System.Data.SQLite

      SetTimeout(0);
    }

    internal override void ClearPool()
    {
      SQLiteConnectionPool.ClearPool(_fileName);
    }

    internal override int CountPool()
    {
        Dictionary<string, int> counts = null;
        int totalCount = 0;

        SQLiteConnectionPool.GetCounts(_fileName,
            ref counts, ref totalCount);

        return totalCount;
    }

    internal override void SetTimeout(int nTimeoutMS)
    {
      int n = UnsafeNativeMethods.sqlite3_busy_timeout(_sql, nTimeoutMS);
      if (n > 0) throw new SQLiteException(n, SQLiteLastError());
    }

/********************************************************
 * ADO.NET 2.0 Data Provider for SQLite Version 3.X
 * Written by Robert Simpson (robert@blackcastlesoft.com)
 * 
 * Released to the public domain, use at your own risk!
 ********************************************************/

namespace System.Data.SQLite
{
  using System;
  using System.Collections.Generic;

  /// <summary>
  /// This internal class provides the foundation of SQLite support.  It defines all the abstract members needed to implement
  /// a SQLite data provider, and inherits from SQLiteConvert which allows for simple translations of string to and from SQLite.
  /// </summary>
  internal abstract class SQLiteBase : SQLiteConvert, IDisposable
  {

    internal abstract string SQLiteLastError();

    /// <summary>
    /// When pooling is enabled, force this connection to be disposed rather than returned to the pool
    /// </summary>
    internal abstract void ClearPool();

    /// <summary>
    /// When pooling is enabled, returns the number of pool entries matching the current file name.
    /// </summary>
    /// <returns>The number of pool entries matching the current file name.</returns>
    internal abstract int CountPool();

    /// <summary>
    /// Prepares a SQL statement for execution.
    /// </summary>
    /// <param name="cnn">The source connection preparing the command.  Can be null for any caller except LINQ</param>
    /// <param name="strSql">The SQL command text to prepare</param>
    /// <param name="previous">The previous statement in a multi-statement command, or null if no previous statement exists</param>
    /// <param name="timeoutMS">The timeout to wait before aborting the prepare</param>

          _sql.Close();
          _sql = null;
        }
        _transactionLevel = 0;
      }
      OnStateChange(ConnectionState.Closed);
    }

    /// <summary>
    /// Returns the number of pool entries for the file name associated with this connection.
    /// </summary>
    public int PoolCount
    {
        get
        {
            if (_sql == null) return 0;
            return _sql.CountPool();
        }
    }

    /// <summary>
    /// Clears the connection pool associated with the connection.  Any other active connections using the same database file
    /// will be discarded instead of returned to the pool when they are closed.
    /// </summary>
    /// <param name="connection"></param>
    public static void ClearPool(SQLiteConnection connection)

    /// </summary>
    private static SortedList<string, Pool> _connections = new SortedList<string, Pool>(StringComparer.OrdinalIgnoreCase);

    /// <summary>
    /// The default version number new pools will get
    /// </summary>
    private static int _poolVersion = 1;

    /// <summary>
    /// Counts the number of pool entries matching the specified file name.
    /// </summary>
    /// <param name="fileName">The file name to match or null to match all files.</param>
    /// <param name="counts">The pool entry counts for each matching file.</param>
    /// <param name="totalCount">The total number of pool entries for all matching files.</param>
    internal static void GetCounts(
        string fileName,
        ref Dictionary<string, int> counts,
        ref int totalCount
        )
    {
        lock (_connections)
        {
            if (counts == null)
            {
                counts = new Dictionary<string, int>(
                    StringComparer.OrdinalIgnoreCase);
            }

            if (fileName != null)
            {
                Pool queue;

                if (_connections.TryGetValue(fileName, out queue))
                {
                    Queue<WeakReference> poolQueue = queue.Queue;
                    int count = (poolQueue != null) ? poolQueue.Count : 0;

                    counts.Add(fileName, count);
                    totalCount += count;
                }
            }
            else
            {
                foreach (KeyValuePair<string, Pool> pair in _connections)
                {
                    if (pair.Value == null)
                        continue;

                    Queue<WeakReference> poolQueue = pair.Value.Queue;
                    int count = (poolQueue != null) ? poolQueue.Count : 0;

                    counts.Add(pair.Key, count);
                    totalCount += count;
                }
            }
        }
    }

    /// <summary>
    /// Attempt to pull a pooled connection out of the queue for active duty
    /// </summary>
    /// <param name="fileName">The filename for a desired connection</param>
    /// <param name="maxPoolSize">The maximum size the connection pool for the filename can be</param>
    /// <param name="version">The pool version the returned connection will belong to</param>