WIP: X-to-C transfer

1 files changed, 142 insertions, 0 deletions

diff --git a/plugin/evm/user.go b/plugin/evm/user.go
new file mode 100644
index 0000000..651f202
--- /dev/null
+++ b/plugin/evm/user.go
@@ -0,0 +1,142 @@
+// (c) 2019-2020, Ava Labs, Inc. All rights reserved.
+// See the file LICENSE for licensing terms.
+
+package evm
+
+import (
+	"errors"
+
+	"crypto/ecdsa"
+	"github.com/ava-labs/gecko/database"
+	"github.com/ava-labs/gecko/ids"
+	"github.com/ava-labs/go-ethereum/common"
+	"github.com/ava-labs/go-ethereum/crypto"
+)
+
+// Key in the database whose corresponding value is the list of
+// addresses this user controls
+var addressesKey = ids.Empty.Bytes()
+
+var (
+	errDBNil        = errors.New("db uninitialized")
+	errKeyNil       = errors.New("key uninitialized")
+	errEmptyAddress = errors.New("address is empty")
+)
+
+type user struct {
+	// This user's database, acquired from the keystore
+	db database.Database
+}
+
+// Get the addresses controlled by this user
+func (u *user) getAddresses() ([]common.Address, error) {
+	if u.db == nil {
+		return nil, errDBNil
+	}
+
+	// If user has no addresses, return empty list
+	hasAddresses, err := u.db.Has(addressesKey)
+	if err != nil {
+		return nil, err
+	}
+	if !hasAddresses {
+		return nil, nil
+	}
+
+	// User has addresses. Get them.
+	bytes, err := u.db.Get(addressesKey)
+	if err != nil {
+		return nil, err
+	}
+	addresses := []common.Address{}
+	if err := Codec.Unmarshal(bytes, &addresses); err != nil {
+		return nil, err
+	}
+	return addresses, nil
+}
+
+// controlsAddress returns true iff this user controls the given address
+func (u *user) controlsAddress(address common.Address) (bool, error) {
+	if u.db == nil {
+		return false, errDBNil
+		//} else if address.IsZero() {
+		//	return false, errEmptyAddress
+	}
+	return u.db.Has(address.Bytes())
+}
+
+// putAddress persists that this user controls address controlled by [privKey]
+func (u *user) putAddress(privKey *ecdsa.PrivateKey) error {
+	if privKey == nil {
+		return errKeyNil
+	}
+
+	address := crypto.PubkeyToAddress(privKey.PublicKey) // address the privKey controls
+	controlsAddress, err := u.controlsAddress(address)
+	if err != nil {
+		return err
+	}
+	if controlsAddress { // user already controls this address. Do nothing.
+		return nil
+	}
+
+	if err := u.db.Put(address.Bytes(), crypto.FromECDSA(privKey)); err != nil { // Address --> private key
+		return err
+	}
+
+	addresses := make([]common.Address, 0) // Add address to list of addresses user controls
+	userHasAddresses, err := u.db.Has(addressesKey)
+	if err != nil {
+		return err
+	}
+	if userHasAddresses { // Get addresses this user already controls, if they exist
+		if addresses, err = u.getAddresses(); err != nil {
+			return err
+		}
+	}
+	addresses = append(addresses, address)
+	bytes, err := Codec.Marshal(addresses)
+	if err != nil {
+		return err
+	}
+	if err := u.db.Put(addressesKey, bytes); err != nil {
+		return err
+	}
+	return nil
+}
+
+// Key returns the private key that controls the given address
+func (u *user) getKey(address common.Address) (*ecdsa.PrivateKey, error) {
+	if u.db == nil {
+		return nil, errDBNil
+		//} else if address.IsZero() {
+		//	return nil, errEmptyAddress
+	}
+
+	bytes, err := u.db.Get(address.Bytes())
+	if err != nil {
+		return nil, err
+	}
+	sk, err := crypto.ToECDSA(bytes)
+	if err != nil {
+		return nil, err
+	}
+	return sk, nil
+}
+
+// Return all private keys controlled by this user
+func (u *user) getKeys() ([]*ecdsa.PrivateKey, error) {
+	addrs, err := u.getAddresses()
+	if err != nil {
+		return nil, err
+	}
+	keys := make([]*ecdsa.PrivateKey, len(addrs))
+	for i, addr := range addrs {
+		key, err := u.getKey(addr)
+		if err != nil {
+			return nil, err
+		}
+		keys[i] = key
+	}
+	return keys, nil
+}