core, eth/downloader: implement pruning mode sync (ethereum#31414)

This pull request introduces new sync logic for pruning mode. The downloader will now skip
insertion of block bodies and receipts before the configured history cutoff point.

Originally, in snap sync, the header chain and other components (bodies and receipts) were
inserted separately. However, in Proof-of-Stake, this separation is unnecessary since the
sync target is already verified by the CL.

To simplify the process, this pull request modifies `InsertReceiptChain` to insert headers
along with block bodies and receipts together. Besides, `InsertReceiptChain` doesn't have
the notion of reorg, as the common ancestor is always be found before the sync and extra
side chain is truncated at the beginning if they fall in the ancient store. The stale
canonical chain flags will always be rewritten by the new chain. Explicit reorg logic is
no longer required in `InsertReceiptChain`.

Author: rjl493456442

cmd/geth/chaincmd.go

@@ -457,7 +457,7 @@ 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() {