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