blockchain

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README

blockchain

ISC License GoDoc

Package blockchain implements bitcoin block handling and chain selection rules.

The test coverage is currently only around 60%, but will be increasing over time. See test_coverage.txt for the gocov coverage report. Alternatively, if you are running a POSIX OS, you can run the cov_report.sh script for a real-time report. Package blockchain is licensed under the liberal ISC license. There is an associated blog post about the release of this package here.

This package has intentionally been designed so it can be used as a standalone package for any projects needing to handle processing of blocks into the bitcoin block chain.

Installation and Updating

$ go get -u github.com/p9c/node9/blockchain

Bitcoin Chain Processing Overview

Before a block is allowed into the block chain, it must go through an intensive series of validation rules. The following list serves as a general outline of those rules to provide some intuition into what is going on under the hood, but is by no means exhaustive:

  • Reject duplicate blocks

  • Perform a series of sanity checks on the block and its transactions such as verifying proof of work, timestamps, number and character of transactions, transaction amounts, script complexity, and merkle root calculations

  • Compare the block against predetermined checkpoints for expected timestamps and difficulty based on elapsed time since the checkpoint

  • Save the most recent orphan blocks for a limited time in case their parent blocks become available

  • Stop processing if the block is an orphan as the rest of the processing depends on the block's position within the block chain

  • Perform a series of more thorough checks that depend on the block's position within the block chain such as verifying block difficulties adhere to difficulty retarget rules, timestamps are after the median of the last several blocks, all transactions are finalized, checkpoint blocks match, and block versions are in line with the previous blocks

  • Determine how the block fits into the chain and perform different actions accordingly in order to ensure any side chains which have higher difficulty than the main chain become the new main chain

  • When a block is being connected to the main chain (either through reorganization of a side chain to the main chain or just extending the main chain), perform further checks on the block's transactions such as verifying transaction duplicates, script complexity for the combination of connected scripts, coinbase maturity, double spends, and connected transaction values

  • Run the transaction scripts to verify the spender is allowed to spend the coins

  • Insert the block into the block database

Examples

  • ProcessBlock Example
    Demonstrates how to create a new chain instance and use ProcessBlock to attempt to add a block to the chain. This example intentionally attempts to insert a duplicate genesis block to illustrate how an invalid block is handled.

  • CompactToBig Example
    Demonstrates how to convert the compact "bits" in a block header which represent the target difficulty to a big integer and display it using the typical hex notation.

  • BigToCompact Example
    Demonstrates how to convert a target difficulty into the compact "bits" in a block header which represent that target difficulty.

GPG Verification Key

All official release tags are signed by Conformal so users can ensure the code has not been tampered with and is coming from the btcsuite developers. To verify the signature perform the following:

  • Download the public key from the Conformal website at https://opensource.conformal.com/GIT-GPG-KEY-conformal.txt

  • Import the public key into your GPG keyring:

    gpg --import GIT-GPG-KEY-conformal.txt

  • Verify the release tag with the following command where TAG_NAME is a placeholder for the specific tag:

    git tag -v TAG_NAME

License

Package blockchain is licensed under the copyfree ISC License.

Documentation

Overview

Package blockchain implements bitcoin block handling and chain selection rules. The bitcoin block handling and chain selection rules are an integral, and quite likely the most important, part of bitcoin. Unfortunately, at the time of this writing, these rules are also largely undocumented and had to be ascertained from the bitcoind source code. At its core, bitcoin is a distributed consensus of which blocks are valid and which ones will comprise the main block chain (public ledger) that ultimately determines accepted transactions, so it is extremely important that fully validating nodes agree on all rules.

At a high level, this package provides support for inserting new blocks into the block chain according to the aforementioned rules. It includes functionality such as rejecting duplicate blocks, ensuring blocks and transactions follow all rules, orphan handling, and best chain selection along with reorganization.

Since this package does not deal with other bitcoin specifics such as network communication or wallets, it provides a notification system which gives the caller a high level of flexibility in how they want to react to certain events such as orphan blocks which need their parents requested and newly connected main chain blocks which might result in wallet updates.

Bitcoin Chain Processing Overview

Before a block is allowed into the block chain, it must go through an intensive series of validation rules. The following list serves as a general outline of those rules to provide some intuition into what is going on under the hood, but is by no means exhaustive:

  • Reject duplicate blocks
  • Perform a series of sanity checks on the block and its transactions such as verifying proof of work, timestamps, number and character of transactions, transaction amounts, script complexity, and merkle root calculations
  • Compare the block against predetermined checkpoints for expected timestamps and difficulty based on elapsed time since the checkpoint
  • Save the most recent orphan blocks for a limited time in case their parent blocks become available
  • Stop processing if the block is an orphan as the rest of the processing depends on the block's position within the block chain
  • Perform a series of more thorough checks that depend on the block's position within the block chain such as verifying block difficulties adhere to difficulty retarget rules, timestamps are after the median of the last several blocks, all transactions are finalized, checkpoint blocks match, and block versions are in line with the previous blocks
  • Determine how the block fits into the chain and perform different actions accordingly in order to ensure any side chains which have higher difficulty than the main chain become the new main chain
  • When a block is being connected to the main chain (either through reorganization of a side chain to the main chain or just extending the main chain), perform further checks on the block's transactions such as verifying transaction duplicates, script complexity for the combination of connected scripts, coinbase maturity, double spends, and connected transaction values
  • Run the transaction scripts to verify the spender is allowed to spend the coins
  • Insert the block into the block database

Errors

Errors returned by this package are either the raw errors provided by underlying calls or of type blockchain.RuleError. This allows the caller to differentiate between unexpected errors, such as database errors, versus errors due to rule violations through type assertions. In addition, callers can programmatically determine the specific rule violation by examining the ErrorCode field of the type asserted blockchain.RuleError.

Bitcoin Improvement Proposals

This package includes spec changes outlined by the following BIPs: 

  BIP0016 (https://en.bitcoin.it/wiki/BIP_0016)
	BIP0030 (https://en.bitcoin.it/wiki/BIP_0030)
	BIP0034 (https://en.bitcoin.it/wiki/BIP_0034)

Index

Examples

Constants

View Source 
const (
	// CoinbaseWitnessDataLen is the required length of the only element within the coinbase's witness data if the coinbase transaction contains a witness commitment.
	CoinbaseWitnessDataLen = 32
	// CoinbaseWitnessPkScriptLength is the length of the public key script containing an OP_RETURN, the WitnessMagicBytes, and the witness commitment itself. In order to be a valid candidate for the output containing the witness commitment
	CoinbaseWitnessPkScriptLength = 38
)
View Source 
const (
	// MaxTimeOffsetSeconds is the maximum number of seconds a block time is
	// allowed to be ahead of the current time.  This is currently 2 hours.
	MaxTimeOffsetSeconds = 2 * 60 * 60
	// MinCoinbaseScriptLen is the minimum length a coinbase script can be.
	MinCoinbaseScriptLen = 2
	// MaxCoinbaseScriptLen is the maximum length a coinbase script can be.
	MaxCoinbaseScriptLen = 100
)
View Source 
const (
	// MaxBlockWeight defines the maximum block weight, where "block weight" is interpreted as defined in BIP0141. A block's weight is calculated as the sum of the of bytes in the existing transactions and header, plus the weight of each byte within a transaction. The weight of a "base" byte is 4, while the weight of a witness byte is 1. As a result, for a block to be valid, the BlockWeight MUST be less than, or equal to MaxBlockWeight.
	MaxBlockWeight = 4000000
	// MaxBlockBaseSize is the maximum number of bytes within a block which can be allocated to non-witness data.
	MaxBlockBaseSize = 1000000
	// MaxBlockSigOpsCost is the maximum number of signature operations allowed for a block. It is calculated via a weighted algorithm which weights segregated witness sig ops lower than regular sig ops.
	MaxBlockSigOpsCost = 80000
	// WitnessScaleFactor determines the level of "discount" witness data receives compared to "base" data. A scale factor of 4, denotes that witness data is 1/4 as cheap as regular non-witness data.
	WitnessScaleFactor = 4
	// MinTxOutputWeight is the minimum possible weight for a transaction output.
	MinTxOutputWeight = WitnessScaleFactor * wire.MinTxOutPayload
	// MaxOutputsPerBlock is the maximum number of transaction outputs there can be in a block of max weight size.
	MaxOutputsPerBlock = MaxBlockWeight / MinTxOutputWeight
)
View Source 
const CheckpointConfirmations = 2016

CheckpointConfirmations is the number of blocks before the end of the current best block chain that a good checkpoint candidate must be. TODO: review this and add it to the fork spec

Variables

View Source 
var (
	// ScryptPowLimit is
	ScryptPowLimit = scryptPowLimit
	// ScryptPowLimitBits is
	ScryptPowLimitBits = BigToCompact(&scryptPowLimit)
)
View Source 
var (
	// WitnessMagicBytes is the prefix marker within the public key script of a coinbase output to indicate that this output holds the witness commitment for a block.
	WitnessMagicBytes = []byte{
		txscript.OP_RETURN,
		txscript.OP_DATA_36,
		0xaa,
		0x21,
		0xa9,
		0xed,
	}
)

Functions

func BigToCompact 

func BigToCompact(n *big.Int) uint32
Example

This example demonstrates how to convert a target difficulty into the compact "bits" in a block header which represent that target difficulty . 

package main

import (
	"fmt"
	"math/big"

	blockchain "github.com/p9c/node9/pkg/chain"
	_ "github.com/p9c/node9/pkg/db/ffldb"
)

func main() {
	// Convert the target difficulty from block 300000 in the main block
	// chain to compact form.
	t := "0000000000000000896c00000000000000000000000000000000000000000000"
	targetDifficulty, success := new(big.Int).SetString(t, 16)
	if !success {
		fmt.Println("invalid target difficulty")
		return
	}
	bits := blockchain.BigToCompact(targetDifficulty)
	fmt.Println(bits)
}

Output:

419465580

func BuildMerkleTreeStore 

func BuildMerkleTreeStore(transactions []*util.Tx, witness bool) []*chainhash.Hash

BuildMerkleTreeStore creates a merkle tree from a slice of transactions, stores it using a linear array, and returns a slice of the backing array. A linear array was chosen as opposed to an actual tree structure since it uses about half as much memory. The following describes a merkle tree and how it is stored in a linear array. A merkle tree is a tree in which every non-leaf node is the hash of its children nodes. A diagram depicting how this works for bitcoin transactions where h(x) is a double sha256 follows: 

         root = h1234 = h(h12 + h34)
        /                           \
  h12 = h(h1 + h2)            h34 = h(h3 + h4)
   /            \              /            \
h1 = h(tx1)  h2 = h(tx2)    h3 = h(tx3)  h4 = h(tx4)

The above stored as a linear array is as follows: 

[h1 h2 h3 h4 h12 h34 root]

As the above shows, the merkle root is always the last element in the array. The number of inputs is not always a power of two which results in a balanced tree structure as above. In that case, parent nodes with no children are also zero and parent nodes with only a single left node are calculated by concatenating the left node with itself before hashing. Since this function uses nodes that are pointers to the hashes, empty nodes will be nil. The additional bool parameter indicates if we are generating the merkle tree using witness transaction id's rather than regular transaction id's. This also presents an additional case wherein the wtxid of the coinbase transaction is the zeroHash.

func CalcBlockSubsidy 

func CalcBlockSubsidy(height int32, chainParams *netparams.Params) (r int64)

func CalcWork 

func CalcWork(bits uint32, height int32, algover int32) *big.Int

func CheckBlockSanity 

func CheckBlockSanity(block *util.Block, powLimit *big.Int, timeSource MedianTimeSource, DoNotCheckPow bool, height int32) error

func CheckProofOfWork 

func CheckProofOfWork(block *util.Block, powLimit *big.Int, height int32) error

func CheckTransactionInputs 

func CheckTransactionInputs(tx *util.Tx, txHeight int32, utxoView *UtxoViewpoint, chainParams *netparams.Params) (int64, error)

func CheckTransactionSanity 

func CheckTransactionSanity(tx *util.Tx) error

func CompactToBig 

func CompactToBig(compact uint32) *big.Int
Example

This example demonstrates how to convert the compact "bits" in a block header which represent the target difficulty to a big integer and display it using the typical hex notation. 

package main

import (
	"fmt"

	blockchain "github.com/p9c/node9/pkg/chain"
	_ "github.com/p9c/node9/pkg/db/ffldb"
)

func main() {
	// Convert the bits from block 300000 in the main block chain.
	bits := uint32(419465580)
	targetDifficulty := blockchain.CompactToBig(bits)
	// Display it in hex.
	fmt.Printf("%064x\n", targetDifficulty.Bytes())
}

Output:

0000000000000000896c00000000000000000000000000000000000000000000

func ContainsBlacklisted 

func ContainsBlacklisted(b *BlockChain, tx *util.Tx, blacklist []util.Address) (hasBlacklisted bool)

ContainsBlacklisted returns true if one of the given addresses is found in the transaction

func CountP2SHSigOps 

func CountP2SHSigOps(tx *util.Tx, isCoinBaseTx bool, utxoView *UtxoViewpoint) (int, error)

func CountSigOps 

func CountSigOps(tx *util.Tx) int

func ExtractCoinbaseHeight 

func ExtractCoinbaseHeight(coinbaseTx *util.Tx) (int32, error)

func ExtractWitnessCommitment 

func ExtractWitnessCommitment(tx *util.Tx) ([]byte, bool)

ExtractWitnessCommitment attempts to locate, and return the witness commitment for a block. The witness commitment is of the form: SHA256(witness root || witness nonce). The function additionally returns a boolean indicating if the witness root was located within any of the txOut's in the passed transaction. The witness commitment is stored as the data push for an OP_RETURN with special magic bytes to aide in location.

func GetBlockWeight 

func GetBlockWeight(blk *util.Block) int64

GetBlockWeight computes the value of the weight metric for a given block. Currently the weight metric is simply the sum of the block's serialized size without any witness data scaled proportionally by the WitnessScaleFactor, and the block's serialized size including any witness data.

func GetSigOpCost 

func GetSigOpCost(tx *util.Tx, isCoinBaseTx bool, utxoView *UtxoViewpoint, bip16, segWit bool) (int, error)

GetSigOpCost returns the unified sig op cost for the passed transaction respecting current active soft-forks which modified sig op cost counting. The unified sig op cost for a transaction is computed as the sum of: the legacy sig op count scaled according to the WitnessScaleFactor, the sig op count for all p2sh inputs scaled by the WitnessScaleFactor, and finally the unscaled sig op count for any inputs spending witness programs.

func GetTransactionWeight 

func GetTransactionWeight(tx *util.Tx) int64

GetTransactionWeight computes the value of the weight metric for a given transaction. Currently the weight metric is simply the sum of the transactions's serialized size without any witness data scaled proportionally by the WitnessScaleFactor, and the transaction's serialized size including any witness data.

func HashMerkleBranches 

func HashMerkleBranches(left *chainhash.Hash, right *chainhash.Hash) *chainhash.Hash

HashMerkleBranches takes two hashes, treated as the left and right tree nodes, and returns the hash of their concatenation. This is a helper function used to aid in the generation of a merkle tree.

func HashToBig 

func HashToBig(hash *chainhash.Hash) *big.Int

func Intersects 

func Intersects(a, b []util.Address) bool

Intersects returns whether one slice of byte slices contains a match in another

func IsCoinBase 

func IsCoinBase(tx *util.Tx) bool

func IsCoinBaseTx 

func IsCoinBaseTx(msgTx *wire.MsgTx) bool

func IsFinalizedTransaction 

func IsFinalizedTransaction(tx *util.Tx, blockHeight int32, blockTime time.Time) bool

func LockTimeToSequence 

func LockTimeToSequence(isSeconds bool, locktime uint32) uint32

func RightJustify 

func RightJustify(s string, w int) string

func SequenceLockActive 

func SequenceLockActive(sequenceLock *SequenceLock, blockHeight int32, medianTimePast time.Time) bool

func ShouldHaveSerializedBlockHeight 

func ShouldHaveSerializedBlockHeight(header *wire.BlockHeader) bool

func ValidateTransactionScripts 

func ValidateTransactionScripts(b *BlockChain, tx *util.Tx, utxoView *UtxoViewpoint, flags txscript.ScriptFlags, sigCache *txscript.SigCache,
	hashCache *txscript.HashCache) error

func ValidateWitnessCommitment 

func ValidateWitnessCommitment(blk *util.Block) error

ValidateWitnessCommitment validates the witness commitment (if any) found within the coinbase transaction of the passed block.

Types

type AssertError 

type AssertError string

AssertError identifies an error that indicates an internal code consistency issue and should be treated as a critical and unrecoverable error.

func (AssertError) Error 

func (e AssertError) Error() string

Error returns the assertion error as a human-readable string and satisfies the error interface.

type BehaviorFlags 

type BehaviorFlags uint32
const (
	// BFFastAdd may be set to indicate that several checks can be avoided
	// for the block since it is already known to fit into the chain due to
	// already proving it correct links into the chain up to a known
	// checkpoint.  This is primarily used for headers-first mode.
	BFFastAdd BehaviorFlags = 1 << iota
	// BFNoPoWCheck may be set to indicate the proof of work check which
	// ensures a block hashes to a value less than the required target will
	// not be performed.
	BFNoPoWCheck
	// BFNone is a convenience value to specifically indicate no flags.
	BFNone BehaviorFlags = 0
)

type BestState 

type BestState struct {
	Hash        chainhash.Hash // The hash of the block.
	Height      int32          // The height of the block.
	Version     int32
	Bits        uint32    // The difficulty bits of the block.
	BlockSize   uint64    // The size of the block.
	BlockWeight uint64    // The weight of the block.
	NumTxns     uint64    // The number of txns in the block.
	TotalTxns   uint64    // The total number of txns in the chain.
	MedianTime  time.Time // Median time as per CalcPastMedianTime.
}

type BlockChain 

type BlockChain struct {

	// These fields are related to the memory block index.
	// They both have their own locks,
	// however they are often also protected by the chain lock to help
	// prevent logic races when blocks are being processed.
	// index houses the entire block index in memory.
	// The block index is a tree-shaped structure.
	// bestChain tracks the current active chain by making use of an
	// efficient chain view into the block index.
	Index *blockIndex

	// DifficultyAdjustments keeps track of the latest difficulty adjustment
	// for each algorithm
	DifficultyAdjustments map[string]float64
	// contains filtered or unexported fields
}

func New 

func New(config *Config) (*BlockChain, error)

func (*BlockChain) BestSnapshot 

func (b *BlockChain) BestSnapshot() *BestState

func (*BlockChain) BlockByHash 

func (b *BlockChain) BlockByHash(hash *chainhash.Hash) (*util.Block, error)

func (*BlockChain) BlockByHeight 

func (b *BlockChain) BlockByHeight(blockHeight int32) (*util.Block, error)

func (*BlockChain) BlockHashByHeight 

func (b *BlockChain) BlockHashByHeight(blockHeight int32) (*chainhash.Hash, error)

func (*BlockChain) BlockHeightByHash 

func (b *BlockChain) BlockHeightByHash(hash *chainhash.Hash) (int32, error)

func (*BlockChain) BlockLocatorFromHash 

func (b *BlockChain) BlockLocatorFromHash(hash *chainhash.Hash) BlockLocator

func (*BlockChain) CalcNextBlockVersion 

func (b *BlockChain) CalcNextBlockVersion() (uint32, error)

func (*BlockChain) CalcNextRequiredDifficulty 

func (b *BlockChain) CalcNextRequiredDifficulty(workerNumber uint32, timestamp time.
	Time, algo string) (difficulty uint32, err error)

func (*BlockChain) CalcNextRequiredDifficultyHalcyon 

func (b *BlockChain) CalcNextRequiredDifficultyHalcyon(
	workerNumber uint32, lastNode *blockNode,
	newBlockTime time.Time, algoname string, l bool) (newTargetBits uint32,
	err error)

calcNextRequiredDifficultyHalcyon calculates the required difficulty for the block after the passed previous block node based on the difficulty retarget rules. This function differs from the exported CalcNextRequiredDifficulty in that the exported version uses the current best chain as the previous block node while this function accepts any block node.

func (*BlockChain) CalcNextRequiredDifficultyPlan9 

func (b *BlockChain) CalcNextRequiredDifficultyPlan9(
	workerNumber uint32, lastNode *blockNode,
	newBlockTime time.Time, algoname string, l bool) (newTargetBits uint32,
	adjustment float64, err error)

CalcNextRequiredDifficultyPlan9 calculates the required difficulty for the block after the passed previous block node based on the difficulty retarget rules. This function differs from the exported CalcNextRequiredDifficulty in that the exported version uses the current best chain as the previous block node while this function accepts any block node.

func (*BlockChain) CalcSequenceLock 

func (b *BlockChain) CalcSequenceLock(tx *util.Tx, utxoView *UtxoViewpoint, mempool bool) (*SequenceLock, error)

func (*BlockChain) CheckConnectBlockTemplate 

func (b *BlockChain) CheckConnectBlockTemplate(workerNumber uint32, block *util.
	Block) error

CheckConnectBlockTemplate fully validates that connecting the passed block to the main chain does not violate any consensus rules, aside from the proof of work requirement. The block must connect to the current tip of the main chain. This function is safe for concurrent access.

func (*BlockChain) Checkpoints 

func (b *BlockChain) Checkpoints() []chaincfg.Checkpoint

func (*BlockChain) FetchSpendJournal 

func (b *BlockChain) FetchSpendJournal(targetBlock *util.Block) ([]SpentTxOut, error)

func (*BlockChain) FetchUtxoEntry 

func (b *BlockChain) FetchUtxoEntry(outpoint wire.OutPoint) (*UtxoEntry, error)

FetchUtxoEntry loads and returns the requested unspent transaction output from the point of view of the end of the main chain. NOTE: Requesting an output for which there is no data will NOT return an error. Instead both the entry and the error will be nil. This is done to allow pruning of spent transaction outputs. In practice this means the caller must check if the returned entry is nil before invoking methods on it. This function is safe for concurrent access however the returned entry (if any) is NOT.

func (*BlockChain) FetchUtxoView 

func (b *BlockChain) FetchUtxoView(tx *util.Tx) (*UtxoViewpoint, error)

FetchUtxoView loads unspent transaction outputs for the inputs referenced by the passed transaction from the point of view of the end of the main chain. It also attempts to fetch the utxos for the outputs of the transaction itself so the returned view can be examined for duplicate transactions. This function is safe for concurrent access however the returned view is NOT.

func (*BlockChain) GetOrphanRoot 

func (b *BlockChain) GetOrphanRoot(hash *chainhash.Hash) *chainhash.Hash

func (*BlockChain) HasCheckpoints 

func (b *BlockChain) HasCheckpoints() bool

func (*BlockChain) HaveBlock 

func (b *BlockChain) HaveBlock(hash *chainhash.Hash) (bool, error)

func (*BlockChain) HeaderByHash 

func (b *BlockChain) HeaderByHash(hash *chainhash.Hash) (wire.BlockHeader, error)

func (*BlockChain) HeightRange 

func (b *BlockChain) HeightRange(startHeight, endHeight int32) ([]chainhash.
	Hash, error)

func (*BlockChain) HeightToHashRange 

func (b *BlockChain) HeightToHashRange(startHeight int32,
	endHash *chainhash.Hash, maxResults int) ([]chainhash.Hash, error)

func (*BlockChain) IntervalBlockHashes 

func (b *BlockChain) IntervalBlockHashes(endHash *chainhash.Hash, interval int,
) ([]chainhash.Hash, error)

func (*BlockChain) IsCheckpointCandidate 

func (b *BlockChain) IsCheckpointCandidate(block *util.Block) (bool, error)

func (*BlockChain) IsCurrent 

func (b *BlockChain) IsCurrent() bool

func (*BlockChain) IsDeploymentActive 

func (b *BlockChain) IsDeploymentActive(deploymentID uint32) (bool, error)

IsDeploymentActive returns true if the target deploymentID is active, and false otherwise. This function is safe for concurrent access.

func (*BlockChain) IsKnownOrphan 

func (b *BlockChain) IsKnownOrphan(hash *chainhash.Hash) bool

func (*BlockChain) LatestBlockLocator 

func (b *BlockChain) LatestBlockLocator() (BlockLocator, error)

func (*BlockChain) LatestCheckpoint 

func (b *BlockChain) LatestCheckpoint() *chaincfg.Checkpoint

func (*BlockChain) LocateBlocks 

func (b *BlockChain) LocateBlocks(locator BlockLocator, hashStop *chainhash.Hash, maxHashes uint32) []chainhash.Hash

func (*BlockChain) LocateHeaders 

func (b *BlockChain) LocateHeaders(locator BlockLocator, hashStop *chainhash.Hash) []wire.BlockHeader

func (*BlockChain) MainChainHasBlock 

func (b *BlockChain) MainChainHasBlock(hash *chainhash.Hash) bool

func (*BlockChain) ProcessBlock 

func (b *BlockChain) ProcessBlock(workerNumber uint32, block *util.Block,
	flags BehaviorFlags, height int32) (bool, bool, error)

func (*BlockChain) Subscribe 

func (b *BlockChain) Subscribe(callback NotificationCallback)

Subscribe to block chain notifications. Registers a callback to be executed when various events take place. See the documentation on Notification and NotificationType for details on the types and contents of notifications.

func (*BlockChain) ThresholdState 

func (b *BlockChain) ThresholdState(deploymentID uint32) (ThresholdState, error)

ThresholdState returns the current rule change threshold state of the given deployment ID for the block AFTER the end of the current best chain. This function is safe for concurrent access.

type BlockLocator 

type BlockLocator []*chainhash.Hash

type Config 

type Config struct {
	// DB defines the database which houses the blocks and will be used to
	// store all metadata created by this package such as the utxo set.
	// This field is required.
	DB database.DB
	// Interrupt specifies a channel the caller can close to signal that long
	// running operations,
	// such as catching up indexes or performing database migrations,
	// should be interrupted. This field can be nil if the caller does not
	// desire the behavior.
	Interrupt <-chan struct{}
	// ChainParams identifies which chain parameters the chain is associated
	// with. This field is required.
	ChainParams *netparams.Params
	// Checkpoints hold caller-defined checkpoints that should be added to
	// the default checkpoints in ChainParams.
	// Checkpoints must be sorted by height.
	// This field can be nil if the caller does not wish to specify any
	// checkpoints.
	Checkpoints []chaincfg.Checkpoint
	// TimeSource defines the median time source to use for things such as
	// block processing and determining whether or not the chain is current.
	// The caller is expected to keep a reference to the time source as well
	// and add time samples from other peers on the network so the local time
	// is adjusted to be in agreement with other peers.
	TimeSource MedianTimeSource
	// SigCache defines a signature cache to use when when validating
	// signatures.  This is typically most useful when individual
	// transactions are already being validated prior to their inclusion in a
	// block such as what is usually done via a transaction memory pool.
	// This field can be nil if the caller is not interested in using a
	// signature cache.
	SigCache *txscript.SigCache
	// IndexManager defines an index manager to use when initializing the
	// chain and connecting and disconnecting blocks.
	// This field can be nil if the caller does not wish to make use of an
	// index manager.
	IndexManager IndexManager
	// HashCache defines a transaction hash mid-state cache to use when
	// validating transactions. This cache has the potential to greatly speed
	// up transaction validation as re-using the pre-calculated mid-state
	// eliminates the O(N^2) validation complexity due to the SigHashAll
	// flag. This field can be nil if the caller is not interested in using a
	// signature cache.
	HashCache *txscript.HashCache
}

type DeploymentError 

type DeploymentError uint32

DeploymentError identifies an error that indicates a deployment ID was specified that does not exist.

func (DeploymentError) Error 

func (e DeploymentError) Error() string

Error returns the assertion error as a human-readable string and satisfies the error interface.

type ErrorCode 

type ErrorCode int

ErrorCode identifies a kind of error. 

const (
	// ErrDuplicateBlock indicates a block with the same hash already exists.
	ErrDuplicateBlock ErrorCode = iota
	// ErrBlockTooBig indicates the serialized block size exceeds the maximum allowed size.
	ErrBlockTooBig
	// ErrBlockWeightTooHigh indicates that the block's computed weight metric exceeds the maximum allowed value.
	ErrBlockWeightTooHigh
	// ErrBlockVersionTooOld indicates the block version is too old and is no longer accepted since the majority of the network has upgraded to a newer version.
	ErrBlockVersionTooOld
	// ErrInvalidTime indicates the time in the passed block has a precision that is more than one second.  The chain consensus rules require timestamps to have a maximum precision of one second.
	ErrInvalidTime
	// ErrTimeTooOld indicates the time is either before the median time of the last several blocks per the chain consensus rules or prior to the most recent checkpoint.
	ErrTimeTooOld
	// ErrTimeTooNew indicates the time is too far in the future as compared the current time.
	ErrTimeTooNew
	// ErrDifficultyTooLow indicates the difficulty for the block is lower than the difficulty required by the most recent checkpoint.
	ErrDifficultyTooLow
	// ErrUnexpectedDifficulty indicates specified bits do not align with the expected value either because it doesn't match the calculated valued based on difficulty regarted rules or it is out of the valid range.
	ErrUnexpectedDifficulty
	// ErrHighHash indicates the block does not hash to a value which is lower than the required target difficultly.
	ErrHighHash
	// ErrBadMerkleRoot indicates the calculated merkle root does not match the expected value.
	ErrBadMerkleRoot
	// ErrBadCheckpoint indicates a block that is expected to be at a checkpoint height does not match the expected one.
	ErrBadCheckpoint
	// ErrForkTooOld indicates a block is attempting to fork the block chain before the most recent checkpoint.
	ErrForkTooOld
	// ErrCheckpointTimeTooOld indicates a block has a timestamp before the most recent checkpoint.
	ErrCheckpointTimeTooOld
	// ErrNoTransactions indicates the block does not have a least one transaction.  A valid block must have at least the coinbase transaction.
	ErrNoTransactions
	// ErrNoTxInputs indicates a transaction does not have any inputs. A valid transaction must have at least one input.
	ErrNoTxInputs
	// ErrNoTxOutputs indicates a transaction does not have any outputs. A valid transaction must have at least one output.
	ErrNoTxOutputs
	// ErrTxTooBig indicates a transaction exceeds the maximum allowed size when serialized.
	ErrTxTooBig
	// ErrBadTxOutValue indicates an output value for a transaction is invalid in some way such as being out of range.
	ErrBadTxOutValue
	// ErrDuplicateTxInputs indicates a transaction references the same input more than once.
	ErrDuplicateTxInputs
	// ErrBadTxInput indicates a transaction input is invalid in some way such as referencing a previous transaction outpoint which is out of range or not referencing one at all.
	ErrBadTxInput
	// ErrMissingTxOut indicates a transaction output referenced by an input either does not exist or has already been spent.
	ErrMissingTxOut
	// ErrUnfinalizedTx indicates a transaction has not been finalized. A valid block may only contain finalized transactions.
	ErrUnfinalizedTx
	// ErrDuplicateTx indicates a block contains an identical transaction (or at least two transactions which hash to the same value). A valid block may only contain unique transactions.
	ErrDuplicateTx
	// ErrOverwriteTx indicates a block contains a transaction that has the same hash as a previous transaction which has not been fully spent.
	ErrOverwriteTx
	// ErrImmatureSpend indicates a transaction is attempting to spend a coinbase that has not yet reached the required maturity.
	ErrImmatureSpend
	// ErrSpendTooHigh indicates a transaction is attempting to spend more value than the sum of all of its inputs.
	ErrSpendTooHigh
	// ErrBadFees indicates the total fees for a block are invalid due to exceeding the maximum possible value.
	ErrBadFees
	// ErrTooManySigOps indicates the total number of signature operations for a transaction or block exceed the maximum allowed limits.
	ErrTooManySigOps
	// ErrFirstTxNotCoinbase indicates the first transaction in a block is not a coinbase transaction.
	ErrFirstTxNotCoinbase
	// ErrMultipleCoinbases indicates a block contains more than one coinbase transaction.
	ErrMultipleCoinbases
	// ErrBadCoinbaseScriptLen indicates the length of the signature script for a coinbase transaction is not within the valid range.
	ErrBadCoinbaseScriptLen
	// ErrBadCoinbaseValue indicates the amount of a coinbase value does not match the expected value of the subsidy plus the sum of all fees.
	ErrBadCoinbaseValue
	// ErrMissingCoinbaseHeight indicates the coinbase transaction for a block does not start with the serialized block block height as required for version 2 and higher blocks.
	ErrMissingCoinbaseHeight
	// ErrBadCoinbaseHeight indicates the serialized block height in the coinbase transaction for version 2 and higher blocks does not match the expected value.
	ErrBadCoinbaseHeight
	// ErrScriptMalformed indicates a transaction script is malformed in some way.  For example, it might be longer than the maximum allowed length or fail to parse.
	ErrScriptMalformed
	// ErrScriptValidation indicates the result of executing transaction script failed.  The error covers any failure when executing scripts such signature verification failures and execution past the end of the stack.
	ErrScriptValidation
	// ErrUnexpectedWitness indicates that a block includes transactions with witness data, but doesn't also have a witness commitment within the coinbase transaction.
	ErrUnexpectedWitness
	// ErrInvalidWitnessCommitment indicates that a block's witness commitment is not well formed.
	ErrInvalidWitnessCommitment
	// ErrWitnessCommitmentMismatch indicates that the witness commitment included in the block's coinbase transaction doesn't match the manually computed witness commitment.
	ErrWitnessCommitmentMismatch
	// ErrPreviousBlockUnknown indicates that the previous block is not known.
	ErrPreviousBlockUnknown
	// ErrInvalidAncestorBlock indicates that an ancestor of this block has already failed validation.
	ErrInvalidAncestorBlock
	// ErrPrevBlockNotBest indicates that the block's previous block is not the current chain tip. This is not a block validation rule, but is required for block proposals submitted via getblocktemplate RPC.
	ErrPrevBlockNotBest
	// ErrBlacklisted indicates a transaction contains a blacklisted address
	ErrBlacklisted
)

These constants are used to identify a specific RuleError.

func (ErrorCode) String 

func (e ErrorCode) String() string

String returns the ErrorCode as a human-readable name.

type IndexManager 

type IndexManager interface {
	// Init is invoked during chain initialize in order to allow the index
	// manager to initialize itself and any indexes it is managing.
	// The channel parameter specifies a channel the caller can close to
	// signal that the process should be interrupted.
	// It can be nil if that behavior is not desired.
	Init(*BlockChain, <-chan struct{}) error
	// ConnectBlock is invoked when a new block has been connected to the
	// main chain. The set of output spent within a block is also passed in
	// so indexers can access the previous output scripts input spent if
	// required.
	ConnectBlock(database.Tx, *util.Block, []SpentTxOut) error
	// DisconnectBlock is invoked when a block has been disconnected from the
	// main chain. The set of outputs scripts that were spent within this
	// block is also returned so indexers can clean up the prior index state
	// for this block.
	DisconnectBlock(database.Tx, *util.Block, []SpentTxOut) error
}

IndexManager provides a generic interface that the is called when blocks are connected and disconnected to and from the tip of the main chain for the purpose of supporting optional indexes.

type MedianTimeSource 

type MedianTimeSource interface {
	// AdjustedTime returns the current time adjusted by the median time offset
	// as calculated from the time samples added by AddTimeSample.
	AdjustedTime() time.Time
	// AddTimeSample adds a time sample that is used when determining the median
	// time of the added samples.
	AddTimeSample(id string, timeVal time.Time)
	// Offset returns the number of seconds to adjust the local clock based upon
	// the median of the time samples added by AddTimeData.
	Offset() time.Duration
}

func NewMedianTime 

func NewMedianTime() MedianTimeSource

type Notification 

type Notification struct {
	Type NotificationType
	Data interface{}
}

Notification defines notification that is sent to the caller via the callback function provided during the call to New and consists of a notification type as well as associated data that depends on the type as follows:

  • NTBlockAccepted: *util.Block
  • NTBlockConnected: *util.Block
  • NTBlockDisconnected: *util.Block

type NotificationCallback 

type NotificationCallback func(*Notification)

NotificationCallback is used for a caller to provide a callback for notifications about various chain events.

type NotificationType 

type NotificationType int

NotificationType represents the type of a notification message. 

const (
	// NTBlockAccepted indicates the associated block was accepted into the block chain.  Note that this does not necessarily mean it was added to the main chain.  For that, use NTBlockConnected.
	NTBlockAccepted NotificationType = iota
	// NTBlockConnected indicates the associated block was connected to the main chain.
	NTBlockConnected
	// NTBlockDisconnected indicates the associated block was disconnected from the main chain.
	NTBlockDisconnected
)

Constants for the type of a notification message.

func (NotificationType) String 

func (n NotificationType) String() string

String returns the NotificationType in human-readable form.

type RuleError 

type RuleError struct {
	ErrorCode   ErrorCode // Describes the kind of error
	Description string    // Human readable description of the issue
}

RuleError identifies a rule violation. It is used to indicate that processing of a block or transaction failed due to one of the many validation rules. The caller can use type assertions to determine if a failure was specifically due to a rule violation and access the ErrorCode field to ascertain the specific reason for the rule violation.

func (RuleError) Error 

func (e RuleError) Error() string

Error satisfies the error interface and prints human-readable errors.

type SequenceLock 

type SequenceLock struct {
	Seconds     int64
	BlockHeight int32
}

type SpentTxOut 

type SpentTxOut struct {
	// Amount is the amount of the output.
	Amount int64
	// PkScipt is the the public key script for the output.
	PkScript []byte
	// Height is the height of the the block containing the creating tx.
	Height int32
	// Denotes if the creating tx is a coinbase.
	IsCoinBase bool
}

type ThresholdState 

type ThresholdState byte

ThresholdState define the various threshold states used when voting on consensus changes. 

const (
	// ThresholdDefined is the first state for each deployment and is the state for the genesis block has by definition for all deployments.
	ThresholdDefined ThresholdState = iota
	// ThresholdStarted is the state for a deployment once its start time has been reached.
	ThresholdStarted
	// ThresholdLockedIn is the state for a deployment during the retarget period which is after the ThresholdStarted state period and the number of blocks that have voted for the deployment equal or exceed the required number of votes for the deployment.
	ThresholdLockedIn
	// ThresholdActive is the state for a deployment for all blocks after a retarget period in which the deployment was in the ThresholdLockedIn state.
	ThresholdActive
	// ThresholdFailed is the state for a deployment once its expiration time has been reached and it did not reach the ThresholdLockedIn state.
	ThresholdFailed
)

These constants are used to identify specific threshold states.

func (ThresholdState) String 

func (t ThresholdState) String() string

String returns the ThresholdState as a human-readable name.

type UtxoEntry 

type UtxoEntry struct {
	// contains filtered or unexported fields
}

UtxoEntry houses details about an individual transaction output in a utxo view such as whether or not it was contained in a coinbase tx, the height of the block that contains the tx, whether or not it is spent, its public key script, and how much it pays.

func (*UtxoEntry) Amount 

func (entry *UtxoEntry) Amount() int64

Amount returns the amount of the output.

func (*UtxoEntry) BlockHeight 

func (entry *UtxoEntry) BlockHeight() int32

BlockHeight returns the height of the block containing the output.

func (*UtxoEntry) Clone 

func (entry *UtxoEntry) Clone() *UtxoEntry

Clone returns a shallow copy of the utxo entry.

func (*UtxoEntry) IsCoinBase 

func (entry *UtxoEntry) IsCoinBase() bool

IsCoinBase returns whether or not the output was contained in a coinbase transaction.

func (*UtxoEntry) IsSpent 

func (entry *UtxoEntry) IsSpent() bool

IsSpent returns whether or not the output has been spent based upon the current state of the unspent transaction output view it was obtained from.

func (*UtxoEntry) PkScript 

func (entry *UtxoEntry) PkScript() []byte

PkScript returns the public key script for the output.

func (*UtxoEntry) Spend 

func (entry *UtxoEntry) Spend()

Spend marks the output as spent. Spending an output that is already spent has no effect.

type UtxoViewpoint 

type UtxoViewpoint struct {
	// contains filtered or unexported fields
}

UtxoViewpoint represents a view into the set of unspent transaction outputs from a specific point of view in the chain. For example, it could be for the end of the main chain, some point in the history of the main chain, or down a side chain. The unspent outputs are needed by other transactions for things such as script validation and double spend prevention.

func NewUtxoViewpoint 

func NewUtxoViewpoint() *UtxoViewpoint

NewUtxoViewpoint returns a new empty unspent transaction output view.

func (*UtxoViewpoint) AddTxOut 

func (view *UtxoViewpoint) AddTxOut(tx *util.Tx, txOutIdx uint32, blockHeight int32)

AddTxOut adds the specified output of the passed transaction to the view if it exists and is not provably unspendable. When the view already has an entry for the output, it will be marked unspent. All fields will be updated for existing entries since it's possible it has changed during a reorg.

func (*UtxoViewpoint) AddTxOuts 

func (view *UtxoViewpoint) AddTxOuts(tx *util.Tx, blockHeight int32)

AddTxOuts adds all outputs in the passed transaction which are not provably unspendable to the view. When the view already has entries for any of the outputs, they are simply marked unspent. All fields will be updated for existing entries since it's possible it has changed during a reorg.

func (*UtxoViewpoint) BestHash 

func (view *UtxoViewpoint) BestHash() *chainhash.Hash

BestHash returns the hash of the best block in the chain the view currently respresents.

func (*UtxoViewpoint) Entries 

func (view *UtxoViewpoint) Entries() map[wire.OutPoint]*UtxoEntry

Entries returns the underlying map that stores of all the utxo entries.

func (*UtxoViewpoint) LookupEntry 

func (view *UtxoViewpoint) LookupEntry(outpoint wire.OutPoint) *UtxoEntry

LookupEntry returns information about a given transaction output according to the current state of the view. It will return nil if the passed output does not exist in the view or is otherwise not available such as when it has been disconnected during a reorg.

func (*UtxoViewpoint) RemoveEntry 

func (view *UtxoViewpoint) RemoveEntry(outpoint wire.OutPoint)

RemoveEntry removes the given transaction output from the current state of the view. It will have no effect if the passed output does not exist in the view.

func (*UtxoViewpoint) SetBestHash 

func (view *UtxoViewpoint) SetBestHash(hash *chainhash.Hash)

SetBestHash sets the hash of the best block in the chain the view currently respresents.

Source Files

View all Source files

Directories

Path Synopsis
Package chaincfg defines chain configuration parameters.
 Package chaincfg defines chain configuration parameters.
netparams
Package fork handles tracking the hard fork status and is used to determine which consensus rules apply on a block
 Package fork handles tracking the hard fork status and is used to determine which consensus rules apply on a block
bench
Package fullblocktests provides a set of block consensus validation tests.
 Package fullblocktests provides a set of block consensus validation tests.
Package chainhash provides abstracted hash functionality.
 Package chainhash provides abstracted hash functionality.
Package indexers implements optional block chain indexes.
 Package indexers implements optional block chain indexes.
addresses
cpu
Package netsync implements a concurrency safe block syncing protocol.
 Package netsync implements a concurrency safe block syncing protocol.
tx
Package wallettx provides ...
 Package wallettx provides ...
author
Package txauthor provides transaction creation code for wallets.
 Package txauthor provides transaction creation code for wallets.
mgr
Package wtxmgr provides an implementation of a transaction database handling spend tracking for a bitcoin wallet.
 Package wtxmgr provides an implementation of a transaction database handling spend tracking for a bitcoin wallet.
rules
Package txrules provides transaction rules that should be followed by transaction authors for wide mempool acceptance and quick mining.
 Package txrules provides transaction rules that should be followed by transaction authors for wide mempool acceptance and quick mining.
script
Package txscript implements the bitcoin transaction script language.
 Package txscript implements the bitcoin transaction script language.
sizes
sort
Package txsort provides the transaction sorting according to BIP 69.
 Package txsort provides the transaction sorting according to BIP 69.
Package wire implements the bitcoin wire protocol.
 Package wire implements the bitcoin wire protocol.

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