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         [System.Runtime.InteropServices.ComVisible (true)]
  40         [Serializable]
  41         public abstract class MulticastDelegate : Delegate
  42         {
  43                 private MulticastDelegate prev;
  44                 private MulticastDelegate kpm_next;
  45
  46                 protected MulticastDelegate (object target, string method)
  47                         : base (target, method)
  48                 {
  49                         prev = null;
  50                 }
  51
  52                 protected MulticastDelegate (Type target, string method)
  53                         : base (target, method)
  54                 {
  55                         prev = null;
  56                 }
  57
  58                 public override void GetObjectData (SerializationInfo info, StreamingContext context)
  59                 {
  60                         base.GetObjectData  (info, context);
  61                 }
  62
  63
  64                 protected sealed override object DynamicInvokeImpl (object[] args)
  65                 {
  66                         if (prev != null)
  67                                 prev.DynamicInvokeImpl (args);
  68
  69                         return base.DynamicInvokeImpl (args);
  70                 }
  71
  72                 internal bool HasSingleTarget {
  73                         get { return prev == null; }
  74                 }
  75                 // <remarks>
  76                 //   Equals: two multicast delegates are equal if their base is equal
  77                 //   and their invocations list is equal.
  78                 // </remarks>
  79                 public sealed override bool Equals (object obj)
  80                 {
  81                         if (!base.Equals (obj))
  82                                 return false;
  83
  84                         MulticastDelegate d = obj as MulticastDelegate;
  85                         if (d == null)
  86                                 return false;
  87
  88                         if (this.prev == null) {
  89                                 if (d.prev == null)
  90                                         return true;
  91                                 else
  92                                         return false;
  93                         }
  94
  95                         return this.prev.Equals (d.prev);
  96                 }
  97
  98                 //
  99                 // FIXME: This could use some improvements.
 100                 //
 101                 public sealed override int GetHashCode ()
 102                 {
 103                         return base.GetHashCode ();
 104                 }
 105
 106                 // <summary>
 107                 //   Return, in order of invocation, the invocation list
 108                 //   of a MulticastDelegate
 109                 // </summary>
 110                 public sealed override Delegate[] GetInvocationList ()
 111                 {
 112                         MulticastDelegate d;
 113                         d = (MulticastDelegate) this.Clone ();
 114                         for (d.kpm_next = null; d.prev != null; d = d.prev)
 115                                 d.prev.kpm_next = d;
 116
 117                         if (d.kpm_next == null) {
 118                                 MulticastDelegate other = (MulticastDelegate) d.Clone ();
 119                                 other.prev = null;
 120                                 other.kpm_next = null;
 121                                 return new Delegate [1] { other };
 122                         }
 123
 124                         ArrayList list = new ArrayList ();
 125                         for (; d != null; d = d.kpm_next) {
 126                                 MulticastDelegate other = (MulticastDelegate) d.Clone ();
 127                                 other.prev = null;
 128                                 other.kpm_next = null;
 129                                 list.Add (other);
 130                         }
 131
 132                         return (Delegate []) list.ToArray (typeof (Delegate));
 133                 }
 134
 135                 // <summary>
 136                 //   Combines this MulticastDelegate with the (Multicast)Delegate `follow'.
 137                 //   This does _not_ combine with Delegates. ECMA states the whole delegate
 138                 //   thing should have better been a simple System.Delegate class.
 139                 //   Compiler generated delegates are always MulticastDelegates.
 140                 // </summary>
 141                 protected sealed override Delegate CombineImpl (Delegate follow)
 142                 {
 143                         MulticastDelegate combined, orig, clone;
 144
 145                         if (this.GetType() != follow.GetType ())
 146                                 throw new ArgumentException (Locale.GetText ("Incompatible Delegate Types."));
 147
 148                         combined = (MulticastDelegate)follow.Clone ();
 149                         combined.SetMulticastInvoke ();
 150
 151                         for (clone = combined, orig = ((MulticastDelegate)follow).prev; orig != null; orig = orig.prev) {
 152
 153                                 clone.prev = (MulticastDelegate)orig.Clone ();
 154                                 clone = clone.prev;
 155                         }
 156
 157                         clone.prev = (MulticastDelegate)this.Clone ();
 158
 159                         for (clone = clone.prev, orig = this.prev; orig != null; orig = orig.prev) {
 160
 161                                 clone.prev = (MulticastDelegate)orig.Clone ();
 162                                 clone = clone.prev;
 163                         }
 164
 165                         return combined;
 166                 }
 167
 168                 private bool BaseEquals (MulticastDelegate value)
 169                 {
 170                         return base.Equals (value);
 171                 }
 172
 173                 /*
 174                  * Perform a slightly crippled version of
 175                  * Knuth-Pratt-Morris over MulticastDelegate chains.
 176                  * Border values are set as pointers in kpm_next;
 177                  * Generally, KPM border arrays are length n+1 for
 178                  * strings of n. This one works with length n at the
 179                  * expense of a few additional comparisions.
 180                  */
 181                 private static MulticastDelegate KPM (MulticastDelegate needle, MulticastDelegate haystack,
 182                                                       out MulticastDelegate tail)
 183                 {
 184                         MulticastDelegate nx, hx;
 185
 186                         // preprocess
 187                         hx = needle;
 188                         nx = needle.kpm_next = null;
 189                         do {
 190                                 while ((nx != null) && (!nx.BaseEquals (hx)))
 191                                         nx = nx.kpm_next;
 192
 193                                 hx = hx.prev;
 194                                 if (hx == null)
 195                                         break;
 196
 197                                 nx = nx == null ? needle : nx.prev;
 198                                 if (hx.BaseEquals (nx))
 199                                         hx.kpm_next = nx.kpm_next;
 200                                 else
 201                                         hx.kpm_next = nx;
 202
 203                         } while (true);
 204
 205                         // match
 206                         MulticastDelegate match = haystack;
 207                         nx = needle;
 208                         hx = haystack;
 209                         do {
 210                                 while (nx != null && !nx.BaseEquals (hx)) {
 211                                         nx = nx.kpm_next;
 212                                         match = match.prev;
 213                                 }
 214
 215                                 nx = nx == null ? needle : nx.prev;
 216                                 if (nx == null) {
 217                                         // bingo
 218                                         tail = hx.prev;
 219                                         return match;
 220                                 }
 221
 222                                 hx = hx.prev;
 223                         } while (hx != null);
 224
 225                         tail = null;
 226                         return null;
 227                 }
 228
 229                 protected sealed override Delegate RemoveImpl (Delegate value)
 230                 {
 231                         if (value == null)
 232                                 return this;
 233
 234                         // match this with value
 235                         MulticastDelegate head, tail;
 236                         head = KPM ((MulticastDelegate)value, this, out tail);
 237                         if (head == null)
 238                                 return this;
 239
 240                         // duplicate chain without head..tail
 241                         MulticastDelegate prev = null, retval = null, orig;
 242                         for (orig = this; (object)orig != (object)head; orig = orig.prev) {
 243                                 MulticastDelegate clone = (MulticastDelegate)orig.Clone ();
 244                                 if (prev != null)
 245                                         prev.prev = clone;
 246                                 else
 247                                         retval = clone;
 248                                 prev = clone;
 249                         }
 250                         for (orig = tail; (object)orig != null; orig = orig.prev) {
 251                                 MulticastDelegate clone = (MulticastDelegate)orig.Clone ();
 252                                 if (prev != null)
 253                                         prev.prev = clone;
 254                                 else
 255                                         retval = clone;
 256                                 prev = clone;
 257                         }
 258                         if (prev != null)
 259                                 prev.prev = null;
 260
 261                         return retval;
 262                 }
 263
 264                 public static bool operator == (MulticastDelegate d1, MulticastDelegate d2)
 265                 {
 266                         if (d1 == null)
 267                                 return d2 == null;
 268
 269                         return d1.Equals (d2);
 270                 }
 271
 272                 public static bool operator != (MulticastDelegate d1, MulticastDelegate d2)
 273                 {
 274                         if (d1 == null)
 275                                 return d2 != null;
 276
 277                         return !d1.Equals (d2);
 278                 }
 279         }
 280 }