//
// System.Web.Configuration.HandlersUtil
//
// Authors:
//	Gonzalo Paniagua Javier (gonzalo@ximian.com)
//
// (C) 2002 Ximian, Inc (http://www.ximian.com)
// (C) 2005-2009 Novell, inc (http://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.
//

using System.Collections;
using System.Configuration;
using System.Xml;
using System.Globalization;

namespace System.Web.Configuration
{
	sealed class HandlersUtil
	{
		HandlersUtil ()
		{
		}

		static public string ExtractAttributeValue (string attKey, XmlNode node)
		{
			return ExtractAttributeValue (attKey, node, false);
		}
			
		static public string ExtractAttributeValue (string attKey, XmlNode node, bool optional)
		{
			return ExtractAttributeValue (attKey, node, optional, false);
		}
		
		static public string ExtractAttributeValue (string attKey, XmlNode node, bool optional,
							      bool allowEmpty)
		{
			if (node.Attributes == null) {
				if (optional)
					return null;

				ThrowException ("Required attribute not found: " + attKey, node);
			}

			XmlNode att = node.Attributes.RemoveNamedItem (attKey);
			if (att == null) {
				if (optional)
					return null;
				ThrowException ("Required attribute not found: " + attKey, node);
			}

			string value = att.Value;
			if (!allowEmpty && value == String.Empty) {
				string opt = optional ? "Optional" : "Required";
				ThrowException (opt + " attribute is empty: " + attKey, node);
			}

			return value;
		}

		static public void ThrowException (string msg, XmlNode node)
		{
			if (node != null && node.Name != String.Empty)
				msg = msg + " (node name: " + node.Name + ") ";
			throw new ConfigurationException (msg, node);
		}
	}
}