Struct QueryProcedureHost 

pub struct QueryProcedureHost { /* private fields */ }

Host facade exposing a snapshot of GraphExecutionContext to in-tree procedure plugins.

Built-in host-coupled procedures invoked via CALL uni.X receive a ProcedureContext whose host field points at a QueryProcedureHost constructed by the dispatch sites (procedure_call::execute_plugin_procedure and executor::procedure). Plugins downcast to recover the concrete type, then call the typed accessors below.

All fields are owned (Arc-shared) rather than borrowed, so the host is 'static-friendly — which is the constraint std::any::Any imposes for downcasting. Construction is a small number of Arc-clones; the per-call cost is negligible.

Implementations

impl QueryProcedureHost

pub fn from_graph_ctx(graph_ctx: &GraphExecutionContext) -> Self

Snapshot the host-shaped components of graph_ctx. The per-request fields start empty; use Self::from_graph_ctx_with_request when the surrounding query has projection / yield context.

pub fn from_graph_ctx_with_request( graph_ctx: &GraphExecutionContext, target_properties: HashMap<String, Vec<String>>, yield_items: Vec<(String, Option<String>)>, expected_schema: Option<SchemaRef>, ) -> Self

Snapshot the host-shaped components of graph_ctx along with the per-request projection map, YIELD list, and planner-expected output schema. Used by the DataFusion procedure dispatcher (procedure_call.rs::execute_plugin_procedure) to feed search procedures (uni.vector.query etc.) everything they need to expand node yields into the planner-expected column shape.

pub fn from_components( storage: Arc<StorageManager>, algo_registry: Option<Arc<AlgorithmRegistry>>, procedure_registry: Option<Arc<ProcedureRegistry>>, ) -> Self

Construct a host from raw components (used by the simple executor, which holds these directly rather than via a GraphExecutionContext).

pub fn with_writer(self, writer: Arc<Writer>) -> Self

Attach the outer transaction’s writer handle to this host.

Required for Write/Schema/Dbms-mode invocations of Self::execute_inner_query. Call sites that construct a host inside a write transaction should thread the writer through; the inner-query path otherwise has no path to mutate the graph.

pub fn allocate_transient_id(&self) -> u64

Allocate a fresh transient id, unique within this host’s lifetime. Wraps the bottom 63 bits and OR-s in the ephemeral bit before returning. Use Vid::ephemeral / Eid::ephemeral when you want the typed Vid / Eid form.

Always available — no capability is required. Per proposal §4.13.1, IDs are stable only within a single query execution.

pub fn storage(&self) -> &Arc<StorageManager>

Storage manager — schema, datasets, vector / fts search.

pub fn algo_registry(&self) -> Option<&Arc<AlgorithmRegistry>>

Algorithm registry, if the host wired one in.

pub fn procedure_registry(&self) -> Option<&Arc<ProcedureRegistry>>

Procedure registry, if the host wired one in.

pub fn xervo_runtime(&self) -> Option<&Arc<ModelRuntime>>

Uni-Xervo runtime for query-time auto-embedding, if wired.

pub fn property_manager(&self) -> Option<&Arc<PropertyManager>>

Property manager for lazy property loading, if the host wired one in. Returns None on the simple-executor path (from_components does not have access to it).

pub fn target_properties(&self) -> &HashMap<String, Vec<String>>

Per-request projection map (output variable name → requested property names). Empty unless the host was constructed via Self::from_graph_ctx_with_request with non-empty data.

pub fn yield_items(&self) -> &[(String, Option<String>)]

Per-request YIELD list as (yield_name, alias) pairs.

pub fn expected_schema(&self) -> Option<&SchemaRef>

Planner-expected output schema. Used by search procedures to emit columns matching the schema the surrounding query plan expects, avoiding a name-mismatch reprojection step in the dispatcher.

pub fn l0_context(&self) -> &L0Context

L0 visibility context (current / pending / transaction buffers).

pub fn query_context(&self) -> QueryContext

Build a QueryContext for property-manager calls. Mirrors GraphExecutionContext::query_context.

pub async fn execute_inner_query( &self, cypher: &str, params: &HashMap<String, Value>, mode: ProcedureMode, ) -> Result<Vec<HashMap<String, Value>>>

Run an inner Cypher query against the same storage / L0 snapshot the outer procedure sees, returning the materialised row vector.

Used by:

• the V2 algorithm adapter (M5c.3) to materialise ProjectionInput::Cypher { node_query, edge_query, ... };
• the meta-plugin persistence backend (M9 cutover) to issue MERGE (:_DeclaredPlugin {...}) through Cypher;
• the synthetic-procedure plugin (M9 cutover) to evaluate the stored body of a CALL uni.plugin.declareProcedure(...).

mode controls which Cypher operations are accepted:

• ProcedureMode::Read constructs the inner executor without a writer; mutation clauses (CREATE, SET, MERGE, DELETE, REMOVE) fail with “Database is in read-only mode”.
• ProcedureMode::Write / ProcedureMode::Schema / ProcedureMode::Dbms construct the inner executor with the outer transaction’s writer handle (set via Self::with_writer); mutations land in the outer transaction’s L0 buffer. If no writer was threaded through, write-mode invocations error with "inner write requires a writer-enabled procedure host".

L0 visibility mirrors the outer query’s snapshot (l0_context.current_l0 / transaction_l0 / pending_flush_l0s) so recently-written rows are visible. The PropertyManager is reused from the outer host when present; otherwise a fresh per-call one is constructed.

params are bound into the inner executor by name, exactly as session.query(cypher, params) would for a top-level Cypher query.

Errors

Returns any parse / plan / execution error from the inner query. Write-attempt errors in Read mode propagate as the host’s “Database is in read-only mode” string. Write-mode invocations without a writer attached return a clear error rather than silently downgrading to read-only.

pub fn check_timeout(&self) -> Result<()>

Check whether the query has timed out or been cancelled.

Errors

Returns an error if the deadline has passed or the cancellation token has been triggered.

Trait Implementations

impl Clone for QueryProcedureHost

fn clone(&self) -> QueryProcedureHost

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl ProcedureHost for QueryProcedureHost

fn as_any(&self) -> &dyn Any

Returns the host as a downcastable &dyn Any.