Struct DatasetPrebuffer 

pub struct DatasetPrebuffer { /* private fields */ }

Eagerly download all facets for a dataset profile into the local cache, returning a DatasetHandle::Group handle that downstream facet accessors take as their first argument. After this returns, every subsequent facet read served by vectordata::TestDataView hits the merkle- verified mmap fast path with no further network traffic.

Signature: dataset_prebuffer(source) -> Handle

Why a handle, not a count. Returning a value the downstream accessors consume makes prebuffer part of the dataflow graph: DCE keeps the chain alive because vector_at(prebuffered, q) needs prebuffered to be resolvable, which forces evaluation. Bindings such as init prebuffered = dataset_prebuffer(...) whose result nothing reads would still be pruned (TODO: rationalise dangling-init dataflow as a separate followup; the established pattern is to thread the handle through).

source is the canonical dataset:profile string. The returned handle is a Group handle — accessors that take it route through the same DatasetHandle::open(...) resolver path used by other group-aware nodes (dataset_facets, dataset_distance_function, …).

Errors during prebuffer surface via stderr; the node still returns the group handle so downstream binds don’t fail with a “missing value” cascade — the operator’s intent is “best effort warm-up”, and a workload that wants strict guarantees can wrap this in a required(...) predicate or check facet readiness explicitly.

Implementations

impl DatasetPrebuffer

pub fn new() -> Self

A node of this kind.

Trait Implementations

impl Default for DatasetPrebuffer

fn default() -> Self

Returns the “default value” for a type.

impl PolydatNode for DatasetPrebuffer

fn meta(&self) -> &NodeMeta

Return this node’s metadata (port names and types).

fn eval(&self, inputs: &[Value], outputs: &mut [Value])

Evaluate the node: read from inputs, write to outputs.

fn scratch_layout(&self) -> Vec<ScratchElem>

The scratch entries a state owns for this node’s evaluation (axiom S3), one per entry in the order the node expects them in Self::eval_in. Empty for a node that evaluates over Values alone, which is every node but a native cone.

fn eval_in( &self, scratch: &mut [ScratchBuf], inputs: &[Value], outputs: &mut [Value], )

Self::eval with the node’s scratch, which the evaluating state owns and hands in: storage belongs to the state, never to the node, which is shared by every state of the program.

fn commutativity(&self) -> Commutativity

Declare which inputs are interchangeable for this node.

fn accepts_none_inputs(&self) -> bool

True iff this node should receive Value::None inputs directly rather than have the kernel propagate None through it. Default: false — most nodes follow SRD-74 Rule 1 (None in → None out, no eval invocation).

fn compiled_u64(&self) -> Option<CompiledU64Op>

Return a compiled u64-only evaluation closure, if this node operates entirely in u64 space.

fn compiled_slot(&self, _wire_types: &[PortType]) -> Option<CompiledSlotKit>

Return a slot-compiled closure for nodes with typed-slice ports (§8.4 layer 3): slice inputs read (ptr, len) slot pairs; vector outputs write into kernel-owned scratch. Checked by the compiled-kernel builders AFTER Self::compiled_u64 — pure-scalar nodes never need it. Default None: the node stays on typed eval.

fn jit_constants(&self) -> Vec<u64>

Return assembly-time constants for JIT compilation.

fn purity(&self) -> Purity

Declare this node’s purity status per the runtime_model.md’s D2 axiom. Default: Purity::Pure. Override to declare an observable side channel (Purity::SideChannel) or eval-call-spanning state (Purity::Nondeterministic).

fn simd_variant(&self) -> Option<SimdVariant>

Explicit SIMD-native implementation of this scalar node, if one has been registered with a semantic contract.

fn fusion_subgraph(&self) -> Option<FusionSubgraph<'_>>

A synthetic fusion node’s view of the subgraph it stands in for (SRD-105 cone extraction). Program-identity hashing (PolydatProgram::canonical_hash) walks THROUGH fusion nodes into this subgraph, so identity is invariant to the engine mix: jit=off and jit=auto compiles of the same source hash identically, and resume-skip matching survives mode changes. Default None: ordinary nodes hash as themselves.