JSON: Add encode / decode shortcut

[project/luci.git] / libs / json / luasrc / json.lua

diff --git a/libs/json/luasrc/json.lua b/libs/json/luasrc/json.lua
index 5d1abcf..5b09285 100644 (file)
--- a/libs/json/luasrc/json.lua
+++ b/libs/json/luasrc/json.lua
@@ -52,6 +52,7 @@ local type        = type
 local pairs        = pairs
 local ipairs    = ipairs
 local next      = next
+local pcall            = pcall
 
 local getmetatable = getmetatable
 
@@ -59,6 +60,33 @@ local getmetatable = getmetatable
 -- @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 chnk
+       return not err and table.concat(out) or nil
+end
+
+
 --- Null replacement function
 -- @return null
 function null()
@@ -498,4 +526,41 @@ Decoder.parsers = {
        ['n'] = Decoder.parse_null,
        ['['] = Decoder.parse_array,
        ['{'] = Decoder.parse_object
-}
\ No newline at end of file
+}
+
+
+--- 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