Precompute is_empty for body downloader targets

Author: remagpie

sync/src/block/downloader/body.rs

@@ -18,16 +18,13 @@ use std::collections::{HashMap, HashSet};
 
 use ccore::UnverifiedTransaction;
 use ctypes::{BlockHash, Header};
-use primitives::H256;
 
 use super::super::message::RequestMessage;
 
 #[derive(Clone)]
 struct Target {
     hash: BlockHash,
-    parent_hash: BlockHash,
-    transactions_root: H256,
-    transaction_root: H256,
+    is_empty: bool,
 }
 
 #[derive(Default)]
@@ -62,7 +59,7 @@ impl BodyDownloader {
             if self.downloading.remove(&hash) {
                 if body.is_empty() {
                     let target = self.targets.iter().find(|t| t.hash == hash).expect("Downloading target must exist");
-                    if target.transaction_root != target.transactions_root {
+                    if !target.is_empty {
                         continue
                     }
                 }
@@ -72,13 +69,11 @@ impl BodyDownloader {
         self.downloading.shrink_to_fit();
     }
 
-    pub fn add_target(&mut self, header: &Header, parent: &Header) {
+    pub fn add_target(&mut self, header: &Header, is_empty: bool) {
         cdebug!(SYNC, "Add download target: {}", header.hash());
         self.targets.push(Target {
             hash: header.hash(),
-            parent_hash: parent.hash(),
-            transactions_root: *header.transactions_root(),
-            transaction_root: *parent.transactions_root(),
+            is_empty,
         });
     }
 

sync/src/block/extension.rs

@@ -85,7 +85,8 @@ impl Extension {
             let child = &neighbors[0];
             let parent = &neighbors[1];
             cdebug!(SYNC, "Adding block #{} (hash: {}) for initial body download target", child.number(), child.hash());
-            body_downloader.add_target(child, parent);
+            let is_empty = child.transactions_root() == parent.transactions_root();
+            body_downloader.add_target(child, is_empty);
         }
         cinfo!(SYNC, "Sync extension initialized");
         Extension {
@@ -410,7 +411,8 @@ impl Extension {
                 .client
                 .block_header(&BlockId::Hash(header.parent_hash()))
                 .expect("Enacted header must have parent");
-            self.body_downloader.add_target(&header.decode(), &parent.decode());
+            let is_empty = header.transactions_root() == parent.transactions_root();
+            self.body_downloader.add_target(&header.decode(), is_empty);
         }
         self.body_downloader.remove_target(&retracted);
     }