btcd/blockchain/accept.go
Olaoluwa Osuntokun caac0f821a
multi: update btcutil imports to point to new sub-module
In this commit, we update all the btcutil imports to point to the new
sub-module.

In the same commit, we also modify the recently added `btcutil/go.mod`
file as we need to continue pointing to the _old_ version of btcd, until
we merge this PR and push a new tag.
2022-01-10 18:44:58 -08:00

93 lines
3.4 KiB
Go

// 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 (
"fmt"
"github.com/btcsuite/btcd/database"
"github.com/btcsuite/btcd/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 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) {
// The height of this block is one more than the referenced previous
// block.
prevHash := &block.MsgBlock().Header.PrevBlock
prevNode := b.index.LookupNode(prevHash)
if prevNode == nil {
str := fmt.Sprintf("previous block %s is unknown", prevHash)
return false, ruleError(ErrPreviousBlockUnknown, str)
} else if b.index.NodeStatus(prevNode).KnownInvalid() {
str := fmt.Sprintf("previous block %s is known to be invalid", prevHash)
return false, ruleError(ErrInvalidAncestorBlock, str)
}
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 dbStoreBlock(dbTx, block)
})
if err != nil {
return false, err
}
// Create a new block node for the block and add it to the node index. Even
// if the block ultimately gets connected to the main chain, it starts out
// on a side chain.
blockHeader := &block.MsgBlock().Header
newNode := newBlockNode(blockHeader, prevNode)
newNode.status = statusDataStored
b.index.AddNode(newNode)
err = b.index.flushToDB()
if err != nil {
return false, err
}
// 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.
b.chainLock.Unlock()
b.sendNotification(NTBlockAccepted, block)
b.chainLock.Lock()
return isMainChain, nil
}