Route

class Route

Which stages run for one request, decided once and then frozen.

Optional inputs and optional outputs are the same computation. Two passes, each exactly once – there is no fixed point to iterate towards:

forward available: topological order, prune a stage whose source is gone according to its OnMissing. Only propagates downstream. backward required: reverse order from the terminals the caller attached a sink to. Only propagates upstream. active = available AND required, then two checks.

The backward pass cannot undo the forward one: a stage the backward pass drops is by construction not upstream of any required stage. Iteration would only be needed if a stage’s survival depended on something downstream of it – a cycle, or a “required only when X is active” input. The topology has neither.

Public Functions

Route() = default

inline std::vector<int32_t> const &order() const noexcept

Topological order of the active stages.

inline std::vector<RouteEdge> const &edges() const noexcept

bool isActive(int32_t stageIndex) const noexcept

bool isActive(std::string const &stageId) const = delete

A Route holds indices, not ids; resolve one with MultiStageConfig::stageIndex() first.

inline uint64_t fingerprint() const noexcept

Two requests may share a batch only when these are equal.

inline std::vector<std::pair<int32_t, std::string>> const &skippedInputs(

) const noexcept

Inputs of active stages whose source is absent from this route and whose OnMissing is kSkip.

Public Static Functions

static bool resolve(

MultiStageConfig const &config,

std::vector<std::string> const &wanted,

RequestCapabilities const &available,

Route &out,

std::string &error

)

Resolve the active subgraph for one request.

Parameters:

• config – Already validated (see multiStage::validate).

• wanted – Terminal port ids the caller attached a sink to.

• available – What the request supplies.

• error – Filled with a human-readable reason when this returns false.

struct RequestCapabilities

What this request actually supplies, built once in submit() from the payload’s bound names. No stage may re-derive the modality set, or two stages can disagree on it.

Public Functions

bool supplies(std::string const &requestKey) const

Public Members

std::vector<std::string> suppliedRequestKeys

Fully-qualified request keys, e.g. “request:messages”, “request:audio”.

struct RouteEdge

One edge that survived resolution.

Public Members

int32_t producer = {-1}

Stage index. -1 means the value comes from the request.

int32_t consumer = {-1}

std::string port

Producer’s port id, or the request field.

std::string inputName

Consumer’s input name.

Transport transport = {Transport::kDeviceTensor}

bool crossLane = {false}