les: implement request distributor, fix blocking issues (#3660)

* les: implement request distributor, fix blocking issues
* core: moved header validation before chain mutex lock

2 files changed, 15 insertions, 5 deletions

diff --git a/core/blockchain.go b/core/blockchain.go
index 207c21a65..a57832df0 100644
--- a/core/blockchain.go
+++ b/core/blockchain.go
@@ -1313,6 +1313,11 @@ Error: %v
 // of the header retrieval mechanisms already need to verify nonces, as well as
 // because nonces can be verified sparsely, not needing to check each.
 func (self *BlockChain) InsertHeaderChain(chain []*types.Header, checkFreq int) (int, error) {
+	start := time.Now()
+	if i, err := self.hc.ValidateHeaderChain(chain, checkFreq); err != nil {
+		return i, err
+	}
+
 	// Make sure only one thread manipulates the chain at once
 	self.chainmu.Lock()
 	defer self.chainmu.Unlock()
@@ -1328,7 +1333,7 @@ func (self *BlockChain) InsertHeaderChain(chain []*types.Header, checkFreq int)
 		return err
 	}
 
-	return self.hc.InsertHeaderChain(chain, checkFreq, whFunc)
+	return self.hc.InsertHeaderChain(chain, whFunc, start)
 }
 
 // writeHeader writes a header into the local chain, given that its parent is
diff --git a/core/headerchain.go b/core/headerchain.go
index a3d622087..57da9771b 100644
--- a/core/headerchain.go
+++ b/core/headerchain.go
@@ -219,7 +219,8 @@ type WhCallback func(*types.Header) error
 // should be done or not. The reason behind the optional check is because some
 // of the header retrieval mechanisms already need to verfy nonces, as well as
 // because nonces can be verified sparsely, not needing to check each.
-func (hc *HeaderChain) InsertHeaderChain(chain []*types.Header, checkFreq int, writeHeader WhCallback) (int, error) {
+
+func (hc *HeaderChain) ValidateHeaderChain(chain []*types.Header, checkFreq int) (int, error) {
 	// Do a sanity check that the provided chain is actually ordered and linked
 	for i := 1; i < len(chain); i++ {
 		if chain[i].Number.Uint64() != chain[i-1].Number.Uint64()+1 || chain[i].ParentHash != chain[i-1].Hash() {
@@ -231,9 +232,6 @@ func (hc *HeaderChain) InsertHeaderChain(chain []*types.Header, checkFreq int, w
 				chain[i-1].Hash().Bytes()[:4], i, chain[i].Number, chain[i].Hash().Bytes()[:4], chain[i].ParentHash[:4])
 		}
 	}
-	// Collect some import statistics to report on
-	stats := struct{ processed, ignored int }{}
-	start := time.Now()
 
 	// Generate the list of headers that should be POW verified
 	verify := make([]bool, len(chain))
@@ -309,6 +307,13 @@ func (hc *HeaderChain) InsertHeaderChain(chain []*types.Header, checkFreq int, w
 			}
 		}
 	}
+
+	return 0, nil
+}
+
+func (hc *HeaderChain) InsertHeaderChain(chain []*types.Header, writeHeader WhCallback, start time.Time) (int, error) {
+	// Collect some import statistics to report on
+	stats := struct{ processed, ignored int }{}
 	// All headers passed verification, import them into the database
 	for i, header := range chain {
 		// Short circuit insertion if shutting down