mcs/class/System.Web/System.Web.Configuration/HandlerItem.cs

   1 //
   2 // System.Web.Configuration.HandlerItem
   3 //
   4 // Authors:
   5 //      Patrik Torstensson (ptorsten@hotmail.com)
   6 //      Gonzalo Paniagua Javier (gonzalo@ximian.com)
   7 //
   8 //   (c) 2002 Ximian, Inc. (http://www.ximian.com)
   9 //
  10
  11 //
  12 // Permission is hereby granted, free of charge, to any person obtaining
  13 // a copy of this software and associated documentation files (the
  14 // "Software"), to deal in the Software without restriction, including
  15 // without limitation the rights to use, copy, modify, merge, publish,
  16 // distribute, sublicense, and/or sell copies of the Software, and to
  17 // permit persons to whom the Software is furnished to do so, subject to
  18 // the following conditions:
  19 //
  20 // The above copyright notice and this permission notice shall be
  21 // included in all copies or substantial portions of the Software.
  22 //
  23 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  27 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  28 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  29 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  30 //
  31 using System;
  32 using System.Collections;
  33 using System.Text;
  34 using System.Text.RegularExpressions;
  35 using System.Threading;
  36
  37 namespace System.Web.Configuration
  38 {
  39         class HandlerItem
  40         {
  41                 private Type _type;
  42                 private string _typeName;
  43                 private string _path;
  44                 private string _requestType;
  45                 private Regex requestRegex;
  46                 private Regex pathRegex;
  47                 static Hashtable regexCache;
  48                 object instance;
  49                 bool validated;
  50
  51                 public HandlerItem (string requestType, string path, string type, bool validate)
  52                 {
  53                         _typeName = type;
  54                         _path = path;
  55                         _requestType = requestType.Replace (" ", "");
  56                         requestRegex = GetRegex (_requestType, true);
  57                         pathRegex = GetRegex (_path, false);
  58                         if (validate)
  59                                 DoValidation ();
  60                 }
  61
  62                 public object GetInstance ()
  63                 {
  64                         object obj = Interlocked.CompareExchange (ref instance, null, null);
  65                         if (obj != null)
  66                                 return obj;
  67
  68                         DoValidation ();
  69                         obj = Activator.CreateInstance (_type, true);
  70                         IHttpHandler hnd = obj as IHttpHandler;
  71                         if (hnd != null && hnd.IsReusable)
  72                                 Interlocked.CompareExchange (ref instance, hnd, null);
  73
  74                         return obj;
  75                 }
  76
  77                 public Type Type
  78                 {
  79                         get {
  80                                 DoValidation ();
  81                                 return _type;
  82                         }
  83                 }
  84
  85                 public bool IsMatch (string type, string path)
  86                 {
  87                         return (MatchVerb (type) && MatchPath (path));
  88                 }
  89
  90                 bool MatchVerb (string verb)
  91                 {
  92                         return requestRegex.IsMatch (verb);
  93                 }
  94
  95                 bool MatchPath (string path)
  96                 {
  97                         if (pathRegex.IsMatch (path))
  98                                 return true;
  99
 100                         int slash = path.LastIndexOf ('/');
 101                         if (slash != -1 && path.Length > slash + 1)
 102                                 return pathRegex.IsMatch (path.Substring (slash + 1));
 103
 104                         return false;
 105                 }
 106
 107                 void DoValidation ()
 108                 {
 109                         if (validated)
 110                                 return;
 111
 112                         lock (this) {
 113                                 Type t = Type.GetType (_typeName, true);
 114                                 _type = t;
 115                                 validated = true;
 116                         }
 117
 118                         if (typeof (IHttpHandler).IsAssignableFrom (_type))
 119                                 return;
 120
 121                         if (typeof (IHttpHandlerFactory).IsAssignableFrom (_type))
 122                                 return;
 123
 124                         throw new HttpException (HttpRuntime.FormatResourceString ("type_not_factory_or_handler"));
 125                 }
 126
 127                 static string ToRegexPattern (string dosPattern)
 128                 {
 129                         string result = dosPattern.Replace (".", "\\.");
 130                         result = result.Replace ("*", ".*");
 131                         result = result.Replace ('?', '.');
 132                         return result;
 133                 }
 134
 135                 static Regex GetRegex (string verb, bool match_all)
 136                 {
 137                         EnsureCache ();
 138                         if (regexCache.ContainsKey (verb))
 139                                 return (Regex) regexCache [verb];
 140
 141                         StringBuilder result = new StringBuilder ((match_all) ? "\\A" : "");
 142                         string [] expressions = verb.Split (',');
 143                         int end = expressions.Length;
 144                         for (int i = 0; i < end; i++) {
 145                                 string regex = ToRegexPattern (expressions [i]);
 146                                 if (i + 1 < end) {
 147                                         result.AppendFormat ("{0}\\z|\\A", regex);
 148                                 } else {
 149                                         result.AppendFormat ("({0})\\z", regex);
 150                                 }
 151                         }
 152
 153                         Regex r = new Regex (result.ToString ());
 154                         regexCache [verb] = r;
 155                         return r;
 156                 }
 157
 158                 static void EnsureCache ()
 159                 {
 160                         if (regexCache == null)
 161                                 regexCache = new Hashtable ();
 162                 }
 163         }
 164 }
 165