asset

Documentation

Index

• Constants
• func DecodeCoinID(assetID uint32, coinID []byte) (string, error)
• func IsToken(assetID uint32) (is bool, parentID uint32)
• func Register(assetID uint32, drv Driver)
• func RegisterToken(assetID uint32, drv TokenDriver)
• func Tokens(assetID uint32) map[uint32]*dex.Token
• func UnitInfo(assetID uint32) (dex.UnitInfo, error)
• func Version(assetID uint32) (uint32, error)
• type AccountBalancer
• type Addresser
  • func NewAddresser(assetID uint32, acctXPub string, keyIndexer KeyIndexer, network dex.Network) (Addresser, uint32, error)
• type AddresserFactory
• type BackedAsset
• type Backend
  • func Setup(assetID uint32, configPath string, logger dex.Logger, network dex.Network) (Backend, error)
• type BackendInfo
• type BlockUpdate
• type Coin
• type ConnectionError
  • func NewConnectionError(s string, a ...interface{}) ConnectionError
• type Contract
• type Driver
• type FundingCoin
• type KeyIndexer
• type OutputTracker
• type TokenBacker
• type TokenDriver

Constants

const (
	CoinNotFoundError = dex.ErrorKind("coin not found")
	ErrRequestTimeout = dex.ErrorKind("request timeout")
)

CoinNotFoundError is to be returned from Contract, Redemption, and FundingCoin when the specified transaction cannot be found. Used by the server to handle network latency.

Functions

func DecodeCoinID

func DecodeCoinID(assetID uint32, coinID []byte) (string, error)

DecodeCoinID creates a human-readable representation of a coin ID for a named asset with a corresponding driver registered with this package.

func IsToken

func IsToken(assetID uint32) (is bool, parentID uint32)

IsToken checks if the asset ID is for a token and returns the token's parent ID.

func Register

func Register(assetID uint32, drv Driver)

Register should be called by the init function of an asset's package.

func RegisterToken

func RegisterToken(assetID uint32, drv TokenDriver)

RegisterToken is called to register a token. The parent asset should be registered first.

func Tokens

func Tokens(assetID uint32) map[uint32]*dex.Token

Tokens returns the child tokens registered for a base chain asset.

func UnitInfo

func UnitInfo(assetID uint32) (dex.UnitInfo, error)

asset with a corresponding driver registered with this package.

func Version

func Version(assetID uint32) (uint32, error)

Version retrieves the version of the named asset's Backend implementation.

Types

type AccountBalancer

type AccountBalancer interface {
	// AccountBalance retrieves the current account balance.
	AccountBalance(addr string) (uint64, error)
	// ValidateSignature checks that the pubkey is correct for the address and
	// that the signature shows ownership of the associated private key.
	// IMPORTANT: As part of signature validation, the asset backend should
	// validate the address against a STRICT standard. Case, prefixes, suffixes,
	// etc. must be exactly the same order-to-order, since the address string
	// is used as a key for various accounting operations throughout DEX.
	ValidateSignature(addr string, pubkey, msg, sig []byte) error
	// RedeemSize is the gas used for a single redemption.
	RedeemSize() uint64
}

AccountBalancer is implemented by backends for account-based blockchains. An AccountBalancer reports the current balance for an account.

type Addresser

type Addresser interface {
	NextAddress() (string, error)
}

Addresser retrieves unique addresses.

func NewAddresser

func NewAddresser(assetID uint32, acctXPub string, keyIndexer KeyIndexer, network dex.Network) (Addresser, uint32, error)

NewAddresser creates an Addresser for a named asset for deriving addresses for the given extended public key on a certain network while maintaining the address index in an external HDKeyIndex.

type AddresserFactory

type AddresserFactory interface {
	NewAddresser(acctXPub string, keyIndexer KeyIndexer, network dex.Network) (Addresser, uint32, error)
}

AddresserFactory describes a type that can construct new Addressers.

type BackedAsset

type BackedAsset struct {
	dex.Asset
	Backend Backend
}

BackedAsset is a dex.Asset with a Backend.

type Backend

type Backend interface {
	// It is expected that Connect from dex.Connector is called and returns
	// before use of the asset, and that it is only called once for the life
	// of the asset.
	dex.Connector
	// Contract returns a Contract only for outputs that would be spendable on
	// the blockchain immediately. Contract data (e.g. the redeem script for
	// UTXO assets) is required in order to calculate sigScript length and
	// verify pubkeys.
	Contract(coinID []byte, contractData []byte) (*Contract, error)
	// TxData fetches the raw transaction data for the specified coin.
	TxData(coinID []byte) ([]byte, error)
	// ValidateSecret checks that the secret satisfies the contract.
	ValidateSecret(secret, contractData []byte) bool
	// Redemption returns a Coin for redemptionID, a transaction input, that
	// spends contract ID, an output containing the swap contract.
	Redemption(redemptionID, contractID, contractData []byte) (Coin, error)
	// BlockChannel creates and returns a new channel on which to receive updates
	// when new blocks are connected.
	BlockChannel(size int) <-chan *BlockUpdate
	// InitTxSize is the size of a serialized atomic swap initialization
	// transaction with 1 input spending a P2PKH utxo, 1 swap contract output and
	// 1 change output.
	InitTxSize() uint32
	// InitTxSizeBase is InitTxSize not including an input.
	InitTxSizeBase() uint32
	// CheckAddress checks that the given address is parseable.
	CheckAddress(string) bool
	// ValidateCoinID checks the coinID to ensure it can be decoded, returning a
	// human-readable string if it is valid.
	// Note: ValidateCoinID is NOT used for funding coin IDs for account-based
	// assets. This rule is only enforced by code patterns right now, but we may
	// consider adding separate methods in the future.
	ValidateCoinID(coinID []byte) (string, error)
	// ValidateContract ensures that the swap contract is constructed properly
	// for the asset.
	ValidateContract(contract []byte) error
	// FeeRate returns the current optimal fee rate in atoms / byte.
	FeeRate(context.Context) (uint64, error)
	// Synced should return true when the blockchain is synced and ready for
	// fee rate estimation.
	Synced() (bool, error)
	// Info provides auxillary information about a backend.
	Info() *BackendInfo
	// ValidateFeeRate checks that the transaction fees used to initiate the
	// contract are sufficient.
	ValidateFeeRate(contract *Contract, reqFeeRate uint64) bool
}

Backend is a blockchain backend. TODO: Plumb every method with a cancellable request with a Context, which will prevent backend shutdown from cancelling requests, but is more idiomatic these days.

func Setup

func Setup(assetID uint32, configPath string, logger dex.Logger, network dex.Network) (Backend, error)

Setup sets up the named asset. The RPC connection parameters are obtained from the asset's configuration file located at configPath. Setup is only called for base chain assets, not tokens.

type BackendInfo

type BackendInfo struct {
	SupportsDynamicTxFee bool
}

BackendInfo provides auxillary information about a backend.

type BlockUpdate

type BlockUpdate struct {
	Err   error
	Reorg bool
}

BlockUpdate is sent over the update channel when a tip change is detected.

type Coin

type Coin interface {
	// Confirmations returns the number of confirmations for a Coin's
	// transaction. Because a Coin can become invalid after once being
	// considered valid, this condition should be checked for during
	// confirmation counting and an error returned if this Coin is no longer
	// ready to spend. An unmined transaction should have zero confirmations. A
	// transaction in the current best block should have one confirmation. A
	// negative number can be returned if error is not nil.
	Confirmations(context.Context) (int64, error)
	// ID is the coin ID.
	ID() []byte
	// TxID is a transaction identifier for the coin.
	TxID() string
	// String is a human readable representation of the Coin.
	String() string
	// Value is the coin value.
	Value() uint64
	// FeeRate returns the transaction fee rate, in atoms/byte equivalent.
	FeeRate() uint64
}

Coin represents a transaction input or output.

type ConnectionError

type ConnectionError error

ConnectionError error should be sent over the block update channel if a connection error is detected by the Backend.

func NewConnectionError

func NewConnectionError(s string, a ...interface{}) ConnectionError

NewConnectionError is a constructor for a ConnectionError.

type Contract

type Contract struct {
	Coin
	// SwapAddress is the receiving address of the swap contract.
	SwapAddress string
	// ContractData is essential data about this swap. For example, the redeem
	// script for UTXO contracts, or a secret hash that keys swaps for account-
	// based contracts.
	ContractData []byte
	// SecretHash is the secret key hash used for this swap. This should be used
	// to validate a counterparty contract on another chain.
	SecretHash []byte
	// LockTime is the refund locktime.
	LockTime time.Time
	// TxData is raw transaction data. This data is provided for some assets
	// to aid in SPV compatibility.
	TxData []byte
}

Contract is an atomic swap contract.

type Driver

type Driver interface {

	// Setup should create a Backend, but not start the backend connection.
	Setup(configPath string, logger dex.Logger, network dex.Network) (Backend, error)
	// contains filtered or unexported methods
}

Driver is the interface required of all base chain assets.

type FundingCoin

type FundingCoin interface {
	Coin
	// Auth checks that the owner of the provided pubkeys can spend the
	// FundingCoin. The signatures (sigs) generated with the private keys
	// corresponding to pubkeys must validate against the pubkeys and signing
	// message (msg).
	Auth(pubkeys, sigs [][]byte, msg []byte) error
	// SpendSize returns the size of the serialized input that spends this
	// FundingCoin.
	SpendSize() uint32
}

FundingCoin is some unspent value on the blockchain.

type KeyIndexer

type KeyIndexer interface {
	KeyIndex(xpub string) (uint32, error)
	SetKeyIndex(idx uint32, xpub string) error
}

KeyIndexer retrieves and stores child indexes for an extended public key.

type OutputTracker

type OutputTracker interface {
	// VerifyUnspentCoin attempts to verify a coin ID by decoding the coin ID
	// and retrieving the corresponding Coin. If the coin is not found or no
	// longer unspent, an asset.CoinNotFoundError is returned. Use FundingCoin
	// for more UTXO data.
	VerifyUnspentCoin(ctx context.Context, coinID []byte) error
	// FundingCoin returns the unspent coin at the specified location. Coins
	// with non-standard pkScripts or scripts that require zero signatures to
	// redeem must return an error.
	FundingCoin(ctx context.Context, coinID []byte, redeemScript []byte) (FundingCoin, error)
}

OutputTracker is implemented by backends for UTXO-based blockchains. OutputTracker tracks the value and spend-status of transaction outputs.

type TokenBacker

type TokenBacker interface {
	TokenBackend(assetID uint32, configPath string) (Backend, error)
}

TokenBacker is implemented by Backends that support degenerate tokens.

type TokenDriver

type TokenDriver interface {
	TokenInfo() *dex.Token
	// contains filtered or unexported methods
}

TokenDriver is the interface required of all token assets.