DataViewListener.cs

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using System.Collections.Generic;
using System.ComponentModel;
 
namespace System.Data;
 
internal sealed class DataViewListener
{
    private readonly WeakReference _dvWeak;
 
    private DataTable _table;
 
    private Index _index;
 
    internal readonly int _objectID;
 
    internal DataViewListener(DataView dv)
    {
        _objectID = dv.ObjectID;
        _dvWeak = new WeakReference(dv);
    }
 
    private void ChildRelationCollectionChanged(object sender, CollectionChangeEventArgs e)
    {
        DataView dataView = (DataView)_dvWeak.Target;
        if (dataView != null)
        {
            dataView.ChildRelationCollectionChanged(sender, e);
        }
        else
        {
            CleanUp(updateListeners: true);
        }
    }
 
    private void ParentRelationCollectionChanged(object sender, CollectionChangeEventArgs e)
    {
        DataView dataView = (DataView)_dvWeak.Target;
        if (dataView != null)
        {
            dataView.ParentRelationCollectionChanged(sender, e);
        }
        else
        {
            CleanUp(updateListeners: true);
        }
    }
 
    private void ColumnCollectionChanged(object sender, CollectionChangeEventArgs e)
    {
        DataView dataView = (DataView)_dvWeak.Target;
        if (dataView != null)
        {
            dataView.ColumnCollectionChangedInternal(sender, e);
        }
        else
        {
            CleanUp(updateListeners: true);
        }
    }
 
    internal void MaintainDataView(ListChangedType changedType, DataRow row, bool trackAddRemove)
    {
        DataView dataView = (DataView)_dvWeak.Target;
        if (dataView != null)
        {
            dataView.MaintainDataView(changedType, row, trackAddRemove);
        }
        else
        {
            CleanUp(updateListeners: true);
        }
    }
 
    internal void IndexListChanged(ListChangedEventArgs e)
    {
        DataView dataView = (DataView)_dvWeak.Target;
        if (dataView != null)
        {
            dataView.IndexListChangedInternal(e);
        }
        else
        {
            CleanUp(updateListeners: true);
        }
    }
 
    internal void RegisterMetaDataEvents(DataTable table)
    {
        _table = table;
        if (table != null)
        {
            RegisterListener(table);
            CollectionChangeEventHandler value = ColumnCollectionChanged;
            table.Columns.ColumnPropertyChanged += value;
            table.Columns.CollectionChanged += value;
            CollectionChangeEventHandler value2 = ChildRelationCollectionChanged;
            ((DataRelationCollection.DataTableRelationCollection)table.ChildRelations).RelationPropertyChanged += value2;
            table.ChildRelations.CollectionChanged += value2;
            CollectionChangeEventHandler value3 = ParentRelationCollectionChanged;
            ((DataRelationCollection.DataTableRelationCollection)table.ParentRelations).RelationPropertyChanged += value3;
            table.ParentRelations.CollectionChanged += value3;
        }
    }
 
    internal void UnregisterMetaDataEvents()
    {
        UnregisterMetaDataEvents(updateListeners: true);
    }
 
    private void UnregisterMetaDataEvents(bool updateListeners)
    {
        DataTable table = _table;
        _table = null;
        if (table == null)
        {
            return;
        }
        CollectionChangeEventHandler value = ColumnCollectionChanged;
        table.Columns.ColumnPropertyChanged -= value;
        table.Columns.CollectionChanged -= value;
        CollectionChangeEventHandler value2 = ChildRelationCollectionChanged;
        ((DataRelationCollection.DataTableRelationCollection)table.ChildRelations).RelationPropertyChanged -= value2;
        table.ChildRelations.CollectionChanged -= value2;
        CollectionChangeEventHandler value3 = ParentRelationCollectionChanged;
        ((DataRelationCollection.DataTableRelationCollection)table.ParentRelations).RelationPropertyChanged -= value3;
        table.ParentRelations.CollectionChanged -= value3;
        if (updateListeners)
        {
            List<DataViewListener> listeners = table.GetListeners();
            lock (listeners)
            {
                listeners.Remove(this);
            }
        }
    }
 
    internal void RegisterListChangedEvent(Index index)
    {
        _index = index;
        if (index != null)
        {
            lock (index)
            {
                index.AddRef();
                index.ListChangedAdd(this);
            }
        }
    }
 
    internal void UnregisterListChangedEvent()
    {
        Index index = _index;
        _index = null;
        if (index == null)
        {
            return;
        }
        lock (index)
        {
            index.ListChangedRemove(this);
            if (index.RemoveRef() <= 1)
            {
                index.RemoveRef();
            }
        }
    }
 
    private void CleanUp(bool updateListeners)
    {
        UnregisterMetaDataEvents(updateListeners);
        UnregisterListChangedEvent();
    }
 
    private void RegisterListener(DataTable table)
    {
        List<DataViewListener> listeners = table.GetListeners();
        lock (listeners)
        {
            int num = listeners.Count - 1;
            while (0 <= num)
            {
                DataViewListener dataViewListener = listeners[num];
                if (!dataViewListener._dvWeak.IsAlive)
                {
                    listeners.RemoveAt(num);
                    dataViewListener.CleanUp(updateListeners: false);
                }
                num--;
            }
            listeners.Add(this);
        }
    }
}