Generated by XState Viz: https://xstate.js.org/viz

machine.js

Machine({
  id: 'Lock',
  initial: 'acquiring',
  context: {
    held_time: 0 // Cumulative time the lock has been held
  },
  states: {
    // Read lock and either keep waiting or write & hold
    acquiring: {
      entry() {
        // Read lock and determine if it is held.
        // if it is held, send WAIT
        // if it is available, write to lock and send HOLD, held_time: 0
      },
      on: {
        HOLD: 'holding',
        WAIT: 'waiting'
      }
    },
    // Wait random time before attempting to acquire again
    waiting: {
      entry() {
        // Wait random time, then send ACQUIRE
      },
      on: {
        ACQUIRE: 'acquiring'
      }
    },
    // Wait deterministic time before reading lock
    holding: {
      entry(ctx, event) {
        // Wait appropriate hold time
        // send CHECK, held_time += hold time
      },
      on: {
        CHECK_HOLD: 'checking',
      }
    },
    // read lock to see if we still have it and either keep holding, assume lock is acquired, or go back to waiting if it isn't
    checking: {
      entry(ctx, event) {
        // read lock
        // if still ours and min hold time is not met, send HOLD
        // if still ours and hold time is met, send ACQUIRED,
        // if not ours, send WAIT
      },
      on: {
        HOLD: 'holding',
        WAIT: 'waiting',
        ACQUIRED: 'acquired'
      }
    },
    // done!
    acquired: {
      type: 'final'
    }
  }
})