README ¶
blockchain
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/bitcoinsv/bsvd/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.
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 ¶
- Constants
- func BigToCompact(n *big.Int) uint32
- func BuildMerkleTreeStore(transactions []*bsvutil.Tx) []*chainhash.Hash
- func CalcBlockSubsidy(height int32, chainParams *chaincfg.Params) int64
- func CalcWork(bits uint32) *big.Int
- func CheckBlockSanity(block *bsvutil.Block, powLimit *big.Int, timeSource MedianTimeSource) error
- func CheckProofOfWork(block *bsvutil.Block, powLimit *big.Int) error
- func CheckTransactionInputs(tx *bsvutil.Tx, txHeight int32, utxoView *UtxoViewpoint, ...) (int64, error)
- func CheckTransactionSanity(tx *bsvutil.Tx, scriptFlags txscript.ScriptFlags) error
- func CompactToBig(compact uint32) *big.Int
- func CountP2SHSigOps(tx *bsvutil.Tx, isCoinBaseTx bool, utxoView *UtxoViewpoint, ...) (int, error)
- func CountSigOps(tx *bsvutil.Tx, scriptFlags txscript.ScriptFlags) int
- func DeserializeOutpointKey(key []byte) *wire.OutPoint
- func DisableLog()
- func ExtractCoinbaseHeight(coinbaseTx *bsvutil.Tx) (int32, error)
- func GetSigOps(tx *bsvutil.Tx, isCoinBaseTx bool, utxoView *UtxoViewpoint, ...) (int, error)
- func HashMerkleBranches(left *chainhash.Hash, right *chainhash.Hash) *chainhash.Hash
- func HashToBig(hash *chainhash.Hash) *big.Int
- func IsCoinBase(tx *bsvutil.Tx) bool
- func IsCoinBaseTx(msgTx *wire.MsgTx) bool
- func IsFinalizedTransaction(tx *bsvutil.Tx, blockHeight int32, blockTime time.Time) bool
- func LockTimeToSequence(isSeconds bool, locktime uint32) uint32
- func SequenceLockActive(sequenceLock *SequenceLock, blockHeight int32, medianTimePast time.Time) bool
- func ShouldHaveSerializedBlockHeight(header *wire.BlockHeader) bool
- func UseLogger(logger bsvlog.Logger)
- func ValidateTransactionScripts(tx *bsvutil.Tx, utxoView *UtxoViewpoint, flags txscript.ScriptFlags, ...) error
- type AssertError
- type BehaviorFlags
- type BestState
- type BlockChain
- func (b *BlockChain) BestSnapshot() *BestState
- func (b *BlockChain) BlockByHash(hash *chainhash.Hash) (*bsvutil.Block, error)
- func (b *BlockChain) BlockByHeight(blockHeight int32) (*bsvutil.Block, error)
- func (b *BlockChain) BlockHashByHeight(blockHeight int32) (*chainhash.Hash, error)
- func (b *BlockChain) BlockHeightByHash(hash *chainhash.Hash) (int32, error)
- func (b *BlockChain) BlockLocatorFromHash(hash *chainhash.Hash) BlockLocator
- func (b *BlockChain) CachedStateSize() uint64
- func (b *BlockChain) CalcNextBlockVersion() (int32, error)
- func (b *BlockChain) CalcNextRequiredDifficulty(timestamp time.Time) (uint32, error)
- func (b *BlockChain) CalcSequenceLock(tx *bsvutil.Tx, utxoView *UtxoViewpoint, mempool bool) (*SequenceLock, error)
- func (b *BlockChain) CheckConnectBlockTemplate(block *bsvutil.Block) error
- func (b *BlockChain) Checkpoints() []chaincfg.Checkpoint
- func (b *BlockChain) FetchSpendJournal(targetBlock *bsvutil.Block) ([]SpentTxOut, error)
- func (b *BlockChain) FetchUtxoEntry(outpoint wire.OutPoint) (*UtxoEntry, error)
- func (b *BlockChain) FetchUtxoView(tx *bsvutil.Tx) (*UtxoViewpoint, error)
- func (b *BlockChain) FlushCachedState(mode FlushMode) error
- func (b *BlockChain) GetOrphanRoot(hash *chainhash.Hash) *chainhash.Hash
- func (b *BlockChain) HasCheckpoints() bool
- func (b *BlockChain) HaveBlock(hash *chainhash.Hash) (bool, error)
- func (b *BlockChain) HeaderByHash(hash *chainhash.Hash) (wire.BlockHeader, error)
- func (b *BlockChain) HeightRange(startHeight, endHeight int32) ([]chainhash.Hash, error)
- func (b *BlockChain) HeightToHashRange(startHeight int32, endHash *chainhash.Hash, maxResults int) ([]chainhash.Hash, error)
- func (b *BlockChain) IntervalBlockHashes(endHash *chainhash.Hash, interval int) ([]chainhash.Hash, error)
- func (b *BlockChain) IsCheckpointCandidate(block *bsvutil.Block) (bool, error)
- func (b *BlockChain) IsCurrent() bool
- func (b *BlockChain) IsDeploymentActive(deploymentID uint32) (bool, error)
- func (b *BlockChain) IsKnownOrphan(hash *chainhash.Hash) bool
- func (b *BlockChain) LatestBlockLocator() (BlockLocator, error)
- func (b *BlockChain) LatestCheckpoint() *chaincfg.Checkpoint
- func (b *BlockChain) LocateBlocks(locator BlockLocator, hashStop *chainhash.Hash, maxHashes uint32) []chainhash.Hash
- func (b *BlockChain) LocateHeaders(locator BlockLocator, hashStop *chainhash.Hash) []wire.BlockHeader
- func (b *BlockChain) MainChainHasBlock(hash *chainhash.Hash) bool
- func (b *BlockChain) MaxBlockSigOps(uahfActive bool) int
- func (b *BlockChain) MaxBlockSize(uahfActive bool) int
- func (b *BlockChain) ProcessBlock(block *bsvutil.Block, flags BehaviorFlags) (bool, bool, error)
- func (b *BlockChain) Prune() error
- func (b *BlockChain) PruneMode() bool
- func (b *BlockChain) ReIndexChainState() error
- func (b *BlockChain) ReconsiderBlock(hash *chainhash.Hash) error
- func (b *BlockChain) RollbackUtxoSet(height int32) (*UtxoViewpoint, error)
- func (b *BlockChain) SelectDifficultyAdjustmentAlgorithm(height int32) DifficultyAlgorithm
- func (b *BlockChain) Subscribe(callback NotificationCallback)
- func (b *BlockChain) ThresholdState(deploymentID uint32) (ThresholdState, error)
- func (b *BlockChain) UtxoCacheFlushInProgress() bool
- type BlockLocator
- type Config
- type DeploymentError
- type DifficultyAlgorithm
- type ErrorCode
- type FlushMode
- type IndexManager
- type MedianTimeSource
- type Notification
- type NotificationCallback
- type NotificationType
- type RuleError
- type SequenceLock
- type SpentTxOut
- type ThresholdState
- type UtxoEntry
- type UtxoViewpoint
- func (view *UtxoViewpoint) AddTxOut(tx *bsvutil.Tx, txOutIdx uint32, blockHeight int32)
- func (view *UtxoViewpoint) AddTxOuts(tx *bsvutil.Tx, blockHeight int32)
- func (view *UtxoViewpoint) Entries() map[wire.OutPoint]*UtxoEntry
- func (view *UtxoViewpoint) LookupEntry(outpoint wire.OutPoint) *UtxoEntry
- func (view *UtxoViewpoint) RemoveEntry(outpoint wire.OutPoint)
Examples ¶
Constants ¶
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 // LegacyMaxBlockSize is the maximum number of bytes allowed in a block // prior to the August 1st, 2018 UAHF hardfork LegacyMaxBlockSize = 1000000 // MaxBlockSigOpsPerMB is the maximum number of allowed sigops allowed // per one megabyte allowed in a block MaxBlockSigOpsPerMB = 20000 // MaxTransactionSize is the maximum allowable size of a transaction MaxTransactionSize = 1000000 // MaxTransactionSigOps is the maximum allowable number of sigops per transaction MaxTransactionSigOps = 20000 )
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.
const DifficultyAdjustmentWindow = 144
DifficultyAdjustmentWindow is the size of the window used by the DAA adjustment algorithm when calculating the current difficulty. The algorithm requires fetching a 'suitable' block out of blocks n-144, n-145, and n-146. We set this value equal to n-144 as that is the first of the three candidate blocks and we will use it to fetch the previous two.
Variables ¶
This section is empty.
Functions ¶
func BigToCompact ¶
BigToCompact converts a whole number N to a compact representation using an unsigned 32-bit number. The compact representation only provides 23 bits of precision, so values larger than (2^23 - 1) only encode the most significant digits of the number. See CompactToBig for details.
Example ¶
This example demonstrates how to convert a target difficulty into the compact "bits" in a block header which represent that target difficulty .
Output: 419465580
func BuildMerkleTreeStore ¶
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 ¶
CalcBlockSubsidy returns the subsidy amount a block at the provided height should have. This is mainly used for determining how much the coinbase for newly generated blocks awards as well as validating the coinbase for blocks has the expected value.
The subsidy is halved every SubsidyReductionInterval blocks. Mathematically this is: baseSubsidy / 2^(height/SubsidyReductionInterval)
At the target block generation rate for the main network, this is approximately every 4 years.
func CalcWork ¶
CalcWork calculates a work value from difficulty bits. Bitcoin increases the difficulty for generating a block by decreasing the value which the generated hash must be less than. This difficulty target is stored in each block header using a compact representation as described in the documentation for CompactToBig. The main chain is selected by choosing the chain that has the most proof of work (highest difficulty). Since a lower target difficulty value equates to higher actual difficulty, the work value which will be accumulated must be the inverse of the difficulty. Also, in order to avoid potential division by zero and really small floating point numbers, the result adds 1 to the denominator and multiplies the numerator by 2^256.
func CheckBlockSanity ¶
CheckBlockSanity performs some preliminary checks on a block to ensure it is sane before continuing with block processing. These checks are context free.
func CheckProofOfWork ¶
CheckProofOfWork ensures the block header bits which indicate the target difficulty is in min/max range and that the block hash is less than the target difficulty as claimed.
func CheckTransactionInputs ¶
func CheckTransactionInputs(tx *bsvutil.Tx, txHeight int32, utxoView *UtxoViewpoint, chainParams *chaincfg.Params) (int64, error)
CheckTransactionInputs performs a series of checks on the inputs to a transaction to ensure they are valid. An example of some of the checks include verifying all inputs exist, ensuring the coinbase seasoning requirements are met, detecting double spends, validating all values and fees are in the legal range and the total output amount doesn't exceed the input amount, and verifying the signatures to prove the spender was the owner of the bitcoins and therefore allowed to spend them. As it checks the inputs, it also calculates the total fees for the transaction and returns that value.
NOTE: The transaction MUST have already been sanity checked with the CheckTransactionSanity function prior to calling this function.
func CheckTransactionSanity ¶
func CheckTransactionSanity(tx *bsvutil.Tx, scriptFlags txscript.ScriptFlags) error
CheckTransactionSanity performs some preliminary checks on a transaction to ensure it is sane. These checks are context free.
func CompactToBig ¶
CompactToBig converts a compact representation of a whole number N to an unsigned 32-bit number. The representation is similar to IEEE754 floating point numbers.
Like IEEE754 floating point, there are three basic components: the sign, the exponent, and the mantissa. They are broken out as follows:
the most significant 8 bits represent the unsigned base 256 exponent
bit 23 (the 24th bit) represents the sign bit
the least significant 23 bits represent the mantissa
------------------------------------------------- | Exponent | Sign | Mantissa | ------------------------------------------------- | 8 bits [31-24] | 1 bit [23] | 23 bits [22-00] | -------------------------------------------------
The formula to calculate N is:
N = (-1^sign) * mantissa * 256^(exponent-3)
This compact form is only used in bitcoin to encode unsigned 256-bit numbers which represent difficulty targets, thus there really is not a need for a sign bit, but it is implemented here to stay consistent with bitcoind.
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.
Output: 0000000000000000896c00000000000000000000000000000000000000000000
func CountP2SHSigOps ¶
func CountP2SHSigOps(tx *bsvutil.Tx, isCoinBaseTx bool, utxoView *UtxoViewpoint, scriptFlags txscript.ScriptFlags) (int, error)
CountP2SHSigOps returns the number of signature operations for all input transactions which are of the pay-to-script-hash type. This uses the precise, signature operation counting mechanism from the script engine which requires access to the input transaction scripts.
func CountSigOps ¶
func CountSigOps(tx *bsvutil.Tx, scriptFlags txscript.ScriptFlags) int
CountSigOps returns the number of signature operations for all transaction input and output scripts in the provided transaction. This uses the quicker, but imprecise, signature operation counting mechanism from txscript.
func DeserializeOutpointKey ¶
DeserializeOutpointKey takes in a Utxo database key and deserializes it into an outpoint.
func DisableLog ¶
func DisableLog()
DisableLog disables all library log output. Logging output is disabled by default until UseLogger is called.
func ExtractCoinbaseHeight ¶
ExtractCoinbaseHeight attempts to extract the height of the block from the scriptSig of a coinbase transaction. Coinbase heights are only present in blocks of version 2 or later. This was added as part of BIP0034.
func GetSigOps ¶
func GetSigOps(tx *bsvutil.Tx, isCoinBaseTx bool, utxoView *UtxoViewpoint, scriptFlags txscript.ScriptFlags) (int, error)
GetSigOps returns the unified sig op count for the passed transaction respecting current active soft-forks which modified sig op cost counting.
func HashMerkleBranches ¶
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 ¶
HashToBig converts a chainhash.Hash into a big.Int that can be used to perform math comparisons.
func IsCoinBase ¶
IsCoinBase determines whether or not a transaction is a coinbase. A coinbase is a special transaction created by miners that has no inputs. This is represented in the block chain by a transaction with a single input that has a previous output transaction index set to the maximum value along with a zero hash.
This function only differs from IsCoinBaseTx in that it works with a higher level util transaction as opposed to a raw wire transaction.
func IsCoinBaseTx ¶
IsCoinBaseTx determines whether or not a transaction is a coinbase. A coinbase is a special transaction created by miners that has no inputs. This is represented in the block chain by a transaction with a single input that has a previous output transaction index set to the maximum value along with a zero hash.
This function only differs from IsCoinBase in that it works with a raw wire transaction as opposed to a higher level util transaction.
func IsFinalizedTransaction ¶
IsFinalizedTransaction determines whether or not a transaction is finalized.
func LockTimeToSequence ¶
LockTimeToSequence converts the passed relative locktime to a sequence number in accordance to BIP-68. See: https://github.com/bitcoin/bips/blob/master/bip-0068.mediawiki
- (Compatibility)
func SequenceLockActive ¶
func SequenceLockActive(sequenceLock *SequenceLock, blockHeight int32, medianTimePast time.Time) bool
SequenceLockActive determines if a transaction's sequence locks have been met, meaning that all the inputs of a given transaction have reached a height or time sufficient for their relative lock-time maturity.
func ShouldHaveSerializedBlockHeight ¶
func ShouldHaveSerializedBlockHeight(header *wire.BlockHeader) bool
ShouldHaveSerializedBlockHeight determines if a block should have a serialized block height embedded within the scriptSig of its coinbase transaction. Judgement is based on the block version in the block header. Blocks with version 2 and above satisfy this criteria. See BIP0034 for further information.
func ValidateTransactionScripts ¶
func ValidateTransactionScripts(tx *bsvutil.Tx, utxoView *UtxoViewpoint, flags txscript.ScriptFlags, sigCache *txscript.SigCache, hashCache *txscript.HashCache) error
ValidateTransactionScripts validates the scripts for the passed transaction using multiple goroutines.
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
BehaviorFlags is a bitmask defining tweaks to the normal behavior when performing chain processing and consensus rules checks.
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 // BFNoDupBlockCheck signals if the block should skip existence // checks. BFNoDupBlockCheck // BFNone is a convenience value to specifically indicate no flags. BFNone BehaviorFlags = 0 )
func (BehaviorFlags) HasFlag ¶
func (behaviorFlags BehaviorFlags) HasFlag(flag BehaviorFlags) bool
HasFlag returns whether the BehaviorFlags has the passed flag set.
type BestState ¶
type BestState struct { Hash chainhash.Hash // The hash of the block. Height int32 // The height of the block. Bits uint32 // The difficulty bits of the block. BlockSize uint64 // The size 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. }
BestState houses information about the current best block and other info related to the state of the main chain as it exists from the point of view of the current best block.
The BestSnapshot method can be used to obtain access to this information in a concurrent safe manner and the data will not be changed out from under the caller when chain state changes occur as the function name implies. However, the returned snapshot must be treated as immutable since it is shared by all callers.
type BlockChain ¶
type BlockChain struct {
// contains filtered or unexported fields
}
BlockChain provides functions for working with the bitcoin block chain. It includes functionality such as rejecting duplicate blocks, ensuring blocks follow all rules, orphan handling, checkpoint handling, and best chain selection with reorganization.
func New ¶
func New(config *Config) (*BlockChain, error)
New returns a BlockChain instance using the provided configuration details.
func (*BlockChain) BestSnapshot ¶
func (b *BlockChain) BestSnapshot() *BestState
BestSnapshot returns information about the current best chain block and related state as of the current point in time. The returned instance must be treated as immutable since it is shared by all callers.
This function is safe for concurrent access.
func (*BlockChain) BlockByHash ¶
BlockByHash returns the block from the main chain with the given hash with the appropriate chain height set.
This function is safe for concurrent access.
func (*BlockChain) BlockByHeight ¶
func (b *BlockChain) BlockByHeight(blockHeight int32) (*bsvutil.Block, error)
BlockByHeight returns the block at the given height in the main chain.
This function is safe for concurrent access.
func (*BlockChain) BlockHashByHeight ¶
func (b *BlockChain) BlockHashByHeight(blockHeight int32) (*chainhash.Hash, error)
BlockHashByHeight returns the hash of the block at the given height in the main chain.
This function is safe for concurrent access.
func (*BlockChain) BlockHeightByHash ¶
func (b *BlockChain) BlockHeightByHash(hash *chainhash.Hash) (int32, error)
BlockHeightByHash returns the height of the block with the given hash in the main chain.
This function is safe for concurrent access.
func (*BlockChain) BlockLocatorFromHash ¶
func (b *BlockChain) BlockLocatorFromHash(hash *chainhash.Hash) BlockLocator
BlockLocatorFromHash returns a block locator for the passed block hash. See BlockLocator for details on the algorithm used to create a block locator.
In addition to the general algorithm referenced above, this function will return the block locator for the latest known tip of the main (best) chain if the passed hash is not currently known.
This function is safe for concurrent access.
func (*BlockChain) CachedStateSize ¶
func (b *BlockChain) CachedStateSize() uint64
CachedStateSize returns the total size of the cached state of the blockchain in bytes.
func (*BlockChain) CalcNextBlockVersion ¶
func (b *BlockChain) CalcNextBlockVersion() (int32, error)
CalcNextBlockVersion calculates the expected version of the block after the end of the current best chain based on the state of started and locked in rule change deployments.
This function is safe for concurrent access.
func (*BlockChain) CalcNextRequiredDifficulty ¶
func (b *BlockChain) CalcNextRequiredDifficulty(timestamp time.Time) (uint32, error)
CalcNextRequiredDifficulty calculates the required difficulty for the block after the end of the current best chain based on the difficulty retarget rules.
This function is safe for concurrent access.
func (*BlockChain) CalcSequenceLock ¶
func (b *BlockChain) CalcSequenceLock(tx *bsvutil.Tx, utxoView *UtxoViewpoint, mempool bool) (*SequenceLock, error)
CalcSequenceLock computes a relative lock-time SequenceLock for the passed transaction using the passed UtxoViewpoint to obtain the past median time for blocks in which the referenced inputs of the transactions were included within. The generated SequenceLock lock can be used in conjunction with a block height, and adjusted median block time to determine if all the inputs referenced within a transaction have reached sufficient maturity allowing the candidate transaction to be included in a block.
This function is safe for concurrent access.
func (*BlockChain) CheckConnectBlockTemplate ¶
func (b *BlockChain) CheckConnectBlockTemplate(block *bsvutil.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
Checkpoints returns a slice of checkpoints (regardless of whether they are already known). When there are no checkpoints for the chain, it will return nil.
This function is safe for concurrent access.
func (*BlockChain) FetchSpendJournal ¶
func (b *BlockChain) FetchSpendJournal(targetBlock *bsvutil.Block) ([]SpentTxOut, error)
FetchSpendJournal attempts to retrieve the spend journal, or the set of outputs spent for the target block. This provides a view of all the outputs that will be consumed once the target block is connected to the end of the main chain.
This function is safe for concurrent access.
func (*BlockChain) FetchUtxoEntry ¶
func (b *BlockChain) FetchUtxoEntry(outpoint wire.OutPoint) (*UtxoEntry, error)
FetchUtxoEntry 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.
func (*BlockChain) FetchUtxoView ¶
func (b *BlockChain) FetchUtxoView(tx *bsvutil.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 get 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) FlushCachedState ¶
func (b *BlockChain) FlushCachedState(mode FlushMode) error
FlushCachedState flushes all the cached state of the blockchain to the database.
This method is safe for concurrent access.
func (*BlockChain) GetOrphanRoot ¶
func (b *BlockChain) GetOrphanRoot(hash *chainhash.Hash) *chainhash.Hash
GetOrphanRoot returns the head of the chain for the provided hash from the map of orphan blocks.
This function is safe for concurrent access.
func (*BlockChain) HasCheckpoints ¶
func (b *BlockChain) HasCheckpoints() bool
HasCheckpoints returns whether this BlockChain has checkpoints defined.
This function is safe for concurrent access.
func (*BlockChain) HaveBlock ¶
func (b *BlockChain) HaveBlock(hash *chainhash.Hash) (bool, error)
HaveBlock returns whether or not the chain instance has the block represented by the passed hash. This includes checking the various places a block can be like part of the main chain, on a side chain, or in the orphan pool.
This function is safe for concurrent access.
func (*BlockChain) HeaderByHash ¶
func (b *BlockChain) HeaderByHash(hash *chainhash.Hash) (wire.BlockHeader, error)
HeaderByHash returns the block header identified by the given hash or an error if it doesn't exist. Note that this will return headers from both the main and side chains.
func (*BlockChain) HeightRange ¶
func (b *BlockChain) HeightRange(startHeight, endHeight int32) ([]chainhash.Hash, error)
HeightRange returns a range of block hashes for the given start and end heights. It is inclusive of the start height and exclusive of the end height. The end height will be limited to the current main chain height.
This function is safe for concurrent access.
func (*BlockChain) HeightToHashRange ¶
func (b *BlockChain) HeightToHashRange(startHeight int32, endHash *chainhash.Hash, maxResults int) ([]chainhash.Hash, error)
HeightToHashRange returns a range of block hashes for the given start height and end hash, inclusive on both ends. The hashes are for all blocks that are ancestors of endHash with height greater than or equal to startHeight. The end hash must belong to a block that is known to be valid.
This function is safe for concurrent access.
func (*BlockChain) IntervalBlockHashes ¶
func (b *BlockChain) IntervalBlockHashes(endHash *chainhash.Hash, interval int, ) ([]chainhash.Hash, error)
IntervalBlockHashes returns hashes for all blocks that are ancestors of endHash where the block height is a positive multiple of interval.
This function is safe for concurrent access.
func (*BlockChain) IsCheckpointCandidate ¶
func (b *BlockChain) IsCheckpointCandidate(block *bsvutil.Block) (bool, error)
IsCheckpointCandidate returns whether or not the passed block is a good checkpoint candidate.
The factors used to determine a good checkpoint are:
- The block must be in the main chain
- The block must be at least 'CheckpointConfirmations' blocks prior to the current end of the main chain
- The timestamps for the blocks before and after the checkpoint must have timestamps which are also before and after the checkpoint, respectively (due to the median time allowance this is not always the case)
- The block must not contain any strange transaction such as those with nonstandard scripts
The intent is that candidates are reviewed by a developer to make the final decision and then manually added to the list of checkpoints for a network.
This function is safe for concurrent access.
func (*BlockChain) IsCurrent ¶
func (b *BlockChain) IsCurrent() bool
IsCurrent returns whether or not the chain believes it is current. Several factors are used to guess, but the key factors that allow the chain to believe it is current are:
- Latest block height is after the latest checkpoint (if enabled)
- Latest block has a timestamp newer than 24 hours ago
This function is safe for concurrent access.
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
IsKnownOrphan returns whether the passed hash is currently a known orphan. Keep in mind that only a limited number of orphans are held onto for a limited amount of time, so this function must not be used as an absolute way to test if a block is an orphan block. A full block (as opposed to just its hash) must be passed to ProcessBlock for that purpose. However, calling ProcessBlock with an orphan that already exists results in an error, so this function provides a mechanism for a caller to intelligently detect *recent* duplicate orphans and react accordingly.
This function is safe for concurrent access.
func (*BlockChain) LatestBlockLocator ¶
func (b *BlockChain) LatestBlockLocator() (BlockLocator, error)
LatestBlockLocator returns a block locator for the latest known tip of the main (best) chain.
This function is safe for concurrent access.
func (*BlockChain) LatestCheckpoint ¶
func (b *BlockChain) LatestCheckpoint() *chaincfg.Checkpoint
LatestCheckpoint returns the most recent checkpoint (regardless of whether it is already known). When there are no defined checkpoints for the active chain instance, it will return nil.
This function is safe for concurrent access.
func (*BlockChain) LocateBlocks ¶
func (b *BlockChain) LocateBlocks(locator BlockLocator, hashStop *chainhash.Hash, maxHashes uint32) []chainhash.Hash
LocateBlocks returns the hashes of the blocks after the first known block in the locator until the provided stop hash is reached, or up to the provided max number of block hashes.
In addition, there are two special cases:
- When no locators are provided, the stop hash is treated as a request for that block, so it will either return the stop hash itself if it is known, or nil if it is unknown
- When locators are provided, but none of them are known, hashes starting after the genesis block will be returned
This function is safe for concurrent access.
func (*BlockChain) LocateHeaders ¶
func (b *BlockChain) LocateHeaders(locator BlockLocator, hashStop *chainhash.Hash) []wire.BlockHeader
LocateHeaders returns the headers of the blocks after the first known block in the locator until the provided stop hash is reached, or up to a max of wire.MaxBlockHeadersPerMsg headers.
In addition, there are two special cases:
- When no locators are provided, the stop hash is treated as a request for that header, so it will either return the header for the stop hash itself if it is known, or nil if it is unknown
- When locators are provided, but none of them are known, headers starting after the genesis block will be returned
This function is safe for concurrent access.
func (*BlockChain) MainChainHasBlock ¶
func (b *BlockChain) MainChainHasBlock(hash *chainhash.Hash) bool
MainChainHasBlock returns whether or not the block with the given hash is in the main chain.
This function is safe for concurrent access.
func (*BlockChain) MaxBlockSigOps ¶
func (b *BlockChain) MaxBlockSigOps(uahfActive bool) int
MaxBlockSigOps returns the maximum allowable number of signature operations per block. If the UAHF hardfork is active the returned value is a function of the excessive blocksize. Otherwise it's a function of the legacy blocksize.
func (*BlockChain) MaxBlockSize ¶
func (b *BlockChain) MaxBlockSize(uahfActive bool) int
MaxBlockSize returns the is the maximum number of bytes allowed in a block. If the UAHF hardfork is active the returned value is the excessive blocksize. Otherwise it's the legacy blocksize.
func (*BlockChain) ProcessBlock ¶
func (b *BlockChain) ProcessBlock(block *bsvutil.Block, flags BehaviorFlags) (bool, bool, error)
ProcessBlock is the main workhorse for handling insertion of new blocks into the block chain. It includes functionality such as rejecting duplicate blocks, ensuring blocks follow all rules, orphan handling, and insertion into the block chain along with best chain selection and reorganization.
When no errors occurred during processing, the first return value indicates whether or not the block is on the main chain and the second indicates whether or not the block is an orphan.
This function is safe for concurrent access.
Example ¶
This example demonstrates how to create a new chain instance and use ProcessBlock to attempt to add a block to the chain. As the package overview documentation describes, this includes all of the Bitcoin consensus rules. This example intentionally attempts to insert a duplicate genesis block to illustrate how an invalid block is handled.
Output: Failed to process block: already have block 000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f
func (*BlockChain) Prune ¶
func (b *BlockChain) Prune() error
Prune deletes the block data and spend journals for all blocks deeper than the set prune depth.
This function is safe for concurrent access.
func (*BlockChain) PruneMode ¶
func (b *BlockChain) PruneMode() bool
PruneMode returns whether or not the blockchain is running in prune mode.
func (*BlockChain) ReIndexChainState ¶
func (b *BlockChain) ReIndexChainState() error
ReIndexChainState will delete the UTXO database bucket and rebuild the UTXO set from blocks on disk. This will take a while.
This function is safe for concurrent access.
func (*BlockChain) ReconsiderBlock ¶
func (b *BlockChain) ReconsiderBlock(hash *chainhash.Hash) error
ReconsiderBlock takes a block hash and allows it to be revalidated.
This function is safe for concurrent access.
func (*BlockChain) RollbackUtxoSet ¶
func (b *BlockChain) RollbackUtxoSet(height int32) (*UtxoViewpoint, error)
RollbackUtxoSet will perform an in-memory rollback of the Utxo set to the given block height and return a UtxoViewpoint containing the diff between the current Utxo set and the Utxo set at the provided height. Calling this function will not modify the current Utxo state either in the memory cache or on disk.
This function is safe for concurrent access.
func (*BlockChain) SelectDifficultyAdjustmentAlgorithm ¶
func (b *BlockChain) SelectDifficultyAdjustmentAlgorithm(height int32) DifficultyAlgorithm
SelectDifficultyAdjustmentAlgorithm returns the difficulty adjustment algorithm that should be used when validating a block at the given height.
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.
func (*BlockChain) UtxoCacheFlushInProgress ¶
func (b *BlockChain) UtxoCacheFlushInProgress() bool
UtxoCacheFlushInProgress returns whether or not we are currently flushing the utxo cache to disk.
type BlockLocator ¶
BlockLocator is used to help locate a specific block. The algorithm for building the block locator is to add the hashes in reverse order until the genesis block is reached. In order to keep the list of locator hashes to a reasonable number of entries, first the most recent previous 12 block hashes are added, then the step is doubled each loop iteration to exponentially decrease the number of hashes as a function of the distance from the block being located.
For example, assume a block chain with a side chain as depicted below:
genesis -> 1 -> 2 -> ... -> 15 -> 16 -> 17 -> 18 \-> 16a -> 17a
The block locator for block 17a would be the hashes of blocks: [17a 16a 15 14 13 12 11 10 9 8 7 6 4 genesis]
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 // The maximum size in bytes of the UTXO cache. // // This field is required. UtxoCacheMaxSize uint64 // 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 *chaincfg.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 // ExcessiveBlockSize is the user-configurable max block size ExcessiveBlockSize uint32 // Prune controls whether or not the blockchain should delete // historical blocks and metadata. Prune bool // PruneDepth is the minimum amount of blocks to keep to protect // against a reorg. Everything after the depth will be deleted // whenever we connect a new block. PruneDepth uint32 // ReIndexChainState will delete the UTXO db bucket and rebuild the // UTXO set from blocks on disk on startup. ReIndexChainState bool }
Config is a descriptor which specifies the blockchain instance configuration.
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 DifficultyAlgorithm ¶
type DifficultyAlgorithm uint32
The DifficultyAlgorithm specifies which algorithm to use and is passed into the calcNextRequiredDifficulty function.
Bitcoin Cash has had three different difficulty adjustment algorithms during its life. What this means for us is our node needs to select which algorithm to use when calculating difficulty based on where it is in the chain.
const ( // DifficultyLegacy was in effect from genesis through August 1st, 2017. DifficultyLegacy DifficultyAlgorithm = 0 // DifficultyEDA (Emergency Difficulty Adjustment) was a short lived changed // right after the August 1st, 2017 hardfork and lasted until November 15th, 2017. DifficultyEDA DifficultyAlgorithm = 1 // DifficultyDAA (Difficulty Adjustment Algorithm) is the current Bitcoin Cash // difficulty algorithm in effect since Novemeber 15th, 2017. DifficultyDAA DifficultyAlgorithm = 2 )
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 // 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 // ErrTxTooSmall indicates a transaction is smaller than the minimum // allowed size when serialized. ErrTxTooSmall // ErrTxTooManySigOps indicates a transaction exceeds the maximum allowable // number of signature operations. ErrTxTooManySigOps // 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 // that does not exist ErrMissingTxOut // ErrSpentTxOut indicates a transaction output referenced by an input // that has already been spent. ErrSpentTxOut // 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 // 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 // ErrBlockTooSmall indicates the serialized block size is less than the // minimum allowed size. This consensus rule currently only applies to // the first block after the Uahf. ErrBlockTooSmall // ErrInvalidTxOrder indicates the order of the transactions in the block // does not follow the active transaction ordering consensus rule. ErrInvalidTxOrder )
These constants are used to identify a specific RuleError.
type FlushMode ¶
type FlushMode uint8
FlushMode is used to indicate the different urgency types for a flush.
const ( // FlushRequired is the flush mode that means a flush must be performed // regardless of the cache state. For example right before shutting down. FlushRequired FlushMode = iota // FlushPeriodic is the flush mode that means a flush can be performed // when it would be almost needed. This is used to periodically signal when // no I/O heavy operations are expected soon, so there is time to flush. FlushPeriodic // FlushIfNeeded is the flush mode that means a flush must be performed only // if the cache is exceeding a safety threshold very close to its maximum // size. This is used mostly internally in between operations that can // increase the cache size. FlushIfNeeded )
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, *bsvutil.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, *bsvutil.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 }
MedianTimeSource provides a mechanism to add several time samples which are used to determine a median time which is then used as an offset to the local clock.
func NewMedianTime ¶
func NewMedianTime() MedianTimeSource
NewMedianTime returns a new instance of concurrency-safe implementation of the MedianTimeSource interface. The returned implementation contains the rules necessary for proper time handling in the chain consensus rules and expects the time samples to be added from the timestamp field of the version message received from remote peers that successfully connect and negotiate.
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: *bsvutil.Block
- NTBlockConnected: *bsvutil.Block
- NTBlockDisconnected: *bsvutil.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.
type SequenceLock ¶
SequenceLock represents the converted relative lock-time in seconds, and absolute block-height for a transaction input's relative lock-times. According to SequenceLock, after the referenced input has been confirmed within a block, a transaction spending that input can be included into a block either after 'seconds' (according to past median time), or once the 'BlockHeight' has been reached.
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 }
SpentTxOut contains a spent transaction output and potentially additional contextual information such as whether or not it was contained in a coinbase transaction, the version of the transaction it was contained in, and which block height the containing transaction was included in. As described in the comments above, the additional contextual information will only be valid when this spent txout is spending the last unspent output of the containing transaction.
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 DeserializeUtxoEntry ¶
DeserializeUtxoEntry decodes a utxo entry from the passed serialized byte slice into a new UtxoEntry using a format that is suitable for long-term storage. The format is described in detail above.
func (*UtxoEntry) BlockHeight ¶
BlockHeight returns the height of the block containing the output.
func (*UtxoEntry) IsCoinBase ¶
IsCoinBase returns whether or not the output was contained in a coinbase transaction.
func (*UtxoEntry) IsSpent ¶
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.
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 *bsvutil.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 *bsvutil.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) 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.
Source Files ¶
Directories ¶
Path | Synopsis |
---|---|
Package fullblocktests provides a set of block consensus validation tests.
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Package fullblocktests provides a set of block consensus validation tests. |
Package indexers implements optional block chain indexes.
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Package indexers implements optional block chain indexes. |