Module native_stack 

Keeping the recursion of the JSON-LD algorithms off the caller’s native stack.

Context conversion, the Context Processing algorithm, Expansion and Compaction all recurse once per nesting level of their input. An embedder may run them on a thread whose stack it has already partly used, such as a Tokio worker deep inside a request handler, so the recursion depth alone cannot decide whether the thread’s stack suffices.

A synchronous recursion point runs its callee through on_sufficient_stack. An async one wraps its callee in Recursion: boxing a recursive call moves the callee’s state to the heap but not its polling, because a parent polls its child from inside its own poll, so the native stack still deepens by one set of poll frames per level. Either way, when less than RED_ZONE of the current stack is left, the callee runs on a freshly allocated segment of SEGMENT bytes instead. Whatever bounds a recursion stays what bounds it; this only guarantees the bound is reached on any thread.

Structs

Recursion

A recursive call of an async algorithm.

Constants

RED_ZONE

Stack left below which a recursion level moves to a fresh segment.

SEGMENT

Size of each fresh stack segment.

Functions

on_sufficient_stack

Runs callee, on a fresh stack segment when the current one is nearly used.