Fix header_by_height (#922)

Currently for fast sync index header_by_height is created only for headers above the horizon

api/src/handlers.rs

@@ -419,6 +419,21 @@ impl Handler for ChainValidationHandler {
 	}
 }
 
+/// Temporary - fix header by height index.
+/// POST /v1/chain/height-index
+pub struct HeaderByHeightHandler {
+	pub chain: Weak<chain::Chain>,
+}
+
+impl Handler for HeaderByHeightHandler {
+	fn handle(&self, _req: &mut Request) -> IronResult<Response> {
+		match w(&self.chain).rebuild_header_by_height() {
+			Ok(_) => Ok(Response::with((status::Ok, ""))),
+			Err(_) => Ok(Response::with((status::InternalServerError, ""))),
+		}
+	}
+}
+
 /// Chain compaction handler. Trigger a compaction of the chain state to regain
 /// storage space.
 /// GET /v1/chain/compact
@@ -650,6 +665,9 @@ pub fn start_rest_apis<T>(
 			let chain_compact_handler = ChainCompactHandler {
 				chain: chain.clone(),
 			};
+			let header_height_handler = HeaderByHeightHandler {
+				chain: chain.clone(),
+			};
 			let chain_validation_handler = ChainValidationHandler {
 				chain: chain.clone(),
 			};
@@ -686,6 +704,7 @@ pub fn start_rest_apis<T>(
 				"get chain/compact".to_string(),
 				"get chain/validate".to_string(),
 				"get chain/outputs".to_string(),
+				"post chain/height-index".to_string(),
 				"get status".to_string(),
 				"get txhashset/roots".to_string(),
 				"get txhashset/lastoutputs?n=10".to_string(),
@@ -708,6 +727,7 @@ pub fn start_rest_apis<T>(
 				chain_compact: get "/chain/compact" => chain_compact_handler,
 				chain_validate: get "/chain/validate" => chain_validation_handler,
 				chain_outputs: get "/chain/outputs/*" => output_handler,
+				header_height: post "/chain/height-index" => header_height_handler,
 				status: get "/status" => status_handler,
 				txhashset_roots: get "/txhashset/*" => txhashset_handler,
 				pool_info: get "/pool" => pool_info_handler,

chain/src/chain.rs

@@ -750,4 +750,11 @@ impl Chain {
 			.get_block_pmmr_file_metadata(h)
 			.map_err(|e| Error::StoreErr(e, "retrieve block pmmr metadata".to_owned()))
 	}
+
+	pub fn rebuild_header_by_height(&self) -> Result<(), Error> {
+		let head = self.head_header()?;
+		self.store
+			.build_by_height_index(&head, true)
+			.map_err(|e| Error::StoreErr(e, "rebuilf header by height index".to_owned()))
+	}
 }

chain/src/store.rs

@@ -229,15 +229,20 @@ impl ChainStore for ChainKVStore {
 		for n in header.height..old_tip.height {
 			self.delete_header_by_height(n)?;
 		}
+		self.build_by_height_index(header, false)
+	}
 
+	fn build_by_height_index(&self, header: &BlockHeader, force: bool) -> Result<(), Error> {
 		self.save_header_height(&header)?;
 
 		if header.height > 0 {
 			let mut prev_header = self.get_block_header(&header.previous)?;
 			while prev_header.height > 0 {
+				if !force {
 					if let Ok(_) = self.is_on_current_chain(&prev_header) {
 						break;
 					}
+				}
 				self.save_header_height(&prev_header)?;
 
 				prev_header = self.get_block_header(&prev_header.previous)?;

chain/src/types.rs

@@ -330,6 +330,9 @@ pub trait ChainStore: Send + Sync {
 	/// the consistency of the height chain in store by assuring previous
 	/// headers are also at their respective heights.
 	fn setup_height(&self, bh: &BlockHeader, old_tip: &Tip) -> Result<(), store::Error>;
+
+	/// Similar to setup_height but without handling fork
+	fn build_by_height_index(&self, header: &BlockHeader, force: bool) -> Result<(), store::Error>;
 }
 
 /// Single serializable struct to hold metadata about all PMMR file position

grin/tests/simulnet.rs

@@ -265,6 +265,9 @@ fn simulate_fast_sync() {
 	while s2.head().height != s2.header_head().height || s2.head().height < 20 {
 		thread::sleep(time::Duration::from_millis(1000));
 	}
+	s2.chain.rebuild_header_by_height();
+	let h2 = s2.chain.get_header_by_height(1).unwrap();
+
 	s1.stop();
 	s2.stop();
 }