lua/json/encode/output.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 assert, error = assert, error
   7 local table_concat = require("table").concat
   8 local loadstring = loadstring or load
   9
  10 local io = require("io")
  11
  12 local setmetatable = setmetatable
  13
  14 local output_utility = require("json.encode.output_utility")
  15
  16 local _ENV = nil
  17
  18 local tableCompositeCache = setmetatable({}, {__mode = 'v'})
  19
  20 local TABLE_VALUE_WRITER = [[
  21         ret[#ret + 1] = %VALUE%
  22 ]]
  23
  24 local TABLE_INNER_WRITER = ""
  25
  26 --[[
  27         nextValues can output a max of two values to throw into the data stream
  28         expected to be called until nil is first return value
  29         value separator should either be attached to v1 or in innerValue
  30 ]]
  31 local function defaultTableCompositeWriter(nextValues, beginValue, closeValue, innerValue, composite, encode, state)
  32         if type(nextValues) == 'string' then
  33                 local fun = output_utility.prepareEncoder(defaultTableCompositeWriter, nextValues, innerValue, TABLE_VALUE_WRITER, TABLE_INNER_WRITER)
  34                 local ret = {}
  35                 fun(composite, ret, encode, state)
  36                 return beginValue .. table_concat(ret, innerValue) .. closeValue
  37         end
  38 end
  39
  40 -- no 'simple' as default action is just to return the value
  41 local function getDefault()
  42         return { composite = defaultTableCompositeWriter }
  43 end
  44
  45 -- BEGIN IO-WRITER OUTPUT
  46 local IO_INNER_WRITER = [[
  47         if %WRITE_INNER% then
  48                 state.__outputFile:write(%INNER_VALUE%)
  49         end
  50 ]]
  51 local IO_VALUE_WRITER = [[
  52         state.__outputFile:write(%VALUE%)
  53 ]]
  54
  55 local function buildIoWriter(output)
  56         if not output then -- Default to stdout
  57                 output = io.output()
  58         end
  59         local function ioWriter(nextValues, beginValue, closeValue, innerValue, composite, encode, state)
  60                 -- HOOK OUTPUT STATE
  61                 state.__outputFile = output
  62                 if type(nextValues) == 'string' then
  63                         local fun = output_utility.prepareEncoder(ioWriter, nextValues, innerValue, IO_VALUE_WRITER, IO_INNER_WRITER)
  64                         local ret = {}
  65                         output:write(beginValue)
  66                         fun(composite, ret, encode, state)
  67                         output:write(closeValue)
  68                         return nil
  69                 end
  70         end
  71
  72         local function ioSimpleWriter(encoded)
  73                 if encoded then
  74                         output:write(encoded)
  75                 end
  76                 return nil
  77         end
  78         return { composite = ioWriter, simple = ioSimpleWriter }
  79 end
  80 local function getIoWriter(output)
  81         return function()
  82                 return buildIoWriter(output)
  83         end
  84 end
  85
  86 local output = {
  87         getDefault = getDefault,
  88         getIoWriter = getIoWriter
  89 }
  90
  91 return output