141 lines
8.5 KiB
Lua
141 lines
8.5 KiB
Lua
local n, v = "serpent", "0.302" -- (C) 2012-18 Paul Kulchenko; MIT License
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local c, d = "Paul Kulchenko", "Lua serializer and pretty printer"
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local snum = {[tostring(1/0)]='1/0 --[[math.huge]]',[tostring(-1/0)]='-1/0 --[[-math.huge]]',[tostring(0/0)]='0/0'}
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local badtype = {thread = true, userdata = true, cdata = true}
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local getmetatable = debug and debug.getmetatable or getmetatable
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local pairs = function(t) return next, t end -- avoid using __pairs in Lua 5.2+
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local keyword, globals, G = {}, {}, (_G or _ENV)
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for _,k in ipairs({'and', 'break', 'do', 'else', 'elseif', 'end', 'false',
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'for', 'function', 'goto', 'if', 'in', 'local', 'nil', 'not', 'or', 'repeat',
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'return', 'then', 'true', 'until', 'while'}) do keyword[k] = true end
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for k,v in pairs(G) do globals[v] = k end -- build func to name mapping
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for _,g in ipairs({'coroutine', 'debug', 'io', 'math', 'string', 'table', 'os'}) do
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for k,v in pairs(type(G[g]) == 'table' and G[g] or {}) do globals[v] = g..'.'..k end end
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local function s(t, opts)
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local name, indent, fatal, maxnum = opts.name, opts.indent, opts.fatal, opts.maxnum
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local sparse, custom, huge = opts.sparse, opts.custom, not opts.nohuge
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local space, maxl = (opts.compact and '' or ' '), (opts.maxlevel or math.huge)
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local maxlen, metatostring = tonumber(opts.maxlength), opts.metatostring
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local iname, comm = '_'..(name or ''), opts.comment and (tonumber(opts.comment) or math.huge)
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local numformat = opts.numformat or "%.17g"
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local seen, sref, syms, symn = {}, {'local '..iname..'={}'}, {}, 0
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local function gensym(val) return '_'..(tostring(tostring(val)):gsub("[^%w]",""):gsub("(%d%w+)",
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-- tostring(val) is needed because __tostring may return a non-string value
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function(s) if not syms[s] then symn = symn+1; syms[s] = symn end return tostring(syms[s]) end)) end
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local function safestr(s) return type(s) == "number" and tostring(huge and snum[tostring(s)] or numformat:format(s))
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or type(s) ~= "string" and tostring(s) -- escape NEWLINE/010 and EOF/026
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or ("%q"):format(s):gsub("\010","n"):gsub("\026","\\026") end
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local function comment(s,l) return comm and (l or 0) < comm and ' --[['..select(2, pcall(tostring, s))..']]' or '' end
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local function globerr(s,l) return globals[s] and globals[s]..comment(s,l) or not fatal
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and safestr(select(2, pcall(tostring, s))) or error("Can't serialize "..tostring(s)) end
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local function safename(path, name) -- generates foo.bar, foo[3], or foo['b a r']
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local n = name == nil and '' or name
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local plain = type(n) == "string" and n:match("^[%l%u_][%w_]*$") and not keyword[n]
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local safe = plain and n or '['..safestr(n)..']'
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return (path or '')..(plain and path and '.' or '')..safe, safe end
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local alphanumsort = type(opts.sortkeys) == 'function' and opts.sortkeys or function(k, o, n) -- k=keys, o=originaltable, n=padding
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local maxn, to = tonumber(n) or 12, {number = 'a', string = 'b'}
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local function padnum(d) return ("%0"..tostring(maxn).."d"):format(tonumber(d)) end
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table.sort(k, function(a,b)
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-- sort numeric keys first: k[key] is not nil for numerical keys
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return (k[a] ~= nil and 0 or to[type(a)] or 'z')..(tostring(a):gsub("%d+",padnum))
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< (k[b] ~= nil and 0 or to[type(b)] or 'z')..(tostring(b):gsub("%d+",padnum)) end) end
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local function val2str(t, name, indent, insref, path, plainindex, level)
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local ttype, level, mt = type(t), (level or 0), getmetatable(t)
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local spath, sname = safename(path, name)
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local tag = plainindex and
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((type(name) == "number") and '' or name..space..'='..space) or
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(name ~= nil and sname..space..'='..space or '')
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if seen[t] then -- already seen this element
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sref[#sref+1] = spath..space..'='..space..seen[t]
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return tag..'nil'..comment('ref', level) end
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-- protect from those cases where __tostring may fail
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if type(mt) == 'table' and metatostring ~= false then
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local to, tr = pcall(function() return mt.__tostring(t) end)
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local so, sr = pcall(function() return mt.__serialize(t) end)
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if (to or so) then -- knows how to serialize itself
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seen[t] = insref or spath
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t = so and sr or tr
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ttype = type(t)
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end -- new value falls through to be serialized
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end
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if ttype == "table" then
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if level >= maxl then return tag..'{}'..comment('maxlvl', level) end
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seen[t] = insref or spath
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if next(t) == nil then return tag..'{}'..comment(t, level) end -- table empty
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if maxlen and maxlen < 0 then return tag..'{}'..comment('maxlen', level) end
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local maxn, o, out = math.min(#t, maxnum or #t), {}, {}
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for key = 1, maxn do o[key] = key end
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if not maxnum or #o < maxnum then
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local n = #o -- n = n + 1; o[n] is much faster than o[#o+1] on large tables
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for key in pairs(t) do if o[key] ~= key then n = n + 1; o[n] = key end end end
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if maxnum and #o > maxnum then o[maxnum+1] = nil end
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if opts.sortkeys and #o > maxn then alphanumsort(o, t, opts.sortkeys) end
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local sparse = sparse and #o > maxn -- disable sparsness if only numeric keys (shorter output)
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for n, key in ipairs(o) do
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local value, ktype, plainindex = t[key], type(key), n <= maxn and not sparse
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if opts.valignore and opts.valignore[value] -- skip ignored values; do nothing
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or opts.keyallow and not opts.keyallow[key]
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or opts.keyignore and opts.keyignore[key]
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or opts.valtypeignore and opts.valtypeignore[type(value)] -- skipping ignored value types
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or sparse and value == nil then -- skipping nils; do nothing
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elseif ktype == 'table' or ktype == 'function' or badtype[ktype] then
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if not seen[key] and not globals[key] then
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sref[#sref+1] = 'placeholder'
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local sname = safename(iname, gensym(key)) -- iname is table for local variables
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sref[#sref] = val2str(key,sname,indent,sname,iname,true) end
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sref[#sref+1] = 'placeholder'
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local path = seen[t]..'['..tostring(seen[key] or globals[key] or gensym(key))..']'
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sref[#sref] = path..space..'='..space..tostring(seen[value] or val2str(value,nil,indent,path))
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else
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out[#out+1] = val2str(value,key,indent,nil,seen[t],plainindex,level+1)
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if maxlen then
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maxlen = maxlen - #out[#out]
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if maxlen < 0 then break end
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end
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end
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end
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local prefix = string.rep(indent or '', level)
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local head = indent and '{\n'..prefix..indent or '{'
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local body = table.concat(out, ','..(indent and '\n'..prefix..indent or space))
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local tail = indent and "\n"..prefix..'}' or '}'
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return (custom and custom(tag,head,body,tail,level) or tag..head..body..tail)..comment(t, level)
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elseif badtype[ttype] then
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seen[t] = insref or spath
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return tag..globerr(t, level)
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elseif ttype == 'function' then
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seen[t] = insref or spath
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if opts.nocode then return tag.."function() --[[..skipped..]] end"..comment(t, level) end
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local ok, res = pcall(string.dump, t)
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local func = ok and "((loadstring or load)("..safestr(res)..",'@serialized'))"..comment(t, level)
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return tag..(func or globerr(t, level))
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else return tag..safestr(t) end -- handle all other types
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end
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local sepr = indent and "\n" or ";"..space
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local body = val2str(t, name, indent) -- this call also populates sref
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local tail = #sref>1 and table.concat(sref, sepr)..sepr or ''
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local warn = opts.comment and #sref>1 and space.."--[[incomplete output with shared/self-references skipped]]" or ''
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return not name and body..warn or "do local "..body..sepr..tail.."return "..name..sepr.."end"
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end
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local function deserialize(data, opts)
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local env = (opts and opts.safe == false) and G
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or setmetatable({}, {
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__index = function(t,k) return t end,
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__call = function(t,...) error("cannot call functions") end
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})
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local f, res = (loadstring or load)('return '..data, nil, nil, env)
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if not f then f, res = (loadstring or load)(data, nil, nil, env) end
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if not f then return f, res end
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if setfenv then setfenv(f, env) end
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return pcall(f)
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end
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local function merge(a, b) if b then for k,v in pairs(b) do a[k] = v end end; return a; end
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return { _NAME = n, _COPYRIGHT = c, _DESCRIPTION = d, _VERSION = v, serialize = s,
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load = deserialize,
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dump = function(a, opts) return s(a, merge({name = '_', compact = true, sparse = true}, opts)) end,
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line = function(a, opts) return s(a, merge({sortkeys = true, comment = true}, opts)) end,
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block = function(a, opts) return s(a, merge({indent = ' ', sortkeys = true, comment = true}, opts)) end }
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