less txhashset locking (#2163)

* less txhashset locking

* rework server stats a bit

servers/src/common/adapters.rs

@@ -260,6 +260,9 @@ impl p2p::ChainAdapter for NetToChainAdapter {
 
 		let max_height = self.chain().header_head().unwrap().height;
 
+		let txhashset = self.chain().txhashset();
+		let txhashset = txhashset.read();
+
 		// looks like we know one, getting as many following headers as allowed
 		let hh = header.height;
 		let mut headers = vec![];
@@ -268,7 +271,7 @@ impl p2p::ChainAdapter for NetToChainAdapter {
 				break;
 			}
 
-			if let Ok(header) = self.chain().get_header_by_height(h) {
+			if let Ok(header) = txhashset.get_header_by_height(h) {
 				headers.push(header);
 			} else {
 				error!("Failed to locate headers successfully.");
@@ -399,9 +402,12 @@ impl NetToChainAdapter {
 
 	// Find the first locator hash that refers to a known header on our main chain.
 	fn find_common_header(&self, locator: &[Hash]) -> Option<BlockHeader> {
+		let txhashset = self.chain().txhashset();
+		let txhashset = txhashset.read();
+
 		for hash in locator {
 			if let Ok(header) = self.chain().get_block_header(&hash) {
-				if let Ok(header_at_height) = self.chain().get_header_by_height(header.height) {
+				if let Ok(header_at_height) = txhashset.get_header_by_height(header.height) {
 					if header.hash() == header_at_height.hash() {
 						return Some(header);
 					}

servers/src/grin/server.rs

@@ -374,6 +374,9 @@ impl Server {
 			let tip_height = self.chain.head().unwrap().height as i64;
 			let mut height = tip_height as i64 - last_blocks.len() as i64 + 1;
 
+			let txhashset = self.chain.txhashset();
+			let txhashset = txhashset.read();
+
 			let diff_entries: Vec<DiffBlock> = last_blocks
 				.windows(2)
 				.map(|pair| {
@@ -385,7 +388,7 @@ impl Server {
 					// Use header hash if real header.
 					// Default to "zero" hash if synthetic header_info.
 					let hash = if height >= 0 {
-						if let Ok(header) = self.chain.get_header_by_height(height as u64) {
+						if let Ok(header) = txhashset.get_header_by_height(height as u64) {
 							header.hash()
 						} else {
 							ZERO_HASH