C# Implementierung von BSON-ID-Generator?

Question

Weiß jemand, ob es eine vorhandene C# Implementierung eines BSON ID Generators gibt?

Ich muss Mongodb ObjectIDs auf einem .NET-Client generieren, kann aber keine externen DLLs verwenden, also müssen Sie es in Code tun. Ich konnte bei Google nichts finden, also werde ich wohl am Ende mein eigenes schreiben müssen, wollte aber erst mal mit anderen nachsehen.

Danke.

Answer 1

Sie können die implementation einfach in Ihre Codebasis kopieren, wenn Sie nicht auf das Paket verweisen dürfen. Unten ist eine vereinfachte Version davon.

using System; 
using System.Diagnostics; 
using System.Runtime.CompilerServices; 
using System.Security; 
using System.Threading; 

public struct ObjectId 
{ 
    private static readonly ObjectId __emptyInstance = default(ObjectId); 
    private static readonly int __staticMachine = (GetMachineHash() + GetAppDomainId()) & 0x00ffffff; 
    private static readonly short __staticPid = GetPid(); 
    private static int __staticIncrement = new Random().Next(); 
    private static readonly DateTime __unixEpoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc); 

    private readonly int _a; 
    private readonly int _b; 
    private readonly int _c; 

    private ObjectId(int timestamp, int machine, short pid, int increment) 
    { 
     _a = timestamp; 
     _b = (machine << 8) | ((pid >> 8) & 0xff); 
     _c = (pid << 24) | increment; 
    } 

    public static ObjectId GenerateNewId() 
    { 
     return GenerateNewId(GetTimestampFromDateTime(DateTime.UtcNow)); 
    } 

    public static ObjectId GenerateNewId(int timestamp) 
    { 
     var increment = Interlocked.Increment(ref __staticIncrement) & 0x00ffffff; // only use low order 3 bytes 
     return new ObjectId(timestamp, __staticMachine, __staticPid, increment); 
    } 

    private static int GetAppDomainId() 
    { 
     return AppDomain.CurrentDomain.Id; 
    } 

    [MethodImpl(MethodImplOptions.NoInlining)] 
    private static int GetCurrentProcessId() 
    { 
     return Process.GetCurrentProcess().Id; 
    } 

    private static int GetMachineHash() 
    { 
     var machineName = GetMachineName(); 
     return 0x00ffffff & machineName.GetHashCode(); // use first 3 bytes of hash 
    } 

    private static string GetMachineName() 
    { 
     return Environment.MachineName; 
    } 

    private static short GetPid() 
    { 
     try 
     { 
      return (short) GetCurrentProcessId(); // use low order two bytes only 
     } 
     catch (SecurityException) 
     { 
      return 0; 
     } 
    } 

    private static int GetTimestampFromDateTime(DateTime timestamp) 
    { 
     var secondsSinceEpoch = (long) Math.Floor((ToUniversalTime(timestamp) - __unixEpoch).TotalSeconds); 
     if (secondsSinceEpoch < int.MinValue || secondsSinceEpoch > int.MaxValue) 
      throw new ArgumentOutOfRangeException("timestamp"); 
     return (int) secondsSinceEpoch; 
    } 

    public override string ToString() 
    { 
     var c = new char[24]; 
     c[0] = ToHexChar((_a >> 28) & 0x0f); 
     c[1] = ToHexChar((_a >> 24) & 0x0f); 
     c[2] = ToHexChar((_a >> 20) & 0x0f); 
     c[3] = ToHexChar((_a >> 16) & 0x0f); 
     c[4] = ToHexChar((_a >> 12) & 0x0f); 
     c[5] = ToHexChar((_a >> 8) & 0x0f); 
     c[6] = ToHexChar((_a >> 4) & 0x0f); 
     c[7] = ToHexChar(_a & 0x0f); 
     c[8] = ToHexChar((_b >> 28) & 0x0f); 
     c[9] = ToHexChar((_b >> 24) & 0x0f); 
     c[10] = ToHexChar((_b >> 20) & 0x0f); 
     c[11] = ToHexChar((_b >> 16) & 0x0f); 
     c[12] = ToHexChar((_b >> 12) & 0x0f); 
     c[13] = ToHexChar((_b >> 8) & 0x0f); 
     c[14] = ToHexChar((_b >> 4) & 0x0f); 
     c[15] = ToHexChar(_b & 0x0f); 
     c[16] = ToHexChar((_c >> 28) & 0x0f); 
     c[17] = ToHexChar((_c >> 24) & 0x0f); 
     c[18] = ToHexChar((_c >> 20) & 0x0f); 
     c[19] = ToHexChar((_c >> 16) & 0x0f); 
     c[20] = ToHexChar((_c >> 12) & 0x0f); 
     c[21] = ToHexChar((_c >> 8) & 0x0f); 
     c[22] = ToHexChar((_c >> 4) & 0x0f); 
     c[23] = ToHexChar(_c & 0x0f); 
     return new string(c); 
    } 

    private static char ToHexChar(int value) 
    { 
     return (char) (value + (value < 10 ? '0' : 'a' - 10)); 
    } 

    private static DateTime ToUniversalTime(DateTime dateTime) 
    { 
     if (dateTime == DateTime.MinValue) 
      return DateTime.SpecifyKind(DateTime.MinValue, DateTimeKind.Utc); 
     if (dateTime == DateTime.MaxValue) 
      return DateTime.SpecifyKind(DateTime.MaxValue, DateTimeKind.Utc); 
     return dateTime.ToUniversalTime(); 
    } 
}