Finality Jasmine

A finality gadget for Substrate using a modified version of Jasmine.

Design notes

• Block generation module: block generation in Jasmine.
  • How to trigger: rather than on-slot, it gets triggered with on-event.
    • When became leader, the replica is allowed to propose in-between blocks.
    • When gather a QC, the replica is allowed to propose key blocks. (And exits.)
  • How to know if a replica is the leader?
    • The consensus module maintain leader, and expose the state to the generation module.
• Block consensus module: block vote in Jasmine (on key blocks).
  • How to know if a replica is the leader?
    • round-robin + round number.
  • How to track blocks' state, if its in prevote or precommit?
    • track it inside the consensus module.
  • Where to store the QC?
  • justification or in the block itself?