core, eth, les: fix messy code (#15367)

* core, eth, les: fix messy code

* les: fixed tx status test and rlp encoding

* core: add a workaround for light sync

core/chain_indexer.go

@@ -36,17 +36,25 @@ import (
 type ChainIndexerBackend interface {
 	// Reset initiates the processing of a new chain segment, potentially terminating
 	// any partially completed operations (in case of a reorg).
-	Reset(section uint64, lastSectionHead common.Hash) error
+	Reset(section uint64, prevHead common.Hash) error
 
 	// Process crunches through the next header in the chain segment. The caller
 	// will ensure a sequential order of headers.
 	Process(header *types.Header)
 
-	// Commit finalizes the section metadata and stores it into the database. This
-	// interface will usually be a batch writer.
+	// Commit finalizes the section metadata and stores it into the database.
 	Commit() error
 }
 
+// ChainIndexerChain interface is used for connecting the indexer to a blockchain
+type ChainIndexerChain interface {
+	// CurrentHeader retrieves the latest locally known header.
+	CurrentHeader() *types.Header
+
+	// SubscribeChainEvent subscribes to new head header notifications.
+	SubscribeChainEvent(ch chan<- ChainEvent) event.Subscription
+}
+
 // ChainIndexer does a post-processing job for equally sized sections of the
 // canonical chain (like BlooomBits and CHT structures). A ChainIndexer is
 // connected to the blockchain through the event system by starting a
@@ -114,21 +122,14 @@ func (c *ChainIndexer) AddKnownSectionHead(section uint64, shead common.Hash) {
 	c.setValidSections(section + 1)
 }
 
-// IndexerChain interface is used for connecting the indexer to a blockchain
-type IndexerChain interface {
-	CurrentHeader() *types.Header
-	SubscribeChainEvent(ch chan<- ChainEvent) event.Subscription
-}
-
 // Start creates a goroutine to feed chain head events into the indexer for
 // cascading background processing. Children do not need to be started, they
 // are notified about new events by their parents.
-func (c *ChainIndexer) Start(chain IndexerChain) {
-	ch := make(chan ChainEvent, 10)
-	sub := chain.SubscribeChainEvent(ch)
-	currentHeader := chain.CurrentHeader()
+func (c *ChainIndexer) Start(chain ChainIndexerChain) {
+	events := make(chan ChainEvent, 10)
+	sub := chain.SubscribeChainEvent(events)
 
-	go c.eventLoop(currentHeader, ch, sub)
+	go c.eventLoop(chain.CurrentHeader(), events, sub)
 }
 
 // Close tears down all goroutines belonging to the indexer and returns any error
@@ -149,14 +150,12 @@ func (c *ChainIndexer) Close() error {
 			errs = append(errs, err)
 		}
 	}
-
 	// Close all children
 	for _, child := range c.children {
 		if err := child.Close(); err != nil {
 			errs = append(errs, err)
 		}
 	}
-
 	// Return any failures
 	switch {
 	case len(errs) == 0:
@@ -173,7 +172,7 @@ func (c *ChainIndexer) Close() error {
 // eventLoop is a secondary - optional - event loop of the indexer which is only
 // started for the outermost indexer to push chain head events into a processing
 // queue.
-func (c *ChainIndexer) eventLoop(currentHeader *types.Header, ch chan ChainEvent, sub event.Subscription) {
+func (c *ChainIndexer) eventLoop(currentHeader *types.Header, events chan ChainEvent, sub event.Subscription) {
 	// Mark the chain indexer as active, requiring an additional teardown
 	atomic.StoreUint32(&c.active, 1)
 
@@ -193,7 +192,7 @@ func (c *ChainIndexer) eventLoop(currentHeader *types.Header, ch chan ChainEvent
 			errc <- nil
 			return
 
-		case ev, ok := <-ch:
+		case ev, ok := <-events:
 			// Received a new event, ensure it's not nil (closing) and update
 			if !ok {
 				errc := <-c.quit
@@ -202,6 +201,8 @@ func (c *ChainIndexer) eventLoop(currentHeader *types.Header, ch chan ChainEvent
 			}
 			header := ev.Block.Header()
 			if header.ParentHash != prevHash {
+				// Reorg to the common ancestor (might not exist in light sync mode, skip reorg then)
+				// TODO(karalabe, zsfelfoldi): This seems a bit brittle, can we detect this case explicitly?
 				if h := FindCommonAncestor(c.chainDb, prevHeader, header); h != nil {
 					c.newHead(h.Number.Uint64(), true)
 				}
@@ -259,8 +260,8 @@ func (c *ChainIndexer) newHead(head uint64, reorg bool) {
 // down into the processing backend.
 func (c *ChainIndexer) updateLoop() {
 	var (
-		updated   time.Time
-		updateMsg bool
+		updating bool
+		updated  time.Time
 	)
 
 	for {
@@ -277,7 +278,7 @@ func (c *ChainIndexer) updateLoop() {
 				// Periodically print an upgrade log message to the user
 				if time.Since(updated) > 8*time.Second {
 					if c.knownSections > c.storedSections+1 {
-						updateMsg = true
+						updating = true
 						c.log.Info("Upgrading chain index", "percentage", c.storedSections*100/c.knownSections)
 					}
 					updated = time.Now()
@@ -300,8 +301,8 @@ func (c *ChainIndexer) updateLoop() {
 				if err == nil && oldHead == c.SectionHead(section-1) {
 					c.setSectionHead(section, newHead)
 					c.setValidSections(section + 1)
-					if c.storedSections == c.knownSections && updateMsg {
-						updateMsg = false
+					if c.storedSections == c.knownSections && updating {
+						updating = false
 						c.log.Info("Finished upgrading chain index")
 					}
 
@@ -412,7 +413,7 @@ func (c *ChainIndexer) setValidSections(sections uint64) {
 	c.storedSections = sections // needed if new > old
 }
 
-// sectionHead retrieves the last block hash of a processed section from the
+// SectionHead retrieves the last block hash of a processed section from the
 // index database.
 func (c *ChainIndexer) SectionHead(section uint64) common.Hash {
 	var data [8]byte