colddb/flatdb.lua
zengxiangbin 16c5401b2e fix #1
2017-10-25 16:10:49 +08:00

87 lines
1.6 KiB
Lua

local mp = require("MessagePack")
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)
path = string.gsub(path.."/", "//", "/")
local ok, err, code = os.rename(path, path)
if ok or code == 13 then
return true
end
return false
end
local function load_page(path)
local ret
local f = io.open(path, "rb")
if f then
ret = mp.unpack(f:read("*a"))
f:close()
end
return ret
end
local function store_page(path, page)
if type(page) == "table" then
local f = io.open(path, "wb")
if f then
f:write(mp.pack(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
})