//
// System.Data.Common.DbProviderFactories.cs
//
// Author:
//   Sureshkumar T (tsureshkumar@novell.com)
//   Tim Coleman (tim@timcoleman.com)
//
// Copyright (C) Tim Coleman, 2003
//

//
// Copyright (C) 2004 Novell, Inc (http://www.novell.com)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//

#if NET_2_0

using System.Threading;
using System.Reflection;
using System.Collections;
using System.Configuration;

namespace System.Data.Common {
	public static class DbProviderFactories
	{
		private static object configEntries = null; // DataSet

                private const string CONFIG_SECTION_NAME        = "system.data";
                private const string CONFIG_SEC_TABLE_NAME      = "DbProviderFactories";
                
		#region Methods

		public static DbProviderFactory GetFactory (DataRow providerRow)
		{
                        string assemblyType = (string) providerRow ["AssemblyQualifiedName"];
#if TARGET_JVM // case insensitive GetType is not supported
                        Type type = Type.GetType (assemblyType, false);
#else
                        Type type = Type.GetType (assemblyType, false, true);
#endif
                        if (type != null && type.IsSubclassOf (typeof (DbProviderFactory))) {
                                // Provider factories are singletons with Instance field having
                                // the sole instance
                                FieldInfo field = type.GetField ("Instance", BindingFlags.Public |
                                                                 BindingFlags.Static);
                                if (field != null) {
                                        return field.GetValue (null) as DbProviderFactory;
                                }
                                
                        }
                        
                        throw new ConfigurationException("DataProvider is missing!");
		}

		public static DbProviderFactory GetFactory (string providerInvariantName)
		{
                        DataTable table = GetFactoryClasses ();
                        if (table != null) {
                                DataRow row = table.Rows.Find (providerInvariantName);
                                if (row != null)
                                        return GetFactory (row);
                        }
                        throw new ConfigurationException ("DataProvider is not found!");
		}

		public static DataTable GetFactoryClasses ()
		{
                        DataSet ds = GetConfigEntries ();
                        DataTable table = ds != null ? ds.Tables [CONFIG_SEC_TABLE_NAME] : null;
                        if (table != null)
                                table = table.Copy (); // avoid modifications by user
                        return table;
		}

		#endregion // Methods

		#region Internal Methods
		internal static DataSet GetConfigEntries ()
		{
                        
                        if (configEntries != null)
                                return configEntries as DataSet;
                        
                        DataSet ds = (DataSet) ConfigurationSettings.GetConfig (CONFIG_SECTION_NAME);
                        Interlocked.CompareExchange (ref configEntries, ds, null);
                        return configEntries as DataSet;
		}
		#endregion Internal Methods
	}
}

#endif // NET_2_0