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 fs = require "nixio.fs"
  18 local util = require "luci.util"
  19 local nixio = require "nixio"
  20 local debug = require "debug"
  21 local string = require "string"
  22 local package = require "package"
  23
  24 local type, loadfile = type, loadfile
  25
  26
  27 module "luci.ccache"
  28
  29 function cache_ondemand(...)
  30         if debug.getinfo(1, 'S').source ~= "=?" then
  31                 cache_enable(...)
  32         end
  33 end
  34
  35 function cache_enable(cachepath, mode)
  36         cachepath = cachepath or "/tmp/luci-modulecache"
  37         mode = mode or "r--r--r--"
  38
  39         local loader = package.loaders[2]
  40         local uid    = nixio.getuid()
  41
  42         if not fs.stat(cachepath) then
  43                 fs.mkdir(cachepath)
  44         end
  45
  46         local function _encode_filename(name)
  47                 local encoded = ""
  48                 for i=1, #name do
  49                         encoded = encoded .. ("%2X" % string.byte(name, i))
  50                 end
  51                 return encoded
  52         end
  53
  54         local function _load_sane(file)
  55                 local stat = fs.stat(file)
  56                 if stat and stat.uid == uid and stat.modestr == mode then
  57                         return loadfile(file)
  58                 end
  59         end
  60
  61         local function _write_sane(file, func)
  62                 if nixio.getuid() == uid then
  63                         local fp = io.open(file, "w")
  64                         if fp then
  65                                 fp:write(util.get_bytecode(func))
  66                                 fp:close()
  67                                 fs.chmod(file, mode)
  68                         end
  69                 end
  70         end
  71
  72         package.loaders[2] = function(mod)
  73                 local encoded = cachepath .. "/" .. _encode_filename(mod)
  74                 local modcons = _load_sane(encoded)
  75
  76                 if modcons then
  77                         return modcons
  78                 end
  79
  80                 -- No cachefile
  81                 modcons = loader(mod)
  82                 if type(modcons) == "function" then
  83                         _write_sane(encoded, modcons)
  84                 end
  85                 return modcons
  86         end
  87 end