sae: Add C-chain custom tx serialization

.github/CODEOWNERS

@@ -10,3 +10,4 @@
 /graft/evm @ava-labs/platform-evm
 /graft/subnet-evm @ava-labs/platform-evm
 /vms/saevm @ARR4N @StephenButtolph
+/vms/saevm/cchain @StephenButtolph

graft/coreth/BUILD.bazel

@@ -19,6 +19,7 @@ package_group(
         "//tests/reexecute/c",
         "//tests/reexecute/chaos",
         "//vms/evm/emulate",
+        "//vms/saevm/cchain/...",
         "//wallet/chain/c",
         "//wallet/subnet/primary",
     ],

ids/short.go

@@ -40,6 +40,16 @@ func ShortFromString(idStr string) (ShortID, error) {
 	return ToShortID(bytes)
 }
 
+// ShortFromStringOrPanic is the same as ShortFromString, but will panic on
+// error.
+func ShortFromStringOrPanic(idStr string) ShortID {
+	id, err := ShortFromString(idStr)
+	if err != nil {
+		panic(err)
+	}
+	return id
+}
+
 // ShortFromPrefixedString returns a ShortID assuming the cb58 format is
 // prefixed
 func ShortFromPrefixedString(idStr, prefix string) (ShortID, error) {

vms/saevm/cchain/tx/BUILD.bazel

@@ -0,0 +1,44 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+load("//.bazel:defs.bzl", "go_test")
+
+go_library(
+    name = "tx",
+    srcs = [
+        "codec.go",
+        "export.go",
+        "import.go",
+        "tx.go",
+    ],
+    importpath = "github.com/ava-labs/avalanchego/vms/saevm/cchain/tx",
+    visibility = ["//visibility:public"],
+    deps = [
+        "//codec",
+        "//codec/linearcodec",
+        "//ids",
+        "//utils/hashing",
+        "//utils/wrappers",
+        "//vms/components/avax",
+        "//vms/secp256k1fx",
+        "@com_github_ava_labs_libevm//common",
+    ],
+)
+
+go_test(
+    name = "tx_test",
+    srcs = ["tx_test.go"],
+    data = glob(["testdata/**"]),
+    embed = [":tx"],
+    deps = [
+        "//graft/coreth/plugin/evm/atomic",
+        "//graft/coreth/plugin/evm/atomic/vm",
+        "//ids",
+        "//vms/components/avax",
+        "//vms/components/verify",
+        "//vms/secp256k1fx",
+        "@com_github_ava_labs_libevm//common",
+        "@com_github_google_go_cmp//cmp",
+        "@com_github_google_go_cmp//cmp/cmpopts",
+        "@com_github_stretchr_testify//assert",
+        "@com_github_stretchr_testify//require",
+    ],
+)

vms/saevm/cchain/tx/codec.go

@@ -0,0 +1,75 @@
+// Copyright (C) 2019, Ava Labs, Inc. All rights reserved.
+// See the file LICENSE for licensing terms.
+
+package tx
+
+import (
+	"errors"
+
+	"github.com/ava-labs/avalanchego/codec"
+	"github.com/ava-labs/avalanchego/codec/linearcodec"
+	"github.com/ava-labs/avalanchego/utils/wrappers"
+	"github.com/ava-labs/avalanchego/vms/secp256k1fx"
+)
+
+const codecVersion uint16 = 0
+
+var c codec.Manager
+
+func init() {
+	c = codec.NewDefaultManager()
+
+	// Registration order impacts the typeID included in the canonical format.
+	// We skip registrations in specific locations so that UTXOs in shared
+	// memory share the same serialized format as on the P-Chain and X-Chain.
+	var (
+		lc   = linearcodec.NewDefault()
+		errs = wrappers.Errs{}
+	)
+	errs.Add(
+		lc.RegisterType(&Import{}),
+		lc.RegisterType(&Export{}),
+	)
+	lc.SkipRegistrations(3)
+	errs.Add(
+		lc.RegisterType(&secp256k1fx.TransferInput{}),
+	)
+	lc.SkipRegistrations(1)
+	errs.Add(
+		lc.RegisterType(&secp256k1fx.TransferOutput{}),
+	)
+	lc.SkipRegistrations(1)
+	errs.Add(
+		lc.RegisterType(&secp256k1fx.Credential{}),
+		c.RegisterCodec(codecVersion, lc),
+	)
+	if errs.Errored() {
+		panic(errs.Err)
+	}
+}
+
+// MarshalSlice returns the canonical binary format of a slice of transactions.
+func MarshalSlice(txs []*Tx) ([]byte, error) {
+	if len(txs) == 0 {
+		return nil, nil
+	}
+	return c.Marshal(codecVersion, txs)
+}
+
+var errInefficientSlicePacking = errors.New("inefficient slice packing: empty slices should be packed as nil")
+
+// ParseSlice deserializes a slice of [Tx] from its canonical binary format.
+func ParseSlice(b []byte) ([]*Tx, error) {
+	if len(b) == 0 {
+		return nil, nil
+	}
+
+	var txs []*Tx
+	if _, err := c.Unmarshal(b, &txs); err != nil {
+		return nil, err
+	}
+	if len(txs) == 0 {
+		return nil, errInefficientSlicePacking
+	}
+	return txs, nil
+}

vms/saevm/cchain/tx/export.go

@@ -0,0 +1,38 @@
+// Copyright (C) 2019, Ava Labs, Inc. All rights reserved.
+// See the file LICENSE for licensing terms.
+
+package tx
+
+import (
+	"github.com/ava-labs/libevm/common"
+
+	"github.com/ava-labs/avalanchego/ids"
+	"github.com/ava-labs/avalanchego/vms/components/avax"
+)
+
+// Export is the unsigned component of a transaction that transfers assets from
+// the C-Chain to either the P-Chain or the X-Chain. It modifies the C-Chain
+// state and produces UTXOs in the shared memory between the C-Chain and the
+// destination chain.
+type Export struct {
+	NetworkID        uint32                     `serialize:"true" json:"networkID"`
+	BlockchainID     ids.ID                     `serialize:"true" json:"blockchainID"`
+	DestinationChain ids.ID                     `serialize:"true" json:"destinationChain"`
+	Ins              []Input                    `serialize:"true" json:"inputs"`
+	ExportedOutputs  []*avax.TransferableOutput `serialize:"true" json:"exportedOutputs"`
+}
+
+// TODO(StephenButtolph): Remove this with its removal from the interface.
+func (*Export) isUnsigned() {}
+
+// Input identifies an account + nonce pair on the C-Chain that authorizes the
+// asset and quantity to deduct.
+//
+// If the AssetID is AVAX, the amount will be scaled up to account for the EVM's
+// higher denomination.
+type Input struct {
+	Address common.Address `serialize:"true" json:"address"`
+	Amount  uint64         `serialize:"true" json:"amount"`
+	AssetID ids.ID         `serialize:"true" json:"assetID"`
+	Nonce   uint64         `serialize:"true" json:"nonce"`
+}

vms/saevm/cchain/tx/import.go

@@ -0,0 +1,37 @@
+// Copyright (C) 2019, Ava Labs, Inc. All rights reserved.
+// See the file LICENSE for licensing terms.
+
+package tx
+
+import (
+	"github.com/ava-labs/libevm/common"
+
+	"github.com/ava-labs/avalanchego/ids"
+	"github.com/ava-labs/avalanchego/vms/components/avax"
+)
+
+// Import is the unsigned component of a transaction that transfers assets from
+// either the P-Chain or the X-Chain to the C-Chain. It consumes UTXOs in the
+// shared memory between the C-Chain and the source chain and increases balances
+// in the C-Chain state.
+type Import struct {
+	NetworkID      uint32                    `serialize:"true" json:"networkID"`
+	BlockchainID   ids.ID                    `serialize:"true" json:"blockchainID"`
+	SourceChain    ids.ID                    `serialize:"true" json:"sourceChain"`
+	ImportedInputs []*avax.TransferableInput `serialize:"true" json:"importedInputs"`
+	Outs           []Output                  `serialize:"true" json:"outputs"`
+}
+
+// TODO(StephenButtolph): Remove this with its removal from the interface.
+func (*Import) isUnsigned() {}
+
+// Output specifies an account on the C-Chain whose balance of the specified
+// asset should be increased.
+//
+// If the AssetID is AVAX, the amount will be scaled up to account for the EVM's
+// higher denomination.
+type Output struct {
+	Address common.Address `serialize:"true" json:"address"`
+	Amount  uint64         `serialize:"true" json:"amount"`
+	AssetID ids.ID         `serialize:"true" json:"assetID"`
+}

vms/saevm/cchain/tx/testdata/fuzz/FuzzParseCompatibility/0ff1164eb2ab2c0b

@@ -0,0 +1,2 @@
+go test fuzz v1
+[]byte("\x00\x00\x00\x00\x00\x0000000000000000000000000000000000000000000000000000000000000000000000\x00\x00\x00\x0100000000000000000000000000000000000000000000000000000000000000000000\x00\x00\x00\x0500000000\x00\x00\x00\x010000\x00\x00\x00\x01000000000000000000000000000000000000000000000000000000000000\x00\x00\x00\x01\x00\x00\x00\x0500000000\x00\x00\x00\x010000")

vms/saevm/cchain/tx/testdata/fuzz/FuzzParseCompatibility/befe02d645ceffe6

@@ -0,0 +1,2 @@
+go test fuzz v1
+[]byte("\x00\x00\x00\x00\x00\x0000000000000000000000000000000000000000000000000000000000000000000000\x00\x00\x00\x0100000000000000000000000000000000000000000000000000000000000000000000\x00\x00\x00\x0500000000\x00\x00\x00\x010000\x00\x00\x00\x01000000000000000000000000000000000000000000000000000000000000\x00\x00\x00\x01\x00\x00\x00\n\x00\x00\x00\x010000")

vms/saevm/cchain/tx/tx.go

@@ -0,0 +1,72 @@
+// Copyright (C) 2019, Ava Labs, Inc. All rights reserved.
+// See the file LICENSE for licensing terms.
+
+// Package tx defines the Avalanche-specific transaction types used on the
+// C-Chain to interact with the shared memory between the C-Chain and other
+// chains on the Primary Network.
+package tx
+
+import (
+	"github.com/ava-labs/avalanchego/ids"
+	"github.com/ava-labs/avalanchego/utils/hashing"
+	"github.com/ava-labs/avalanchego/vms/secp256k1fx"
+)
+
+// Tx is a signed transaction that interacts with shared memory.
+// The [Unsigned] body can be implemented by either [Export] or [Import].
+// The [Credential] values are implemented by [secp256k1fx.Credential].
+type Tx struct {
+	Unsigned `serialize:"true" json:"unsignedTx"`
+	Creds    []Credential `serialize:"true" json:"credentials"`
+}
+
+// Unsigned is a common interface implemented by [Import] and [Export].
+//
+// TODO(StephenButtolph): Expand this interface to include UTXO handling,
+// verification, and state execution.
+type Unsigned interface {
+	// This function ensures that [Tx.Unsigned] can only be parsed as [Export]
+	// or [Import].
+	//
+	// TODO(StephenButtolph): Once [Unsigned] includes other unexported
+	// functions, remove this function.
+	isUnsigned()
+}
+
+// Credential is used in [Tx] to authorize an input of a transaction.
+//
+// It is only implemented by [secp256k1fx.Credential]. An interface must be used
+// to correctly produce the canonical binary format during serialization.
+type Credential interface {
+	Self() *secp256k1fx.Credential
+}
+
+// ID returns the unique hash of the transaction.
+func (t *Tx) ID() ids.ID {
+	// TODO(StephenButtolph): Optimize ID by caching previously calculated
+	// values.
+	bytes, err := t.Bytes()
+	// This error can happen, but only with invalid transactions. To avoid
+	// polluting the interface, we represent all invalid transactions with
+	// the zero ID.
+	if err != nil {
+		return ids.ID{}
+	}
+	return hashing.ComputeHash256Array(bytes)
+}
+
+// Bytes returns the canonical binary format of the transaction.
+func (t *Tx) Bytes() ([]byte, error) {
+	// TODO(StephenButtolph): Optimize Bytes by caching previously calculated
+	// values.
+	return c.Marshal(codecVersion, t)
+}
+
+// Parse deserializes a [Tx] from its canonical binary format.
+func Parse(b []byte) (*Tx, error) {
+	var tx Tx
+	if _, err := c.Unmarshal(b, &tx); err != nil {
+		return nil, err
+	}
+	return &tx, nil
+}