colddb/flatdb.lua

84 lines
1.5 KiB
Lua

local pp = require("pp")
local function isFile(path)
local f = io.open(path, "r")
if f then
f:close()
return true
end
return false
end
local function isDir(path)
local tmp = path.."/"..os.tmpname()
local f = io.open(tmp, "w")
if f then
f:close()
os.remove(tmp)
return true
end
return false
end
local function load_page(path)
return dofile(path)
end
local function store_page(path, page)
if type(page) == "table" then
local f = io.open(path, "wb")
if f then
f:write("return ")
f:write(pp.format(page))
f:close()
return true
end
end
return false
end
local pool = {}
local db_funcs = {
save = function(db, p)
if p then
if type(p) == "string" and type(db[p]) == "table" then
return store_page(pool[db].."/"..p, db[p])
else
return false
end
end
for p, page in pairs(db) do
if not store_page(pool[db].."/"..p, page) then
return false
end
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_page(pool[db].."/"..k)
end
return rawget(db, k)
end
}
pool.hack = db_funcs
return setmetatable(pool, {
__mode = "kv",
__call = function(pool, path)
assert(isDir(path), path.." is not a directory.")
if pool[path] then return pool[path] end
local db = {}
setmetatable(db, mt)
pool[path] = db
pool[db] = path
return db
end
})