libs/core/luasrc/ccache.lua

   1 --[[
   2 LuCI - Lua Configuration Interface
   3
   4 Copyright 2008 Steven Barth <steven@midlink.org>
   5 Copyright 2008 Jo-Philipp Wich <xm@leipzig.freifunk.net>
   6
   7 Licensed under the Apache License, Version 2.0 (the "License");
   8 you may not use this file except in compliance with the License.
   9 You may obtain a copy of the License at
  10
  11 http://www.apache.org/licenses/LICENSE-2.0
  12
  13 $Id$
  14 ]]--
  15
  16 local io = require "io"
  17 local util = require "luci.util"
  18 local posix = require "posix"
  19 local debug = require "debug"
  20 local string = require "string"
  21 local package = require "package"
  22
  23 local type, loadfile = type, loadfile
  24
  25
  26 module "luci.ccache"
  27
  28 function cache_ondemand(...)
  29         if debug.getinfo(1, 'S').source ~= "=?" then
  30                 cache_enable(...)
  31         end
  32 end
  33
  34 function cache_enable(cachepath, mode)
  35         cachepath = cachepath or "/tmp/.luciccache"
  36         mode = mode or "r--r--r--"
  37
  38         local loader = package.loaders[2]
  39         local uid    = posix.getpid("uid")
  40
  41         if not posix.stat(cachepath) then
  42                 posix.mkdir(cachepath)
  43         end
  44
  45         local function _encode_filename(name)
  46                 local encoded = ""
  47                 for i=1, #name do
  48                         encoded = encoded .. ("%2X" % string.byte(name, i))
  49                 end
  50                 return encoded
  51         end
  52
  53         local function _load_sane(file)
  54                 local stat = posix.stat(file)
  55                 if stat and stat.uid == uid and stat.mode == mode then
  56                         return loadfile(file)
  57                 end
  58         end
  59
  60         local function _write_sane(file, func)
  61                 if posix.getpid("uid") == uid then
  62                         local fp = io.open(file, "w")
  63                         if fp then
  64                                 fp:write(util.get_bytecode(func))
  65                                 fp:close()
  66                                 posix.chmod(file, mode)
  67                         end
  68                 end
  69         end
  70
  71         package.loaders[2] = function(mod)
  72                 local encoded = cachepath .. "/" .. _encode_filename(mod)
  73                 local modcons = _load_sane(encoded)
  74
  75                 if modcons then
  76                         return modcons
  77                 end
  78
  79                 -- No cachefile
  80                 modcons = loader(mod)
  81                 if type(modcons) == "function" then
  82                         _write_sane(encoded, modcons)
  83                 end
  84                 return modcons
  85         end
  86 end