxFuture<H256> {

rpc/src/v1/impls/parity_set.rs

@@ -211,8 +211,7 @@ impl<C, M, U, F> ParitySet for ParitySetClient<C, M, U, F> where
 	}
 
 	fn set_spec_name(&self, spec_name: String) -> Result<bool> {
-		self.client.set_spec_name(spec_name);
+		self.client.set_spec_name(spec_name).map(|_| true).map_err(|()| errors::cannot_restart())
-		Ok(true)
 	}
 
 	fn hash_content(&self, url: String) -> BoxFuture<H256> {