OutputCache.cs :  » 2.6.4-mono-.net-core » System.Web » System » Web » Caching » C# / CSharp Open Source

//
// Authors:
//   Marek Habersack <mhabersack@novell.com>
//
// (C) 2010 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.Configuration;
using System.Configuration.Provider;
using System.IO;
using System.Runtime.Serialization.Formatters.Binary;
using System.Security.Permissions;
using System.Web;
using System.Web.Configuration;

namespace System.Web.Caching{
  public static class OutputCache
  {
    internal const string DEFAULT_PROVIDER_NAME = "AspNetInternalProvider";
    
    static readonly object initLock = new object ();
    static bool initialized;
    static string defaultProviderName;
    static OutputCacheProviderCollection providers;
    
    public static string DefaultProviderName {
      get {
        Init ();
        if (String.IsNullOrEmpty (defaultProviderName))
          return DEFAULT_PROVIDER_NAME;
        
        return defaultProviderName;
      }
    }

    public static OutputCacheProviderCollection Providers {
      get {
        Init ();
        return providers;
      }
    }
    
    [SecurityPermission (SecurityAction.Assert, Flags = SecurityPermissionFlag.SerializationFormatter)]
    public static object Deserialize (Stream stream)
    {
      if (stream == null)
        throw new ArgumentNullException ("stream");

      object o = new BinaryFormatter ().Deserialize (stream);
      if (o == null || IsInvalidType (o))
        throw new ArgumentException ("The provided parameter is not of a supported type for serialization and/or deserialization.");

      return o;
    }

    [SecurityPermission (SecurityAction.Assert, Flags = SecurityPermissionFlag.SerializationFormatter)]
    public static void Serialize (Stream stream, object data)
    {
      if (stream == null)
        throw new ArgumentNullException ("stream");      

      // LAMESPEC: data == null doesn't throw ArgumentNullException
      if (data == null || IsInvalidType (data))
        throw new ArgumentException ("The provided parameter is not of a supported type for serialization and/or deserialization.");
      
      new BinaryFormatter ().Serialize (stream, data);
    }

    static bool IsInvalidType (object data)
    {
      return !(data is MemoryResponseElement) &&
        !(data is FileResponseElement) &&
        !(data is SubstitutionResponseElement);
    }
    
    static void Init ()
    {
      if (initialized)
        return;

      lock (initLock) {
        if (initialized)
          return;
        
        var cfg = WebConfigurationManager.GetWebApplicationSection ("system.web/caching/outputCache") as OutputCacheSection;
        ProviderSettingsCollection cfgProviders = cfg.Providers;

        defaultProviderName = cfg.DefaultProviderName;
        if (cfgProviders != null && cfgProviders.Count > 0) {
          var coll = new OutputCacheProviderCollection ();

          foreach (ProviderSettings ps in cfgProviders)
            coll.Add (LoadProvider (ps));

          coll.SetReadOnly ();
          providers = coll;
        }

        initialized = true;
      }
    }

    static OutputCacheProvider LoadProvider (ProviderSettings ps)
    {
      Type type = HttpApplication.LoadType (ps.Type, false);
      if (type == null)
        throw new ConfigurationErrorsException (String.Format ("Could not load type '{0}'.", ps.Type));
      
      var ret = Activator.CreateInstance (type) as OutputCacheProvider;
      ret.Initialize (ps.Name, ps.Parameters);

      return ret;
    }

    internal static void RemoveFromProvider (string key, string providerName)
    {
      if (providerName == null)
        return;

      OutputCacheProviderCollection providers = Providers;
      OutputCacheProvider provider;
      
      if (providers == null || providers.Count == 0)
        provider = null;
      else
        provider = providers [providerName];

      if (provider == null)
        throw new ProviderException ("Provider '" + providerName + "' was not found.");

      provider.Remove (key);
    }
  }
}