feat: rework serialization

Fixes #102

sonic-radiance.love/birb/classes/serializable/init.lua

@@ -0,0 +1,139 @@
+-- classes/serializable :: a serializable object, can give its field as data
+
+--[[
+  Copyright © 2021 Kazhnuz
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy of
+  this software and associated documentation files (the "Software"), to deal in
+  the Software without restriction, including without limitation the rights to
+  use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+  the Software, and to permit persons to whom the Software is furnished to do so,
+  subject to the following conditions:
+
+  The above copyright notice and this permission notice shall be included in all
+  copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+  FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+  COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+  IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+  CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+]]
+
+local Serializable = Object:extend()
+
+function Serializable:new(serializeFields, listSerializable)
+    self.serializeFields = serializeFields
+    self.listSerializable = listSerializable
+end
+
+function Serializable:getData()
+    local data = {}
+    -- We serialize all fields
+    if (self.serializeFields ~= nil) then
+        for _, key in ipairs(self.serializeFields) do
+            data[key] = self:wrapField(key)
+        end
+    end
+    -- We serialize all list of serializable 
+    if (self.listSerializable ~= nil) then
+        for _, key in ipairs(self.listSerializable) do
+            data[key] = self:wrapList(key)
+        end
+    end
+    return data
+end
+
+function Serializable:wrapField(key)
+    local serializedField = self[key]
+    if (serializedField ~= nil) then
+        if (type(serializedField) == "table" and serializedField.is ~= nil) then
+            if (serializedField:is(Serializable)) then
+                serializedField = serializedField:getData()
+                serializedField.isSerializable = true
+            end
+        end
+        self:print(key, serializedField, false)
+        return serializedField
+    end
+end
+
+function Serializable:wrapList(key)
+    local serializedList = {}
+    serializedList.isListSerializable = true
+    for listKey, listElement in pairs(self[key]) do
+        serializedList[listKey] = listElement:getData()
+    end
+    self:print(key, serializedList, false)
+    return serializedList
+end
+
+function Serializable:setData(data)
+    for key, value in pairs(data) do
+        if (key ~= "serializedField") then
+            self:unwrapField(key, value)
+        end
+    end
+    self:finishDeserialization()
+end
+
+function Serializable:unwrapField(key, value)
+    local serializedField = value
+    if (serializedField ~= nil) then
+        if (type(serializedField) == "table") then
+            if (serializedField.isSerializable == true) then
+                self[key]:setData(serializedField)
+            elseif (serializedField.isListSerializable) then
+                self:unwrapList(key, serializedField)
+            else
+                self[key] = serializedField or self[key]
+            end
+        else
+            self[key] = serializedField or self[key]
+            self:print(key, serializedField, true)
+        end
+    end
+end
+
+function Serializable:unwrapList(key, list)
+    if (list == nil) then
+        error("List " .. key .. " shouldn't be null in the save")
+    end
+    for listKey, listElement in pairs(list) do
+        if (listKey ~= "isListSerializable") then
+            self[key][listKey]:setData(listElement)
+        end
+    end
+    self:print(key, list, true)
+end
+
+function Serializable:print(key, value, isLoading)
+    local loadString = "Loading "
+    if (isLoading == false) then
+        loadString = "Saving "
+    end
+    local valueString = value
+    if type(valueString) == "boolean" then
+        if valueString then
+            valueString = "true"
+        else
+            valueString = "false"
+        end
+    end
+    if (type(value) == "table") then
+        valueString = utils.table.toString(value)
+    end
+    loadString = loadString .. key .. " " .. ": " .. valueString
+    if (core ~= nil) then
+        core.debug:debug("serializable", loadString)
+    else
+        print("serializable", loadString)
+    end
+end
+
+function Serializable:finishDeserialization()
+    -- Empty function callback
+end
+
+return Serializable

sonic-radiance.love/birb/classes/serializable/serializer.lua

@@ -0,0 +1,73 @@
+-- classes/serializable/serializer :: a serializer, able to put stuff into a bin file
+
+--[[
+  Copyright © 2021 Kazhnuz
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy of
+  this software and associated documentation files (the "Software"), to deal in
+  the Software without restriction, including without limitation the rights to
+  use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+  the Software, and to permit persons to whom the Software is furnished to do so,
+  subject to the following conditions:
+
+  The above copyright notice and this permission notice shall be included in all
+  copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+  FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+  COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+  IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+  CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+]]
+local Serializable = require "birb.classes.serializable"
+local Serializer = Serializable:extend()
+local binser = require("birb.libs.binser")
+
+function Serializer:new(serializeFields, listSerializable)
+    Serializer.super.new(self, serializeFields, listSerializable)
+end
+
+function Serializer:reset()
+
+end
+
+function Serializer:delete(filename)
+    local filepath = self:getFile(true, filename)
+    if utils.filesystem.exists(filename) then
+        love.filesystem.remove(filepath)
+    end
+end
+
+function Serializer:deserialize(filename)
+    local filepath = self:getFile(true, filename)
+    if utils.filesystem.exists(filename) then
+        local loadedDatas = binser.readFile(filepath)
+        self:setData(loadedDatas[1])
+    else
+        self:reset()
+    end
+end
+
+function Serializer:serialize(filename)
+    local data = self:getData()
+
+    local filepath = self:getFile(true, filename)
+    binser.writeFile(filepath, data)
+end
+
+function Serializer:getFile(absolute, filename)
+    local dir = ""
+    if absolute then
+        dir = love.filesystem.getSaveDirectory() .. "/"
+        if (not utils.filesystem.exists(dir)) then
+            love.filesystem.createDirectory("")
+        end
+    end
+
+    local filepath = dir .. filename
+
+    return filepath
+end
+
+return Serializer

sonic-radiance.love/birb/core/options.lua

@@ -21,26 +21,30 @@
   IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
   CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 ]]
-
-local OptionsManager = Object:extend()
-
-local binser = require("birb.libs.binser")
+local Serializer = require "birb.classes.serializable.serializer"
+local OptionsManager = Serializer:extend()
 
 local TRANSLATION_PATH = "datas/languages/"
 
+local OPTION_FILE = "options.data"
+
 -- INIT FUNCTIONS
 -- Initialize and configure the game options
 
 function OptionsManager:new(controller)
+  OptionsManager.super.new(self, {"data"})
+
   self.controller = controller
   -- We begin by creating an empty data table before reading the data.
-  self.data = {}
+  self:reset()
   self:read()
 end
 
 function OptionsManager:reset()
   local conf = self.controller:getDefaultConf()
   -- Reset the option to the game defaults.
+  self.data = {}
+
   self.data.video = {}
   self.data.video.crtfilter   = (conf.window.crtfilter == true)
   self.data.video.resolution  = conf.window.resolution or 1
@@ -62,20 +66,6 @@ end
 -- INFO FUNCTIONS
 -- Get informations from the option managers
 
-function OptionsManager:getFile(absolute)
-  local dir = ""
-  if absolute then
-    dir = love.filesystem.getSaveDirectory() .. "/"
-    if not utils.filesystem.exists(dir) then
-      love.filesystem.createDirectory( "" )
-    end
-  end
-
-  local filepath = dir .. "options.data"
-
-  return filepath
-end
-
 function OptionsManager:getInputDefaultData()
   local _path = "datas/inputs.lua"
   local datas = {}
@@ -142,30 +132,11 @@ end
 -- FIXME: maybe subclass a special module for that ?
 
 function OptionsManager:write()
-  local data = self:getData()
-
-  local filepath = self:getFile(true)
-  binser.writeFile(filepath, data)
+  self:serialize(OPTION_FILE)
 end
 
 function OptionsManager:read()
-  local filepath = self:getFile(true)
-  if utils.filesystem.exists("options.data") then
-    local loadedDatas = binser.readFile(filepath)
-    self.controller.debug:print("core/options", "data file found, loading it")
-    self:setData(loadedDatas[1])
-  else
-    self:reset()
-    self.controller.debug:print("core/options", "no data file found, reseting data")
-  end
-end
-
-function OptionsManager:getData(data)
-  return self.data
-end
-
-function OptionsManager:setData(data)
-  self.data = data
+  self:deserialize(OPTION_FILE)
 end
 
 return OptionsManager

sonic-radiance.love/game/abstractmobs/character/datas.lua

@@ -8,34 +8,4 @@ function CharacterData:getCommonData()
     self.turns = self.data.turns
 end
 
-function CharacterData:getData()
-    local data = {}
-    data.simplename = self.simplename
-    data.level = self.level
-    data.exp = self.exp
-    data.exp_next = self.exp_next
-    data.hp = self.hp
-    data.pp = self.pp
-    data.statuts = self.statuts
-    data.equip = self.equip
-
-    return data
-end
-
-function CharacterData:setData(data)
-    self.simplename = data.simplename
-    self:getCommonData()
-
-    self.level = data.level
-    self.exp = data.exp
-    self.exp_next = data.exp_next
-
-    self.hp = data.hp
-    self.pp = data.pp
-    self.statuts = data.statuts
-
-    self.equip = data.equip
-    self:createStats()
-end
-
 return CharacterData

sonic-radiance.love/game/abstractmobs/character/init.lua

@@ -12,7 +12,7 @@ AbstractCharacter:implement(CharacterEquip)
 
 function AbstractCharacter:new(name)
     self.simplename = name
-    self.super.new(self)
+    self.super.new(self, {"simplename", "level", "exp", "exp_next", "hp", "pp", "statuts", "equip"})
 end
 
 function AbstractCharacter:initBasicElements()
@@ -72,4 +72,8 @@ function AbstractCharacter:createSkills()
     return learnedlist
 end
 
+function AbstractCharacter:finishDeserialization()
+    self:createStats()
+end
+
 return AbstractCharacter

sonic-radiance.love/game/abstractmobs/parent.lua

@@ -1,11 +1,13 @@
-local AbstractMobParent = Object:extend()
+local Serializable = require "birb.classes.serializable"
+local AbstractMobParent = Serializable:extend()
 
-function AbstractMobParent:new()
+function AbstractMobParent:new(serializeFields, listSerializable)
   self:initBasicElements()
   self.stats = self:createStats()
   self.skills = self:createSkills()
   self.statuts = {}
   self:initLife()
+  AbstractMobParent.super.new(self, serializeFields, listSerializable)
 end
 
 function AbstractMobParent:initBasicElements()

sonic-radiance.love/game/characters.lua

@@ -22,7 +22,8 @@
   CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 ]]
 
-local CharacterManager = Object:extend()
+local Serializable = require "birb.classes.serializable"
+local CharacterManager = Serializable:extend()
 
 local charutils = require "game.utils.characters"
 local AbstractCharacter = require "game.abstractmobs.character"
@@ -35,6 +36,7 @@ function CharacterManager:new(controller)
   self.team     = startdata.baseteam
   self.active   = 1
   self:init()
+  CharacterManager.super.new(self, {"team"}, {"list"}, {list = AbstractCharacter})
 end
 
 function CharacterManager:init()
@@ -80,11 +82,9 @@ end
 function CharacterManager:setData(data)
   local data = data
   self.team = data.team
-  self.list = {}
   for name, charData in pairs(data.list) do
-    local character = AbstractCharacter(name)
-    character:setData(charData)
-    self.list[name] = character
+    print(self.list[name])
+    self.list[name]:setData(charData)
   end
 end
 

sonic-radiance.love/game/difficulty.lua

@@ -1,4 +1,5 @@
-local Difficulty = Object:extend()
+local Serializable = require "birb.classes.serializable"
+local Difficulty = Serializable:extend()
 
 function Difficulty:new()
     self.toggles = {}
@@ -8,6 +9,7 @@ function Difficulty:new()
     self.toggles.checkPointRegen = false
     self.toggles.levelUpHeal = false
     self.toggles.allDamage = true
+    Difficulty.super.new(self, {"toggles"})
 end
 
 function Difficulty:toggle(toggleName)
@@ -18,12 +20,4 @@ function Difficulty:get(toggleName)
     return self.toggles[toggleName]
 end
 
-function Difficulty:getData()
-    return self.toggles
-end
-
-function Difficulty:setData(toggles)
-    self.toggles = toggles
-end
-
 return Difficulty

sonic-radiance.love/game/init.lua

@@ -23,13 +23,16 @@
   CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 ]]
 
-local Game        = Object:extend()
+local Serializer  = require "birb.classes.serializable.serializer"
+
+local Game        = Serializer:extend()
 local Characters  = require "game.characters"
 local Ennemies    = require "game.ennemies"
 local Skills      = require "game.skills"
 local Loot        = require "game.loot"
 local CBSCore     = require "game.battle"
 local Difficulty  = require "game.difficulty"
+local Metadata    = require "game.metadata"
 
 local binser      = require "birb.libs.binser"
 
@@ -38,11 +41,25 @@ local startdata   = require "datas.gamedata.startdata"
 Game.utils  = require "game.modules.utils"
 Game.gui    = require "game.modules.gui"
 
+local VAR_TO_SERIALIZE = {
+  "gametime",
+  "destroyedGizmo",
+  "variables",
+  "flags",
+  "position",
+  "actions",
+  "characters",
+  "loot",
+  "difficulty"
+}
+
 function Game:new()
   self.slot = -1
   self.slotNumber = 3
   self.version = core.conf.gameversion or "N/A"
-  self:resetData()
+  self:reset()
+  self.metadata = Metadata(self)
+  Game.super.new(self, VAR_TO_SERIALIZE)
 end
 
 function Game:initPosition()
@@ -52,34 +69,6 @@ function Game:initPosition()
   self.position.area = startdata.position.area
 end
 
-function Game:setData(data)
-  local data = data
-  self.gametime   = data.gametime
-  self.destroyedGizmo = data.destroyedGizmo
-  self.variables = data.variables
-  self.flags = data.flags
-  self.position = data.position
-  self.actions = data.actions
-  self.characters:setData(data.characters)
-  self.loot:setData(data.loot)
-  self.difficulty:setData(data.difficulty)
-end
-
-function Game:getData()
-  local data = {}
-  data.gametime   = self.gametime
-  data.characters = self.characters:getData()
-  data.loot = self.loot:getData()
-  data.difficulty = self.difficulty:getData()
-  data.flags = self.flags
-  data.destroyedGizmo = self.destroyedGizmo
-  data.variables = self.variables
-  data.position = self.position
-  data.actions = self.actions
-
-  return data
-end
-
 function Game:getMetadataFile(absolute)
   local dir = ""
   if absolute then
@@ -95,50 +84,10 @@ function Game:getMetadataFile(absolute)
 end
 
 function Game:getMetadata()
-  local metadata = {}
-  local filepath = self:getMetadataFile(true)
-  if utils.filesystem.exists("metadata.save") then
-    metadata = binser.readFile(filepath)[1]
-  else
-    metadata = self:newMetadata()
-  end
-  return metadata
+  return self.metadata:get()
 end
 
-function Game:newMetadata()
-  local metadata = {}
-  for i = 1, self.slotNumber, 1 do
-    local newMetadata = {}
-    newMetadata.exist = false
-    newMetadata.completion = 0
-    newMetadata.gametime = 0
-    newMetadata.team = {}
-    newMetadata.rings = 0
-    newMetadata.emeralds = 0
-    newMetadata.location = ""
-    table.insert(metadata, newMetadata)
-  end
-  return metadata
-end
-
-function Game:writeMetadata(metadata)
-  local filepath = self:getMetadataFile(true)
-  binser.writeFile(filepath, metadata)
-end
-
-function Game:addtoMetadata()
-  local metadata = self:getMetadata()
-  metadata[self.slot].exist = true
-  metadata[self.slot].completion = self.completion
-  metadata[self.slot].gametime = self.gametime
-  metadata[self.slot].team = self.characters.team
-  metadata[self.slot].rings = self.loot.rings
-  metadata[self.slot].emeralds = 0
-  metadata[self.slot].location = self.mapName
-  self:writeMetadata(metadata)
-end
-
-function Game:resetData()
+function Game:reset()
   self.gametime = 0
 
   self.characters = Characters(self)
@@ -158,12 +107,6 @@ function Game:resetData()
   self.actions = startdata.actions
 end
 
-function Game:removeFromMetadata()
-  local metadata = self:getMetadata()
-  metadata[self.slot].exist = false
-  self:writeMetadata(metadata)
-end
-
 function Game:reload()
   self:read(self.slot)
 end
@@ -171,57 +114,32 @@ end
 function Game:read(save_id)
   self.slot = save_id
   if (self.slot > 0) then
-    local filepath = self:getSaveFile(self.slot, true)
-    if utils.filesystem.exists("save" .. self.slot .. ".save") then
-      local loadedDatas = binser.readFile(filepath)
-
-      self:setData(loadedDatas[1])
-    else
-      self:resetData()
-    end
+    self:deserialize(self:getSaveName())
   end
 end
 
 function Game:deleteCurrentSave()
   if (self.slot > 0) then
-
-    local filepath = self:getSaveFile(self.slot, false)
-    local success = love.filesystem.remove(filepath)
-    print(success)
-    self:removeFromMetadata()
+    self:delete(self:getSaveName())
+    self.metadata:remove(self.slot)
   end
 end
 
 function Game:write()
   if (self.slot > 0) then
-    local data = self:getData()
-
-    local filepath = self:getSaveFile(self.slot, true)
-    binser.writeFile(filepath, data)
-    self:addtoMetadata()
+    self:serialize(self:getSaveName())
+    self.metadata:update()
   end
 end
 
-function Game:getSaveFile(saveslot, absolute)
-  local dir = ""
-  if absolute then
-    dir = love.filesystem.getSaveDirectory() .. "/"
-    if not utils.filesystem.exists(dir) then
-      love.filesystem.createDirectory( "" )
-    end
-  end
-
-  local filepath = dir .. "save" .. saveslot .. ".save"
-
-  return filepath
+function Game:getSaveName(saveslot)
+  local saveslot = saveslot or self.slot
+  return "save" .. saveslot .. ".save"
 end
 
 function Game:resetSaves()
   for i=1, self.slotNumber do
-    local filepath = self:getSaveFile(i, true)
-    if utils.filesystem.exists("save" .. i .. ".save") then
-      love.filesystem.remove( "save" .. i .. ".save" )
-    end
+    self:delete(self:getSaveName(i))
   end
 end
 

sonic-radiance.love/game/loot/init.lua

@@ -1,4 +1,5 @@
-local LootManager = Object:extend()
+local Serializable = require "birb.classes.serializable"
+local LootManager = Serializable:extend()
 local Pocket = require "game.loot.pocket"
 local EffectManager = require "game.loot.effectManager"
 
@@ -12,24 +13,7 @@ function LootManager:new(controller)
   self.effects = EffectManager()
 
   self:generatePockets()
-end
-
-function LootManager:getData()
-  local data = {}
-  data.rings = self.rings
-  data.inventory = {}
-  for i, pocket in ipairs(self.inventory) do
-    data.inventory[i] = pocket:getData()
-  end
-  return data
-end
-
-function LootManager:setData(data)
-  local data = data
-  self.rings = data.rings
-  for i, pocket in ipairs(self.inventory) do
-    pocket:setData(data.inventory[i])
-  end
+  LootManager.super.new(self, {}, {"inventory"})
 end
 
 function LootManager:generatePockets()

sonic-radiance.love/game/loot/pocket.lua

@@ -1,4 +1,5 @@
-local Pocket = Object:extend()
+local Serializable = require "birb.classes.serializable"
+local Pocket = Serializable:extend()
 
 function Pocket:new(pocketdata)
   self.name = pocketdata.name
@@ -7,14 +8,7 @@ function Pocket:new(pocketdata)
   self.description = pocketdata.description
   self.isEquipement = pocketdata.isEquipement
   self.list = {}
-end
-
-function Pocket:getData()
-  return self.list
-end
-
-function Pocket:setData(data)
-  self.list = data
+  Pocket.super.new(self, {"list"})
 end
 
 function Pocket:addItem(item, number)

sonic-radiance.love/game/metadata.lua

@@ -0,0 +1,83 @@
+-- game.metadata :: Basic metadata subsystem
+
+--[[
+  Copyright © 2021 Kazhnuz
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy of
+  this software and associated documentation files (the "Software"), to deal in
+  the Software without restriction, including without limitation the rights to
+  use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+  the Software, and to permit persons to whom the Software is furnished to do so,
+  subject to the following conditions:
+
+  The above copyright notice and this permission notice shall be included in all
+  copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+  FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+  COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+  IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+  CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+]]
+
+local Serializer = require "birb.classes.serializable.serializer"
+local Metadata = Serializer:extend()
+
+local META_FILE = "metadata.save"
+
+function Metadata:new(game)
+    self.game = game
+    self:reset()
+    Metadata.super.new(self, {"data"})
+end
+
+function Metadata:reset()
+    self.data = {}
+    for i = 1, self.game.slotNumber, 1 do
+        local newMetadata = {}
+        newMetadata.exist = false
+        newMetadata.completion = 0
+        newMetadata.gametime = 0
+        newMetadata.team = {}
+        newMetadata.rings = 0
+        newMetadata.emeralds = 0
+        newMetadata.location = ""
+        table.insert(self.data, newMetadata)
+    end
+end
+
+function Metadata:update()
+    self:read()
+    if (self.data[self.game.slot] == nil) then
+        self.data[self.game.slot] = {}
+    end
+    self.data[self.game.slot].exist = true
+    self.data[self.game.slot].completion = self.game.completion
+    self.data[self.game.slot].gametime = self.game.gametime
+    self.data[self.game.slot].team = self.game.characters.team
+    self.data[self.game.slot].rings = self.game.loot.rings
+    self.data[self.game.slot].emeralds = 0
+    self.data[self.game.slot].location = self.game.mapName
+    self:write()
+end
+
+function Metadata:get()
+    self:read()
+    return self.data
+end
+
+function Metadata:write()
+    self:serialize(META_FILE)
+end
+
+function Metadata:read()
+    self:deserialize(META_FILE)
+end
+
+function Metadata:remove(slot)
+    self.data[slot].exist = false
+    self:write()
+  end
+
+return Metadata