MV源码解析之存档序列化与反序列化 - Project1

DataManager.makeSaveContents = function() {
// A save data does not contain $gameTemp, $gameMessage, and $gameTroop.
var contents = {};
contents.system = $gameSystem;
contents.screen = $gameScreen;
contents.timer = $gameTimer;
contents.switches = $gameSwitches;
contents.variables = $gameVariables;
contents.selfSwitches = $gameSelfSwitches;
contents.actors = $gameActors;
contents.party = $gameParty;
contents.map = $gameMap;
contents.player = $gamePlayer;
return contents;
};

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const stringify = value => {
// 初始化循环引用数组
const circular = [];
// 编码, 详情请阅下文
encode(value, circular);
// 将编码后的对象序列化
const string = JSON.stringify(value);
// 还原编码对象
restoreObject(value, circular);
// 返回字符串
return string;
};

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for (const key in value) {
encode(value[key], circular);
}

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const isPrimitive = o => o !== Object(o);

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const encode = (value, circular) => {
if (!isPrimitive(value)) {
circular.push(value);
value["@constructor"] = value.constructor.name;
value["@circularID"] = circular.length - 1;
for (const key in value) {
if (circular.includes(value[key])) {
value[key] = { "@reference": value[key]["@circularID"] };
} else {
encode(value[key], circular);
}
}
}
};

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const restoreObject = (value, circular) => {
if (!isPrimitive(value)) {
delete value["@constructor"];
delete value["@circularID"];
for (const key in value) {
const circularID = value[key]["@reference"];
if (circularID !== undefined) {
value[key] = circular[circularID];
} else {
restoreObject(value[key], circular);
}
}
}
};

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const parse = string => {
const value = JSON.parse(string);
const circular = [];
decode(value, circular);
return value;
};

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const decode = (value, circular) => {
if (!isPrimitive(value)) {
circular[value["@circularID"]] = value;
// 下面这一句可以改写来支持独立命名空间的类的访问
const constructor = window[value["@constructor"]] || Object;
Object.setPrototypeOf(value, constructor.prototype);
delete value["@constructor"];
delete value["@circularID"];
for (const key in value) {
const circularID = value[key]["@reference"];
if (circularID !== undefined) {
value[key] = circular[circularID];
} else {
decode(value[key], circular);
}
}
}
};

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const namespaces = [window];
const registerNamespace = namespaces.push.bind(namespaces);
const isPrimitive = o => o !== Object(o);
const encode = (value, circular) => {
if (!isPrimitive(value)) {
circular.push(value);
value["@constructor"] = value.constructor.name;
value["@circularID"] = circular.length - 1;
for (const key in value) {
if (circular.includes(value[key])) {
value[key] = { "@reference": value[key]["@circularID"] };
} else {
encode(value[key], circular);
}
}
}
};
const stringify = value => {
const circular = [];
encode(value, circular);
const string = JSON.stringify(value);
restoreObject(value, circular);
return string;
};
const restoreObject = (value, circular) => {
if (!isPrimitive(value)) {
delete value["@constructor"];
delete value["@circularID"];
for (const key in value) {
const circularID = value[key]["@reference"];
if (circularID !== undefined) {
value[key] = circular[circularID];
} else {
restoreObject(value[key], circular);
}
}
}
};
const parse = string => {
const value = JSON.parse(string);
const circular = [];
decode(value, circular);
return value;
};
const getConstructor = name => {
const constructor = namespaces.find(namespace =>
namespace.hasOwnProperty(name)
)[name];
if (constructor) {
return constructor;
}
return Object;
};
const decode = (value, circular) => {
if (!isPrimitive(value)) {
circular[value["@circularID"]] = value;
const constructor = getConstructor(value["@constructor"]);
Object.setPrototypeOf(value, constructor.prototype);
delete value["@constructor"];
delete value["@circularID"];
for (const key in value) {
const circularID = value[key]["@reference"];
if (circularID !== undefined) {
value[key] = circular[circularID];
} else {
decode(value[key], circular);
}
}
}
};
// 以下是测试
{
const obj = {};
obj.self = obj;
obj.array = ["a", "b", obj.self];
const string = stringify(obj);
console.debug(parse(string));
}

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