Interface IScyllaReadOnlyGraph

Extended read-only inspection interface for graph structures. Adds individual edge retrieval, node flag access, and allocation-free bulk copy operations on top of the structural query contract established by IScyllaGraph.

Inherited Members
Namespace: Scylla.Core.Structures
Assembly: ScyllaCore.dll
Syntax
public interface IScyllaReadOnlyGraph : IScyllaGraph, IScyllaCollection
Remarks

Position in the hierarchy. This interface is the first read-only extension above IScyllaGraph. It is further extended by IScyllaReadOnlyGraph<TNodeData> for graphs with per-node typed user data, and by IScyllaMutableGraph for graphs that also support structural mutation.

Clear on read-only graphs. This interface inherits Clear() from the base collection interface. Graph implementations that are truly read-only (i.e., the Mutable flag is NOT set in Properties) must throw InvalidOperationException from Clear() to signal that structural mutation is not permitted.

Allocation-free bulk access. CopyAllNodes(Span<ScyllaGraphNode>) and CopyAllEdges(Span<ScyllaGraphEdge>) are designed for zero-allocation inspection patterns. Callers should rent a buffer (e.g. via System.Buffers.ArrayPool) or use a stack-allocated span sized to NodeCount or EdgeCount respectively, then pass it to these methods to avoid heap pressure in performance-sensitive code paths.

Methods

CopyAllEdges(Span<ScyllaGraphEdge>)

Copies all edge descriptors from the graph into the provided span without allocating any managed memory.

Declaration
int CopyAllEdges(Span<ScyllaGraphEdge> destination)
Parameters
Type Name Description
Span<ScyllaGraphEdge> destination

The caller-supplied span into which ScyllaGraphEdge descriptors will be written. The span should be at least EdgeCount elements long to receive all edges; if it is smaller, only as many edges as fit are copied.
Returns
Type Description
int

The number of ScyllaGraphEdge descriptors written to destination. This equals Min(EdgeCount, destination.Length).
Remarks

For undirected graphs, each conceptual edge is copied exactly once. The FromID and ToID fields reflect the canonical storage direction and may not match the order in which the edge was originally added.

For directed graphs, each directed edge appears as a separate descriptor; reciprocal edges (A->B and B->A) produce two distinct entries.

The order of edges within destination is implementation-defined and should not be relied upon. For typed edge graphs, retrieve per-edge user data via TryGetEdgeData(int, int, out TEdgeData) after copying the base descriptors.

See Also

CopyAllNodes(Span<ScyllaGraphNode>)

Copies all node descriptors from the graph into the provided span without allocating any managed memory.

Declaration
int CopyAllNodes(Span<ScyllaGraphNode> destination)
Parameters
Type Name Description
Span<ScyllaGraphNode> destination

The caller-supplied span into which ScyllaGraphNode descriptors will be written. The span should be at least NodeCount elements long to receive all nodes; if it is smaller, only as many nodes as fit are copied.
Returns
Type Description
int

The number of ScyllaGraphNode descriptors written to destination. This equals Min(NodeCount, destination.Length).
Remarks

The order in which nodes are written into destination is implementation-defined. Callers must not assume any particular ordering.

For typed graphs, this method copies only the base descriptor (ID and flags). To retrieve per-node user data alongside the descriptor, call TryGetNodeData(int, out TNodeData) for each node after copying. See the remarks on that interface for guidance on performing typed bulk operations.

See Also

TryGetEdge(int, int, out ScyllaGraphEdge)

Attempts to retrieve the edge descriptor for the edge between two nodes.

Declaration
bool TryGetEdge(int fromID, int toID, out ScyllaGraphEdge edge)
Parameters
Type Name Description
int fromID

The ID of the source node. For undirected graphs, argument order is irrelevant.
int toID

The ID of the target node. For undirected graphs, argument order is irrelevant.
ScyllaGraphEdge edge

When this method returns true, contains a ScyllaGraphEdge descriptor with the source ID, target ID, and weight for the requested edge. When the method returns false, the value is default(ScyllaGraphEdge).
Returns
Type Description
bool

true if the edge was found; false if the edge does not exist or either endpoint node is absent from the graph.
Remarks

For undirected graphs, the fromID and toID arguments are interchangeable. The returned FromID and ToID will match the canonical storage direction used internally, which may differ from the argument order supplied.

For directed graphs, only the edge in the direction (fromID -> toID) is looked up. The reverse direction is independent; call this method again with swapped arguments to check the reverse edge separately.

To check existence without retrieving the descriptor, prefer ContainsEdge(int, int) which may be implemented more efficiently in some graph representations.

See Also

TryGetNodeFlags(int, out ScyllaGraphNodeFlags)

Attempts to retrieve the flags associated with the specified node.

Declaration
bool TryGetNodeFlags(int nodeID, out ScyllaGraphNodeFlags flags)
Parameters
Type Name Description
int nodeID

The ID of the node to query.
ScyllaGraphNodeFlags flags

When this method returns true, contains the ScyllaGraphNodeFlags value for the specified node, including the walkability bit and any user-defined tag bits. When the method returns false, the value is ScyllaGraphNodeFlags.None.
Returns
Type Description
bool

true if the node exists in the graph; false otherwise.
Remarks

Node flags are bitpacked into a uint. Bit 0 is the Walkable flag; bits 1-31 are user-defined tags (Tag0 through Tag30) that callers may use for domain-specific categorization such as terrain type, cost multiplier tier, or zone membership.

Flags can be mutated on mutable graphs via TrySetNodeFlags(int, ScyllaGraphNodeFlags).

See Also

Extension Methods

See Also