mod_storage_appendmap/mod_storage_appendmap.lua

   1 local dump = require "util.serialization".serialize;
   2 local load = require "util.envload".envloadfile;
   3 local dm = require "core.storagemanager".olddm;
   4
   5 local REMOVE = {}; -- Special value for removing keys
   6
   7 local driver = {};
   8
   9
  10 local keywords = {
  11         ["do"] = true; ["and"] = true; ["else"] = true; ["break"] = true;
  12         ["if"] = true; ["end"] = true; ["goto"] = true; ["false"] = true;
  13         ["in"] = true; ["for"] = true; ["then"] = true; ["local"] = true;
  14         ["or"] = true; ["nil"] = true; ["true"] = true; ["until"] = true;
  15         ["elseif"] = true; ["function"] = true; ["not"] = true;
  16         ["repeat"] = true; ["return"] = true; ["while"] = true;
  17
  18         -- _ENV is not technically a keyword but we need to treat it as such
  19         ["_ENV"] = true;
  20 };
  21
  22 local function is_usable_identifier(s)
  23         return type(s) == "string" and not keywords[s] and s:find("^[%a_][%w_]*$");
  24 end
  25
  26 local function serialize_key(key)
  27         if is_usable_identifier(key) then
  28                 return key;
  29         else
  30                 return "_ENV[" .. dump(key) .. "]";
  31         end
  32 end
  33
  34 local function serialize_value(value)
  35         if value == REMOVE then
  36                 return "nil";
  37         else
  38                 return dump(value);
  39         end
  40 end
  41
  42 local function serialize_pair(key, value)
  43         key = serialize_key(key);
  44         value = serialize_value(value);
  45         return key .. " = " .. value .. ";\n";
  46 end
  47
  48 local function serialize_map(keyvalues)
  49         local keys, values = {}, {};
  50         for key, value in pairs(keyvalues) do
  51                 key = serialize_key(key);
  52                 value = serialize_value(value);
  53                 table.insert(keys, key);
  54                 table.insert(values, value);
  55         end
  56         return table.concat(keys, ", ") .. " = " .. table.concat(values, ", ") .. ";\n";
  57 end
  58
  59 local map = { remove = REMOVE };
  60 local map_mt = { __index = map };
  61
  62 function map:get(user, key)
  63         module:log("debug", "map:get(%s, %s)", tostring(user), tostring(key))
  64         local filename = dm.getpath(user, module.host, self.store, "map");
  65         module:log("debug", "File is %s", filename);
  66         local env = {};
  67         if _VERSION == "Lua 5.1" then -- HACK
  68                 env._ENV = env; -- HACK
  69         end -- SO MANY HACKS
  70         local chunk, err, errno = load(filename, env);
  71         if not chunk then if errno == 2 then return end return chunk, err; end
  72         local ok, err = pcall(chunk);
  73         if not ok then return ok, err; end
  74         if _VERSION == "Lua 5.1" then -- HACK
  75                 env._ENV = nil; -- HACK
  76         end -- HACKS EVERYWHERE
  77         if key == nil then
  78                 return env;
  79         end
  80         return env[key];
  81 end
  82
  83 function map:set_keys(user, keyvalues)
  84         local data = serialize_map(keyvalues);
  85         return dm.append_raw(user, module.host, self.store, "map", data);
  86 end
  87
  88 function map:set(user, key, value)
  89         if _VERSION == "Lua 5.1" then
  90                 assert(key ~= "_ENV", "'_ENV' is a restricted key");
  91         end
  92         if key == nil then
  93                 local filename = dm.getpath(user, module.host, self.store, "map");
  94                 return os.remove(filename);
  95         end
  96         local data = serialize_pair(key, value);
  97         return dm.append_raw(user, module.host, self.store, "map", data);
  98 end
  99
 100 local keyval = { remove = REMOVE };
 101 local keyval_mt = { __index = keyval };
 102
 103 function keyval:get(user)
 104         return map.get(self, user, nil);
 105 end
 106
 107 function keyval:set(user, keyvalues)
 108         local data = serialize_map(keyvalues);
 109         return dm.store_raw(user, module.host, self.store, "map", data);
 110 end
 111
 112 -- TODO some kind of periodic compaction thing?
 113 function map:_compact(user)
 114         local data = self:get(user);
 115         return keyval.set(self, user, data);
 116 end
 117
 118 function driver:open(store, typ)
 119         if typ == "map" then
 120                 return setmetatable({ store = store, }, map_mt);
 121         elseif typ == nil or typ == "keyval" then
 122                 return setmetatable({ store = store, }, keyval_mt);
 123         end
 124         return nil, "unsupported-store";
 125 end
 126
 127 module:provides("storage", driver);
 128