7fd7f7bc52
These checks are no longer necessary since they applied to orphans and blockchain no longer handles orphans. Further, orphans are currently otherwise limited by the block manager and this is another step towards the overall effort to decouple the connection code from the download logic. Ultimately, the goal is to remove orphan handling altogether. Finally, it also has the added benefit of further minimizing the reliance on trusted known good checkpoints.
95 lines
3.2 KiB
Go
95 lines
3.2 KiB
Go
// Copyright (c) 2013-2016 The btcsuite developers
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// Copyright (c) 2015-2019 The Decred 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 (
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"fmt"
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"time"
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"github.com/decred/dcrd/dcrutil/v3"
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)
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// BehaviorFlags is a bitmask defining tweaks to the normal behavior when
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// performing chain processing and consensus rules checks.
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type BehaviorFlags uint32
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const (
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// BFFastAdd may be set to indicate that several checks can be avoided
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// for the block since it is already known to fit into the chain due to
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// already proving it correct links into the chain up to a known
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// checkpoint. This is primarily used for headers-first mode.
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BFFastAdd BehaviorFlags = 1 << iota
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// BFNoPoWCheck may be set to indicate the proof of work check which
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// ensures a block hashes to a value less than the required target will
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// not be performed.
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BFNoPoWCheck
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// BFNone is a convenience value to specifically indicate no flags.
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BFNone BehaviorFlags = 0
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)
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// ProcessBlock is the main workhorse for handling insertion of new blocks into
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// the block chain. It includes functionality such as rejecting duplicate
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// blocks, ensuring blocks follow all rules, and insertion into the block chain
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// along with best chain selection and reorganization.
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//
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// It is up to the caller to ensure the blocks are processed in order since
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// orphans are rejected.
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//
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// When no errors occurred during processing, the first return value indicates
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// the length of the fork the block extended. In the case it either extended
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// the best chain or is now the tip of the best chain due to causing a
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// reorganize, the fork length will be 0.
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//
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// This function is safe for concurrent access.
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func (b *BlockChain) ProcessBlock(block *dcrutil.Block, flags BehaviorFlags) (int64, error) {
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b.chainLock.Lock()
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defer b.chainLock.Unlock()
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blockHash := block.Hash()
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log.Tracef("Processing block %v", blockHash)
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currentTime := time.Now()
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defer func() {
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elapsedTime := time.Since(currentTime)
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log.Debugf("Block %v (height %v) finished processing in %s",
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blockHash, block.Height(), elapsedTime)
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}()
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// The block must not already exist in the main chain or side chains.
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if b.index.HaveBlock(blockHash) {
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str := fmt.Sprintf("already have block %v", blockHash)
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return 0, ruleError(ErrDuplicateBlock, str)
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}
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// Perform preliminary sanity checks on the block and its transactions.
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err := checkBlockSanity(block, b.timeSource, flags, b.chainParams)
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if err != nil {
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return 0, err
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}
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// This function should never be called with orphans or the genesis block.
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blockHeader := &block.MsgBlock().Header
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prevHash := &blockHeader.PrevBlock
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if !b.index.HaveBlock(prevHash) {
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// The fork length of orphans is unknown since they, by definition, do
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// not connect to the best chain.
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str := fmt.Sprintf("previous block %s is not known", prevHash)
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return 0, ruleError(ErrMissingParent, str)
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}
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// The block has passed all context independent checks and appears sane
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// enough to potentially accept it into the block chain.
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forkLen, err := b.maybeAcceptBlock(block, flags)
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if err != nil {
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return 0, err
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}
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log.Debugf("Accepted block %v", blockHash)
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return forkLen, nil
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}
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