Struct RunContext 

pub struct RunContext<'a, S> {
    pub state: &'a mut S,
    pub node_id: NodeId,
    pub ctx: &'a BspContext,
    pub execution_no: u64,
    /* private fields */
}

Everything a node may touch, nothing it may not.

The engine hands one of these to each execute call. Nodes mutate the consumer state through RunContext::state, read gathered pin inputs, and stage pin outputs; they never name their successors — the engine decides what happens next from the edges.

Retry & rollback contract

When a node carries a retry policy, a failed attempt is re-invoked with the same gathered inputs and an incremented RunContext::execution_no. A node that stages writes into state should therefore treat execution_no > 0 as “undo my partial writes from the previous attempt first” — that is the exactly-once-ish rollback hook.

Fields

state: &'a mut S

The consumer state (history, stores, metrics…). &mut, owned by the engine between executions — required for fork/merge and suspension snapshots.

node_id: NodeId

The id of the node being executed.

ctx: &'a BspContext

Dependency-injection context (unchanged from the dataflow engine).

execution_no: u64

This node’s Nth execute invocation, 0-based (loop- and retry-aware).

Implementations

impl<'a, S> RunContext<'a, S>

pub fn input<T: Any + Send + Sync + Clone>(&self, port: PortIndex) -> Option<T>

Reads a gathered input value, downcast to T, without consuming it.

pub fn input_value(&self, port: PortIndex) -> Option<&BspValue>

Reads a gathered input value without consuming it.

pub fn take_input(&mut self, port: PortIndex) -> Option<BspValue>

Takes a gathered input value out of the context (dataflow profile; used by the #[node] macros to unpack named ports).

pub fn set_output<T: Any + Send + Sync>(&mut self, port: PortIndex, value: T)

Stages a typed value for an output port.

Values staged here merge with (and are overridden by) the port map returned in crate::node::NodeOutcome::Success.

pub fn skip_outputs(&mut self)

Marks every declared output port to be written with the BspSkip marker (dataflow profile skip propagation), regardless of any staged outputs.