兄弟连Go语言+区块链技术培训以太坊源码分析(35)eth-fetcher源码分析.docx

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1、兄弟连Go语言+区块链技术培训以太坊源码分析(35)eth-fetcher源码分析fetcher包含基于块通知的同步。当我们接收到NewBlockHashesMsg消息得时候，我们只收到了很多Block的hash值。需要通过hash值来同步区块，然后更新本地区块链。fetcher就提供了这样的功能。数据结构    //announceisthehashnotificationoftheavailabilityofanewblockinthe    //network.    //announce是一个hash通知，表示网络上有合适的新区块出现。    typeannouncestruct{ 

2、       hashcommon.Hash//Hashoftheblockbeingannounced//新区块的hash值        numberuint64//Numberoftheblockbeingannounced(0=unknown

3、oldprotocol)区块的高度值，        header*types.Header//Headeroftheblockpartiallyreassembled(newprotocol)    重新组装的区块头        timetime.Time//Timestampoftheannouncement            ori

4、ginstring//Identifierofthepeeroriginatingthenotification            fetchHeaderheaderRequesterFn//Fetcherfunctiontoretrievetheheaderofanannouncedblock获取区块头的函数指针，里面包含了peer的信息。就是说找谁要这个区块头        fetchBodiesbodyRequesterFn//Fetcherfunctiontoretrievethebodyofanannouncedblock获取区块体的函数指针    }        //hea

5、derFilterTaskrepresentsabatchofheadersneedingfetcherfiltering.    typeheaderFilterTaskstruct{        peerstring//Thesourcepeerofblockheaders        headers[]*types.Header//Collectionofheaderstofilter        timetime.Time//Arrivaltimeoftheheaders    }        //headerFilterTaskrepresentsabatchofblock

6、bodies(transactionsanduncles)    //needingfetcherfiltering.    typebodyFilterTaskstruct{        peerstring//Thesourcepeerofblockbodies        transactions[][]*types.Transaction//Collectionoftransactionsperblockbodies        uncles[][]*types.Header//Collectionofunclesperblockbodies        timetime.T

7、ime//Arrivaltimeoftheblocks'contents    }        //injectrepresentsaschedulesimportoperation.    //当节点收到NewBlockMsg的消息时候，会插入一个区块    typeinjectstruct{        originstring        block*types.Block    }        //Fetcherisresponsibleforaccumulatingblockannouncementsfromvariouspeers    //andschedulingth

8、emforretrieval.    typeFetcherstruct{        //Variouseventchannels        notifychan*announce   //announce的通道，        injectchan*inject     //inject的通道            blockFilterchanchan[]*types.Block   //通道的通