6a54323258
This modifies the blockchain code to store all blocks that have passed proof-of-work and contextual validity tests in the database even if they may ultimately fail to connect. This eliminates the need to store those blocks in memory, allows them to be available as orphans later even if they were never part of the main chain, and helps pave the way toward being able to separate the download logic from the connection logic.
96 lines
3.5 KiB
Go
96 lines
3.5 KiB
Go
// Copyright (c) 2013-2016 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 memory chain index will not be pruned 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
|
|
|
|
// Get a block node for the block previous to this one. Will be nil
|
|
// if this is the genesis block.
|
|
prevNode, err := b.getPrevNodeFromBlock(block)
|
|
if err != nil {
|
|
log.Errorf("getPrevNodeFromBlock: %v", err)
|
|
return false, err
|
|
}
|
|
|
|
// The height of this block is one more than the referenced previous
|
|
// block.
|
|
blockHeight := int32(0)
|
|
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, block.Hash(), blockHeight)
|
|
if prevNode != nil {
|
|
newNode.parent = prevNode
|
|
newNode.height = blockHeight
|
|
newNode.workSum.Add(prevNode.workSum, newNode.workSum)
|
|
}
|
|
|
|
// 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
|
|
}
|