lua/json/util.lua

   1 --[[
   2         Licensed according to the included 'LICENSE' document
   3         Author: Thomas Harning Jr <harningt@gmail.com>
   4 ]]
   5 local type = type
   6 local print = print
   7 local tostring = tostring
   8 local pairs = pairs
   9 local getmetatable, setmetatable = getmetatable, setmetatable
  10 local select = select
  11
  12 local _ENV = nil
  13
  14 local function foreach(tab, func)
  15         for k, v in pairs(tab) do
  16                 func(k,v)
  17         end
  18 end
  19 local function printValue(tab, name)
  20         local parsed = {}
  21         local function doPrint(key, value, space)
  22                 space = space or ''
  23                 if type(value) == 'table' then
  24                         if parsed[value] then
  25                                 print(space .. key .. '= <' .. parsed[value] .. '>')
  26                         else
  27                                 parsed[value] = key
  28                                 print(space .. key .. '= {')
  29                                 space = space .. ' '
  30                                 foreach(value, function(key, value) doPrint(key, value, space) end)
  31                         end
  32                 else
  33                                         if type(value) == 'string' then
  34                                                 value = '[[' .. tostring(value) .. ']]'
  35                                         end
  36                                         print(space .. key .. '=' .. tostring(value))
  37                 end
  38         end
  39         doPrint(name, tab)
  40 end
  41
  42 local function clone(t)
  43         local ret = {}
  44         for k,v in pairs(t) do
  45                 ret[k] = v
  46         end
  47         return ret
  48 end
  49
  50 local function inner_merge(t, remaining, from, ...)
  51         if remaining == 0 then
  52                 return t
  53         end
  54         if from then
  55                 for k,v in pairs(from) do
  56                         t[k] = v
  57                 end
  58         end
  59         return inner_merge(t, remaining - 1, ...)
  60 end
  61
  62 --[[*
  63     Shallow-merges tables in order onto the first table.
  64
  65     @param t table to merge entries onto
  66     @param ... sequence of 0 or more tables to merge onto 't'
  67
  68     @returns table 't' from input
  69 ]]
  70 local function merge(t, ...)
  71         return inner_merge(t, select('#', ...), ...)
  72 end
  73
  74 -- Function to insert nulls into the JSON stream
  75 local function null()
  76         return null
  77 end
  78
  79 -- Marker for 'undefined' values
  80 local function undefined()
  81         return undefined
  82 end
  83
  84 local ArrayMT = {}
  85
  86 --[[
  87         Return's true if the metatable marks it as an array..
  88         Or false if it has no array component at all
  89         Otherwise nil to get the normal detection component working
  90 ]]
  91 local function IsArray(value)
  92         if type(value) ~= 'table' then return false end
  93         local meta = getmetatable(value)
  94         local ret = meta == ArrayMT or (meta ~= nil and meta.__is_luajson_array)
  95         if not ret then
  96                 if #value == 0 then return false end
  97         else
  98                 return ret
  99         end
 100 end
 101 local function InitArray(array)
 102         setmetatable(array, ArrayMT)
 103         return array
 104 end
 105
 106 local CallMT = {}
 107
 108 local function isCall(value)
 109         return CallMT == getmetatable(value)
 110 end
 111
 112 local function buildCall(name, ...)
 113         local callData = {
 114                 name = name,
 115                 parameters = {n = select('#', ...), ...}
 116         }
 117         return setmetatable(callData, CallMT)
 118 end
 119
 120 local function decodeCall(callData)
 121         if not isCall(callData) then return nil end
 122         return callData.name, callData.parameters
 123 end
 124
 125 local function doOptionMerge(options, nested, name, defaultOptions, modeOptions)
 126         if nested then
 127                 modeOptions = modeOptions and modeOptions[name]
 128                 defaultOptions = defaultOptions and defaultOptions[name]
 129         end
 130         options[name] = merge(
 131                 {},
 132                 defaultOptions,
 133                 modeOptions,
 134                 options[name]
 135         )
 136 end
 137
 138 local json_util = {
 139         printValue = printValue,
 140         clone = clone,
 141         merge = merge,
 142         null = null,
 143         undefined = undefined,
 144         IsArray = IsArray,
 145         InitArray = InitArray,
 146         isCall = isCall,
 147         buildCall = buildCall,
 148         decodeCall = decodeCall,
 149         doOptionMerge = doOptionMerge
 150 }
 151
 152 return json_util