diff options
| -rw-r--r-- | fallbacks/lxp.lua | 149 |
1 files changed, 149 insertions, 0 deletions
diff --git a/fallbacks/lxp.lua b/fallbacks/lxp.lua new file mode 100644 index 00000000..6d3297d1 --- /dev/null +++ b/fallbacks/lxp.lua @@ -0,0 +1,149 @@ + +local coroutine = coroutine; +local tonumber = tonumber; +local string = string; +local setmetatable, getmetatable = setmetatable, getmetatable; +local pairs = pairs; + +local deadroutine = coroutine.create(function() end); +coroutine.resume(deadroutine); + +module("lxp") + +local entity_map = setmetatable({ + ["amp"] = "&"; + ["gt"] = ">"; + ["lt"] = "<"; + ["apos"] = "'"; + ["quot"] = "\""; +}, {__index = function(_, s) + if s:sub(1,1) == "#" then + if s:sub(2,2) == "x" then + return string.char(tonumber(s:sub(3), 16)); + else + return string.char(tonumber(s:sub(2))); + end + end + end +}); +local function xml_unescape(str) + return (str:gsub("&(.-);", entity_map)); +end +local function parse_tag(s) + local name,sattr=(s):gmatch("([^%s]+)(.*)")(); + local attr = {}; + for a,b in (sattr):gmatch("([^=%s]+)=['\"]([^'\"]*)['\"]") do attr[a] = xml_unescape(b); end + return name, attr; +end + +local function parser(data, handlers, ns_separator) + local function read_until(str) + local pos = data:find(str, nil, true); + while not pos do + data = data..coroutine.yield(); + pos = data:find(str, nil, true); + end + local r = data:sub(1, pos); + data = data:sub(pos+1); + return r; + end + local function read_before(str) + local pos = data:find(str, nil, true); + while not pos do + data = data..coroutine.yield(); + pos = data:find(str, nil, true); + end + local r = data:sub(1, pos-1); + data = data:sub(pos); + return r; + end + local function peek() + while #data == 0 do data = coroutine.yield(); end + return data:sub(1,1); + end + + local ns = { xml = "http://www.w3.org/XML/1998/namespace" }; + ns.__index = ns; + local function apply_ns(name, dodefault) + local prefix,n = name:match("^([^:]*):(.*)$"); + if prefix and ns[prefix] then + return ns[prefix]..ns_separator..n; + end + if dodefault and ns[""] then + return ns[""]..ns_separator..name; + end + return name; + end + local function push(tag, attr) + ns = setmetatable({}, ns); + for k,v in pairs(attr) do + local xmlns = k == "xmlns" and "" or k:match("^xmlns:(.*)$"); + if xmlns then + ns[xmlns] = v; + attr[k] = nil; + end + end + local newattr, n = {}, 0; + for k,v in pairs(attr) do + n = n+1; + k = apply_ns(k); + newattr[n] = k; + newattr[k] = v; + end + tag = apply_ns(tag, true); + ns[0] = tag; + ns.__index = ns; + return tag, newattr; + end + local function pop() + local tag = ns[0]; + ns = getmetatable(ns); + return tag; + end + + while true do + if peek() == "<" then + local elem = read_until(">"):sub(2,-2); + if elem:sub(1,1) == "!" or elem:sub(1,1) == "?" then -- neglect comments and processing-instructions + elseif elem:sub(1,1) == "/" then -- end tag + elem = elem:sub(2); + local name = pop(); + handlers:EndElement(name); -- TODO check for start-end tag name match + elseif elem:sub(-1,-1) == "/" then -- empty tag + elem = elem:sub(1,-2); + local name,attr = parse_tag(elem); + name,attr = push(name,attr); + handlers:StartElement(name,attr); + name = pop(); + handlers:EndElement(name); + else -- start tag + local name,attr = parse_tag(elem); + name,attr = push(name,attr); + handlers:StartElement(name,attr); + end + else + local text = read_before("<"); + handlers:CharacterData(xml_unescape(text)); + end + end +end + +function new(handlers, ns_separator) + local co = coroutine.create(parser); + return { + parse = function(self, data) + if not data then + co = deadroutine; + return true; -- eof + end + local success, result = coroutine.resume(co, data, handlers, ns_separator); + if result then + co = deadroutine; + return nil, result; -- error + end + return true; -- success + end; + }; +end + +return _M; |