woop/rpc/types.go

package rpc

import (
	"context"
	"fmt"
	"math"
	"strings"

	"github.com/ethereum/go-ethereum/common/hexutil"
)

// API describes the set of methods offered over the RPC interface
type API struct {
	Namespace string      // namespace under which the rpc methods of Service are exposed
	Version   string      // api version for DApp's
	Service   interface{} // receiver instance which holds the methods
	Public    bool        // indication if the methods must be considered safe for public use
}

// Error wraps RPC errors, which contain an error code in addition to the message.
type Error interface {
	Error() string  // returns the message
	ErrorCode() int // returns the code
}

// ServerCodec implements reading, parsing and writing RPC messages for the server side of
// a RPC session. Implementations must be go-routine safe since the codec can be called in
// multiple go-routines concurrently.
type ServerCodec interface {
	Read() (msgs []*jsonrpcMessage, isBatch bool, err error)
	Close()
	jsonWriter
}

// jsonWriter can write JSON messages to its underlying connection.
// Implementations must be safe for concurrent use.
type jsonWriter interface {
	Write(context.Context, interface{}) error
	// Closed returns a channel which is closed when the connection is closed.
	Closed() <-chan interface{}
	// RemoteAddr returns the peer address of the connection.
	RemoteAddr() string
}

// BlockNumber ...
type BlockNumber int64

const (
	// PendingBlockNumber ...
	PendingBlockNumber  = BlockNumber(-2)
	latestBlockNumber   = BlockNumber(-1)
	earliestBlockNumber = BlockNumber(0)
)

// 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 = PendingBlockNumber
		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 turns blockNumber to int64
func (bn BlockNumber) Int64() int64 {
	return (int64)(bn)
}