-- Savegame facilities for Lunatic. local string = require("string") local table = require("table") local format = string.format local assert = assert local getmetatable = getmetatable local pairs = pairs local setmetatable = setmetatable local tostring = tostring local type = type local cansave_cdata = require("lprivate").cansave_cdata module(...) ---=== Serialization, based on the idea from PiL ===--- assert(tostring(0/0)=="nan") assert(tostring(1/0)=="inf") -- Serialize a 'primitive' Lua value. local function basicSerialize(o) -- Compare with sb_get_initial_strbuf() below. -- XXX: nil? if (type(o) == "number") then -- NOTE: NaN and infinity handled. return tostring(o) elseif (type(o) == "boolean") then return o and "t" or "f" elseif (type(o) == "string") then -- TODO: return refname if it's shorter return format("%q", o) end end local function isSerializeable(obj) return (getmetatable(obj)=="serializeable" or cansave_cdata(obj)) end -- 'Save buffer' class. Objects of this class keep track of a string buffer -- contiaining Lua code to recreate the values of particular variables from a -- user Lunatic environment. local savebuffer_mt = { __index = { -- Called on starting processing one module. startmod = function(self, modname) self:addrawf("if (N==%q) then", modname) -- Will contain all tables and cdata refs of this module, indexed -- by number. self:addraw("local T={}") self:resetRefs() end, -- Called on finishing processing one module. endmod = function(self) self:addraw("end") end, --== vvv INTERNAL vvv ===--- resetRefs = function(self) self.numrefs = 0 self.val2ref = {} self.havereq = {} end, -- Get the code necessary to create this object, usually 'require'ing a -- module into a local variable. getRequire = function(self, value) local reqcode = value:_get_require() if (self.havereq[reqcode] == nil) then self.havereq[reqcode] = true self.strbuf[#self.strbuf+1] = reqcode end end, emitT = function(self, refcode, valcode, obj) self:addrawf("%s=%s", refcode, valcode) self.val2ref[obj] = refcode end, emitAssign = function(self, lhscode, refcode) self:addrawf("%s=%s", lhscode, refcode) end, --== ^^^ INTERNAL ^^^ ===--- -- Add an entry of Lua object <value> that can be referenced by -- <lhscode> on the left hand side of an assignment. -- Returns 'true' if <value> cannot be serialized. add = function(self, lhscode, value) local valcode = basicSerialize(value) if (valcode == nil) then -- <value> is a not a 'basic' Lua object, but one passed by -- reference. if (not self.val2ref[value]) then -- Object is being serialized for the first time. -- Create a slot in 'T' for this object by which we can -- refer to it in the following. self.numrefs = self.numrefs+1 local refcode = format("T[%d]", self.numrefs) if (isSerializeable(value)) then -- We have a serializeable object from Lunatic -- (e.g. actorvar). self:getRequire(value) local restoreCode = value:_serialize() if (restoreCode == nil) then -- XXX: check UNUSED? return true end self:emitT(refcode, restoreCode, value) valcode = refcode elseif (type(value)=="table") then -- Create a new table for this gamevar. -- TODO: emit table initializations where possible. self:emitT(refcode, "{}", value) for k,v in pairs(value) do local keystr = basicSerialize(k) if (keystr == nil) then return true end -- Generate the name under which the table element -- is referenced. local refcode2 = format("%s[%s]", refcode, keystr) -- Recurse! if (self:add(refcode2, v)) then return true end end valcode = refcode else -- We have anything else: can't serialize. return true end else -- Object was previously serialized, get Lua expression it -- can be referenced with. valcode = self.val2ref[value] end end self:emitAssign(lhscode, valcode) end, -- Add a single string to the buffer. addraw = function(self, str) self.strbuf[#self.strbuf+1] = str end, -- Add a single formatted string to the buffer. addrawf = function(self, fmt, ...) self:addraw(format(fmt, ...)) end, -- Get the Lua code recreating the values as a string. getcode = function(self) self.strbuf[#self.strbuf+1] = "" -- add newline at EOS return table.concat(self.strbuf, "\n") end, } } local function sb_get_initial_strbuf() return { "local nan, inf = 0/0, 1/0", "local t, f = true, false", } end -- Create a new savebuffer object. function savebuffer() -- .numrefs: how many table or cdata objects we have serialized -- .val2ref: [<Lua object>] = <Lua code string> -- .havereq = [<string>] = true -- .strbuf: array of Lua code pieces local sb = { numrefs=0, val2ref={}, havereq={}, strbuf=sb_get_initial_strbuf() } return setmetatable(sb, savebuffer_mt) end