colddb/flatdb.lua
2015-04-06 21:44:20 +08:00

71 lines
1.3 KiB
Lua

local lfs = require("lfs")
local pp = require("pp")
local function isFile(path)
return lfs.attributes(path, "mode") == "file"
end
local function isDir(path)
return lfs.attributes(path, "mode") == "directory"
end
local function load_book(path)
return dofile(path)
end
local function store_book(path, book)
if type(book) == "table" then
local f = io.open(path, "wb")
if f then
f:write("return ")
f:write(pp.format(book))
f:close()
return true
end
end
return false
end
local pool = {}
local db_funcs = {
save = function(db, bk)
if bk then
if type(bk) == "string" and type(db[bk]) == "table" then
return store_book(pool[db].."/"..bk, db[bk])
else
return false
end
end
for bk, book in pairs(db) do
store_book(pool[db].."/"..bk, book)
end
return true
end
}
local mt = {
__index = function(db, k)
if db_funcs[k] then return db_funcs[k] end
if isFile(pool[db].."/"..k) then
db[k] = load_book(pool[db].."/"..k)
end
return rawget(db, k)
end
}
pool.hack = db_funcs
return setmetatable(pool, {
__mode = "kv",
__call = function(pool, path)
if pool[path] then return pool[path] end
if not isDir(path) then return end
local db = {}
setmetatable(db, mt)
pool[path] = db
pool[db] = path
return db
end
})