From 0844c8c6919f6d98ebe8a9501360ef5bc362dff3 Mon Sep 17 00:00:00 2001
From: Determinant <tederminant@gmail.com>
Date: Wed, 19 Aug 2020 01:25:20 -0400
Subject: catch up with the new P-Chain cross-chain impl

---
 plugin/evm/tx.go | 105 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 105 insertions(+)
 create mode 100644 plugin/evm/tx.go

(limited to 'plugin/evm/tx.go')

diff --git a/plugin/evm/tx.go b/plugin/evm/tx.go
new file mode 100644
index 0000000..024e54d
--- /dev/null
+++ b/plugin/evm/tx.go
@@ -0,0 +1,105 @@
+// (c) 2019-2020, Ava Labs, Inc. All rights reserved.
+// See the file LICENSE for licensing terms.
+
+package evm
+
+import (
+	"fmt"
+
+	"github.com/ava-labs/gecko/database"
+	"github.com/ava-labs/gecko/database/versiondb"
+	"github.com/ava-labs/gecko/ids"
+	"github.com/ava-labs/gecko/snow"
+	"github.com/ava-labs/gecko/utils/codec"
+	"github.com/ava-labs/gecko/utils/crypto"
+	"github.com/ava-labs/gecko/utils/hashing"
+	"github.com/ava-labs/gecko/vms/components/verify"
+	"github.com/ava-labs/gecko/vms/secp256k1fx"
+)
+
+// UnsignedTx is an unsigned transaction
+type UnsignedTx interface {
+	Initialize(unsignedBytes, signedBytes []byte)
+	ID() ids.ID
+	UnsignedBytes() []byte
+	Bytes() []byte
+}
+
+// UnsignedDecisionTx is an unsigned operation that can be immediately decided
+type UnsignedDecisionTx interface {
+	UnsignedTx
+
+	// Attempts to verify this transaction with the provided state.
+	SemanticVerify(vm *VM, db database.Database, stx *Tx) (
+		onAcceptFunc func() error,
+		err TxError,
+	)
+}
+
+// UnsignedProposalTx is an unsigned operation that can be proposed
+type UnsignedProposalTx interface {
+	UnsignedTx
+
+	// Attempts to verify this transaction with the provided state.
+	SemanticVerify(vm *VM, db database.Database, stx *Tx) (
+		onCommitDB *versiondb.Database,
+		onAbortDB *versiondb.Database,
+		onCommitFunc func() error,
+		onAbortFunc func() error,
+		err TxError,
+	)
+	InitiallyPrefersCommit(vm *VM) bool
+}
+
+// UnsignedAtomicTx is an unsigned operation that can be atomically accepted
+type UnsignedAtomicTx interface {
+	UnsignedTx
+
+	// UTXOs this tx consumes
+	InputUTXOs() ids.Set
+	// Attempts to verify this transaction with the provided state.
+	SemanticVerify(vm *VM, db database.Database, stx *Tx) TxError
+
+	// Accept this transaction with the additionally provided state transitions.
+	Accept(ctx *snow.Context, batch database.Batch) error
+}
+
+// Tx is a signed transaction
+type Tx struct {
+	// The body of this transaction
+	UnsignedTx `serialize:"true" json:"unsignedTx"`
+
+	// The credentials of this transaction
+	Creds []verify.Verifiable `serialize:"true" json:"credentials"`
+}
+
+// Sign this transaction with the provided signers
+func (tx *Tx) Sign(c codec.Codec, signers [][]*crypto.PrivateKeySECP256K1R) error {
+	unsignedBytes, err := c.Marshal(&tx.UnsignedTx)
+	if err != nil {
+		return fmt.Errorf("couldn't marshal UnsignedTx: %w", err)
+	}
+
+	// Attach credentials
+	hash := hashing.ComputeHash256(unsignedBytes)
+	for _, keys := range signers {
+		cred := &secp256k1fx.Credential{
+			Sigs: make([][crypto.SECP256K1RSigLen]byte, len(keys)),
+		}
+		for i, key := range keys {
+			sig, err := key.SignHash(hash) // Sign hash
+			if err != nil {
+				return fmt.Errorf("problem generating credential: %w", err)
+			}
+			copy(cred.Sigs[i][:], sig)
+		}
+		tx.Creds = append(tx.Creds, cred) // Attach credential
+	}
+
+	signedBytes, err := c.Marshal(tx)
+	if err != nil {
+		return fmt.Errorf("couldn't marshal ProposalTx: %w", err)
+	}
+	tx.Initialize(unsignedBytes, signedBytes)
+	return nil
+}
-- 
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