package rpc import ( "fmt" "math" "math/big" "strings" "github.com/ethereum/go-ethereum/common/hexutil" ) // BlockNumber represents decoding hex string to block values type BlockNumber int64 const ( // LatestBlockNumber mapping from "latest" to 0 for tm query LatestBlockNumber = BlockNumber(0) // EarliestBlockNumber mapping from "earliest" to 1 for tm query (earliest query not supported) EarliestBlockNumber = BlockNumber(1) ) // NewBlockNumber creates a new BlockNumber instance. func NewBlockNumber(n *big.Int) BlockNumber { return BlockNumber(n.Int64()) } // UnmarshalJSON parses the given JSON fragment into a BlockNumber. It supports: // - "latest", "earliest" or "pending" as string arguments // - the block number // Returned errors: // - an invalid block number error when the given argument isn't a known strings // - an out of range error when the given block number is either too little or too large func (bn *BlockNumber) UnmarshalJSON(data []byte) error { input := strings.TrimSpace(string(data)) if len(input) >= 2 && input[0] == '"' && input[len(input)-1] == '"' { input = input[1 : len(input)-1] } switch input { case "earliest": *bn = EarliestBlockNumber return nil case "latest": *bn = LatestBlockNumber return nil case "pending": *bn = LatestBlockNumber return nil } blckNum, err := hexutil.DecodeUint64(input) if err != nil { return err } if blckNum > math.MaxInt64 { return fmt.Errorf("blocknumber too high") } *bn = BlockNumber(blckNum) return nil } // Int64 converts block number to primitive type func (bn BlockNumber) Int64() int64 { return (int64)(bn) }