Struct ditto::list::List

pub struct List<T: 'static> { /* fields omitted */ }

A List is a Vec-like ordered sequence of elements. List elements must implement the Clone, Serialize, and Deserialize traits.

Internally, List is based on LSEQ. It allows op-based replication via execute_op and state-based replication via merge. State-based replication allows out-of-order delivery but op-based replication does not.

List's performance characteristics are similar to Vec:

• push: O(1)
• pop: O(1)
• insert: O(N)
• remove: O(N)
• get: O(1)
• execute_op: O(N)
• merge: O(N1 + N2 + S1 + S2), where N1 and N2 are the number of values in each list being merged, and S1 and S2 are the number of sites that have edited each list being merged.

Methods

impl<T: Clone> List<T>

pub fn new() -> Self

Constructs and returns a new List with site id 1.

pub fn len(&self) -> usize

Returns the number of elements in the list.

pub fn is_empty(&self) -> bool

Returns true if the List has a length of 0. Returns false otherwise

pub fn get(&self, idx: usize) -> Option<&T>

Returns a reference to the element at position idx. Returns None if idx is out-of-bounds.

pub fn push(&mut self, value: T) -> Result<Op<T>, Error>

Pushes a value onto the end of the list. If the list does not have a site id, it caches the resulting op and returns an AwaitingSiteId error.

pub fn pop(&mut self) -> Option<(T, Result<Op<T>, Error>)>

Removes the value at the end of the list, if the list is nonempty. If the list is empty, it returns None. If the pop succeeds but the list does not have a site id, it caches the resulting op and returns an AwaitingSiteId error.

pub fn insert(&mut self, idx: usize, value: T) -> Result<Op<T>, Error>

Inserts a value at position idx in the list, shifting all elements after it to the right. Panics if the idx is out of bounds. If the insert succeeds but the list does not have a site id, it caches the resulting op and returns an AwaitingSiteId error.

pub fn remove(&mut self, idx: usize) -> (T, Result<Op<T>, Error>)

Removes the element at position idx from the list, shifting all elements after it to the left. Panics if the idx is out-of-bounds. If the remove succeeds but the list does not have a site id, it caches the resulting op and returns an AwaitingSiteId error.

pub fn site_id(&self) -> SiteId

Returns the site id.

pub fn state(&self) -> ListState<T>

Returns a borrowed CRDT state.

pub fn clone_state(&self) -> ListState<'static, T>

Returns an owned CRDT state of cloned values.

pub fn into_state(self) -> ListState<'static, T>

Consumes the CRDT and returns its state

pub fn from_state(
    state: ListState<T>,
    site_id: Option<SiteId>
) -> Result<Self, Error>

Constructs a new CRDT from a state and optional site id. If the site id is present, it must be nonzero.

pub fn local_value(&self) -> Vec<T>

Returns the CRDT value's equivalent local value.

pub fn execute_op(&mut self, op: Op<T>) -> Option<LocalOp<T>>

Executes an op and returns the equivalent local op. This function assumes that the op always inserts values from the correct site. For untrusted ops, used validate_and_execute_op.

pub fn validate_and_execute_op(
    &mut self,
    op: Op<T>,
    site_id: SiteId
) -> Result<Option<LocalOp<T>>, Error>

Validates that an op only inserts elements from a given site id, then executes the op and returns the equivalent local op.

pub fn merge(&mut self, other: ListState<T>) -> Result<(), Error>

Merges a remote CRDT state into the CRDT. The remote CRDT state must have a site id.

pub fn add_site_id(&mut self, site_id: SiteId) -> Result<Vec<Op<T>>, Error>

Assigns a site id to the CRDT and returns any cached ops. If the CRDT already has a site id, it returns an error.

Trait Implementations

impl<T: Debug + 'static> Debug for List<T>

fn fmt(&self, __arg_0: &mut Formatter) -> Result

Formats the value using the given formatter.

impl<T: Clone + 'static> Clone for List<T>

fn clone(&self) -> List<T>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<T: PartialEq + 'static> PartialEq for List<T>

fn eq(&self, __arg_0: &List<T>) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, __arg_0: &List<T>) -> bool

This method tests for !=.

impl<T: Clone> From<Vec<T>> for List<T>

fn from(local_value: Vec<T>) -> Self

Performs the conversion.