all: integrate the freezer with fast sync

* all: freezer style syncing

core, eth, les, light: clean up freezer relative APIs

core, eth, les, trie, ethdb, light: clean a bit

core, eth, les, light: add unit tests

core, light: rewrite setHead function

core, eth: fix downloader unit tests

core: add receipt chain insertion test

core: use constant instead of hardcoding table name

core: fix rollback

core: fix setHead

core/rawdb: remove canonical block first and then iterate side chain

core/rawdb, ethdb: add hasAncient interface

eth/downloader: calculate ancient limit via cht first

core, eth, ethdb: lots of fixes

* eth/downloader: print ancient disable log only for fast sync

light/lightchain.go

@@ -165,12 +165,12 @@ func (lc *LightChain) loadLastState() error {
 
 // SetHead rewinds the local chain to a new head. Everything above the new
 // head will be deleted and the new one set.
-func (lc *LightChain) SetHead(head uint64) {
+func (lc *LightChain) SetHead(head uint64) error {
 	lc.chainmu.Lock()
 	defer lc.chainmu.Unlock()
 
-	lc.hc.SetHead(head, nil)
-	lc.loadLastState()
+	lc.hc.SetHead(head, nil, nil)
+	return lc.loadLastState()
 }
 
 // GasLimit returns the gas limit of the current HEAD block.

light/nodeset.go

@@ -115,7 +115,7 @@ func (db *NodeSet) NodeList() NodeList {
 }
 
 // Store writes the contents of the set to the given database
-func (db *NodeSet) Store(target ethdb.Writer) {
+func (db *NodeSet) Store(target ethdb.KeyValueWriter) {
 	db.lock.RLock()
 	defer db.lock.RUnlock()
 
@@ -124,11 +124,11 @@ func (db *NodeSet) Store(target ethdb.Writer) {
 	}
 }
 
-// NodeList stores an ordered list of trie nodes. It implements ethdb.Writer.
+// NodeList stores an ordered list of trie nodes. It implements ethdb.KeyValueWriter.
 type NodeList []rlp.RawValue
 
 // Store writes the contents of the list to the given database
-func (n NodeList) Store(db ethdb.Writer) {
+func (n NodeList) Store(db ethdb.KeyValueWriter) {
 	for _, node := range n {
 		db.Put(crypto.Keccak256(node), node)
 	}

light/trie.go

@@ -141,7 +141,7 @@ func (t *odrTrie) GetKey(sha []byte) []byte {
 	return nil
 }
 
-func (t *odrTrie) Prove(key []byte, fromLevel uint, proofDb ethdb.Writer) error {
+func (t *odrTrie) Prove(key []byte, fromLevel uint, proofDb ethdb.KeyValueWriter) error {
 	return errors.New("not implemented, needs client/server interface split")
 }