github.com/linapex/ethereum-dpos-chinese@v0.0.0-20190316121959-b78b3a4a1ece/ethclient/ethclient.go

//<developer>
//    <name>linapex 曹一峰</name>
//    <email>linapex@163.com</email>
//    <wx>superexc</wx>
//    <qqgroup>128148617</qqgroup>
//    <url>https://jsq.ink</url>
//    <role>pku engineer</role>
//    <date>2019-03-16 12:09:39</date>
//</624342638685851648>


//包ethclient为以太坊RPC API提供客户端。
package ethclient

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"math/big"

	"github.com/ethereum/go-ethereum"
	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/common/hexutil"
	"github.com/ethereum/go-ethereum/core/types"
	"github.com/ethereum/go-ethereum/rlp"
	"github.com/ethereum/go-ethereum/rpc"
)

//客户端为以太坊RPC API定义类型化包装器。
type Client struct {
	c *rpc.Client
}

//拨号将客户机连接到给定的URL。
func Dial(rawurl string) (*Client, error) {
	return DialContext(context.Background(), rawurl)
}

func DialContext(ctx context.Context, rawurl string) (*Client, error) {
	c, err := rpc.DialContext(ctx, rawurl)
	if err != nil {
		return nil, err
	}
	return NewClient(c), nil
}

//newclient创建使用给定RPC客户端的客户端。
func NewClient(c *rpc.Client) *Client {
	return &Client{c}
}

func (ec *Client) Close() {
	ec.c.Close()
}

//区块链访问

//blockbyhash返回给定的完整块。
//
//请注意，加载完整块需要两个请求。使用headerbyhash
//如果不需要所有事务或叔叔头。
func (ec *Client) BlockByHash(ctx context.Context, hash common.Hash) (*types.Block, error) {
	return ec.getBlock(ctx, "eth_getBlockByHash", hash, true)
}

//BlockByNumber返回当前规范链中的块。如果数字为零，则
//返回最新的已知块。
//
//请注意，加载完整块需要两个请求。使用HeaderByNumber
//如果不需要所有事务或叔叔头。
func (ec *Client) BlockByNumber(ctx context.Context, number *big.Int) (*types.Block, error) {
	return ec.getBlock(ctx, "eth_getBlockByNumber", toBlockNumArg(number), true)
}

type rpcBlock struct {
	Hash         common.Hash      `json:"hash"`
	Transactions []rpcTransaction `json:"transactions"`
	UncleHashes  []common.Hash    `json:"uncles"`
}

func (ec *Client) getBlock(ctx context.Context, method string, args ...interface{}) (*types.Block, error) {
	var raw json.RawMessage
	err := ec.c.CallContext(ctx, &raw, method, args...)
	if err != nil {
		return nil, err
	} else if len(raw) == 0 {
		return nil, ethereum.NotFound
	}
//解码头和事务。
	var head *types.Header
	var body rpcBlock
	if err := json.Unmarshal(raw, &head); err != nil {
		return nil, err
	}
	if err := json.Unmarshal(raw, &body); err != nil {
		return nil, err
	}
//快速验证事务和叔叔列表。这主要有助于调试服务器。
	if head.UncleHash == types.EmptyUncleHash && len(body.UncleHashes) > 0 {
		return nil, fmt.Errorf("server returned non-empty uncle list but block header indicates no uncles")
	}
	if head.UncleHash != types.EmptyUncleHash && len(body.UncleHashes) == 0 {
		return nil, fmt.Errorf("server returned empty uncle list but block header indicates uncles")
	}
	if head.TxHash == types.EmptyRootHash && len(body.Transactions) > 0 {
		return nil, fmt.Errorf("server returned non-empty transaction list but block header indicates no transactions")
	}
	if head.TxHash != types.EmptyRootHash && len(body.Transactions) == 0 {
		return nil, fmt.Errorf("server returned empty transaction list but block header indicates transactions")
	}
//加载uncles，因为它们不包含在块响应中。
	var uncles []*types.Header
	if len(body.UncleHashes) > 0 {
		uncles = make([]*types.Header, len(body.UncleHashes))
		reqs := make([]rpc.BatchElem, len(body.UncleHashes))
		for i := range reqs {
			reqs[i] = rpc.BatchElem{
				Method: "eth_getUncleByBlockHashAndIndex",
				Args:   []interface{}{body.Hash, hexutil.EncodeUint64(uint64(i))},
				Result: &uncles[i],
			}
		}
		if err := ec.c.BatchCallContext(ctx, reqs); err != nil {
			return nil, err
		}
		for i := range reqs {
			if reqs[i].Error != nil {
				return nil, reqs[i].Error
			}
			if uncles[i] == nil {
				return nil, fmt.Errorf("got null header for uncle %d of block %x", i, body.Hash[:])
			}
		}
	}
//填充块中事务的发送方缓存。
	txs := make([]*types.Transaction, len(body.Transactions))
	for i, tx := range body.Transactions {
		if tx.From != nil {
			setSenderFromServer(tx.tx, *tx.From, body.Hash)
		}
		txs[i] = tx.tx
	}
	return types.NewBlockWithHeader(head).WithBody(txs, uncles), nil
}

//HeaderByHash返回具有给定哈希的块头。
func (ec *Client) HeaderByHash(ctx context.Context, hash common.Hash) (*types.Header, error) {
	var head *types.Header
	err := ec.c.CallContext(ctx, &head, "eth_getBlockByHash", hash, false)
	if err == nil && head == nil {
		err = ethereum.NotFound
	}
	return head, err
}

//HeaderByNumber返回当前规范链的块头。如果数字是
//nil，返回最新的已知头。
func (ec *Client) HeaderByNumber(ctx context.Context, number *big.Int) (*types.Header, error) {
	var head *types.Header
	err := ec.c.CallContext(ctx, &head, "eth_getBlockByNumber", toBlockNumArg(number), false)
	if err == nil && head == nil {
		err = ethereum.NotFound
	}
	return head, err
}

type rpcTransaction struct {
	tx *types.Transaction
	txExtraInfo
}

type txExtraInfo struct {
	BlockNumber *string         `json:"blockNumber,omitempty"`
	BlockHash   *common.Hash    `json:"blockHash,omitempty"`
	From        *common.Address `json:"from,omitempty"`
}

func (tx *rpcTransaction) UnmarshalJSON(msg []byte) error {
	if err := json.Unmarshal(msg, &tx.tx); err != nil {
		return err
	}
	return json.Unmarshal(msg, &tx.txExtraInfo)
}

//TransactionByHash返回具有给定哈希的事务。
func (ec *Client) TransactionByHash(ctx context.Context, hash common.Hash) (tx *types.Transaction, isPending bool, err error) {
	var json *rpcTransaction
	err = ec.c.CallContext(ctx, &json, "eth_getTransactionByHash", hash)
	if err != nil {
		return nil, false, err
	} else if json == nil {
		return nil, false, ethereum.NotFound
	} else if _, r, _ := json.tx.RawSignatureValues(); r == nil {
		return nil, false, fmt.Errorf("server returned transaction without signature")
	}
	if json.From != nil && json.BlockHash != nil {
		setSenderFromServer(json.tx, *json.From, *json.BlockHash)
	}
	return json.tx, json.BlockNumber == nil, nil
}

//TransactionSender返回给定事务的发件人地址。交易
//必须为远程节点所知，并包含在给定块的区块链中，并且
//索引。发送方是包含时协议派生的发送方。
//
//TransactionByHash和
//事务处理块。获取他们的发送者地址可以在没有RPC交互的情况下完成。
func (ec *Client) TransactionSender(ctx context.Context, tx *types.Transaction, block common.Hash, index uint) (common.Address, error) {
//尝试从缓存中加载地址。
	sender, err := types.Sender(&senderFromServer{blockhash: block}, tx)
	if err == nil {
		return sender, nil
	}
	var meta struct {
		Hash common.Hash
		From common.Address
	}
	if err = ec.c.CallContext(ctx, &meta, "eth_getTransactionByBlockHashAndIndex", block, hexutil.Uint64(index)); err != nil {
		return common.Address{}, err
	}
	if meta.Hash == (common.Hash{}) || meta.Hash != tx.Hash() {
		return common.Address{}, errors.New("wrong inclusion block/index")
	}
	return meta.From, nil
}

//TransactionCount返回给定块中的事务总数。
func (ec *Client) TransactionCount(ctx context.Context, blockHash common.Hash) (uint, error) {
	var num hexutil.Uint
	err := ec.c.CallContext(ctx, &num, "eth_getBlockTransactionCountByHash", blockHash)
	return uint(num), err
}

//TransactionBlock返回给定块中索引处的单个事务。
func (ec *Client) TransactionInBlock(ctx context.Context, blockHash common.Hash, index uint) (*types.Transaction, error) {
	var json *rpcTransaction
	err := ec.c.CallContext(ctx, &json, "eth_getTransactionByBlockHashAndIndex", blockHash, hexutil.Uint64(index))
	if err == nil {
		if json == nil {
			return nil, ethereum.NotFound
		} else if _, r, _ := json.tx.RawSignatureValues(); r == nil {
			return nil, fmt.Errorf("server returned transaction without signature")
		}
	}
	if json.From != nil && json.BlockHash != nil {
		setSenderFromServer(json.tx, *json.From, *json.BlockHash)
	}
	return json.tx, err
}

//TransactionReceipt按事务哈希返回事务的接收。
//请注意，收据不可用于待处理的交易。
func (ec *Client) TransactionReceipt(ctx context.Context, txHash common.Hash) (*types.Receipt, error) {
	var r *types.Receipt
	err := ec.c.CallContext(ctx, &r, "eth_getTransactionReceipt", txHash)
	if err == nil {
		if r == nil {
			return nil, ethereum.NotFound
		}
	}
	return r, err
}

func toBlockNumArg(number *big.Int) string {
	if number == nil {
		return "latest"
	}
	return hexutil.EncodeBig(number)
}

type rpcProgress struct {
	StartingBlock hexutil.Uint64
	CurrentBlock  hexutil.Uint64
	HighestBlock  hexutil.Uint64
	PulledStates  hexutil.Uint64
	KnownStates   hexutil.Uint64
}

//SyncProgress检索同步算法的当前进度。如果有
//当前没有运行同步，它返回零。
func (ec *Client) SyncProgress(ctx context.Context) (*ethereum.SyncProgress, error) {
	var raw json.RawMessage
	if err := ec.c.CallContext(ctx, &raw, "eth_syncing"); err != nil {
		return nil, err
	}
//处理可能的响应类型
	var syncing bool
	if err := json.Unmarshal(raw, &syncing); err == nil {
return nil, nil //不同步（始终为假）
	}
	var progress *rpcProgress
	if err := json.Unmarshal(raw, &progress); err != nil {
		return nil, err
	}
	return &ethereum.SyncProgress{
		StartingBlock: uint64(progress.StartingBlock),
		CurrentBlock:  uint64(progress.CurrentBlock),
		HighestBlock:  uint64(progress.HighestBlock),
		PulledStates:  uint64(progress.PulledStates),
		KnownStates:   uint64(progress.KnownStates),
	}, nil
}

//订阅订阅当前区块链头的通知
//在给定的频道上。
func (ec *Client) SubscribeNewHead(ctx context.Context, ch chan<- *types.Header) (ethereum.Subscription, error) {
	return ec.c.EthSubscribe(ctx, ch, "newHeads")
}

//状态访问

//network id返回此链的网络ID（也称为链ID）。
func (ec *Client) NetworkID(ctx context.Context) (*big.Int, error) {
	version := new(big.Int)
	var ver string
	if err := ec.c.CallContext(ctx, &ver, "net_version"); err != nil {
		return nil, err
	}
	if _, ok := version.SetString(ver, 10); !ok {
		return nil, fmt.Errorf("invalid net_version result %q", ver)
	}
	return version, nil
}

//balanceat返回给定帐户的wei余额。
//块编号可以为零，在这种情况下，余额取自最新的已知块。
func (ec *Client) BalanceAt(ctx context.Context, account common.Address, blockNumber *big.Int) (*big.Int, error) {
	var result hexutil.Big
	err := ec.c.CallContext(ctx, &result, "eth_getBalance", account, toBlockNumArg(blockNumber))
	return (*big.Int)(&result), err
}

//storageat返回给定帐户的合同存储中密钥的值。
//块编号可以为零，在这种情况下，值取自最新的已知块。
func (ec *Client) StorageAt(ctx context.Context, account common.Address, key common.Hash, blockNumber *big.Int) ([]byte, error) {
	var result hexutil.Bytes
	err := ec.c.CallContext(ctx, &result, "eth_getStorageAt", account, key, toBlockNumArg(blockNumber))
	return result, err
}

//codeat返回给定帐户的合同代码。
//块编号可以为零，在这种情况下，代码取自最新的已知块。
func (ec *Client) CodeAt(ctx context.Context, account common.Address, blockNumber *big.Int) ([]byte, error) {
	var result hexutil.Bytes
	err := ec.c.CallContext(ctx, &result, "eth_getCode", account, toBlockNumArg(blockNumber))
	return result, err
}

//nonceat返回给定帐户的nonce帐户。
//块编号可以为零，在这种情况下，nonce是从最新的已知块中获取的。
func (ec *Client) NonceAt(ctx context.Context, account common.Address, blockNumber *big.Int) (uint64, error) {
	var result hexutil.Uint64
	err := ec.c.CallContext(ctx, &result, "eth_getTransactionCount", account, toBlockNumArg(blockNumber))
	return uint64(result), err
}

//过滤器

//filterlogs执行筛选器查询。
func (ec *Client) FilterLogs(ctx context.Context, q ethereum.FilterQuery) ([]types.Log, error) {
	var result []types.Log
	err := ec.c.CallContext(ctx, &result, "eth_getLogs", toFilterArg(q))
	return result, err
}

//subscribeFilterLogs订阅流式筛选查询的结果。
func (ec *Client) SubscribeFilterLogs(ctx context.Context, q ethereum.FilterQuery, ch chan<- types.Log) (ethereum.Subscription, error) {
	return ec.c.EthSubscribe(ctx, ch, "logs", toFilterArg(q))
}

func toFilterArg(q ethereum.FilterQuery) interface{} {
	arg := map[string]interface{}{
		"fromBlock": toBlockNumArg(q.FromBlock),
		"toBlock":   toBlockNumArg(q.ToBlock),
		"address":   q.Addresses,
		"topics":    q.Topics,
	}
	if q.FromBlock == nil {
		arg["fromBlock"] = "0x0"
	}
	return arg
}

//预备状态

//PendingBalanceAt返回处于挂起状态的给定帐户的wei余额。
func (ec *Client) PendingBalanceAt(ctx context.Context, account common.Address) (*big.Int, error) {
	var result hexutil.Big
	err := ec.c.CallContext(ctx, &result, "eth_getBalance", account, "pending")
	return (*big.Int)(&result), err
}

//PendingStorageAt返回处于挂起状态的给定帐户的合同存储中密钥的值。
func (ec *Client) PendingStorageAt(ctx context.Context, account common.Address, key common.Hash) ([]byte, error) {
	var result hexutil.Bytes
	err := ec.c.CallContext(ctx, &result, "eth_getStorageAt", account, key, "pending")
	return result, err
}

//PendingCodeAt返回处于挂起状态的给定帐户的合同代码。
func (ec *Client) PendingCodeAt(ctx context.Context, account common.Address) ([]byte, error) {
	var result hexutil.Bytes
	err := ec.c.CallContext(ctx, &result, "eth_getCode", account, "pending")
	return result, err
}

//pendingnonceat返回处于挂起状态的给定帐户的帐户nonce。
//这是应该用于下一个事务的nonce。
func (ec *Client) PendingNonceAt(ctx context.Context, account common.Address) (uint64, error) {
	var result hexutil.Uint64
	err := ec.c.CallContext(ctx, &result, "eth_getTransactionCount", account, "pending")
	return uint64(result), err
}

//PendingtransactionCount返回处于挂起状态的事务总数。
func (ec *Client) PendingTransactionCount(ctx context.Context) (uint, error) {
	var num hexutil.Uint
	err := ec.c.CallContext(ctx, &num, "eth_getBlockTransactionCountByNumber", "pending")
	return uint(num), err
}

//TODO:订阅挂起的事务（需要服务器端）

//合同呼叫

//CallContract执行消息调用事务，该事务直接在VM中执行
//但从未开发到区块链中。
//
//BlockNumber选择运行调用的块高度。可以是零，其中
//如果代码取自最新的已知块。注意这个状态从很老
//块可能不可用。
func (ec *Client) CallContract(ctx context.Context, msg ethereum.CallMsg, blockNumber *big.Int) ([]byte, error) {
	var hex hexutil.Bytes
	err := ec.c.CallContext(ctx, &hex, "eth_call", toCallArg(msg), toBlockNumArg(blockNumber))
	if err != nil {
		return nil, err
	}
	return hex, nil
}

//PendingCallContract使用EVM执行消息调用事务。
//合同调用所看到的状态是挂起状态。
func (ec *Client) PendingCallContract(ctx context.Context, msg ethereum.CallMsg) ([]byte, error) {
	var hex hexutil.Bytes
	err := ec.c.CallContext(ctx, &hex, "eth_call", toCallArg(msg), "pending")
	if err != nil {
		return nil, err
	}
	return hex, nil
}

//SuggestGasprice检索当前建议的天然气价格，以便及时
//交易的执行。
func (ec *Client) SuggestGasPrice(ctx context.Context) (*big.Int, error) {
	var hex hexutil.Big
	if err := ec.c.CallContext(ctx, &hex, "eth_gasPrice"); err != nil {
		return nil, err
	}
	return (*big.Int)(&hex), nil
}

//EstimateGas试图根据
//后端区块链的当前挂起状态。不能保证这是
//矿工可能增加或移除的其他交易的实际气体限制要求，
//但它应为设定合理违约提供依据。
func (ec *Client) EstimateGas(ctx context.Context, msg ethereum.CallMsg) (uint64, error) {
	var hex hexutil.Uint64
	err := ec.c.CallContext(ctx, &hex, "eth_estimateGas", toCallArg(msg))
	if err != nil {
		return 0, err
	}
	return uint64(hex), nil
}

//sendTransaction将签名的事务注入挂起池以执行。
//
//如果事务是合同创建，请使用TransactionReceipt方法获取
//挖掘交易记录后的合同地址。
func (ec *Client) SendTransaction(ctx context.Context, tx *types.Transaction) error {
	data, err := rlp.EncodeToBytes(tx)
	if err != nil {
		return err
	}
	return ec.c.CallContext(ctx, nil, "eth_sendRawTransaction", common.ToHex(data))
}

func toCallArg(msg ethereum.CallMsg) interface{} {
	arg := map[string]interface{}{
		"from": msg.From,
		"to":   msg.To,
	}
	if len(msg.Data) > 0 {
		arg["data"] = hexutil.Bytes(msg.Data)
	}
	if msg.Value != nil {
		arg["value"] = (*hexutil.Big)(msg.Value)
	}
	if msg.Gas != 0 {
		arg["gas"] = hexutil.Uint64(msg.Gas)
	}
	if msg.GasPrice != nil {
		arg["gasPrice"] = (*hexutil.Big)(msg.GasPrice)
	}
	return arg
}