nodemcu-firmware/lua_examples/lfs/init.lua

99 lines
3.7 KiB
Lua

--
-- File: _init.lua
--[[
This is a template for the LFS equivalent of the SPIFFS init.lua.
It is a good idea to such an _init.lua module to your LFS and do most of the LFS
module related initialisaion in this. This example uses standard Lua features to
simplify the LFS API.
The first section adds a 'LFS' table to _G and uses the __index metamethod to
resolve functions in the LFS, so you can execute the main function of module
'fred' by executing LFS.fred(params), etc. It also implements some standard
readonly properties:
LFS._time The Unix Timestamp when the luac.cross was executed. This can be
used as a version identifier.
LFS._config This returns a table of useful configuration parameters, hence
print (("0x%6x"):format(LFS._config.lfs_base))
gives you the parameter to use in the luac.cross -a option.
LFS._list This returns a table of the LFS modules, hence
print(table.concat(LFS._list,'\n'))
gives you a single column listing of all modules in the LFS.
---------------------------------------------------------------------------------]]
local index = node.flashindex
local lfs_t = {
__index = function(_, name)
fn_ut, ba, ma, size, modules = index(name)
if not ba then
return fn_ut
elseif name == '_time' then
return fn_ut
elseif name == '_config' then
fs_ma, fs_size = file.fscfg()
return {lfs_base = ba, lfs_mapped = ma, lfs_size = size,
fs_mapped = fs_ma, fs_size = fs_size}
elseif name == '_list' then
return modules
else
return nil
end
end,
__newindex = function(_, name, value)
error("LFS is readonly. Invalid write to LFS." .. name, 2)
end,
}
_G.LFS = setmetatable(lfs_t,lfs_t)
--[[-------------------------------------------------------------------------------
The second section adds the LFS to the require searchlist, so that you can
require a Lua module 'jean' in the LFS by simply doing require "jean". However
note that this is at the search entry following the FS searcher, so if you also
have jean.lc or jean.lua in SPIFFS, then this SPIFFS version will get loaded into
RAM instead of using. (Useful, for development).
See docs/en/lfs.md and the 'loaders' array in app/lua/loadlib.c for more details.
---------------------------------------------------------------------------------]]
package.loaders[3] = function(module) -- loader_flash
fn, ba = index(module)
return ba and "Module not in LFS" or fn
end
--[[-------------------------------------------------------------------------------
You can add any other initialisation here, for example a couple of the globals
are never used, so setting them to nil saves a couple of global entries
---------------------------------------------------------------------------------]]
_G.module = nil -- disable Lua 5.0 style modules to save RAM
package.seeall = nil
--[[-------------------------------------------------------------------------------
These replaces the builtins loadfile & dofile with ones which preferentially
loads the corresponding module from LFS if present. Flipping the search order
is an exercise left to the reader.-
---------------------------------------------------------------------------------]]
lf, df = loadfile, dofile
_G.loadfile = function(n)
mod, ext = n:match("(.*)%.(l[uc]a?)");
fn, ba = index(mod)
if ba or (ext ~= 'lc' and ext ~= 'lua') then return lf(n) else return fn end
end
_G.dofile = function(n)
mod, ext = n:match("(.*)%.(l[uc]a?)");
fn, ba = index(mod)
if ba or (ext ~= 'lc' and ext ~= 'lua') then return df(n) else return fn() end
end