+--[[
+LuCI - Lua Configuration Interface
+
+Copyright 2008 Steven Barth <steven@midlink.org>
+Copyright 2008 Jo-Philipp Wich <xm@leipzig.freifunk.net>
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+$Id$
+
+Decoder:
+ Info:
+ null will be decoded to luci.json.null if first parameter of Decoder() is true
+
+ Example:
+ decoder = luci.json.Decoder()
+ luci.ltn12.pump.all(luci.ltn12.source.string("decodableJSON"), decoder:sink())
+ luci.util.dumptable(decoder:get())
+
+ Known issues:
+ does not support unicode conversion \uXXYY with XX != 00 will be ignored
+
+
+Encoder:
+ Info:
+ Accepts numbers, strings, nil, booleans as they are
+ Accepts luci.json.null as replacement for nil
+ Accepts full associative and full numerically indexed tables
+ Mixed tables will loose their associative values during conversion
+ Iterator functions will be encoded as an array of their return values
+ Non-iterator functions will probably corrupt the encoder
+
+ Example:
+ encoder = luci.json.Encoder(encodableData)
+ luci.ltn12.pump.all(encoder:source(), luci.ltn12.sink.file(io.open("someFile", w)))
+]]--
+
+local nixio = require "nixio"
+local util = require "luci.util"
+local table = require "table"
+local string = require "string"
+local coroutine = require "coroutine"
+
+local assert = assert
+local tonumber = tonumber
+local tostring = tostring
+local error = error
+local type = type
+local pairs = pairs
+local ipairs = ipairs
+local next = next
+local pcall = pcall
+
+local band = nixio.bit.band
+local bor = nixio.bit.bor
+local rshift = nixio.bit.rshift
+local char = string.char
+
+local getmetatable = getmetatable
+
+--- LuCI JSON-Library
+-- @cstyle instance
+module "luci.json"
+
+
+--- Directly decode a JSON string
+-- @param json JSON-String
+-- @return Lua object
+function decode(json, ...)
+ local a = ActiveDecoder(function() return nil end, ...)
+ a.chunk = json
+ local s, obj = pcall(a.get, a)
+ return s and obj or nil
+end
+
+
+--- Direcly encode a Lua object into a JSON string.
+-- @param obj Lua Object
+-- @return JSON string
+function encode(obj, ...)
+ local out = {}
+ local e = Encoder(obj, 1, ...):source()
+ local chnk, err
+ repeat
+ chnk, err = e()
+ out[#out+1] = chnk
+ until not chnk
+ return not err and table.concat(out) or nil
+end
+
+
+--- Null replacement function
+-- @return null
+function null()
+ return null
+end
+
+--- Create a new JSON-Encoder.
+-- @class function
+-- @name Encoder
+-- @param data Lua-Object to be encoded.
+-- @param buffersize Blocksize of returned data source.
+-- @param fastescape Use non-standard escaping (don't escape control chars)
+-- @return JSON-Encoder
+Encoder = util.class()
+
+function Encoder.__init__(self, data, buffersize, fastescape)
+ self.data = data
+ self.buffersize = buffersize or 512
+ self.buffer = ""
+ self.fastescape = fastescape
+
+ getmetatable(self).__call = Encoder.source
+end
+
+--- Create an LTN12 source providing the encoded JSON-Data.
+-- @return LTN12 source
+function Encoder.source(self)
+ local source = coroutine.create(self.dispatch)
+ return function()
+ local res, data = coroutine.resume(source, self, self.data, true)
+ if res then
+ return data
+ else
+ return nil, data
+ end
+ end
+end
+
+function Encoder.dispatch(self, data, start)
+ local parser = self.parsers[type(data)]
+
+ parser(self, data)
+
+ if start then
+ if #self.buffer > 0 then
+ coroutine.yield(self.buffer)
+ end
+
+ coroutine.yield()
+ end
+end
+
+function Encoder.put(self, chunk)
+ if self.buffersize < 2 then
+ coroutine.yield(chunk)
+ else
+ if #self.buffer + #chunk > self.buffersize then
+ local written = 0
+ local fbuffer = self.buffersize - #self.buffer
+
+ coroutine.yield(self.buffer .. chunk:sub(written + 1, fbuffer))
+ written = fbuffer
+
+ while #chunk - written > self.buffersize do
+ fbuffer = written + self.buffersize
+ coroutine.yield(chunk:sub(written + 1, fbuffer))
+ written = fbuffer
+ end
+
+ self.buffer = chunk:sub(written + 1)
+ else
+ self.buffer = self.buffer .. chunk
+ end
+ end
+end
+
+function Encoder.parse_nil(self)
+ self:put("null")
+end
+
+function Encoder.parse_bool(self, obj)
+ self:put(obj and "true" or "false")
+end
+
+function Encoder.parse_number(self, obj)
+ self:put(tostring(obj))
+end
+
+function Encoder.parse_string(self, obj)
+ if self.fastescape then
+ self:put('"' .. obj:gsub('\\', '\\\\'):gsub('"', '\\"') .. '"')
+ else
+ self:put('"' ..
+ obj:gsub('[%c\\"]',
+ function(char)
+ return '\\u00%02x' % char:byte()
+ end
+ )
+ .. '"')
+ end
+end
+
+function Encoder.parse_iter(self, obj)
+ if obj == null then
+ return self:put("null")
+ end
+
+ if type(obj) == "table" and (#obj == 0 and next(obj)) then
+ self:put("{")
+ local first = true
+
+ for key, entry in pairs(obj) do
+ first = first or self:put(",")
+ first = first and false
+ self:parse_string(tostring(key))
+ self:put(":")
+ self:dispatch(entry)
+ end
+
+ self:put("}")
+ else
+ self:put("[")
+ local first = true
+
+ if type(obj) == "table" then
+ for i=1, #obj do
+ first = first or self:put(",")
+ first = first and nil
+ self:dispatch(obj[i])
+ end
+ else
+ for entry in obj do
+ first = first or self:put(",")
+ first = first and nil
+ self:dispatch(entry)
+ end
+ end
+
+ self:put("]")
+ end
+end
+
+Encoder.parsers = {
+ ['nil'] = Encoder.parse_nil,
+ ['table'] = Encoder.parse_iter,
+ ['number'] = Encoder.parse_number,
+ ['string'] = Encoder.parse_string,
+ ['boolean'] = Encoder.parse_bool,
+ ['function'] = Encoder.parse_iter
+}
+
+
+--- Create a new JSON-Decoder.
+-- @class function
+-- @name Decoder
+-- @param customnull Use luci.json.null instead of nil for decoding null
+-- @return JSON-Decoder
+Decoder = util.class()
+
+function Decoder.__init__(self, customnull)
+ self.cnull = customnull
+ getmetatable(self).__call = Decoder.sink
+end
+
+--- Create an LTN12 sink from the decoder object which accepts the JSON-Data.
+-- @return LTN12 sink
+function Decoder.sink(self)
+ local sink = coroutine.create(self.dispatch)
+ return function(...)
+ return coroutine.resume(sink, self, ...)
+ end
+end
+
+
+--- Get the decoded data packets after the rawdata has been sent to the sink.
+-- @return Decoded data
+function Decoder.get(self)
+ return self.data
+end
+
+function Decoder.dispatch(self, chunk, src_err, strict)
+ local robject, object
+ local oset = false
+
+ while chunk do
+ while chunk and #chunk < 1 do
+ chunk = self:fetch()
+ end
+
+ assert(not strict or chunk, "Unexpected EOS")
+ if not chunk then break end
+
+ local char = chunk:sub(1, 1)
+ local parser = self.parsers[char]
+ or (char:match("%s") and self.parse_space)
+ or (char:match("[0-9-]") and self.parse_number)
+ or error("Unexpected char '%s'" % char)
+
+ chunk, robject = parser(self, chunk)
+
+ if parser ~= self.parse_space then
+ assert(not oset, "Scope violation: Too many objects")
+ object = robject
+ oset = true
+
+ if strict then
+ return chunk, object
+ end
+ end
+ end
+
+ assert(not src_err, src_err)
+ assert(oset, "Unexpected EOS")
+
+ self.data = object
+end
+
+
+function Decoder.fetch(self)
+ local tself, chunk, src_err = coroutine.yield()
+ assert(chunk or not src_err, src_err)
+ return chunk
+end
+
+
+function Decoder.fetch_atleast(self, chunk, bytes)
+ while #chunk < bytes do
+ local nchunk = self:fetch()
+ assert(nchunk, "Unexpected EOS")
+ chunk = chunk .. nchunk
+ end
+
+ return chunk
+end
+
+
+function Decoder.fetch_until(self, chunk, pattern)
+ local start = chunk:find(pattern)
+
+ while not start do
+ local nchunk = self:fetch()
+ assert(nchunk, "Unexpected EOS")
+ chunk = chunk .. nchunk
+ start = chunk:find(pattern)
+ end
+
+ return chunk, start
+end
+
+
+function Decoder.parse_space(self, chunk)
+ local start = chunk:find("[^%s]")
+
+ while not start do
+ chunk = self:fetch()
+ if not chunk then
+ return nil
+ end
+ start = chunk:find("[^%s]")
+ end
+
+ return chunk:sub(start)
+end
+
+
+function Decoder.parse_literal(self, chunk, literal, value)
+ chunk = self:fetch_atleast(chunk, #literal)
+ assert(chunk:sub(1, #literal) == literal, "Invalid character sequence")
+ return chunk:sub(#literal + 1), value
+end
+
+
+function Decoder.parse_null(self, chunk)
+ return self:parse_literal(chunk, "null", self.cnull and null)
+end
+
+
+function Decoder.parse_true(self, chunk)
+ return self:parse_literal(chunk, "true", true)
+end
+
+
+function Decoder.parse_false(self, chunk)
+ return self:parse_literal(chunk, "false", false)
+end
+
+
+function Decoder.parse_number(self, chunk)
+ local chunk, start = self:fetch_until(chunk, "[^0-9eE.+-]")
+ local number = tonumber(chunk:sub(1, start - 1))
+ assert(number, "Invalid number specification")
+ return chunk:sub(start), number
+end
+
+
+function Decoder.parse_string(self, chunk)
+ local str = ""
+ local object = nil
+ assert(chunk:sub(1, 1) == '"', 'Expected "')
+ chunk = chunk:sub(2)
+
+ while true do
+ local spos = chunk:find('[\\"]')
+ if spos then
+ str = str .. chunk:sub(1, spos - 1)
+
+ local char = chunk:sub(spos, spos)
+ if char == '"' then -- String end
+ chunk = chunk:sub(spos + 1)
+ break
+ elseif char == "\\" then -- Escape sequence
+ chunk, object = self:parse_escape(chunk:sub(spos))
+ str = str .. object
+ end
+ else
+ str = str .. chunk
+ chunk = self:fetch()
+ assert(chunk, "Unexpected EOS while parsing a string")
+ end
+ end
+
+ return chunk, str
+end
+
+
+function Decoder.utf8_encode(self, s1, s2)
+ local n = s1 * 256 + s2
+
+ if n >= 0 and n <= 0x7F then
+ return char(n)
+ elseif n >= 0 and n <= 0x7FF then
+ return char(
+ bor(band(rshift(n, 6), 0x1F), 0xC0),
+ bor(band(n, 0x3F), 0x80)
+ )
+ elseif n >= 0 and n <= 0xFFFF then
+ return char(
+ bor(band(rshift(n, 12), 0x0F), 0xE0),
+ bor(band(rshift(n, 6), 0x3F), 0x80),
+ bor(band(n, 0x3F), 0x80)
+ )
+ elseif n >= 0 and n <= 0x10FFFF then
+ return char(
+ bor(band(rshift(n, 18), 0x07), 0xF0),
+ bor(band(rshift(n, 12), 0x3F), 0x80),
+ bor(band(rshift(n, 6), 0x3F), 0x80),
+ bor(band(n, 0x3F), 0x80)
+ )
+ else
+ return "?"
+ end
+end
+
+
+function Decoder.parse_escape(self, chunk)
+ local str = ""
+ chunk = self:fetch_atleast(chunk:sub(2), 1)
+ local char = chunk:sub(1, 1)
+ chunk = chunk:sub(2)
+
+ if char == '"' then
+ return chunk, '"'
+ elseif char == "\\" then
+ return chunk, "\\"
+ elseif char == "u" then
+ chunk = self:fetch_atleast(chunk, 4)
+ local s1, s2 = chunk:sub(1, 2), chunk:sub(3, 4)
+ s1, s2 = tonumber(s1, 16), tonumber(s2, 16)
+ assert(s1 and s2, "Invalid Unicode character")
+
+ return chunk:sub(5), self:utf8_encode(s1, s2)
+ elseif char == "/" then
+ return chunk, "/"
+ elseif char == "b" then
+ return chunk, "\b"
+ elseif char == "f" then
+ return chunk, "\f"
+ elseif char == "n" then
+ return chunk, "\n"
+ elseif char == "r" then
+ return chunk, "\r"
+ elseif char == "t" then
+ return chunk, "\t"
+ else
+ error("Unexpected escaping sequence '\\%s'" % char)
+ end
+end
+
+
+function Decoder.parse_array(self, chunk)
+ chunk = chunk:sub(2)
+ local array = {}
+ local nextp = 1
+
+ local chunk, object = self:parse_delimiter(chunk, "%]")
+
+ if object then
+ return chunk, array
+ end
+
+ repeat
+ chunk, object = self:dispatch(chunk, nil, true)
+ table.insert(array, nextp, object)
+ nextp = nextp + 1
+
+ chunk, object = self:parse_delimiter(chunk, ",%]")
+ assert(object, "Delimiter expected")
+ until object == "]"
+
+ return chunk, array
+end
+
+
+function Decoder.parse_object(self, chunk)
+ chunk = chunk:sub(2)
+ local array = {}
+ local name
+
+ local chunk, object = self:parse_delimiter(chunk, "}")
+
+ if object then
+ return chunk, array
+ end
+
+ repeat
+ chunk = self:parse_space(chunk)
+ assert(chunk, "Unexpected EOS")
+
+ chunk, name = self:parse_string(chunk)
+
+ chunk, object = self:parse_delimiter(chunk, ":")
+ assert(object, "Separator expected")
+
+ chunk, object = self:dispatch(chunk, nil, true)
+ array[name] = object
+
+ chunk, object = self:parse_delimiter(chunk, ",}")
+ assert(object, "Delimiter expected")
+ until object == "}"
+
+ return chunk, array
+end
+
+
+function Decoder.parse_delimiter(self, chunk, delimiter)
+ while true do
+ chunk = self:fetch_atleast(chunk, 1)
+ local char = chunk:sub(1, 1)
+ if char:match("%s") then
+ chunk = self:parse_space(chunk)
+ assert(chunk, "Unexpected EOS")
+ elseif char:match("[%s]" % delimiter) then
+ return chunk:sub(2), char
+ else
+ return chunk, nil
+ end
+ end
+end
+
+
+Decoder.parsers = {
+ ['"'] = Decoder.parse_string,
+ ['t'] = Decoder.parse_true,
+ ['f'] = Decoder.parse_false,
+ ['n'] = Decoder.parse_null,
+ ['['] = Decoder.parse_array,
+ ['{'] = Decoder.parse_object
+}
+
+
+--- Create a new Active JSON-Decoder.
+-- @class function
+-- @name ActiveDecoder
+-- @param customnull Use luci.json.null instead of nil for decoding null
+-- @return Active JSON-Decoder
+ActiveDecoder = util.class(Decoder)
+
+function ActiveDecoder.__init__(self, source, customnull)
+ Decoder.__init__(self, customnull)
+ self.source = source
+ self.chunk = nil
+ getmetatable(self).__call = self.get
+end
+
+
+--- Fetches one JSON-object from given source
+-- @return Decoded object
+function ActiveDecoder.get(self)
+ local chunk, src_err, object
+ if not self.chunk then
+ chunk, src_err = self.source()
+ else
+ chunk = self.chunk
+ end
+
+ self.chunk, object = self:dispatch(chunk, src_err, true)
+ return object
+end
+
+
+function ActiveDecoder.fetch(self)
+ local chunk, src_err = self.source()
+ assert(chunk or not src_err, src_err)
+ return chunk
+end
projects / project / luci.git / blobdiff