Enum LockTime

pub enum LockTime {
    Blocks(Height),
    Time(Time),
}

A relative lock time value, representing either a block height or time (512 second intervals).

Used for sequence numbers (nSequence in Bitcoin Core and crate::TxIn::sequence in this library) and also for the argument to opcode ’OP_CHECKSEQUENCEVERIFY`.

Note on ordering

Locktimes may be height- or time-based, and these metrics are incommensurate; there is no total ordering on locktimes. We therefore have implemented PartialOrd but not Ord. We also implement ordered::ArbitraryOrd if the “ordered” feature is enabled.

Relevant BIPs

• BIP 68 Relative lock-time using consensus-enforced sequence numbers
• BIP 112 CHECKSEQUENCEVERIFY

Variants

Blocks(Height)

A block height lock time value.

Time(Time)

A 512 second time interval value.

Implementations

impl LockTime

pub const ZERO: LockTime = _

A relative locktime of 0 is always valid, and is assumed valid for inputs that are not yet confirmed.

pub const SIZE: usize = 4usize

The number of bytes that the locktime contributes to the size of a transaction.

pub fn from_consensus(n: u32) -> Result<Self, DisabledLockTimeError>

Constructs a LockTime from an nSequence value or the argument to OP_CHECKSEQUENCEVERIFY.

This method will not round-trip with Self::to_consensus_u32, because relative locktimes only use some bits of the underlying u32 value and discard the rest. If you want to preserve the full value, you should use the Sequence type instead.

Examples

// `from_consensus` roundtrips with `to_consensus_u32` for small values.
let n_lock_time: u32 = 7000;
let lock_time = LockTime::from_consensus(n_lock_time).unwrap();
assert_eq!(lock_time.to_consensus_u32(), n_lock_time);

pub fn to_consensus_u32(&self) -> u32

Returns the u32 value used to encode this locktime in an nSequence field or argument to OP_CHECKSEQUENCEVERIFY.

Warning

Locktimes are not ordered by the natural ordering on u32. If you want to compare locktimes, use Self::is_implied_by or similar methods.

pub fn from_sequence(n: Sequence) -> Result<Self, DisabledLockTimeError>

Constructs a LockTime from the sequence number of a Bitcoin input.

This method will not round-trip with Self::to_sequence. See the docs for Self::from_consensus for more information.

pub fn to_sequence(&self) -> Sequence

Encodes the locktime as a sequence number.

pub const fn from_height(n: u16) -> Self

Constructs a LockTime from n, expecting n to be a 16-bit count of blocks.

pub const fn from_512_second_intervals(intervals: u16) -> Self

Constructs a LockTime from n, expecting n to be a count of 512-second intervals.

This function is a little awkward to use, and users may wish to instead use Self::from_seconds_floor or Self::from_seconds_ceil.

pub const fn from_seconds_floor(seconds: u32) -> Result<Self, TimeOverflowError>

Create a LockTime from seconds, converting the seconds into 512 second interval with truncating division.

Errors

Will return an error if the input cannot be encoded in 16 bits.

pub const fn from_seconds_ceil(seconds: u32) -> Result<Self, TimeOverflowError>

Create a LockTime from seconds, converting the seconds into 512 second interval with ceiling division.

Errors

Will return an error if the input cannot be encoded in 16 bits.

pub const fn is_same_unit(&self, other: LockTime) -> bool

Returns true if both lock times use the same unit i.e., both height based or both time based.

pub const fn is_block_height(&self) -> bool

Returns true if this lock time value is in units of block height.

pub const fn is_block_time(&self) -> bool

Returns true if this lock time value is in units of time.

pub fn is_satisfied_by(&self, h: Height, t: Time) -> bool

Returns true if this relative::LockTime is satisfied by either height or time.

Examples

// Users that have chain data can get the current height and time to check against a lock.
let height_and_time = (current_time(), current_height());  // tuple order does not matter.
assert!(lock.is_satisfied_by(current_height(), current_time()));

pub fn is_implied_by(&self, other: LockTime) -> bool

Returns true if satisfaction of other lock time implies satisfaction of this relative::LockTime.

A lock time can only be satisfied by n blocks being mined or n seconds passing. If you have two lock times (same unit) then the larger lock time being satisfied implies (in a mathematical sense) the smaller one being satisfied.

This function is useful when checking sequence values against a lock, first one checks the sequence represents a relative lock time by converting to LockTime then use this function to see if satisfaction of the newly created lock time would imply satisfaction of self.

Can also be used to remove the smaller value of two OP_CHECKSEQUENCEVERIFY operations within one branch of the script.

Examples

let satisfied = match test_sequence.to_relative_lock_time() {
    None => false, // Handle non-lock-time case.
    Some(test_lock) => lock.is_implied_by(test_lock),
};
assert!(satisfied);

pub fn is_implied_by_sequence(&self, other: Sequence) -> bool

Returns true if satisfaction of the sequence number implies satisfaction of this lock time.

When deciding whether an instance of <n> CHECKSEQUENCEVERIFY will pass, this method can be used by parsing n as a LockTime and calling this method with the sequence number of the input which spends the script.

pub fn is_satisfied_by_height( &self, height: Height, ) -> Result<bool, IncompatibleHeightError>

Returns true if this relative::LockTime is satisfied by Height.

Errors

Returns an error if this lock is not lock-by-height.

Examples

let height: u16 = 100;
let lock = Sequence::from_height(height).to_relative_lock_time().expect("valid height");
assert!(lock.is_satisfied_by_height(Height::from(height+1)).expect("a height"));

pub fn is_satisfied_by_time( &self, time: Time, ) -> Result<bool, IncompatibleTimeError>

Returns true if this relative::LockTime is satisfied by Time.

Errors

Returns an error if this lock is not lock-by-time.

Examples

let intervals: u16 = 70; // approx 10 hours;
let lock = Sequence::from_512_second_intervals(intervals).to_relative_lock_time().expect("valid time");
assert!(lock.is_satisfied_by_time(Time::from_512_second_intervals(intervals + 10)).expect("a time"));

Trait Implementations

impl ArbitraryOrd for LockTime

Available on crate feature ordered only.

fn arbitrary_cmp(&self, other: &Self) -> Ordering

Implements a meaningless, arbitrary ordering.

impl Clone for LockTime

fn clone(&self) -> LockTime

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for LockTime

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for LockTime

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Display for LockTime

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl From<Height> for LockTime

fn from(h: Height) -> Self

Converts to this type from the input type.

impl From<LockTime> for Sequence

fn from(lt: LockTime) -> Sequence

Converts to this type from the input type.

impl From<Time> for LockTime

fn from(t: Time) -> Self

Converts to this type from the input type.

impl Hash for LockTime

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for LockTime

fn eq(&self, other: &LockTime) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for LockTime

fn partial_cmp(&self, other: &LockTime) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Serialize for LockTime

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl TryFrom<Sequence> for LockTime

type Error = DisabledLockTimeError

The type returned in the event of a conversion error.

fn try_from(seq: Sequence) -> Result<LockTime, DisabledLockTimeError>

Performs the conversion.

impl Copy for LockTime

impl Eq for LockTime

impl StructuralPartialEq for LockTime