+++ /dev/null
-// Copyright (c) 2013-2017 The btcsuite developers
-// Use of this source code is governed by an ISC
-// license that can be found in the LICENSE file.
-
-package blockchain
-
-import (
- "github.com/btcsuite/btcd/database"
- "github.com/btcsuite/btcutil"
-)
-
-// maybeAcceptBlock potentially accepts a block into the block chain and, if
-// accepted, returns whether or not it is on the main chain. It performs
-// several validation checks which depend on its position within the block chain
-// before adding it. The block is expected to have already gone through
-// ProcessBlock before calling this function with it.
-//
-// The flags modify the behavior of this function as follows:
-// - BFDryRun: The block index will not be updated and no accept notification
-// will be sent since the block is not being accepted.
-//
-// The flags are also passed to checkBlockContext and connectBestChain. See
-// their documentation for how the flags modify their behavior.
-//
-// This function MUST be called with the chain state lock held (for writes).
-func (b *BlockChain) maybeAcceptBlock(block *btcutil.Block, flags BehaviorFlags) (bool, error) {
- dryRun := flags&BFDryRun == BFDryRun
-
- // The height of this block is one more than the referenced previous
- // block.
- blockHeight := int32(0)
- prevNode := b.index.LookupNode(&block.MsgBlock().Header.PrevBlock)
- if prevNode != nil {
- blockHeight = prevNode.height + 1
- }
- block.SetHeight(blockHeight)
-
- // The block must pass all of the validation rules which depend on the
- // position of the block within the block chain.
- err := b.checkBlockContext(block, prevNode, flags)
- if err != nil {
- return false, err
- }
-
- // Insert the block into the database if it's not already there. Even
- // though it is possible the block will ultimately fail to connect, it
- // has already passed all proof-of-work and validity tests which means
- // it would be prohibitively expensive for an attacker to fill up the
- // disk with a bunch of blocks that fail to connect. This is necessary
- // since it allows block download to be decoupled from the much more
- // expensive connection logic. It also has some other nice properties
- // such as making blocks that never become part of the main chain or
- // blocks that fail to connect available for further analysis.
- err = b.db.Update(func(dbTx database.Tx) error {
- return dbMaybeStoreBlock(dbTx, block)
- })
- if err != nil {
- return false, err
- }
-
- // Create a new block node for the block and add it to the in-memory
- // block chain (could be either a side chain or the main chain).
- blockHeader := &block.MsgBlock().Header
- newNode := newBlockNode(blockHeader, blockHeight)
- if prevNode != nil {
- newNode.parent = prevNode
- newNode.height = blockHeight
- newNode.workSum.Add(prevNode.workSum, newNode.workSum)
- }
- b.index.AddNode(newNode)
-
- // Undo changes to the block index when running in dry run mode.
- if dryRun {
- defer func() {
- b.index.RemoveNode(newNode)
- }()
- }
-
- // Connect the passed block to the chain while respecting proper chain
- // selection according to the chain with the most proof of work. This
- // also handles validation of the transaction scripts.
- isMainChain, err := b.connectBestChain(newNode, block, flags)
- if err != nil {
- return false, err
- }
-
- // Notify the caller that the new block was accepted into the block
- // chain. The caller would typically want to react by relaying the
- // inventory to other peers.
- if !dryRun {
- b.chainLock.Unlock()
- b.sendNotification(NTBlockAccepted, block)
- b.chainLock.Lock()
- }
-
- return isMainChain, nil
-}
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