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This article introduces the relevant knowledge of "what are the main methods of BlockChain in Ethernet Square". In the operation of actual cases, many people will encounter such a dilemma, so let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

BlockChain location:

Package core

Github.com/ethereum/go-ethereum/core/BlockChain.go

Release 1.8

Action

BlockChain management has the standard chain of Genesis database, which mainly realizes management block (BLock) formation / introduction chain, reverts (recovery) and reorganization chain.

After the startup node of Ethernet Square, there is only one instance of BlockChain object in the system, and BlockChain is a class in Ethernet Square.

BlockChain saves only the header block of the specification chain

Specification chain

In the process of creating blocks, some bifurcations may occur in a short period of time, and what is actually recorded in our database is a block tree. We would think that one of the most difficult paths is the block chain of our norm. Although many blocks can also form a block chain, it is not a standard block chain.

Blockchain data structure

Blockchain manages all the Block to form an one-way linked list. Headerchain manages all Header and forms an one-way linked list. Headerchain is part of Blockchain, and HeaderChain has only one object in the global scope.

Type BlockChain struct {chainConfig * params.ChainConfig / / Chain & network configuration cacheConfig * CacheConfig / / Cache configuration for pruning db ethdb.Database / / Low level persistent database to store final content in triegc * prque.Prque / / Priority queue mapping block numbers to tries to gc gcproc time.Duration / / Accumulates canonical block processing for trie dumping hc * HeaderChain / / contains the block chain of the block head RmLogsFeed event.Feed / delete message notification component chainFeed event.Feed / the following is the component of many message notification chainSideFeed event.Feed / / branch chain message notification component chainHeadFeed event.Feed / / header chain message notification component logsFeed event.Feed / / log notification component scope event.SubscriptionScope genesisBlock * types.Block / / Genesis block mu sync.RWMutex / / global mutex for locking chain operations global mutex operation chainmu sync.RWMutex / / blockchain insertion lock block chain insertion lock procmu sync.RWMutex / / block processor lock block chain processing lock checkpoint int / / checkpoint counts towards the new checkpoint currentBlock atomic.Value / / Current head of the blockchain current block header currentFastBlock atomic .value / / Current head of the fast-sync chain (may be above the block chain!) The current fast synchronizing block head fast-sync mode: fast synchronizing header Then follow up with header to synchronize all content stateCache state.Database / / State database to reuse between imports (contains state cache) bodyCache * lru.Cache / / Cache for the most recent block bodies bodyRLPCache * lru.Cache / / Cache for the most recent block bodies in RLP encoded format receiptsCache * lru.Cache / / Cache for the most recent receipts per block blockCache * lru.Cache / / Cache for the most recent entire Blocks futureBlocks * lru.Cache / / future blocks are blocks added for later processing Block storage location quit chan struct {} / / blockchain quit channel running int32 / / running must be called atomically / / procInterrupt must be atomically called procInterrupt int32 / / interrupt signaler for block processing wg sync.WaitGroup / / chain processing wait group for shutting down to achieve synchronization Thread semaphores control engine consensus.Engine// consistency engine processor Processor / / block processor interface block processor interface validator Validator / / block and state validator interface block and state verifier interface vmConfig vm.Config / / virtual machine configuration badBlocks * lru.Cache / / Bad block cache illegal block shouldPreserve func (* Types.Block) bool / / Function used to determine whether should preserve the given block. Function used to determine whether a given block should be retained} main method NewBlockChain

Construction, NewBlockChain uses the information available in the database to construct an initialized block chain. At the same time, the default validator and processor of Ethernet Fong (Validator and Processor) are initialized.

In the BlockChain object, the specific tasks are as follows

Instantiate the BlockChain class based on external or default parameters and load the canonical chain state from the database into BlockChain

Traversing the badHash list, if an error block in the badHash list is found in the specification chain, the parent block of the error block to which the specification chain is rolled back

Start the Go thread that processes the future block

Func NewBlockChain (db ethdb.Database, cacheConfig * CacheConfig, chainConfig * params.ChainConfig, engine consensus.Engine, vmConfig vm.Config, shouldPreserve func (block * types.Block) bool) (* BlockChain, error) {if cacheConfig = = nil {cacheConfig = & CacheConfig {TrieNodeLimit: 256 * 1024 * 1024, TrieTimeLimit: 5 * time.Minute,}} bodyCache _: = lru.New (bodyCacheLimit) bodyRLPCache, _: = lru.New (bodyCacheLimit) receiptsCache, _: = lru.New (receiptsCacheLimit) blockCache, _: = lru.New (blockCacheLimit) futureBlocks, _: = lru.New (maxFutureBlocks) badBlocks, _: = lru.New (badBlockLimit) bc: & BlockChain {chainConfig: chainConfig CacheConfig: cacheConfig, db: db, triegc: prque.New (nil), stateCache: state.NewDatabase (db), quit: make (chan struct {}), shouldPreserve: shouldPreserve, bodyCache: bodyCache BodyRLPCache: bodyRLPCache, receiptsCache: receiptsCache, blockCache: blockCache, futureBlocks: futureBlocks, engine: engine, vmConfig: vmConfig, badBlocks: badBlocks,} bc.SetValidator (NewBlockValidator (chainConfig, bc) Engine)) bc.SetProcessor (NewStateProcessor (chainConfig, bc, engine) var err error bc.hc, err = NewHeaderChain (db, chainConfig, engine, bc.getProcInterrupt) / / get the latest block header if err! = nil {return nil based on "LastHeader" Err} bc.genesisBlock = bc.GetBlockByNumber (0) / / get to Genesis Block if bc.genesisBlock = = nil {return nil, ErrNoGenesis} / / loadLastState loads the last known chain state from the database Also build currentBlock currentHeader currentFastBlock if err: = bc.loadLastState () Err! = nil {return nil, err} / / Check the current state of the block hashes and make sure that we do not have any of the bad blocks in our chain for hash: = range BadHashes {if header: = bc.GetHeaderByHash (hash) Header! = nil {/ / get the canonical block corresponding to the offending header's number headerByNumber: = bc.GetHeaderByNumber (header.Number.Uint64 ()) / / make sure the headerByNumber (if present) is in our current canonical chain if headerByNumber! = nil & & headerByNumber.Hash () = = header.Hash () { Log.Error ("Found bad hash" Rewinding chain "," number ", header.Number," hash ", header.ParentHash) bc.SetHead (header.Number.Uint64 ()-1) log.Error (" Chain rewind was successful Resuming normal operation ")} / / start a thread to process futureBlocks sorting and insert block Take ownership of this particular state go bc.update () return bc, nil} NewBlockChain function call time every 5 seconds:

1. In the process of starting the ethernet master service

Geth

-> makeFullNode

-> RegisterEthService

-> eth.New

-> core.NewBlockChain

two。 Command Lin

Geth importChain

-> util.MakeChain

-> core.NewBlockChain

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