19eae8d8a1
This commit refactors the consensus rule checks for block headers and blocks in the blockchain package into separate functions. These changes contain no modifications to consensus rules and the code still passes all block consensus tests. It is only a refactoring. This is being done to help pave the way toward supporting concurrent downloads. While the package already supports headers-first mode up through the latest checkpoint through the use of the BFFastAdd flag and hard-coded checkpoints, it currently only works when downloading from a single peer. In order to support concurrent downloads from multiple peers, the ability for the caller to do things such as independently checking a block header (both context-free and full-context checks) will be needed. There are several more changes that will be necessary to support concurrent downloads as well, such as making the package concurrent safe, modifying it to make use of the new database API, etc. Those changes are planned for future commits.
81 lines
2.6 KiB
Go
81 lines
2.6 KiB
Go
// Copyright (c) 2013-2015 The btcsuite developers
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// Use of this source code is governed by an ISC
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// license that can be found in the LICENSE file.
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package blockchain
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import "github.com/btcsuite/btcutil"
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// maybeAcceptBlock potentially accepts a block into the memory block chain.
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// It performs several validation checks which depend on its position within
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// the block chain before adding it. The block is expected to have already gone
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// through ProcessBlock before calling this function with it.
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//
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// The flags modify the behavior of this function as follows:
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// - BFDryRun: The memory chain index will not be pruned and no accept
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// notification will be sent since the block is not being accepted.
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//
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// The flags are also passed to checkBlockContext and connectBestChain. See
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// their documentation for how the flags modify their behavior.
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func (b *BlockChain) maybeAcceptBlock(block *btcutil.Block, flags BehaviorFlags) error {
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dryRun := flags&BFDryRun == BFDryRun
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// Get a block node for the block previous to this one. Will be nil
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// if this is the genesis block.
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prevNode, err := b.getPrevNodeFromBlock(block)
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if err != nil {
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log.Errorf("getPrevNodeFromBlock: %v", err)
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return err
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}
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// The height of this block is one more than the referenced previous
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// block.
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blockHeight := int64(0)
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if prevNode != nil {
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blockHeight = prevNode.height + 1
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}
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block.SetHeight(blockHeight)
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// The block must pass all of the validation rules which depend on the
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// position of the block within the block chain.
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err = b.checkBlockContext(block, prevNode, flags)
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if err != nil {
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return err
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}
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// Prune block nodes which are no longer needed before creating
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// a new node.
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if !dryRun {
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err = b.pruneBlockNodes()
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if err != nil {
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return err
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}
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}
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// Create a new block node for the block and add it to the in-memory
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// block chain (could be either a side chain or the main chain).
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blockHeader := &block.MsgBlock().Header
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newNode := newBlockNode(blockHeader, block.Sha(), blockHeight)
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if prevNode != nil {
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newNode.parent = prevNode
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newNode.height = blockHeight
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newNode.workSum.Add(prevNode.workSum, newNode.workSum)
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}
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// Connect the passed block to the chain while respecting proper chain
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// selection according to the chain with the most proof of work. This
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// also handles validation of the transaction scripts.
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err = b.connectBestChain(newNode, block, flags)
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if err != nil {
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return err
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}
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// Notify the caller that the new block was accepted into the block
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// chain. The caller would typically want to react by relaying the
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// inventory to other peers.
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if !dryRun {
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b.sendNotification(NTBlockAccepted, block)
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}
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return nil
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}
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