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-rw-r--r--plugin/evm/export_tx.go155
1 files changed, 155 insertions, 0 deletions
diff --git a/plugin/evm/export_tx.go b/plugin/evm/export_tx.go
new file mode 100644
index 0000000..3a544a6
--- /dev/null
+++ b/plugin/evm/export_tx.go
@@ -0,0 +1,155 @@
+// (c) 2019-2020, Ava Labs, Inc. All rights reserved.
+// See the file LICENSE for licensing terms.
+
+package evm
+
+import (
+ "errors"
+ "fmt"
+
+ "github.com/ava-labs/gecko/database"
+ "github.com/ava-labs/gecko/ids"
+ "github.com/ava-labs/gecko/snow"
+ "github.com/ava-labs/gecko/utils/crypto"
+ "github.com/ava-labs/gecko/vms/components/avax"
+ "github.com/ava-labs/gecko/vms/secp256k1fx"
+
+ safemath "github.com/ava-labs/gecko/utils/math"
+)
+
+var (
+ errNoExportOutputs = errors.New("no export outputs")
+ errOutputsNotSorted = errors.New("outputs not sorted")
+ errOverflowExport = errors.New("overflow when computing export amount + txFee")
+
+ _ UnsignedAtomicTx = &UnsignedExportTx{}
+)
+
+// UnsignedExportTx is an unsigned ExportTx
+type UnsignedExportTx struct {
+ avax.Metadata
+ // true iff this transaction has already passed syntactic verification
+ syntacticallyVerified bool
+ // ID of the network on which this tx was issued
+ NetworkID uint32 `serialize:"true" json:"networkID"`
+ // ID of this blockchain.
+ BlockchainID ids.ID `serialize:"true" json:"blockchainID"`
+ // Which chain to send the funds to
+ DestinationChain ids.ID `serialize:"true" json:"destinationChain"`
+ // Inputs
+ Ins []EVMInput `serialize:"true" json:"inputs"`
+ // Outputs that are exported to the chain
+ ExportedOutputs []*avax.TransferableOutput `serialize:"true" json:"exportedOutputs"`
+}
+
+// InputUTXOs returns an empty set
+func (tx *UnsignedExportTx) InputUTXOs() ids.Set { return ids.Set{} }
+
+// Verify this transaction is well-formed
+func (tx *UnsignedExportTx) Verify(
+ avmID ids.ID,
+ ctx *snow.Context,
+ feeAmount uint64,
+ feeAssetID ids.ID,
+) error {
+ switch {
+ case tx == nil:
+ return errNilTx
+ case tx.syntacticallyVerified: // already passed syntactic verification
+ return nil
+ case tx.DestinationChain.IsZero():
+ return errWrongChainID
+ case !tx.DestinationChain.Equals(avmID):
+ return errWrongChainID
+ case len(tx.ExportedOutputs) == 0:
+ return errNoExportOutputs
+ case tx.NetworkID != ctx.NetworkID:
+ return errWrongNetworkID
+ case !ctx.ChainID.Equals(tx.BlockchainID):
+ return errWrongBlockchainID
+ }
+
+ for _, in := range tx.Ins {
+ if err := in.Verify(); err != nil {
+ return err
+ }
+ }
+
+ for _, out := range tx.ExportedOutputs {
+ if err := out.Verify(); err != nil {
+ return err
+ }
+ }
+ if !avax.IsSortedTransferableOutputs(tx.ExportedOutputs, Codec) {
+ return errOutputsNotSorted
+ }
+
+ tx.syntacticallyVerified = true
+ return nil
+}
+
+// SemanticVerify this transaction is valid.
+func (tx *UnsignedExportTx) SemanticVerify(
+ vm *VM,
+ stx *Tx,
+) TxError {
+ if err := tx.Verify(vm.ctx.XChainID, vm.ctx, vm.txFee, vm.ctx.AVAXAssetID); err != nil {
+ return permError{err}
+ }
+
+ // TODO: credential check
+ // TODO: flow check
+ // TODO: verify UTXO outputs via gRPC
+ return nil
+}
+
+// Accept this transaction.
+func (tx *UnsignedExportTx) Accept(ctx *snow.Context, batch database.Batch) error {
+ // TODO: finish this function via gRPC
+ return nil
+}
+
+// Create a new transaction
+func (vm *VM) newExportTx(
+ amount uint64, // Amount of tokens to export
+ chainID ids.ID, // Chain to send the UTXOs to
+ to ids.ShortID, // Address of chain recipient
+ keys []*crypto.PrivateKeySECP256K1R, // Pay the fee and provide the tokens
+) (*Tx, error) {
+ if !vm.ctx.XChainID.Equals(chainID) {
+ return nil, errWrongChainID
+ }
+
+ toBurn, err := safemath.Add64(amount, vm.txFee)
+ if err != nil {
+ return nil, errOverflowExport
+ }
+ ins, signers, err := vm.GetSpendableCanonical(keys, toBurn)
+ if err != nil {
+ return nil, fmt.Errorf("couldn't generate tx inputs/outputs: %w", err)
+ }
+
+ // Create the transaction
+ utx := &UnsignedExportTx{
+ NetworkID: vm.ctx.NetworkID,
+ BlockchainID: vm.ctx.ChainID,
+ DestinationChain: chainID,
+ Ins: ins,
+ ExportedOutputs: []*avax.TransferableOutput{{ // Exported to X-Chain
+ Asset: avax.Asset{ID: vm.ctx.AVAXAssetID},
+ Out: &secp256k1fx.TransferOutput{
+ Amt: amount,
+ OutputOwners: secp256k1fx.OutputOwners{
+ Locktime: 0,
+ Threshold: 1,
+ Addrs: []ids.ShortID{to},
+ },
+ },
+ }},
+ }
+ tx := &Tx{UnsignedTx: utx}
+ if err := tx.Sign(vm.codec, signers); err != nil {
+ return nil, err
+ }
+ return tx, utx.Verify(vm.ctx.XChainID, vm.ctx, vm.txFee, vm.ctx.AVAXAssetID)
+}