Software /
code /
prosody
File
util/fsm.lua @ 13029:8ad432953300
mod_debug_reset: Remove now unused import of util.time (thanks luacheck)
author | Matthew Wild <mwild1@gmail.com> |
---|---|
date | Thu, 06 Apr 2023 14:49:11 +0100 |
parent | 13019:8a2f75e38eb2 |
child | 13165:9c13c11b199d |
line wrap: on
line source
local events = require "util.events"; local fsm_methods = {}; local fsm_mt = { __index = fsm_methods }; local function is_fsm(o) local mt = getmetatable(o); return mt == fsm_mt; end local function notify_transition(fire_event, transition_event) local ret; ret = fire_event("transition", transition_event); if ret ~= nil then return ret; end if transition_event.from ~= transition_event.to then ret = fire_event("leave/"..transition_event.from, transition_event); if ret ~= nil then return ret; end end ret = fire_event("transition/"..transition_event.name, transition_event); if ret ~= nil then return ret; end end local function notify_transitioned(fire_event, transition_event) if transition_event.to ~= transition_event.from then fire_event("enter/"..transition_event.to, transition_event); end if transition_event.name then fire_event("transitioned/"..transition_event.name, transition_event); end fire_event("transitioned", transition_event); end local function do_transition(name) return function (self, attr) local new_state = self.fsm.states[self.state][name] or self.fsm.states["*"][name]; if not new_state then return error(("Invalid state transition: %s cannot %s"):format(self.state, name)); end local transition_event = { instance = self; name = name; to = new_state; to_attr = attr; from = self.state; from_attr = self.state_attr; }; local fire_event = self.fsm.events.fire_event; local ret = notify_transition(fire_event, transition_event); if ret ~= nil then return nil, ret; end self.state = new_state; self.state_attr = attr; notify_transitioned(fire_event, transition_event); return true; end; end local function new(desc) local self = setmetatable({ default_state = desc.default_state; events = events.new(); }, fsm_mt); -- states[state_name][transition_name] = new_state_name local states = { ["*"] = {} }; if desc.default_state then states[desc.default_state] = {}; end self.states = states; local instance_methods = {}; self._instance_mt = { __index = instance_methods }; for _, transition in ipairs(desc.transitions or {}) do local from_states = transition.from; if type(from_states) ~= "table" then from_states = { from_states }; end for _, from in ipairs(from_states) do if not states[from] then states[from] = {}; end if not states[transition.to] then states[transition.to] = {}; end if states[from][transition.name] then return error(("Duplicate transition in FSM specification: %s from %s"):format(transition.name, from)); end states[from][transition.name] = transition.to; end -- Add public method to trigger this transition instance_methods[transition.name] = do_transition(transition.name); end if desc.state_handlers then for state_name, handler in pairs(desc.state_handlers) do self.events.add_handler("enter/"..state_name, handler); end end if desc.transition_handlers then for transition_name, handler in pairs(desc.transition_handlers) do self.events.add_handler("transition/"..transition_name, handler); end end if desc.handlers then self.events.add_handlers(desc.handlers); end return self; end function fsm_methods:init(state_name, state_attr) local initial_state = assert(state_name or self.default_state, "no initial state specified"); if not self.states[initial_state] then return error("Invalid initial state: "..initial_state); end local instance = setmetatable({ fsm = self; state = initial_state; state_attr = state_attr; }, self._instance_mt); if initial_state ~= self.default_state then local fire_event = self.events.fire_event; notify_transitioned(fire_event, { instance = instance; to = initial_state; to_attr = state_attr; from = self.default_state; }); end return instance; end function fsm_methods:is_instance(o) local mt = getmetatable(o); return mt == self._instance_mt; end return { new = new; is_fsm = is_fsm; };