Cherry-picked external block checks and trace updates (dominant-strat…

…egies#267)

* Updated link block checks in blockchain.go and moved extBlockLink

* Reworked TraceBranches to single function

* Remove reorg 50% on equal difficulty

* Added reset extBlockLink after failed reorg

* Update extBlockLink after normal reorg

* Updated genesis hashes

* Additional reportBlock and feed data for invalid writeBlockWithState

* Updated error checking and comments

* Added bracket

consensus/clique/clique.go

@@ -589,6 +589,11 @@ func (c *Clique) GetExternalBlocks(chain consensus.ChainHeaderReader, header *ty
 	return make([]*types.ExternalBlock, 0), nil
 }
 
+// GetExternalBlocks traces all available branches to find external blocks
+func (c *Clique) GetLinkExternalBlocks(chain consensus.ChainHeaderReader, header *types.Header, logging bool) ([]*types.ExternalBlock, error) {
+	return make([]*types.ExternalBlock, 0), nil
+}
+
 // GetCoincidentHeader retrieves the furthest coincident header back
 func (c *Clique) GetDifficultyOrder(header *types.Header) (int, error) {
 	return 0, nil
@@ -614,12 +619,8 @@ func (c *Clique) GetStopHash(chain consensus.ChainHeaderReader, difficultyContex
 	return common.Hash{}, 0
 }
 
-// TraceBranch recursively traces branches to find
-func (c *Clique) PrimeTraceBranch(chain consensus.ChainHeaderReader, header *types.Header, context int, stopHash common.Hash, originalContext int, originalLocation []byte) ([]*types.ExternalBlock, error) {
-	return make([]*types.ExternalBlock, 0), nil
-}
-
-func (c *Clique) RegionTraceBranch(chain consensus.ChainHeaderReader, header *types.Header, context int, stopHash common.Hash, originalContext int, originalLocation []byte) ([]*types.ExternalBlock, error) {
+// TraceBranches recursively traces branches to find external blocks.
+func (c *Clique) TraceBranches(chain consensus.ChainHeaderReader, header *types.Header, context int, originalContext int, originalLocation []byte) ([]*types.ExternalBlock, error) {
 	return make([]*types.ExternalBlock, 0), nil
 }
 

consensus/consensus.go

@@ -48,6 +48,9 @@ type ChainHeaderReader interface {
 	// GetExternalBlocks retrieve all external blocks for a header.
 	GetExternalBlocks(header *types.Header) ([]*types.ExternalBlock, error)
 
+	// GetExternalBlocks retrieve all external link blocks for a header.
+	GetLinkExternalBlocks(header *types.Header) ([]*types.ExternalBlock, error)
+
 	// GetExternalBlock retrieves an external block header by its hash and context.
 	GetExternalBlock(hash common.Hash, number uint64, context uint64) (*types.ExternalBlock, error)
 
@@ -127,14 +130,11 @@ type Engine interface {
 	// This function determines the difficulty order of a block
 	GetDifficultyOrder(header *types.Header) (int, error)
 
-	// GetStopHash retrieves the stop hash for tracing of blocks in a trace branch.
-	GetStopHash(chain ChainHeaderReader, difficultyContext int, originalContext int, startingHeader *types.Header) (common.Hash, int)
-
-	// PrimeTraceBranch recursively traces branches to find.
-	PrimeTraceBranch(chain ChainHeaderReader, header *types.Header, context int, stopHash common.Hash, originalContext int, originalLocation []byte) ([]*types.ExternalBlock, error)
+	// TraceBranches recursively traces region and zone branches to find external blocks.
+	TraceBranches(chain ChainHeaderReader, header *types.Header, context int, originalContext int, originalLocation []byte) ([]*types.ExternalBlock, error)
 
-	// RegionTraceBranch recursively traces region branches to find.
-	RegionTraceBranch(chain ChainHeaderReader, header *types.Header, context int, stopHash common.Hash, originalContext int, originalLocation []byte) ([]*types.ExternalBlock, error)
+	// GetLinkExternalBlocks links every block to the correct previous block
+	GetLinkExternalBlocks(chain ChainHeaderReader, header *types.Header, logging bool) ([]*types.ExternalBlock, error)
 
 	// Seal generates a new sealing request for the given input block and pushes
 	// the result into the given channel.