DirectoryDependency.cs :  » Content-Management-Systems-CMS » Kooboo » Everest » Providers » Caching » C# / CSharp Open Source

/*
Kooboo is a content management system based on ASP.NET MVC framework. Copyright 2009 Yardi Technology Limited.

This program is free software: you can redistribute it and/or modify it under the terms of the
GNU General Public License version 3 as published by the Free Software Foundation.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program.
If not, see http://www.kooboo.com/gpl3/.
*/
using System;
using System.Globalization;
using System.IO;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using System.Runtime.Serialization;
using System.Security.Permissions;
using Microsoft.Practices.EnterpriseLibrary.Caching;
using Microsoft.Practices.EnterpriseLibrary.Caching.Properties;


namespace Everest.Providers.Caching{
    /// <summary>
    ///  This class tracks a file cache dependency.
    /// </summary>
    [Serializable]
    [ComVisible(false)]
    public class DirectoryDependency : ICacheItemExpiration, IDisposable
    {
        private readonly string dependencyDirectory;


        private DateTime preModified = DateTime.Now;



        private Dictionary<string, DateTime> files = new Dictionary<string, DateTime>();

        /// <summary>
        /// Initializes a new instance of the <see cref="DirectoryDependency"/> class.
        /// </summary>
        /// <param name="fullDirectory">The full directory.</param>
        public DirectoryDependency(string fullDirectory)
        {
            if (string.IsNullOrEmpty(fullDirectory))
            {
                throw new ArgumentException("fullDirectory");
            }

            dependencyDirectory = Path.GetFullPath(fullDirectory);
            EnsureTargetFileAccessible();

            if (!Directory.Exists(dependencyDirectory))
            {
                throw new ArgumentException("ExceptionInvalidFileName", "fullFileName");
            }
            preModified = Directory.GetLastWriteTimeUtc(dependencyDirectory);
            //Initialize();
        }
        //private void Initialize()
        //{
        //    preModified = Directory.GetLastWriteTime(this.dependencyDirectory);

        //}
        /// <summary>
        /// Gets the name of the dependent file.
        /// </summary>
        /// <value>
        /// The name of the dependent file.
        /// </value>
        public string DirectoryName
        {
            get { return dependencyDirectory; }
        }

        /// <summary>
        ///  Specifies if the item has expired or not.
        /// </summary>
        /// <returns>Returns true if the item has expired, otherwise false.</returns>
        public bool HasExpired()
        {
            bool expired = false;

            if (!Directory.Exists(this.dependencyDirectory))
            {
                return true;
            }

            var lastestModified = Directory.GetLastWriteTime(this.dependencyDirectory);


            expired = preModified != lastestModified;

            preModified = lastestModified;

            return expired;
        }

        /// <summary>
        ///  Notifies that the item was recently used.
        /// </summary>
        public void Notify()
        {
        }

        /// <summary>
        /// Not used
        /// </summary>
        /// <param name="owningCacheItem">Not used</param>
        public void Initialize(CacheItem owningCacheItem)
        {
        }

        private void EnsureTargetFileAccessible()
        {
            // keep from changing during demand
            string file = dependencyDirectory;
            FileIOPermission permission = new FileIOPermission(FileIOPermissionAccess.Read, file);
            permission.Demand();
        }

        #region IDisposable Members

        public void Dispose()
        {
        }

        #endregion
    }
}