我正在尝试编写一个高级网络库(主要是为了好玩)，用户可以通过派生类轻松定义他们的数据包。这种解析消息的方式非常容易。用户数据包应该只包含基本值 types .
为此，我需要访问每个用户定义数据包的每个字段。这个问题可以很容易地通过反射来解决，但是由于反射非常慢，我不能使用它。为了快速做到这一点，我创建了一个类来在运行时为每个用户定义的数据包字段注入(inject) getter 和 setter(在 StackOverflow 的某处找到)。 setter/getter 是 Func<UserDefinedPacket, fieldType>和 setter 是 Action<UserDefinedPAcket, setValue> .
问题是:因为用户数据包是在另一个程序集中定义的，所以我不可能在编译时知道 getter 或 setter 的类型。我可以用于 getter 和 setter 的最派生类是 Delegate .这意味着我只能使用 DynamicInvoke，所以我再次进行反射...但是因为我知道这些方法实际上是 Funcs 和 Actions 但实际上不能强制转换它们，所以我可以使用动态类型并调用 Invoke。动态类型将性能提高了大约 5 倍，但与普通字段访问(快大约 100 倍)相比，设置和获取值仍然很慢，这使得该库无法使用。
最终我希望能够将用户定义的类转换为字节数组。我也不想序列化这个类，因为序列化包含一些我不想通过网络发送的垃圾数据，而且序列化看起来很慢。
问题来了:我真的可以让 GetVaue 和 SetValue 方法更快吗？我尝试将委托(delegate)转换为所需的函数/操作(在库中移动了自定义数据包类，所以这不好)并且 setter 花费了大约 50 毫秒而不是 300 毫秒。我希望获得通用数据包的性能。
namespace MirrorNet
{
// Base class for packets
// This will be derived by users and should only contain basic type fields
public class UserPacket
{
}
public class MirrorNetManager
{
private static MirrorNetManager instance = new MirrorNetManager();
public static MirrorNetManager Instance
{
get { return instance; }
}
// Dictionary: packetType -> field -> getter | setter
private class PropertyDictionary : Dictionary<Type, Dictionary<FieldInfo, Delegate>>
{
}
private Dictionary<int, PacketConstructor> m_packetConstructors = new Dictionary<int, PacketConstructor>();
private PropertyDictionary m_packetFieldGetters = new PropertyDictionary();
private PropertyDictionary m_packetFieldSetters = new PropertyDictionary();
public void SetValue(UserPacket packet, FieldInfo field, object value)
{
var setDelegate = m_packetFieldSetters[packet.GetType()][field];
dynamic setAction = setDelegate; //Convert.ChangeType(setDelegate, setDelegate.GetType());
dynamic setObject = packet; //Convert.ChangeType(packet, packet.GetType());
dynamic setValue = value; //Convert.ChangeType(value, value.GetType());
setAction.Invoke(setObject, setValue);
//setDelegate.DynamicInvoke(packet, value);
}
public object GetValue(UserPacket packet, FieldInfo field)
{
var getDelegate = m_packetFieldGetters[packet.GetType()][field];
dynamic getFunction = getDelegate; //Convert.ChangeType(getDelegate, getDelegate.GetType());
dynamic getObject = packet; //Convert.ChangeType(packet, packet.GetType());
return getFunction.Invoke(getObject);
//return getDelegate.DynamicInvoke(packet);
}
public void InitializePackets(Assembly packetsAssembly)
{
var typesArray = packetsAssembly.GetTypes();
foreach (Type type in typesArray)
{
if (type.BaseType == typeof(UserPacket))
{
InsertPacketConstructor(type);
InsertSettersAndGetters(type);
}
}
}
private void InsertPacketConstructor(Type packetType)
{
foreach (var member in packetType.GetFields())
{
Console.WriteLine(member);
// TODO: Implement
}
}
private void InsertSettersAndGetters(Type type)
{
Dictionary<FieldInfo, Delegate> getters = new Dictionary<FieldInfo, Delegate>();
Dictionary<FieldInfo, Delegate> setters = new Dictionary<FieldInfo, Delegate>();
foreach (FieldInfo field in type.GetFields())
{
Delegate getDelegate = CreateGetter(type, field.FieldType, field);
Delegate setDelegate = CreateSetter(type, field.FieldType, field);
getters.Add(field, getDelegate);
setters.Add(field, setDelegate);
}
m_packetFieldGetters.Add(type, getters);
m_packetFieldSetters.Add(type, setters);
}
private Delegate CreateGetter(Type classType, Type getReturnType, FieldInfo field)
{
string methodName = field.ReflectedType.FullName + ".get_" + field.Name;
Type[] parameterTypes = new Type[1] { classType };
DynamicMethod getterMethod = new DynamicMethod(methodName, getReturnType, parameterTypes, true);
ILGenerator gen = getterMethod.GetILGenerator();
if (field.IsStatic)
{
gen.Emit(OpCodes.Ldsfld, field);
}
else
{
gen.Emit(OpCodes.Ldarg_0);
gen.Emit(OpCodes.Ldfld, field);
}
gen.Emit(OpCodes.Ret);
// Create the specific Func<,> instance
Type[] typeArgs = new Type[] { classType, getReturnType };
Type generic = typeof(Func<,>);
Type genInstance = generic.MakeGenericType(typeArgs);
Delegate getterDelegate = getterMethod.CreateDelegate(genInstance);
return getterDelegate;
}
private Delegate CreateSetter(Type classType, Type setValueType, FieldInfo field)
{
string methodName = field.ReflectedType.FullName + ".set_" + field.Name;
Type[] parameters = new Type[2]
{
classType,
setValueType
};
DynamicMethod setterMethod = new DynamicMethod(methodName, null, parameters);
ILGenerator gen = setterMethod.GetILGenerator();
if (field.IsStatic)
{
gen.Emit(OpCodes.Ldarg_1);
gen.Emit(OpCodes.Stsfld, field);
}
else
{
gen.Emit(OpCodes.Ldarg_0);
gen.Emit(OpCodes.Ldarg_1);
gen.Emit(OpCodes.Stfld, field);
}
gen.Emit(OpCodes.Ret);
// Create the specific Action<,> instance
Type[] typeArgs = new Type[] { classType, setValueType };
Type generic = typeof(Action<,>);
Type genInstance = generic.MakeGenericType(typeArgs);
Delegate ret = setterMethod.CreateDelegate(genInstance);
return ret;
}
}
}
// THIS IS IN A DIFERENT ASSEMBLY
namespace MirrorNetTesting
{
// This is just an example packet
public class StudentPacket : UserPacket
{
public int age;
public int height;
public double grades;
public string firstName;
public string lastName;
}
class Program
{
static void Main(string[] args)
{
Assembly asm = Assembly.GetAssembly(typeof(StudentPacket));
MirrorNetManager.Instance.InitializePackets(asm);
PerformanceTesting();
Console.ReadLine();
}
public static void PerformanceTesting()
{
int studentsCount = 1000 * 100;
StudentPacket[] studentsArray = new StudentPacket[studentsCount];
//////////////////////////////////////////////////////////////////////////
Random rnd = new Random();
for (int i = 0; i < studentsArray.Length; i++)
{
StudentPacket student = new StudentPacket();
student.age = rnd.Next();
student.height = rnd.Next();
student.grades = rnd.NextDouble();
student.firstName = "First " + rnd.Next().ToString();
student.lastName = "Last " + rnd.Next().ToString();
studentsArray[i] = student;
}
var fieldsArray = typeof(StudentPacket).GetFields().ToArray();
//////////////////////////////////////////////////////////////////////////
// Begin normal getter test
Console.WriteLine("Testing normal getters");
Stopwatch normalGetterSw = new Stopwatch();
normalGetterSw.Start();
foreach (var student in studentsArray)
{
//object getValue;
var getAge = student.age;
var getHeight = student.height;
var getGrades = student.grades;
var getFirstName = student.firstName;
var getLastName = student.lastName;
}
normalGetterSw.Stop();
//////////////////////////////////////////////////////////////////////////
// Begin reflection getter test
Console.WriteLine("Testing reflection getters");
Stopwatch reflectionGetterSw = new Stopwatch();
reflectionGetterSw.Start();
foreach (var student in studentsArray)
{
object getValue;
for (int i = 0; i < fieldsArray.Length; i++ )
{
FieldInfo field = fieldsArray[i];
getValue = MirrorNetManager.Instance.GetValue(student, field);
}
}
reflectionGetterSw.Stop();
//////////////////////////////////////////////////////////////////////////
// Begin normal setter test
Console.WriteLine("Testing normal setters");
Stopwatch normalSetterSw = new Stopwatch();
int age = 10;
int height = 12;
double grades = 1432.523d;
string firstName = "first name";
string lastName = "last name";
normalSetterSw.Start();
foreach (var student in studentsArray)
{
student.age = age;
student.height = height;
student.grades = grades;
student.firstName = firstName;
student.lastName = lastName;
}
normalSetterSw.Stop();
//////////////////////////////////////////////////////////////////////////
// Begin reflection setter test
Console.WriteLine("Testing reflection setters ");
Stopwatch reflectionSetterSw = new Stopwatch();
object[] setValues = new object[]
{
age,
height,
grades,
firstName,
lastName
};
reflectionSetterSw.Start();
foreach (var student in studentsArray)
{
for (int i = 0; i < fieldsArray.Length; i++ )
{
FieldInfo field = fieldsArray[i];
MirrorNetManager.Instance.SetValue(student, field, setValues[i]);
}
}
reflectionSetterSw.Stop();
//////////////////////////////////////////////////////////////////////////
Console.WriteLine("Normal getter: \t {0}", normalGetterSw.ElapsedMilliseconds);
Console.WriteLine("Normal setter: \t {0}", normalSetterSw.ElapsedMilliseconds);
Console.WriteLine("Reflection getter: \t {0}", reflectionGetterSw.ElapsedMilliseconds);
Console.WriteLine("Reflection setter: \t {0}", reflectionSetterSw.ElapsedMilliseconds);
//////////////////////////////////////////////////////////////////////////
}
}
输出(仅相关内容):
Normal getter: 3
Normal setter: 4
Reflection getter: 261
Reflection setter: 183
Reflection getter 和 setter 实际上是动态调用，通常耗时 300ms。
此外，由于代码很长，我将其发布了 here还有。
最佳答案
您是否考虑过稍微不同的方法？由于 getter 和 setter 在这种情况下的主要目的是序列化和反序列化，也许您应该专注于动态生成序列化方法，这将消除使用动态方法逐一访问这些字段的开销。
例如，假设您想使用 BinaryFormatter 进行序列化(尽管您可能会选择更好的东西)，目标是动态生成如下方法:
static private byte[] SerializeStudentPacket(StudentPacket packet)
{
var bf = new BinaryFormatter();
var ms = new MemoryStream();
bf.Serialize(ms, packet.age);
bf.Serialize(ms, packet.firstName);
bf.Serialize(ms, packet.grades);
bf.Serialize(ms, packet.height);
bf.Serialize(ms, packet.lastName);
return ms.ToArray();
}
通过使用 Linq 表达式可以使它比 ILGenerator 更简单:
ParameterExpression @object = Expression.Parameter(typeof(StudentPacket), "@object");
MethodInfo serializeMethodInfo = typeof(BinaryFormatter).GetMethod("Serialize", new Type[] { typeof(Stream), typeof(object) });
MethodInfo toArrayMethodInfo = typeof(MemoryStream).GetMethod("ToArray");
var bf = Expression.Variable(typeof(BinaryFormatter), "bf");
var ms = Expression.Variable(typeof(System.IO.MemoryStream), "ms");
List<Expression> expressions = new List<Expression>();
expressions.Add(
Expression.Assign(bf, Expression.New(typeof(BinaryFormatter))));
expressions.Add(
Expression.Assign(ms, Expression.New(typeof(MemoryStream))));
foreach (FieldInfo field in typeof(StudentPacket).GetFields())
{
expressions.Add(
Expression.Call(bf, serializeMethodInfo, ms,
Expression.Convert(Expression.Field(@object, field.Name),
typeof(object))));
}
expressions.Add(Expression.Call(ms, toArrayMethodInfo));
var lambda = Expression.Lambda(
Expression.Block(
new[] { bf, ms },
expressions
),
@object);
然后您当然可以存储 lambda.Compile() 的结果以序列化 StudentPacket。同样的方法也可以用于反序列化。
关于c# - 注入(inject)通用的 getter 和 setter 以获得比反射更好的性能，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/19882676/