mcs/class/corlib/System/MulticastDelegate.cs

   1 //
   2 // System.MultiCastDelegate.cs
   3 //
   4 // Authors:
   5 //   Miguel de Icaza (miguel@ximian.com)
   6 //   Daniel Stodden (stodden@in.tum.de)
   7 //
   8 // (C) Ximian, Inc.  http://www.ximian.com
   9 //
  10
  11 //
  12 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)
  13 //
  14 // Permission is hereby granted, free of charge, to any person obtaining
  15 // a copy of this software and associated documentation files (the
  16 // "Software"), to deal in the Software without restriction, including
  17 // without limitation the rights to use, copy, modify, merge, publish,
  18 // distribute, sublicense, and/or sell copies of the Software, and to
  19 // permit persons to whom the Software is furnished to do so, subject to
  20 // the following conditions:
  21 //
  22 // The above copyright notice and this permission notice shall be
  23 // included in all copies or substantial portions of the Software.
  24 //
  25 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  26 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  27 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  28 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  29 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  30 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  31 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  32 //
  33
  34 using System.Collections;
  35 using System.Runtime.Serialization;
  36
  37 namespace System
  38 {
  39 #if NET_2_0
  40         [System.Runtime.InteropServices.ComVisible (true)]
  41         [Serializable]
  42 #endif
  43         public abstract class MulticastDelegate : Delegate
  44         {
  45                 private MulticastDelegate prev;
  46                 private MulticastDelegate kpm_next;
  47
  48                 protected MulticastDelegate (object target, string method)
  49                         : base (target, method)
  50                 {
  51                         prev = null;
  52                 }
  53
  54                 protected MulticastDelegate (Type target, string method)
  55                         : base (target, method)
  56                 {
  57                         prev = null;
  58                 }
  59
  60                 public override void GetObjectData (SerializationInfo info, StreamingContext context)
  61                 {
  62                         base.GetObjectData  (info, context);
  63                 }
  64
  65
  66                 protected sealed override object DynamicInvokeImpl (object[] args)
  67                 {
  68                         if (prev != null)
  69                                 prev.DynamicInvokeImpl (args);
  70
  71                         return base.DynamicInvokeImpl (args);
  72                 }
  73
  74                 // <remarks>
  75                 //   Equals: two multicast delegates are equal if their base is equal
  76                 //   and their invocations list is equal.
  77                 // </remarks>
  78                 public sealed override bool Equals (object obj)
  79                 {
  80                         if (!base.Equals (obj))
  81                                 return false;
  82
  83                         MulticastDelegate d = obj as MulticastDelegate;
  84                         if (d == null)
  85                                 return false;
  86
  87                         if (this.prev == null) {
  88                                 if (d.prev == null)
  89                                         return true;
  90                                 else
  91                                         return false;
  92                         }
  93
  94                         return this.prev.Equals (d.prev);
  95                 }
  96
  97                 //
  98                 // FIXME: This could use some improvements.
  99                 //
 100                 public sealed override int GetHashCode ()
 101                 {
 102                         return base.GetHashCode ();
 103                 }
 104
 105                 // <summary>
 106                 //   Return, in order of invocation, the invocation list
 107                 //   of a MulticastDelegate
 108                 // </summary>
 109                 public sealed override Delegate[] GetInvocationList ()
 110                 {
 111                         MulticastDelegate d;
 112                         d = (MulticastDelegate) this.Clone ();
 113                         for (d.kpm_next = null; d.prev != null; d = d.prev)
 114                                 d.prev.kpm_next = d;
 115
 116                         if (d.kpm_next == null) {
 117                                 MulticastDelegate other = (MulticastDelegate) d.Clone ();
 118                                 other.prev = null;
 119                                 other.kpm_next = null;
 120                                 return new Delegate [1] { other };
 121                         }
 122
 123                         ArrayList list = new ArrayList ();
 124                         for (; d != null; d = d.kpm_next) {
 125                                 MulticastDelegate other = (MulticastDelegate) d.Clone ();
 126                                 other.prev = null;
 127                                 other.kpm_next = null;
 128                                 list.Add (other);
 129                         }
 130
 131                         return (Delegate []) list.ToArray (typeof (Delegate));
 132                 }
 133
 134                 // <summary>
 135                 //   Combines this MulticastDelegate with the (Multicast)Delegate `follow'.
 136                 //   This does _not_ combine with Delegates. ECMA states the whole delegate
 137                 //   thing should have better been a simple System.Delegate class.
 138                 //   Compiler generated delegates are always MulticastDelegates.
 139                 // </summary>
 140                 protected sealed override Delegate CombineImpl (Delegate follow)
 141                 {
 142                         MulticastDelegate combined, orig, clone;
 143
 144                         if (this.GetType() != follow.GetType ())
 145                                 throw new ArgumentException (Locale.GetText ("Incompatible Delegate Types."));
 146
 147                         combined = (MulticastDelegate)follow.Clone ();
 148                         combined.SetMulticastInvoke ();
 149
 150                         for (clone = combined, orig = ((MulticastDelegate)follow).prev; orig != null; orig = orig.prev) {
 151
 152                                 clone.prev = (MulticastDelegate)orig.Clone ();
 153                                 clone = clone.prev;
 154                         }
 155
 156                         clone.prev = (MulticastDelegate)this.Clone ();
 157
 158                         for (clone = clone.prev, orig = this.prev; orig != null; orig = orig.prev) {
 159
 160                                 clone.prev = (MulticastDelegate)orig.Clone ();
 161                                 clone = clone.prev;
 162                         }
 163
 164                         return combined;
 165                 }
 166
 167                 private bool BaseEquals (MulticastDelegate value)
 168                 {
 169                         return base.Equals (value);
 170                 }
 171
 172                 /*
 173                  * Perform a slightly crippled version of
 174                  * Knuth-Pratt-Morris over MulticastDelegate chains.
 175                  * Border values are set as pointers in kpm_next;
 176                  * Generally, KPM border arrays are length n+1 for
 177                  * strings of n. This one works with length n at the
 178                  * expense of a few additional comparisions.
 179                  */
 180                 private static MulticastDelegate KPM (MulticastDelegate needle, MulticastDelegate haystack,
 181                                                       out MulticastDelegate tail)
 182                 {
 183                         MulticastDelegate nx, hx;
 184
 185                         // preprocess
 186                         hx = needle;
 187                         nx = needle.kpm_next = null;
 188                         do {
 189                                 while ((nx != null) && (!nx.BaseEquals (hx)))
 190                                         nx = nx.kpm_next;
 191
 192                                 hx = hx.prev;
 193                                 if (hx == null)
 194                                         break;
 195
 196                                 nx = nx == null ? needle : nx.prev;
 197                                 if (hx.BaseEquals (nx))
 198                                         hx.kpm_next = nx.kpm_next;
 199                                 else
 200                                         hx.kpm_next = nx;
 201
 202                         } while (true);
 203
 204                         // match
 205                         MulticastDelegate match = haystack;
 206                         nx = needle;
 207                         hx = haystack;
 208                         do {
 209                                 while (nx != null && !nx.BaseEquals (hx)) {
 210                                         nx = nx.kpm_next;
 211                                         match = match.prev;
 212                                 }
 213
 214                                 nx = nx == null ? needle : nx.prev;
 215                                 if (nx == null) {
 216                                         // bingo
 217                                         tail = hx.prev;
 218                                         return match;
 219                                 }
 220
 221                                 hx = hx.prev;
 222                         } while (hx != null);
 223
 224                         tail = null;
 225                         return null;
 226                 }
 227
 228                 protected sealed override Delegate RemoveImpl (Delegate value)
 229                 {
 230                         if (value == null)
 231                                 return this;
 232
 233                         // match this with value
 234                         MulticastDelegate head, tail;
 235                         head = KPM ((MulticastDelegate)value, this, out tail);
 236                         if (head == null)
 237                                 return this;
 238
 239                         // duplicate chain without head..tail
 240                         MulticastDelegate prev = null, retval = null, orig;
 241                         for (orig = this; (object)orig != (object)head; orig = orig.prev) {
 242                                 MulticastDelegate clone = (MulticastDelegate)orig.Clone ();
 243                                 if (prev != null)
 244                                         prev.prev = clone;
 245                                 else
 246                                         retval = clone;
 247                                 prev = clone;
 248                         }
 249                         for (orig = tail; (object)orig != null; orig = orig.prev) {
 250                                 MulticastDelegate clone = (MulticastDelegate)orig.Clone ();
 251                                 if (prev != null)
 252                                         prev.prev = clone;
 253                                 else
 254                                         retval = clone;
 255                                 prev = clone;
 256                         }
 257                         if (prev != null)
 258                                 prev.prev = null;
 259
 260                         return retval;
 261                 }
 262
 263                 public static bool operator == (MulticastDelegate d1, MulticastDelegate d2)
 264                 {
 265                         if (d1 == null)
 266                                 return d2 == null;
 267
 268                         return d1.Equals (d2);
 269                 }
 270
 271                 public static bool operator != (MulticastDelegate d1, MulticastDelegate d2)
 272                 {
 273                         if (d1 == null)
 274                                 return d2 != null;
 275
 276                         return !d1.Equals (d2);
 277                 }
 278         }
 279 }