Struct TwoPTwoPGraph 

pub struct TwoPTwoPGraph<VA, VR, EA, ER, I>
where
    VA: Clone + TwoPTwoPAddVertex<I>,
    VR: Clone + TwoPTwoPRemoveVertex<I>,
    EA: Clone + TwoPTwoPAddEdge<I>,
    ER: Clone + TwoPTwoPRemoveEdge<I>,
    I: Eq + Hash + Debug + Clone,
{ /* private fields */ }

An op-based 2P2P-Graph CRDT.

Maintains four sets corresponding to the paper’s payload:

• V_A — vertices added
• V_R — vertices removed
• E_A — edges added
• E_R — edges removed

Generic parameters:

• VA / VR — vertex add / remove operation types
• EA / ER — edge add / remove operation types
• I — the shared identifier type

Implementations

impl<VA, VR, EA, ER, I> TwoPTwoPGraph<VA, VR, EA, ER, I>

where VA: Clone + TwoPTwoPAddVertex<I>, VR: Clone + TwoPTwoPRemoveVertex<I>, EA: Clone + TwoPTwoPAddEdge<I>, ER: Clone + TwoPTwoPRemoveEdge<I>, I: Eq + Hash + Debug + Clone,

pub fn new() -> Self

Creates an empty graph with all four sets initialized to ∅.

pub fn lookup_vertex(&self, vertex_id: &I) -> bool

Returns true if the vertex is in V_A \ V_R (added and not removed).

pub fn get_edge_added_from_remove_edge(&self, remove_edge: &ER) -> Option<&EA>

Returns the edge-add operation referenced by a given edge-remove operation, if present.

pub fn lookup_from_remove_edge(&self, remove_edge: &ER) -> bool

Returns true if the edge referenced by remove_edge exists in E_A \ E_R and both of its endpoint vertices are currently in V_A \ V_R.

pub fn update_operation( &mut self, update_operation: UpdateOperation<VA, VR, EA, ER>, ) -> Result<(), TwoPTwoPGraphError<I>>

Convenience method that calls prepare and discards the returned operation.

pub fn prepare( &mut self, op: UpdateOperation<VA, VR, EA, ER>, ) -> Result<UpdateOperation<VA, VR, EA, ER>, TwoPTwoPGraphError<I>>

Executes atSource precondition checks and applies the downstream effect locally. Returns the operation to broadcast to other replicas.

pub fn apply_downstream( &mut self, op: UpdateOperation<VA, VR, EA, ER>, ) -> Result<(), TwoPTwoPGraphError<I>>

Applies an operation received from a remote replica (downstream).

pub fn add_vertex( &mut self, vertex: VA, _update_type: UpdateType, ) -> Result<(), TwoPTwoPGraphError<I>>

Adds a vertex to V_A. Fails if a vertex with the same ID already exists.

Both AtSource and Downstream behave identically (no preconditions per the paper).

pub fn add_edge( &mut self, edge: EA, update_type: UpdateType, ) -> Result<(), TwoPTwoPGraphError<I>>

Adds an edge to E_A.

• AtSource: checks lookup(source) ∧ lookup(target).
• Downstream: skips vertex existence checks (per the paper).

pub fn remove_vertex( &mut self, vertex: VR, update_type: UpdateType, ) -> Result<(), TwoPTwoPGraphError<I>>

Adds a vertex-remove to V_R.

• AtSource: checks lookup(w) and that no active edge references w.
• Downstream: checks that the corresponding addVertex(w) has been delivered.

pub fn remove_edge( &mut self, remove_edge: ER, update_type: UpdateType, ) -> Result<(), TwoPTwoPGraphError<I>>

Adds an edge-remove to E_R.

• AtSource: checks lookup((u,v)).
• Downstream: checks that the corresponding addEdge(u,v) has been delivered.

pub fn generate_petgraph(&self) -> DiGraph<VA, EA>

Converts the current CRDT state into a petgraph::graph::DiGraph.

Only vertices in V_A \ V_R and edges in E_A \ E_R (whose endpoints are present) are included in the resulting directed graph.

pub fn vertex_count(&self) -> usize

Returns the number of active vertices (V_A \ V_R).

pub fn edge_count(&self) -> usize

Returns the number of active edges (E_A \ E_R).

pub fn is_empty(&self) -> bool

Returns true if the graph has no active vertices and no active edges.

pub fn vertices(&self) -> impl Iterator<Item = &VA>

Returns an iterator over all active (non-removed) vertex-add operations.

pub fn edges(&self) -> impl Iterator<Item = &EA>

Returns an iterator over all active (non-removed) edge-add operations.

Trait Implementations

impl<VA, VR, EA, ER, I> Clone for TwoPTwoPGraph<VA, VR, EA, ER, I>

where VA: Clone + TwoPTwoPAddVertex<I> + Clone, VR: Clone + TwoPTwoPRemoveVertex<I> + Clone, EA: Clone + TwoPTwoPAddEdge<I> + Clone, ER: Clone + TwoPTwoPRemoveEdge<I> + Clone, I: Eq + Hash + Debug + Clone + Clone,

fn clone(&self) -> TwoPTwoPGraph<VA, VR, EA, ER, I>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<VA, VR, EA, ER, I> Debug for TwoPTwoPGraph<VA, VR, EA, ER, I>

where VA: Clone + TwoPTwoPAddVertex<I> + Debug, VR: Clone + TwoPTwoPRemoveVertex<I> + Debug, EA: Clone + TwoPTwoPAddEdge<I> + Debug, ER: Clone + TwoPTwoPRemoveEdge<I> + Debug, I: Eq + Hash + Debug + Clone + Debug,

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

Formats the value using the given formatter.

impl<VA, VR, EA, ER, I> Default for TwoPTwoPGraph<VA, VR, EA, ER, I>

where VA: Clone + TwoPTwoPAddVertex<I>, VR: Clone + TwoPTwoPRemoveVertex<I>, EA: Clone + TwoPTwoPAddEdge<I>, ER: Clone + TwoPTwoPRemoveEdge<I>, I: Eq + Hash + Debug + Clone,

fn default() -> Self

Returns the “default value” for a type.