core, eth/downloader: implement pruning mode sync

Author: rjl493456442

cmd/geth/chaincmd.go

@@ -445,7 +445,7 @@ func importHistory(ctx *cli.Context) error {
 		network = networks[0]
 	}
 
-	if err := utils.ImportHistory(chain, db, dir, network); err != nil {
+	if err := utils.ImportHistory(chain, dir, network); err != nil {
 		return err
 	}
 	fmt.Printf("Import done in %v\n", time.Since(start))

cmd/utils/cmd.go

@@ -246,8 +246,9 @@ func readList(filename string) ([]string, error) {
 }
 
 // ImportHistory imports Era1 files containing historical block information,
-// starting from genesis.
-func ImportHistory(chain *core.BlockChain, db ethdb.Database, dir string, network string) error {
+// starting from genesis. The assumption is held that the provided chain
+// segment in Era1 file should all be canonical and verified.
+func ImportHistory(chain *core.BlockChain, dir string, network string) error {
 	if chain.CurrentSnapBlock().Number.BitLen() != 0 {
 		return errors.New("history import only supported when starting from genesis")
 	}
@@ -308,11 +309,6 @@ func ImportHistory(chain *core.BlockChain, db ethdb.Database, dir string, networ
 				if err != nil {
 					return fmt.Errorf("error reading receipts %d: %w", it.Number(), err)
 				}
-				if status, err := chain.HeaderChain().InsertHeaderChain([]*types.Header{block.Header()}, start); err != nil {
-					return fmt.Errorf("error inserting header %d: %w", it.Number(), err)
-				} else if status != core.CanonStatTy {
-					return fmt.Errorf("error inserting header %d, not canon: %v", it.Number(), status)
-				}
 				if _, err := chain.InsertReceiptChain([]*types.Block{block}, []types.Receipts{receipts}, 2^64-1); err != nil {
 					return fmt.Errorf("error inserting body %d: %w", it.Number(), err)
 				}

cmd/utils/history_test.go

@@ -171,7 +171,7 @@ func TestHistoryImportAndExport(t *testing.T) {
 	if err != nil {
 		t.Fatalf("unable to initialize chain: %v", err)
 	}
-	if err := ImportHistory(imported, db2, dir, "mainnet"); err != nil {
+	if err := ImportHistory(imported, dir, "mainnet"); err != nil {
 		t.Fatalf("failed to import chain: %v", err)
 	}
 	if have, want := imported.CurrentHeader(), chain.CurrentHeader(); have.Hash() != want.Hash() {