add exporter

fvm/evm/emulator/state/exporter.go

@@ -0,0 +1,163 @@
+package state
+
+import (
+	"io"
+	"os"
+	"path/filepath"
+
+	"github.com/onflow/atree"
+	gethCommon "github.com/onflow/go-ethereum/common"
+
+	"github.com/onflow/flow-go/model/flow"
+)
+
+const (
+	ExportedAccountsFileName = "accounts.bin"
+	ExportedCodesFileName    = "codes.bin"
+	ExportedSlotsFileName    = "slots.bin"
+)
+
+type Exporter struct {
+	ledger   atree.Ledger
+	root     flow.Address
+	baseView *BaseView
+}
+
+// NewExporter constructs a new Exporter
+func NewExporter(ledger atree.Ledger, root flow.Address) (*Exporter, error) {
+	bv, err := NewBaseView(ledger, root)
+	if err != nil {
+		return nil, err
+	}
+	return &Exporter{
+		ledger:   ledger,
+		root:     root,
+		baseView: bv,
+	}, nil
+}
+
+func (e *Exporter) Export(path string) error {
+	af, err := os.OpenFile(filepath.Join(path, ExportedAccountsFileName), os.O_RDWR, 0644)
+	if err != nil {
+		return err
+	}
+	defer af.Close()
+
+	addrWithStorage, err := e.exportAccounts(af)
+	if err != nil {
+		return err
+	}
+
+	cf, err := os.OpenFile(filepath.Join(path, ExportedCodesFileName), os.O_RDWR, 0644)
+	if err != nil {
+		return err
+	}
+	defer cf.Close()
+
+	err = e.exportCodes(cf)
+	if err != nil {
+		return err
+	}
+
+	sf, err := os.OpenFile(filepath.Join(path, ExportedSlotsFileName), os.O_RDWR, 0644)
+	if err != nil {
+		return err
+	}
+	defer cf.Close()
+
+	err = e.exportSlots(addrWithStorage, sf)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+// exports accounts and returns a list of addresses with non-empty storage
+func (e *Exporter) exportAccounts(writer io.Writer) ([]gethCommon.Address, error) {
+	itr, err := e.baseView.AccountIterator()
+	if err != nil {
+		return nil, err
+	}
+	// make a list of accounts with storage
+	addrWithSlots := make([]gethCommon.Address, 0)
+	for {
+		// TODO: we can optimize by returning the encoded value
+		acc, err := itr.Next()
+		if err != nil {
+			return nil, err
+		}
+		if acc == nil {
+			break
+		}
+		if acc.HasStoredValues() {
+			addrWithSlots = append(addrWithSlots, acc.Address)
+		}
+		encoded, err := acc.Encode()
+		if err != nil {
+			return nil, err
+		}
+		// write every account on a new line
+		_, err = writer.Write(append(encoded, byte('\n')))
+		if err != nil {
+			return nil, err
+		}
+	}
+	return addrWithSlots, nil
+}
+
+// exportCodes exports codes
+func (e *Exporter) exportCodes(writer io.Writer) error {
+	itr, err := e.baseView.CodeIterator()
+	if err != nil {
+		return err
+	}
+	for {
+		cic, err := itr.Next()
+		if err != nil {
+			return err
+		}
+		if cic == nil {
+			break
+		}
+		encoded, err := cic.Encode()
+		if err != nil {
+			return err
+		}
+		// write every codes on a new line
+		_, err = writer.Write(append(encoded, byte('\n')))
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// exportSlots exports slots (key value pairs stored under accounts)
+func (e *Exporter) exportSlots(addresses []gethCommon.Address, writer io.Writer) error {
+	for _, addr := range addresses {
+		itr, err := e.baseView.AccountStorageIterator(addr)
+		if err != nil {
+			return err
+		}
+		for {
+			slot, err := itr.Next()
+			if err != nil {
+				return err
+			}
+			if slot == nil {
+				break
+			}
+			encoded, err := slot.Encode()
+			if err != nil {
+				return err
+			}
+			// write every codes on a new line
+			_, err = writer.Write(append(encoded, byte('\n')))
+			if err != nil {
+				return err
+			}
+		}
+	}
+
+	return nil
+}