Csla.Data.EF6/DbContextManager.cs

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//-----------------------------------------------------------------------
// <copyright file="ObjectContextManager.cs" company="Marimer LLC">
//     Copyright (c) Marimer LLC. All rights reserved.
//     Website: https://cslanet.com
// </copyright>
// <summary>Provides an automated way to reuse </summary>
//-----------------------------------------------------------------------
 
#if !MONO
using System;
using System.Data.Entity;
using System.Data.Entity.Infrastructure;
using System.Data.Entity.Core.Objects;
 
namespace Csla.Data.EF6
{
  public class DbContextManager<C> : IDisposable where C : DbContext
  {
    private static object _lock = new object();
    private C _context;
    private string _label;
    private string ContextLabel { get; set; }
 
 
    public static DbContextManager<C> GetManager()
    {
      return GetManager(string.Empty);
    }
 
    public static DbContextManager<C> GetManager(string database)
    {
      return GetManager(database, "default", null);
    }
 
    public static DbContextManager<C> GetManager(string database, string label)
    {
      return GetManager(database, label, null);
    }
 
    public static DbContextManager<C> GetManager(string database, DbCompiledModel model)
    {
      return GetManager(database, "default", model);
    }
 
 
    public static DbContextManager<C> GetManager(string database, string label, DbCompiledModel model)
    {
      lock (_lock)
      {
        var contextLabel = GetContextName(database, label);
        DbContextManager<C> mgr = null;
        if (ApplicationContext.LocalContext.Contains(contextLabel))
        {
          mgr = (DbContextManager<C>)(ApplicationContext.LocalContext[contextLabel]);
        }
        else
        {
          mgr = new DbContextManager<C>(database, label, model, null);
          mgr.ContextLabel = contextLabel;
          ApplicationContext.LocalContext[contextLabel] = mgr;
        }
        mgr.AddRef();
        return mgr;
      }
    }
 
    public static DbContextManager<C> GetManager(ObjectContext context)
    {
      return GetManager(context, "default");
    }
 
    public static DbContextManager<C> GetManager(ObjectContext context, string label)
    {
      lock (_lock)
      {
        var contextLabel = GetContextName(context.DefaultContainerName, label);
        DbContextManager<C> mgr = null;
        if (ApplicationContext.LocalContext.Contains(contextLabel))
        {
          mgr = (DbContextManager<C>)(ApplicationContext.LocalContext[contextLabel]);
        }
        else
        {
          mgr = new DbContextManager<C>(null, label, null, context);
          mgr.ContextLabel = contextLabel;
          ApplicationContext.LocalContext[contextLabel] = mgr;
        }
        mgr.AddRef();
        return mgr;
      }
    }
 
    private DbContextManager(string database, string label, DbCompiledModel model, ObjectContext context)
    {
      _label = label;
 
      if (model != null)
      {
        if (!string.IsNullOrEmpty(database))
          _context = (C)(Activator.CreateInstance(typeof(C), database, model));
        else
          _context = (C) (Activator.CreateInstance(typeof (C), model));
      }
      else if (context != null)
      {
        _context = (C) (Activator.CreateInstance(typeof (C), context, true));
      }
      else if (string.IsNullOrEmpty(database))
      {
        _context = (C) (Activator.CreateInstance(typeof (C)));
      }
      else
      {
        _context = (C)(Activator.CreateInstance(typeof(C), database));
      }
    }
 
    private static string GetContextName(string database, string label)
    {
      return "__dbctx:" + label + "-" + database;
    }
 
 
    public C DbContext
    {
      get
      {
        return _context;
      }
    }
 
    #region  Reference counting
 
    private int _refCount;
 
    public int RefCount
    {
      get { return _refCount; }
    }
 
    private void AddRef()
    {
      _refCount += 1;
    }
 
    private void DeRef()
    {
 
      lock (_lock)
      {
        _refCount -= 1;
        if (_refCount == 0)
        {
          _context.Dispose();
          ApplicationContext.LocalContext.Remove(ContextLabel);
        }
      }
 
    }
 
    #endregion
 
    #region  IDisposable
 
    public void Dispose()
    {
      DeRef();
    }
 
    #endregion
 
  }
}
#endif