types.go

// Copyright 2015 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package rpc

import (
	"encoding/json"
	"errors"
	"fmt"
	"math"
	"math/big"
	"reflect"
	"strings"
	"sync"

	mapset "github.com/deckarep/golang-set"

	"github.com/ethereum/go-ethereum"
	"github.com/ethereum/go-ethereum/common"
	"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
}

// callback is a method callback which was registered in the server
type callback struct {
	rcvr        reflect.Value  // receiver of method
	method      reflect.Method // callback
	argTypes    []reflect.Type // input argument types
	hasCtx      bool           // method's first argument is a context (not included in argTypes)
	errPos      int            // err return idx, of -1 when method cannot return error
	isSubscribe bool           // indication if the callback is a subscription
}

// service represents a registered object
type service struct {
	name          string        // name for service
	typ           reflect.Type  // receiver type
	callbacks     callbacks     // registered handlers
	subscriptions subscriptions // available subscriptions/notifications
}

// serverRequest is an incoming request
type serverRequest struct {
	id            interface{}
	svcname       string
	callb         *callback
	args          []reflect.Value
	isUnsubscribe bool
	err           Error
}

type serviceRegistry map[string]*service // collection of services
type callbacks map[string]*callback      // collection of RPC callbacks
type subscriptions map[string]*callback  // collection of subscription callbacks

// Server represents a RPC server
type Server struct {
	services serviceRegistry

	run      int32
	codecsMu sync.Mutex
	codecs   mapset.Set
}

// rpcRequest represents a raw incoming RPC request
type rpcRequest struct {
	service  string
	method   string
	id       interface{}
	isPubSub bool
	params   interface{}
	err      Error // invalid batch element
}

// 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 next request
	ReadRequestHeaders() ([]rpcRequest, bool, Error)
	// Parse request argument to the given types
	ParseRequestArguments(argTypes []reflect.Type, params interface{}) ([]reflect.Value, Error)
	// Assemble success response, expects response id and payload
	CreateResponse(id interface{}, reply interface{}) interface{}
	// Assemble error response, expects response id and error
	CreateErrorResponse(id interface{}, err Error) interface{}
	// Assemble error response with extra information about the error through info
	CreateErrorResponseWithInfo(id interface{}, err Error, info interface{}) interface{}
	// Create notification response
	CreateNotification(id, namespace string, event interface{}) interface{}
	// Write msg to client.
	Write(msg interface{}) error
	// Close underlying data stream
	Close()
	// Closed when underlying connection is closed
	Closed() <-chan interface{}
}

type BlockNumber int64

const (
	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
}

func (bn BlockNumber) Int64() int64 {
	return (int64)(bn)
}

func (bn BlockNumber) Uint64() uint64 {
	return (uint64)(bn)
}

type BlockNumberOrHash struct {
	BlockNumber      *BlockNumber `json:"blockNumber,omitempty"`
	BlockHash        *common.Hash `json:"blockHash,omitempty"`
	RequireCanonical bool         `json:"requireCanonical,omitempty"`
}

func (bnh *BlockNumberOrHash) UnmarshalJSON(data []byte) error {
	type erased BlockNumberOrHash
	e := erased{}
	err := json.Unmarshal(data, &e)
	if err == nil {
		if e.BlockNumber != nil && e.BlockHash != nil {
			return fmt.Errorf("cannot specify both BlockHash and BlockNumber, choose one or the other")
		}
		bnh.BlockNumber = e.BlockNumber
		bnh.BlockHash = e.BlockHash
		bnh.RequireCanonical = e.RequireCanonical
		return nil
	}
	var input string
	err = json.Unmarshal(data, &input)
	if err != nil {
		return err
	}
	switch input {
	case "earliest":
		bn := EarliestBlockNumber
		bnh.BlockNumber = &bn
		return nil
	case "latest":
		bn := LatestBlockNumber
		bnh.BlockNumber = &bn
		return nil
	case "pending":
		bn := PendingBlockNumber
		bnh.BlockNumber = &bn
		return nil
	default:
		if len(input) == 66 {
			hash := common.Hash{}
			err := hash.UnmarshalText([]byte(input))
			if err != nil {
				return err
			}
			bnh.BlockHash = &hash
			return nil
		} else {
			blckNum, err := hexutil.DecodeUint64(input)
			if err != nil {
				return err
			}
			if blckNum > math.MaxInt64 {
				return fmt.Errorf("blocknumber too high")
			}
			bn := BlockNumber(blckNum)
			bnh.BlockNumber = &bn
			return nil
		}
	}
}

func (bnh *BlockNumberOrHash) Number() (BlockNumber, bool) {
	if bnh.BlockNumber != nil {
		return *bnh.BlockNumber, true
	}
	return BlockNumber(0), false
}

func (bnh *BlockNumberOrHash) Hash() (common.Hash, bool) {
	if bnh.BlockHash != nil {
		return *bnh.BlockHash, true
	}
	return common.Hash{}, false
}

type FilterQuery struct {
	FullShardId uint32
	ethereum.FilterQuery
}

// UnmarshalJSON sets *args fields with given data.
func (args *FilterQuery) UnmarshalJSON(data []byte) error {
	type input struct {
		BlockHash *common.Hash  `json:"blockHash"`
		FromBlock *BlockNumber  `json:"fromBlock"`
		ToBlock   *BlockNumber  `json:"toBlock"`
		Addresses interface{}   `json:"address"`
		Topics    []interface{} `json:"topics"`
	}

	var raw input
	if err := json.Unmarshal(data, &raw); err != nil {
		return err
	}

	if raw.BlockHash != nil {
		if raw.FromBlock != nil || raw.ToBlock != nil {
			// BlockHash is mutually exclusive with FromBlock/ToBlock criteria
			return fmt.Errorf("cannot specify both BlockHash and FromBlock/ToBlock, choose one or the other")
		}
		args.BlockHash = raw.BlockHash
	} else {
		if raw.FromBlock != nil {
			args.FromBlock = big.NewInt(raw.FromBlock.Int64())
		}

		if raw.ToBlock != nil {
			args.ToBlock = big.NewInt(raw.ToBlock.Int64())
		}
	}

	args.Addresses = []common.Address{}

	if raw.Addresses != nil {
		// raw.Address can contain a single address or an array of addresses
		switch rawAddr := raw.Addresses.(type) {
		case []interface{}:
			for i, addr := range rawAddr {
				if strAddr, ok := addr.(string); ok {
					addr, err := decodeAddress(strAddr)
					if err != nil {
						return fmt.Errorf("invalid address at index %d: %v", i, err)
					}
					args.Addresses = append(args.Addresses, addr)
				} else {
					return fmt.Errorf("non-string address at index %d", i)
				}
			}
		case string:
			addr, err := decodeAddress(rawAddr)
			if err != nil {
				return fmt.Errorf("invalid address: %v", err)
			}
			args.Addresses = []common.Address{addr}
		default:
			return errors.New("invalid addresses in query")
		}
	}

	// topics is an array consisting of strings and/or arrays of strings.
	// JSON null values are converted to common.Hash{} and ignored by the filter manager.
	if len(raw.Topics) > 0 {
		args.Topics = make([][]common.Hash, len(raw.Topics))
		for i, t := range raw.Topics {
			switch topic := t.(type) {
			case nil:
				// ignore topic when matching logs

			case string:
				// match specific topic
				top, err := decodeTopic(topic)
				if err != nil {
					return err
				}
				args.Topics[i] = []common.Hash{top}

			case []interface{}:
				// or case e.g. [null, "topic0", "topic1"]
				for _, rawTopic := range topic {
					if rawTopic == nil {
						// null component, match all
						args.Topics[i] = nil
						break
					}
					if topic, ok := rawTopic.(string); ok {
						parsed, err := decodeTopic(topic)
						if err != nil {
							return err
						}
						args.Topics[i] = append(args.Topics[i], parsed)
					} else {
						return fmt.Errorf("invalid topic(s)")
					}
				}
			default:
				return fmt.Errorf("invalid topic(s)")
			}
		}
	}

	return nil
}

func decodeAddress(s string) (common.Address, error) {
	b, err := hexutil.Decode(s)
	if err == nil && len(b) != common.AddressLength+4 && len(b) != common.AddressLength {
		err = fmt.Errorf("hex has invalid length %d after decoding; expected %d for address", len(b), common.AddressLength)
	}
	return common.BytesToAddress(b[:common.AddressLength]), err
}

func decodeTopic(s string) (common.Hash, error) {
	b, err := hexutil.Decode(s)
	if err == nil && len(b) != common.HashLength {
		err = fmt.Errorf("hex has invalid length %d after decoding; expected %d for topic", len(b), common.HashLength)
	}
	return common.BytesToHash(b), err
}