graphrecords_query/operations/traversal/
via_nodes.rs

1use crate::{
2    EdgeEndpointRole, EntityReference, ExpandedChild, ExpandedIndex, Explain, IndexDomain, Indexed,
3    Operand, Ordered, QueryResult, Unit,
4    element::{Expanding, Pipeline},
5    execution::EvaluationCache,
6    operations::{Apply, ElementKernel, ElementPipeline, Operation, OperationContext, Prepare},
7    optimizer::{OperationInputs, OptimizerHints, PlanIdentity, PlanInputs},
8    registry::operation_manifest,
9    traits::ViaNodes,
10};
11use graphrecords_core::{
12    GraphRecord,
13    graphrecord::{EdgeIndex, NodeIndex},
14};
15
16#[derive(Clone, Explain, Operation, OperationInputs, OptimizerHints, PlanIdentity, PlanInputs)]
17#[operation(scope = Element)]
18#[explain(label = "ViaNodes")]
19#[plan(optimizer_hints(empty = if_any))]
20pub struct ViaNodesOperation;
21
22impl Prepare for ViaNodesOperation {
23    type Prepared<'a> = ();
24
25    fn prepare<'a>(
26        &'a self,
27        _graphrecord: &'a GraphRecord,
28        _cache: &'a EvaluationCache<'a>,
29    ) -> QueryResult<Self::Prepared<'a>> {
30        Ok(())
31    }
32}
33
34impl ElementKernel<Indexed<EdgeIndex, Unit>> for ViaNodesOperation {
35    type Emission = Expanding<Ordered>;
36    type OutShape = Indexed<ExpandedIndex<EdgeIndex, EdgeEndpointRole>, EntityReference<NodeIndex>>;
37
38    fn pipeline<'a>(
39        graphrecord: &'a GraphRecord,
40        _prepared: Self::Prepared<'a>,
41    ) -> QueryResult<ElementPipeline<'a, Indexed<EdgeIndex, Unit>, Self>> {
42        Ok(Pipeline::keyed(move |parent_index, ()| {
43            let (source, target) = graphrecord
44                .edge_endpoints(parent_index)
45                .expect("Edge must exist");
46
47            Ok(vec![
48                ExpandedChild::success(EdgeEndpointRole::Source, source),
49                ExpandedChild::success(EdgeEndpointRole::Target, target),
50            ])
51        }))
52    }
53}
54
55impl<I: IndexDomain> ElementKernel<Indexed<I, EntityReference<EdgeIndex>>> for ViaNodesOperation {
56    type Emission = Expanding<Ordered>;
57    type OutShape = Indexed<ExpandedIndex<I, EdgeEndpointRole>, EntityReference<NodeIndex>>;
58
59    fn pipeline<'a>(
60        graphrecord: &'a GraphRecord,
61        _prepared: Self::Prepared<'a>,
62    ) -> QueryResult<ElementPipeline<'a, Indexed<I, EntityReference<EdgeIndex>>, Self>> {
63        Ok(Pipeline::unkeyed(move |edge| {
64            let (source, target) = graphrecord.edge_endpoints(edge).expect("Edge must exist");
65
66            Ok(vec![
67                ExpandedChild::success(EdgeEndpointRole::Source, source),
68                ExpandedChild::success(EdgeEndpointRole::Target, target),
69            ])
70        }))
71    }
72}
73
74impl<O: Apply<ViaNodesOperation>> ViaNodes for O {
75    type ReturnOperand = O::Output;
76
77    fn via_nodes(&self) -> Self::ReturnOperand {
78        Self::ReturnOperand::new(OperationContext::new(self.clone(), ViaNodesOperation))
79    }
80}
81
82operation_manifest! {
83    ViaNodesOperation {
84        method: ViaNodes::via_nodes;
85        scope: element;
86
87        kernel {
88            parameters: <>;
89            input: Indexed<EdgeIndex, Unit>;
90            output: Indexed<ExpandedIndex<EdgeIndex, EdgeEndpointRole>, EntityReference<NodeIndex>>;
91            emission: Expanding<Ordered>;
92        }
93
94        kernel {
95            parameters: <I: IndexDomain>;
96            input: Indexed<I, EntityReference<EdgeIndex>>;
97            output: Indexed<ExpandedIndex<I, EdgeEndpointRole>, EntityReference<NodeIndex>>;
98            emission: Expanding<Ordered>;
99        }
100    }
101}
graphrecords_query/operations/traversal/via_nodes.rs

graphrecords_query/operations/traversal/
via_nodes.rs
