websocket-sharp/websocket-sharp/Net/HttpListenerPrefix.cs

#region License
/*
 * HttpListenerPrefix.cs
 *
 * This code is derived from ListenerPrefix.cs (System.Net) of Mono
 * (http://www.mono-project.com).
 *
 * The MIT License
 *
 * Copyright (c) 2005 Novell, Inc. (http://www.novell.com)
 * Copyright (c) 2012-2016 sta.blockhead
 *
 * 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.
 */
#endregion

#region Authors
/*
 * Authors:
 * - Gonzalo Paniagua Javier <gonzalo@novell.com>
 * - Oleg Mihailik <mihailik@gmail.com>
 */
#endregion

using System;
using System.Net;

namespace WebSocketSharp.Net
{
  internal sealed class HttpListenerPrefix
  {
    #region Private Fields

    private string       _host;
    private HttpListener _listener;
    private string       _original;
    private string       _path;
    private string       _port;
    private string       _prefix;
    private bool         _secure;

    #endregion

    #region Internal Constructors

    /// <summary>
    /// Initializes a new instance of the <see cref="HttpListenerPrefix"/> class with
    /// the specified <paramref name="uriPrefix"/>.
    /// </summary>
    /// <remarks>
    /// This constructor must be called after calling the CheckPrefix method.
    /// </remarks>
    /// <param name="uriPrefix">
    /// A <see cref="string"/> that represents the URI prefix.
    /// </param>
    internal HttpListenerPrefix (string uriPrefix)
    {
      _original = uriPrefix;
      parse (uriPrefix);
    }

    #endregion

    #region Public Properties

    public string Host {
      get {
        return _host;
      }
    }

    public bool IsSecure {
      get {
        return _secure;
      }
    }

    public HttpListener Listener {
      get {
        return _listener;
      }

      set {
        _listener = value;
      }
    }

    public string Original {
      get {
        return _original;
      }
    }

    public string Path {
      get {
        return _path;
      }
    }

    public string Port {
      get {
        return _port;
      }
    }

    #endregion

    #region Private Methods

    private void parse (string uriPrefix)
    {
      if (uriPrefix.StartsWith ("https"))
        _secure = true;

      var len = uriPrefix.Length;
      var startHost = uriPrefix.IndexOf (':') + 3;
      var root = uriPrefix.IndexOf ('/', startHost + 1, len - startHost - 1);

      var colon = uriPrefix.LastIndexOf (':', root - 1, root - startHost - 1);
      if (uriPrefix[root - 1] != ']' && colon > startHost) {
        _host = uriPrefix.Substring (startHost, colon - startHost);
        _port = uriPrefix.Substring (colon + 1, root - colon - 1);
      }
      else {
        _host = uriPrefix.Substring (startHost, root - startHost);
        _port = _secure ? "443" : "80";
      }

      _path = uriPrefix.Substring (root);

      _prefix =
        String.Format ("http{0}://{1}:{2}{3}", _secure ? "s" : "", _host, _port, _path);
    }

    #endregion

    #region Public Methods

    public static void CheckPrefix (string uriPrefix)
    {
      if (uriPrefix == null)
        throw new ArgumentNullException ("uriPrefix");

      var len = uriPrefix.Length;
      if (len == 0)
        throw new ArgumentException ("An empty string.", "uriPrefix");

      if (!(uriPrefix.StartsWith ("http://") || uriPrefix.StartsWith ("https://")))
        throw new ArgumentException ("The scheme isn't 'http' or 'https'.", "uriPrefix");

      var startHost = uriPrefix.IndexOf (':') + 3;
      if (startHost >= len)
        throw new ArgumentException ("No host is specified.", "uriPrefix");

      if (uriPrefix[startHost] == ':')
        throw new ArgumentException ("No host is specified.", "uriPrefix");

      var root = uriPrefix.IndexOf ('/', startHost, len - startHost);
      if (root == startHost)
        throw new ArgumentException ("No host is specified.", "uriPrefix");

      if (root == -1 || uriPrefix[len - 1] != '/')
        throw new ArgumentException ("Ends without '/'.", "uriPrefix");

      if (uriPrefix[root - 1] == ':')
        throw new ArgumentException ("No port is specified.", "uriPrefix");

      if (root == len - 2)
        throw new ArgumentException ("No path is specified.", "uriPrefix");
    }

    /// <summary>
    /// Determines whether this instance and the specified <see cref="Object"/> have the same value.
    /// </summary>
    /// <remarks>
    /// This method will be required to detect duplicates in any collection.
    /// </remarks>
    /// <param name="obj">
    /// An <see cref="Object"/> to compare to this instance.
    /// </param>
    /// <returns>
    /// <c>true</c> if <paramref name="obj"/> is a <see cref="HttpListenerPrefix"/> and
    /// its value is the same as this instance; otherwise, <c>false</c>.
    /// </returns>
    public override bool Equals (Object obj)
    {
      var pref = obj as HttpListenerPrefix;
      return pref != null && pref._prefix == _prefix;
    }

    /// <summary>
    /// Gets the hash code for this instance.
    /// </summary>
    /// <remarks>
    /// This method will be required to detect duplicates in any collection.
    /// </remarks>
    /// <returns>
    /// An <see cref="int"/> that represents the hash code.
    /// </returns>
    public override int GetHashCode ()
    {
      return _prefix.GetHashCode ();
    }

    public override string ToString ()
    {
      return _prefix;
    }

    #endregion
  }
}