Graphs | UStore for Mojo

An edge is a source, a target and an optional edge identifier, so distinct identifiers let a pair of vertices share several edges. One collection holds an undirected or a directed graph over its own vertices, or a joining graph between two collections.

API

Types

VertexRolesViewA strided run of roles, ustore_vertex_roles_view_t; zeroed stands for ANY.

comptime VertexRolesView[origin: ImmOrigin = ImmUntrackedOrigin]: AnyStruct[StridedView[VertexRole, origin]] = StridedView[VertexRole, origin]

StructVertexRoleThe role a vertex plays in an edge, ustore_vertex_role_t; undirected graphs use ANY.

struct VertexRole

Fields

`code`	`c_int`	The raw `ustore_vertex_role_t` value the ABI exchanges.

Values

`UNKNOWN`	`VertexRole(Int32(0))`	No role.
`SOURCE`	`VertexRole(Int32(1))`	The vertex an edge leaves.
`TARGET`	`VertexRole(Int32(2))`	The vertex an edge enters.
`ANY`	`VertexRole(Int32(3))`	Either end of an edge.

Conforms to

Copyable, Deinitable, Equatable, ImplicitlyCopyable, Movable, RegisterPassable, TrivialRegisterPassable

StructEdgesThe edges of a batch of vertices, three keys per edge, read in place from the arena a read borrows.5

struct Edges[origin: MutOrigin]

Parameters

`originMutOrigin`	comptime	The arena the edges live in, which this result borrows.

Fields

`arena`	`Pointer[Arena, origin]`	The arena holding the edges.
`generation`	`Int`	The arena's call the edges came from.
`written`	`EdgesWritten`	The views the engine wrote.
`count`	`Int`	Vertices the read carried.

Values

`Written`	`EdgesWritten`

Conforms to

Answer, Deinitable, Movable, Sized

__init__

def __init__(out self, arena: Int, generation: Int, written: EdgesWritten, count: Int)

__len__The vertices the read carried.

def __len__(self) -> Int

degreesThe degree of every vertex, VERTEX_DEGREE_MISSING for a missing one.

def degrees(ref self) -> Span[UInt32, origin_of(self)]

offsetsThe vertices' boundaries in edges, one more of them than vertices; empty unless edges were asked for.

def offsets(ref self) -> Span[UInt64, origin_of(self)]

edgesThe edges of vertex vertex, each as its source, target and edge identifier.

def edges(ref self, vertex: Int) -> Span[Key, origin_of(self)]

StructGraphScanConfigThe bounds, order and verdict of a scan over vertices.1

struct GraphScanConfig[end_origin: ImmOrigin = ImmUntrackedOrigin]

Parameters

`end_originImmOrigin`	comptime	The borrowed end keys.

Fields

`end_keys`	`StridedView[Key, end_origin]`	Vertex every scan stops before, exclusive; zeroed bounds nothing.
`direction`	`ScanDirection`	Ascending or descending from the start keys.
`mode`	`ScanMode`	In what order the vertices come.
`predicate`	`Predicate`	The caller's verdict on the listed vertices.
`progress`	`Progress`	Reports the scans finished, and stops the call where it says to.

Conforms to

Copyable, Deinitable, ImplicitlyCopyable, Movable

__init__Names only the knobs that differ from the defaults.

def __init__(
    out self,
    *,
    end_keys: StridedView[Key, end_origin] = StridedView(),
    direction: ScanDirection = ScanDirection.ASCENDING,
    mode: ScanMode = ScanMode.ORDERED,
    predicate: Predicate = Predicate(),
    progress: Progress = Progress()
)

StructGraphVerticesCursorA walk over the vertices of one graph collection, every pull resuming past the last vertex the pull before it handed out, freed when it goes out of scope. It holds its database open, and the transaction or snapshot it reads through.3

struct GraphVerticesCursor

Fields

`library`	`Library`	The loaded engine.
`database`	`Address`	The `ustore_database_t` it walks.
`address`	`Address`	The `ustore_graph_vertices_cursor_t`.

Conforms to

Deinitable, Movable

__init__Adopts a cursor the engine just opened.

def __init__(out self, *, library: Library, database: Int, address: Int)

__deinit__Frees the cursor and the holds it kept. Calls ustore_graph_vertices_cursor_free.

def __deinit__(deinit self)

nextPulls the next page of up to wanted vertices. Calls ustore_graph_vertices_cursor_next.

def next(
    self,
    executor: Executor,
    mut arena: Arena,
    wanted: Int,
    progress: Progress = Progress()
) -> Pulled[origin_of(arena)]

Raises

Error with CANCELLED when progress stops the pull, which leaves the cursor where it was.

Constants

VERTEX_DEGREE_MISSINGThe degree a read reports for a missing vertex.

comptime VERTEX_DEGREE_MISSING = UInt32(4294967295)