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StateMachine.lua
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StateMachine.lua
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local Component = import("..Component")
local StateMachine = class("StateMachine", Component)
--[[--
port from Javascript State Machine Library
https://github.com/jakesgordon/javascript-state-machine
JS Version: 2.2.0
]]
StateMachine.VERSION = "2.2.0"
-- the event transitioned successfully from one state to another
StateMachine.SUCCEEDED = 1
-- the event was successfull but no state transition was necessary
StateMachine.NOTRANSITION = 2
-- the event was cancelled by the caller in a beforeEvent callback
StateMachine.CANCELLED = 3
-- the event is asynchronous and the caller is in control of when the transition occurs
StateMachine.PENDING = 4
-- the event was failure
StateMachine.FAILURE = 5
-- caller tried to fire an event that was innapropriate in the current state
StateMachine.INVALID_TRANSITION_ERROR = "INVALID_TRANSITION_ERROR"
-- caller tried to fire an event while an async transition was still pending
StateMachine.PENDING_TRANSITION_ERROR = "PENDING_TRANSITION_ERROR"
-- caller provided callback function threw an exception
StateMachine.INVALID_CALLBACK_ERROR = "INVALID_CALLBACK_ERROR"
StateMachine.WILDCARD = "*"
StateMachine.ASYNC = "ASYNC"
StateMachine.NONE_STATE = "none"
function StateMachine:ctor()
StateMachine.super.ctor(self, "StateMachine")
end
function StateMachine:setupState(cfg)
assert(type(cfg) == "table", "StateMachine:ctor() - invalid config")
-- cfg.initial allow for a simple string,
-- or an table with { state = "foo", event = "setup", defer = true|false }
if type(cfg.initial) == "string" then
self.initial_ = {state = cfg.initial}
else
self.initial_ = clone(cfg.initial)
end
self.terminal_ = cfg.terminal or cfg.final
self.events_ = cfg.events or {}
self.callbacks_ = cfg.callbacks or {}
self.map_ = {}
self.current_ = StateMachine.NONE_STATE
self.inTransition_ = false
self.states_ = {}
if self.initial_ then
self.states_[self.initial_.state] = true
self.initial_.event = self.initial_.event or "startup"
self:addEvent_({name = self.initial_.event, from = StateMachine.NONE_STATE, to = self.initial_.state})
end
for _, event in ipairs(self.events_) do
self:addEvent_(event)
end
if self.initial_ and not self.initial_.defer then
self:doEvent(self.initial_.event)
end
return self.target_
end
function StateMachine:isReady()
return self.current_ ~= StateMachine.NONE_STATE
end
function StateMachine:getState()
return self.current_
end
function StateMachine:isState(state)
if type(state) == "table" then
for _, s in ipairs(state) do
if s == self.current_ then return true end
end
return false
else
return self.current_ == state
end
end
function StateMachine:canDoEvent(eventName)
return not self.inTransition_
and (self.map_[eventName][self.current_] ~= nil or self.map_[eventName][StateMachine.WILDCARD] ~= nil)
end
function StateMachine:cannotDoEvent(eventName)
return not self:canDoEvent(eventName)
end
function StateMachine:isFinishedState()
return self:isState(self.terminal_)
end
function StateMachine:doEventForce(name, ...)
local from = self.current_
local map = self.map_[name]
local to = (map[from] or map[StateMachine.WILDCARD]) or from
local args = {...}
local event = {
name = name,
from = from,
to = to,
args = args,
}
if self.inTransition_ then self.inTransition_ = false end
self:beforeEvent_(event)
if from == to then
self:afterEvent_(event)
return StateMachine.NOTRANSITION
end
self.current_ = to
self:enterState_(event)
self:changeState_(event)
self:afterEvent_(event)
return StateMachine.SUCCEEDED
end
function StateMachine:doEvent(name, ...)
assert(self.map_[name] ~= nil, string.format("StateMachine:doEvent() - invalid event %s", tostring(name)))
local from = self.current_
local map = self.map_[name]
local to = (map[from] or map[StateMachine.WILDCARD]) or from
local args = {...}
local event = {
name = name,
from = from,
to = to,
args = args,
}
if self.inTransition_ then
self:onError_(event,
StateMachine.PENDING_TRANSITION_ERROR,
"event " .. name .. " inappropriate because previous transition did not complete")
return StateMachine.FAILURE
end
if self:cannotDoEvent(name) then
self:onError_(event,
StateMachine.INVALID_TRANSITION_ERROR,
"event " .. name .. " inappropriate in current state " .. self.current_)
return StateMachine.FAILURE
end
if self:beforeEvent_(event) == false then
return StateMachine.CANCELLED
end
if from == to then
self:afterEvent_(event)
return StateMachine.NOTRANSITION
end
event.transition = function()
self.inTransition_ = false
self.current_ = to -- this method should only ever be called once
self:enterState_(event)
self:changeState_(event)
self:afterEvent_(event)
return StateMachine.SUCCEEDED
end
event.cancel = function()
-- provide a way for caller to cancel async transition if desired
event.transition = nil
self:afterEvent_(event)
end
self.inTransition_ = true
local leave = self:leaveState_(event)
if leave == false then
event.transition = nil
event.cancel = nil
self.inTransition_ = false
return StateMachine.CANCELLED
elseif string.upper(tostring(leave)) == StateMachine.ASYNC then
return StateMachine.PENDING
else
-- need to check in case user manually called transition()
-- but forgot to return StateMachine.ASYNC
if event.transition then
return event.transition()
else
self.inTransition_ = false
end
end
end
function StateMachine:getAllStates()
self.states_[StateMachine.NONE_STATE] = nil
return self.states_ or {}
end
function StateMachine:exportMethods()
self:exportMethods_({
"setupState",
"isReady",
"getState",
"isState",
"canDoEvent",
"cannotDoEvent",
"isFinishedState",
"doEventForce",
"doEvent",
"getAllStates",
})
return self.target_
end
function StateMachine:onBind_()
end
function StateMachine:onUnbind_()
end
function StateMachine:addEvent_(event)
local from = {}
if type(event.from) == "table" then
for _, name in ipairs(event.from) do
from[name] = true
self.states_[name] = true
end
elseif event.from then
from[event.from] = true
self.states_[event.from] = true
else
-- allow "wildcard" transition if "from" is not specified
from[StateMachine.WILDCARD] = true
end
if event.to then
self.states_[event.to] = true
end
self.map_[event.name] = self.map_[event.name] or {}
local map = self.map_[event.name]
for fromName, _ in pairs(from) do
map[fromName] = event.to or fromName
end
end
local function doCallback_(callback, event)
if callback then return callback(event) end
end
function StateMachine:beforeAnyEvent_(event)
return doCallback_(self.callbacks_["onbeforeevent"], event)
end
function StateMachine:afterAnyEvent_(event)
return doCallback_(self.callbacks_["onafterevent"] or self.callbacks_["onevent"], event)
end
function StateMachine:leaveAnyState_(event)
return doCallback_(self.callbacks_["onleavestate"], event)
end
function StateMachine:enterAnyState_(event)
return doCallback_(self.callbacks_["onenterstate"] or self.callbacks_["onstate"], event)
end
function StateMachine:changeState_(event)
return doCallback_(self.callbacks_["onchangestate"], event)
end
function StateMachine:beforeThisEvent_(event)
return doCallback_(self.callbacks_["onbefore" .. event.name], event)
end
function StateMachine:afterThisEvent_(event)
return doCallback_(self.callbacks_["onafter" .. event.name] or self.callbacks_["on" .. event.name], event)
end
function StateMachine:leaveThisState_(event)
return doCallback_(self.callbacks_["onleave" .. event.from], event)
end
function StateMachine:enterThisState_(event)
return doCallback_(self.callbacks_["onenter" .. event.to] or self.callbacks_["on" .. event.to], event)
end
function StateMachine:beforeEvent_(event)
if self:beforeThisEvent_(event) == false or self:beforeAnyEvent_(event) == false then
return false
end
end
function StateMachine:afterEvent_(event)
self:afterThisEvent_(event)
self:afterAnyEvent_(event)
end
function StateMachine:leaveState_(event, transition)
local specific = self:leaveThisState_(event, transition)
local general = self:leaveAnyState_(event, transition)
if specific == false or general == false then
return false
elseif string.upper(tostring(specific)) == StateMachine.ASYNC
or string.upper(tostring(general)) == StateMachine.ASYNC then
return StateMachine.ASYNC
end
end
function StateMachine:enterState_(event)
self:enterThisState_(event)
self:enterAnyState_(event)
end
function StateMachine:onError_(event, error, message)
printf("%s [StateMachine] ERROR: error %s, event %s, from %s to %s", tostring(self.target_), tostring(error), event.name, event.from, event.to)
printError(message)
end
return StateMachine