lbcd/blockchain/accept.go
Dave Collins bd4e64d1d4 chainhash: Abstract hash logic to new package. (#729)
This is mostly a backport of some of the same modifications made in
Decred along with a few additional things cleaned up.  In particular,
this updates the code to make use of the new chainhash package.

Also, since this required API changes anyways and the hash algorithm is
no longer tied specifically to SHA, all other functions throughout the
code base which had "Sha" in their name have been changed to Hash so
they are not incorrectly implying the hash algorithm.

The following is an overview of the changes:

- Remove the wire.ShaHash type
- Update all references to wire.ShaHash to the new chainhash.Hash type
- Rename the following functions and update all references:
  - wire.BlockHeader.BlockSha -> BlockHash
  - wire.MsgBlock.BlockSha -> BlockHash
  - wire.MsgBlock.TxShas -> TxHashes
  - wire.MsgTx.TxSha -> TxHash
  - blockchain.ShaHashToBig -> HashToBig
  - peer.ShaFunc -> peer.HashFunc
- Rename all variables that included sha in their name to include hash
  instead
- Update for function name changes in other dependent packages such as
  btcutil
- Update copyright dates on all modified files
- Update glide.lock file to use the required version of btcutil
2016-08-08 14:04:33 -05:00

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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/btcutil"
// maybeAcceptBlock potentially accepts a block into the memory block 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) 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 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 err
}
// Prune block nodes which are no longer needed before creating
// a new node.
if !dryRun {
err = b.pruneBlockNodes()
if err != nil {
return 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.
err = b.connectBestChain(newNode, block, flags)
if err != nil {
return 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 nil
}