Struct VClock

pub struct VClock(SmallVec<[VTimestamp; 4]>);

A vector clock for detecting data-races, this is conceptually a map from a vector index (and thus a thread id) to a timestamp. The compare operations require that the invariant that the last element in the internal timestamp slice must not be a 0, hence all zero vector clocks are always represented by the empty slice; and allows for the implementation of compare operations to short circuit the calculation and return the correct result faster, also this means that there is only one unique valid length for each set of vector clock values and hence the PartialEq and Eq derivations are correct.

This means we cannot represent a clock where the last entry is a timestamp-0 read that occurs because of a retag. That’s fine, all it does is risk wrong diagnostics in a extreme corner case.

Tuple Fields

0: SmallVec<[VTimestamp; 4]>

Implementations

impl VClock

pub(super) fn new_with_index(index: VectorIdx, timestamp: VTimestamp) -> VClock

Create a new vector-clock containing all zeros except for a value at the given index

pub(super) fn as_slice(&self) -> &[VTimestamp]

Load the internal timestamp slice in the vector clock

pub(super) fn index_mut(&mut self, index: VectorIdx) -> &mut VTimestamp

fn get_mut_with_min_len(&mut self, min_len: usize) -> &mut [VTimestamp]

Get a mutable slice to the internal vector with minimum min_len elements. To preserve invariants, the caller must modify the min_len-1 nth element to a non-zero value

pub(super) fn increment_index(&mut self, idx: VectorIdx, current_span: Span)

Increment the vector clock at a known index this will panic if the vector index overflows

pub fn join(&mut self, other: &Self)

pub(super) fn set_at_index(&mut self, other: &Self, idx: VectorIdx)

Set the element at the current index of the vector. May only increase elements.

pub(super) fn set_zero_vector(&mut self)

Set the vector to the all-zero vector

Trait Implementations

impl Clone for VClock

fn clone(&self) -> Self

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for VClock

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

Formats the value using the given formatter.

impl Default for VClock

fn default() -> VClock

Returns the “default value” for a type.

impl Index<VectorIdx> for VClock

type Output = VTimestamp

The returned type after indexing.

fn index(&self, index: VectorIdx) -> &VTimestamp

Performs the indexing (container[index]) operation.

impl PartialEq for VClock

fn eq(&self, other: &VClock) -> 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 VClock

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

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

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

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

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

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

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

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

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

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

impl Eq for VClock

impl StructuralPartialEq for VClock

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 64 bytes