# Packages
# README
How to add bridge support of new blockchain
1. create a new directory for each block chain
for example, btc, eth, fsn etc.
2. implement methods in CrossChainBridge interface
IsSrcEndpoint() bool
IsSrcEndpoint returns true if this bridge is on the source block chain, otherwise returns false.
SetChainAndGateway(*ChainConfig, *GatewayConfig)
SetChainAndGateway set chain and gateway config.
GetChainConfig() *ChainConfig
GetChainConfig get chain config.
GetGatewayConfig() *GatewayConfig
GetGatewayConfig get gateway config.
GetTokenConfig(pairID string) *TokenConfig
GetTokenConfig get token config.
VerifyTokenConfig(*TokenConfig) error
VerifyTokenConfig verify token config.
IsValidAddress(address string) bool
IsValidAddress check if given address is valid.
GetTransaction(txHash string) (interface{}, error)
GetTransaction get transaction by hash.
GetTransactionStatus(txHash string) *TxStatus
GetTransactionStatus get transaction status by hash.
VerifyTransaction(pairID, txHash string, allowUnstable bool) (*TxSwapInfo, error)
VerifyTransaction verify transaction by hash.
VerifyMsgHash(rawTx interface{}, msgHash []string) error
VerifyMsgHash verify message hash of rawtx in DCRM signing.
BuildRawTransaction(args *BuildTxArgs) (rawTx interface{}, err error)
BuildRawTransaction build raw transaction for swapin/swapout.
SignTransaction(rawTx interface{}, pairID string) (signedTx interface{}, txHash string, err error)
SignTransaction sign transaction with configed private key.
DcrmSignTransaction(rawTx interface{}, args *BuildTxArgs) (signedTx interface{}, txHash string, err error)
DcrmSignTransaction sign transaction in DCRM way.
SendTransaction(signedTx interface{}) (txHash string, err error)
SendTransaction send/broadcast signed transaction.
GetLatestBlockNumber() (uint64, error)
GetLatestBlockNumber get the latest block number.
GetLatestBlockNumberOf(apiAddress string) (uint64, error)
GetLatestBlockNumberOf get the latest block number by connecting to specified full node RPC address.
StartChainTransactionScanJob()
StartChainTransactionScanJob start scan chain transaction and auto register found swapin or swapout of this bridge.
StartPoolTransactionScanJob()
StartPoolTransactionScanJob start scan pool transaction and auto register found swapin or swapout of this bridge.
GetBalance(accountAddress string) (*big.Int, error)
GetBalance get coin balance of given account address.
GetTokenBalance(tokenType, tokenAddress, accountAddress string) (*big.Int, error)
GetTokenBalance get token balance of given token and account.
GetTokenSupply(tokenType, tokenAddress string) (*big.Int, error)
GetTokenSupply get token total supply of give token.
3. other possible way
Because some chain are forked from already implemented blockchain, we can derive from this implemented bridge and update some interface implement.
For example, fsn is forked from eth. So we derive fsn bridge from eth bridge and update some chain verify, and then fsn is also supported now as it has implememted all the required methods in CrossChainBridge interface.