aquavm/crates/air-lib/trace-handler/README.md
Mike Voronov 24f0d66bed
Rename subtree to subgraph (#265)
Intially, a fold instruction was designed based on idea that its iterable can't expand,
so AIR was considered as a subtree. But after introducing recursive streams in #225, it's
no more a subtree, but a subgraph.
2022-05-17 15:53:33 +03:00

1.3 KiB

AIR trace handler

This crate contains implementation of the CRDT-based merging data algorithm. It exposes the TraceHandler struct that based on the visitor pattern and has public methods that should be called in certain places of AIR instructions execution. Internally TraceHandler contains several FSM and each of such public methods does state transitioning of one or more these FSMs. Below are state transition sequences for all instructions that caller must follow.

Ap instruction

Expected sequence of TraceHandler calls for the ap instruction:

meet_ap_start
    -> meet_ap_end

Call instruction

Expected sequence of TraceHandler calls for the call instruction:

meet_call_start
    -> meet_call_end

Par instruction

Expected sequence of TraceHandler calls for the par instruction:

meet_par_start
    -> meet_par_subgraph_end(..., SubgraphType::Left)
    -> meet_par_subgraph_end(..., SubgraphType::Right)

Fold instruction

Expected sequence of TraceHandler calls for the fold instruction:

meet_fold_start.1 ->
    meet_generation_start.N ->
        meet_next.M ->
        meet_prev.M ->
    meet_generation_end.N ->
meet_fold_end.1

where .T means that this function should be called exactly T times.