fallbacks/lxp.lua

   1 \r
   2 local coroutine = coroutine;\r
   3 local tonumber = tonumber;\r
   4 local string = string;\r
   5 local setmetatable, getmetatable = setmetatable, getmetatable;\r
   6 local pairs = pairs;\r
   7 \r
   8 local deadroutine = coroutine.create(function() end);\r
   9 coroutine.resume(deadroutine);\r
  10 \r
  11 module("lxp")\r
  12 \r
  13 local entity_map = setmetatable({\r
  14         ["amp"] = "&";\r
  15         ["gt"] = ">";\r
  16         ["lt"] = "<";\r
  17         ["apos"] = "'";\r
  18         ["quot"] = "\"";\r
  19 }, {__index = function(_, s)\r
  20                 if s:sub(1,1) == "#" then\r
  21                         if s:sub(2,2) == "x" then\r
  22                                 return string.char(tonumber(s:sub(3), 16));\r
  23                         else\r
  24                                 return string.char(tonumber(s:sub(2)));\r
  25                         end\r
  26                 end\r
  27         end\r
  28 });\r
  29 local function xml_unescape(str)\r
  30         return (str:gsub("&(.-);", entity_map));\r
  31 end\r
  32 local function parse_tag(s)\r
  33         local name,sattr=(s):gmatch("([^%s]+)(.*)")();\r
  34         local attr = {};\r
  35         for a,b in (sattr):gmatch("([^=%s]+)=['\"]([^'\"]*)['\"]") do attr[a] = xml_unescape(b); end\r
  36         return name, attr;\r
  37 end\r
  38 \r
  39 local function parser(data, handlers, ns_separator)\r
  40         local function read_until(str)\r
  41                 local pos = data:find(str, nil, true);\r
  42                 while not pos do\r
  43                         data = data..coroutine.yield();\r
  44                         pos = data:find(str, nil, true);\r
  45                 end\r
  46                 local r = data:sub(1, pos);\r
  47                 data = data:sub(pos+1);\r
  48                 return r;\r
  49         end\r
  50         local function read_before(str)\r
  51                 local pos = data:find(str, nil, true);\r
  52                 while not pos do\r
  53                         data = data..coroutine.yield();\r
  54                         pos = data:find(str, nil, true);\r
  55                 end\r
  56                 local r = data:sub(1, pos-1);\r
  57                 data = data:sub(pos);\r
  58                 return r;\r
  59         end\r
  60         local function peek()\r
  61                 while #data == 0 do data = coroutine.yield(); end\r
  62                 return data:sub(1,1);\r
  63         end\r
  64         \r
  65         local ns = { xml = "http://www.w3.org/XML/1998/namespace" };\r
  66         ns.__index = ns;\r
  67         local function apply_ns(name, dodefault)\r
  68                 local prefix,n = name:match("^([^:]*):(.*)$");\r
  69                 if prefix and ns[prefix] then\r
  70                         return ns[prefix]..ns_separator..n;\r
  71                 end\r
  72                 if dodefault and ns[""] then\r
  73                         return ns[""]..ns_separator..name;\r
  74                 end\r
  75                 return name;\r
  76         end\r
  77         local function push(tag, attr)\r
  78                 ns = setmetatable({}, ns);\r
  79                 for k,v in pairs(attr) do\r
  80                         local xmlns = k == "xmlns" and "" or k:match("^xmlns:(.*)$");\r
  81                         if xmlns then\r
  82                                 ns[xmlns] = v;\r
  83                                 attr[k] = nil;\r
  84                         end\r
  85                 end\r
  86                 local newattr, n = {}, 0;\r
  87                 for k,v in pairs(attr) do\r
  88                         n = n+1;\r
  89                         k = apply_ns(k);\r
  90                         newattr[n] = k;\r
  91                         newattr[k] = v;\r
  92                 end\r
  93                 tag = apply_ns(tag, true);\r
  94                 ns[0] = tag;\r
  95                 ns.__index = ns;\r
  96                 return tag, newattr;\r
  97         end\r
  98         local function pop()\r
  99                 local tag = ns[0];\r
 100                 ns = getmetatable(ns);\r
 101                 return tag;\r
 102         end\r
 103         \r
 104         while true do\r
 105                 if peek() == "<" then\r
 106                         local elem = read_until(">"):sub(2,-2);\r
 107                         if elem:sub(1,1) == "!" or elem:sub(1,1) == "?" then -- neglect comments and processing-instructions\r
 108                         elseif elem:sub(1,1) == "/" then -- end tag\r
 109                                 elem = elem:sub(2);\r
 110                                 local name = pop();\r
 111                                 handlers:EndElement(name); -- TODO check for start-end tag name match\r
 112                         elseif elem:sub(-1,-1) == "/" then -- empty tag\r
 113                                 elem = elem:sub(1,-2);\r
 114                                 local name,attr = parse_tag(elem);\r
 115                                 name,attr = push(name,attr);\r
 116                                 handlers:StartElement(name,attr);\r
 117                                 name = pop();\r
 118                                 handlers:EndElement(name);\r
 119                         else -- start tag\r
 120                                 local name,attr = parse_tag(elem);\r
 121                                 name,attr = push(name,attr);\r
 122                                 handlers:StartElement(name,attr);\r
 123                         end\r
 124                 else\r
 125                         local text = read_before("<");\r
 126                         handlers:CharacterData(xml_unescape(text));\r
 127                 end\r
 128         end\r
 129 end\r
 130 \r
 131 function new(handlers, ns_separator)\r
 132         local co = coroutine.create(parser);\r
 133         return {\r
 134                 parse = function(self, data)\r
 135                         if not data then\r
 136                                 co = deadroutine;\r
 137                                 return true; -- eof\r
 138                         end\r
 139                         local success, result = coroutine.resume(co, data, handlers, ns_separator);\r
 140                         if result then\r
 141                                 co = deadroutine;\r
 142                                 return nil, result; -- error\r
 143                         end\r
 144                         return true; -- success\r
 145                 end;\r
 146         };\r
 147 end\r
 148 \r
 149 return _M;\r