util/template.lua

   1 -- luacheck: ignore 213/i
   2 local stanza_mt = require "util.stanza".stanza_mt;
   3 local setmetatable = setmetatable;
   4 local pairs = pairs;
   5 local ipairs = ipairs;
   6 local error = error;
   7 local envload = require "util.envload".envload;
   8 local debug = debug;
   9 local t_remove = table.remove;
  10 local parse_xml = require "util.xml".parse;
  11
  12 local _ENV = nil;
  13 -- luacheck: std none
  14
  15 local function trim_xml(stanza)
  16         for i=#stanza,1,-1 do
  17                 local child = stanza[i];
  18                 if child.name then
  19                         trim_xml(child);
  20                 else
  21                         child = child:gsub("^%s*", ""):gsub("%s*$", "");
  22                         stanza[i] = child;
  23                         if child == "" then t_remove(stanza, i); end
  24                 end
  25         end
  26 end
  27
  28 local function create_string_string(str)
  29         str = ("%q"):format(str);
  30         str = str:gsub("{([^}]*)}", function(s)
  31                 return '"..(data["'..s..'"]or"").."';
  32         end);
  33         return str;
  34 end
  35 local function create_attr_string(attr, xmlns)
  36         local str = '{';
  37         for name,value in pairs(attr) do
  38                 if name ~= "xmlns" or value ~= xmlns then
  39                         str = str..("[%q]=%s;"):format(name, create_string_string(value));
  40                 end
  41         end
  42         return str..'}';
  43 end
  44 local function create_clone_string(stanza, lookup, xmlns)
  45         if not lookup[stanza] then
  46                 local s = ('setmetatable({name=%q,attr=%s,tags={'):format(stanza.name, create_attr_string(stanza.attr, xmlns));
  47                 -- add tags
  48                 for i,tag in ipairs(stanza.tags) do
  49                         s = s..create_clone_string(tag, lookup, stanza.attr.xmlns)..";";
  50                 end
  51                 s = s..'};';
  52                 -- add children
  53                 for i,child in ipairs(stanza) do
  54                         if child.name then
  55                                 s = s..create_clone_string(child, lookup, stanza.attr.xmlns)..";";
  56                         else
  57                                 s = s..create_string_string(child)..";"
  58                         end
  59                 end
  60                 s = s..'}, stanza_mt)';
  61                 s = s:gsub('%.%.""', ""):gsub('([=;])""%.%.', "%1"):gsub(';"";', ";"); -- strip empty strings
  62                 local n = #lookup + 1;
  63                 lookup[n] = s;
  64                 lookup[stanza] = "_"..n;
  65         end
  66         return lookup[stanza];
  67 end
  68 local function create_cloner(stanza, chunkname)
  69         local lookup = {};
  70         local name = create_clone_string(stanza, lookup, "");
  71         local src = "local setmetatable,stanza_mt=...;return function(data)";
  72         for i=1,#lookup do
  73                 src = src.."local _"..i.."="..lookup[i]..";";
  74         end
  75         src = src.."return "..name..";end";
  76         local f,err = envload(src, chunkname);
  77         if not f then error(err); end
  78         return f(setmetatable, stanza_mt);
  79 end
  80
  81 local template_mt = { __tostring = function(t) return t.name end };
  82 local function create_template(templates, text)
  83         local stanza, err = parse_xml(text);
  84         if not stanza then error(err); end
  85         trim_xml(stanza);
  86
  87         local info = debug.getinfo(3, "Sl");
  88         info = info and ("template(%s:%d)"):format(info.short_src:match("[^\\/]*$"), info.currentline) or "template(unknown)";
  89
  90         local template = setmetatable({ apply = create_cloner(stanza, info), name = info, text = text }, template_mt);
  91         templates[text] = template;
  92         return template;
  93 end
  94
  95 local templates = setmetatable({}, { __mode = 'k', __index = create_template });
  96 return function(text)
  97         return templates[text];
  98 end;