RPC: Implements eth_subscribe("syncing") (#10311)

* implement eth_subscibe syncing

* fix imports

* add is_major_syncing to SyncProvider

* add eth_subscribe(syncing) support for light clients

* tests

* fix TestSyncClient

* correct LightFetch impl

* added currentBlock, startingBlock, highestBlock to PubSubSyncStatus

* fixed tests

* fix PR grumbles

* improve code style

* is_syncing -> syncing

* code style

* use ethereum types

parity/informant.rs

@@ -24,7 +24,7 @@ use std::time::{Instant, Duration};
 
 use atty;
 use ethcore::client::{
-	BlockId, BlockChainClient, ChainInfo, BlockInfo, BlockChainInfo,
+	BlockId, ChainInfo, BlockInfo, BlockChainInfo, BlockChainClient,
 	BlockQueueInfo, ChainNotify, NewBlocks, ClientReport, Client, ClientIoMessage
 };
 use types::BlockNumber;

parity/modules.rs

@@ -20,6 +20,7 @@ use ethcore::client::BlockChainClient;
 use sync::{self, AttachedProtocol, SyncConfig, NetworkConfiguration, Params, ConnectionFilter};
 use ethcore::snapshot::SnapshotService;
 use light::Provider;
+use parity_runtime::Executor;
 
 pub use sync::{EthSync, SyncProvider, ManageNetwork, PrivateTxHandler};
 pub use ethcore::client::ChainNotify;
@@ -34,6 +35,7 @@ pub type SyncModules = (
 
 pub fn sync(
 	config: SyncConfig,
+	executor: Executor,
 	network_config: NetworkConfiguration,
 	chain: Arc<BlockChainClient>,
 	snapshot_service: Arc<SnapshotService>,
@@ -45,6 +47,7 @@ pub fn sync(
 ) -> Result<SyncModules, sync::Error> {
 	let eth_sync = EthSync::new(Params {
 		config,
+		executor,
 		chain,
 		provider,
 		snapshot_service,

parity/rpc_apis.rs

@@ -25,6 +25,8 @@ use account_utils::{self, AccountProvider};
 use ethcore::client::Client;
 use ethcore::miner::Miner;
 use ethcore::snapshot::SnapshotService;
+use ethcore::client::BlockChainClient;
+use sync::SyncState;
 use ethcore_logger::RotatingLogger;
 use ethcore_private_tx::Provider as PrivateTransactionManager;
 use ethcore_service::PrivateTxService;
@@ -320,8 +322,22 @@ impl FullDependencies {
 				}
 				Api::EthPubSub => {
 					if !for_generic_pubsub {
-						let client =
+						let mut client =
 							EthPubSubClient::new(self.client.clone(), self.executor.clone());
+						let weak_client = Arc::downgrade(&self.client);
+
+						client.add_sync_notifier(self.sync.sync_notification(), move |state| {
+							let client = weak_client.upgrade()?;
+							let queue_info = client.queue_info();
+
+							let is_syncing_state = match state { SyncState::Idle | SyncState::NewBlocks => false, _ => true };
+							let is_verifying = queue_info.unverified_queue_size + queue_info.verified_queue_size > 3;
+
+							Some(PubSubSyncStatus {
+								syncing: is_verifying || is_syncing_state,
+							})
+						});
+
 						let h = client.handler();
 						self.miner
 							.add_transactions_listener(Box::new(move |hashes| {
@@ -553,7 +569,7 @@ impl<C: LightChainClient + 'static> LightDependencies<C> {
 					}
 				}
 				Api::EthPubSub => {
-					let client = EthPubSubClient::light(
+					let mut client = EthPubSubClient::light(
 						self.client.clone(),
 						self.on_demand.clone(),
 						self.sync.clone(),
@@ -561,6 +577,21 @@ impl<C: LightChainClient + 'static> LightDependencies<C> {
 						self.executor.clone(),
 						self.gas_price_percentile,
 					);
+
+					let weak_client = Arc::downgrade(&self.client);
+
+					client.add_sync_notifier(self.sync.sync_notification(), move |state| {
+						let client = weak_client.upgrade()?;
+						let queue_info = client.queue_info();
+
+						let is_syncing_state = match state { SyncState::Idle | SyncState::NewBlocks => false, _ => true };
+						let is_verifying = queue_info.unverified_queue_size + queue_info.verified_queue_size > 3;
+
+						Some(PubSubSyncStatus {
+							syncing: is_verifying || is_syncing_state,
+						})
+					});
+
 					self.client.add_listener(client.handler() as Weak<_>);
 					let h = client.handler();
 					self.transaction_queue

parity/run.rs

@@ -41,7 +41,7 @@ use node_filter::NodeFilter;
 use parity_runtime::Runtime;
 use sync::{self, SyncConfig, PrivateTxHandler};
 use parity_rpc::{
-	Origin, Metadata, NetworkSettings, informant, is_major_importing, PubSubSession, FutureResult, FutureResponse, FutureOutput
+	Origin, Metadata, NetworkSettings, informant, PubSubSession, FutureResult, FutureResponse, FutureOutput
 };
 use updater::{UpdatePolicy, Updater};
 use parity_version::version;
@@ -661,6 +661,7 @@ fn execute_impl<Cr, Rr>(cmd: RunCmd, logger: Arc<RotatingLogger>, on_client_rq:
 	// create sync object
 	let (sync_provider, manage_network, chain_notify, priority_tasks) = modules::sync(
 		sync_config,
+		runtime.executor(),
 		net_conf.clone().into(),
 		client.clone(),
 		snapshot_service.clone(),
@@ -815,10 +816,9 @@ fn execute_impl<Cr, Rr>(cmd: RunCmd, logger: Arc<RotatingLogger>, on_client_rq:
 		true => None,
 		false => {
 			let sync = sync_provider.clone();
-			let client = client.clone();
 			let watcher = Arc::new(snapshot::Watcher::new(
 				service.client(),
-				move || is_major_importing(Some(sync.status().state), client.queue_info()),
+				move || sync.is_major_syncing(),
 				service.io().channel(),
 				SNAPSHOT_PERIOD,
 				SNAPSHOT_HISTORY,