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.Collections.Generic;
  36 using System.Runtime.Serialization;
  37 using System.Runtime.InteropServices;
  38
  39 namespace System
  40 {
  41         [System.Runtime.InteropServices.ComVisible (true)]
  42         [Serializable]
  43         [StructLayout (LayoutKind.Sequential)]
  44         public abstract class MulticastDelegate : Delegate
  45         {
  46                 private MulticastDelegate prev;
  47                 private MulticastDelegate kpm_next;
  48
  49                 protected MulticastDelegate (object target, string method)
  50                         : base (target, method)
  51                 {
  52                         prev = null;
  53                 }
  54
  55                 protected MulticastDelegate (Type target, string method)
  56                         : base (target, method)
  57                 {
  58                         prev = null;
  59                 }
  60
  61                 public override void GetObjectData (SerializationInfo info, StreamingContext context)
  62                 {
  63                         base.GetObjectData  (info, context);
  64                 }
  65
  66
  67                 protected sealed override object DynamicInvokeImpl (object[] args)
  68                 {
  69                         if (prev != null)
  70                                 prev.DynamicInvokeImpl (args);
  71
  72                         return base.DynamicInvokeImpl (args);
  73                 }
  74
  75                 internal bool HasSingleTarget {
  76                         get { return prev == null; }
  77                 }
  78                 // <remarks>
  79                 //   Equals: two multicast delegates are equal if their base is equal
  80                 //   and their invocations list is equal.
  81                 // </remarks>
  82                 public sealed override bool Equals (object obj)
  83                 {
  84                         if (!base.Equals (obj))
  85                                 return false;
  86
  87                         MulticastDelegate d = obj as MulticastDelegate;
  88                         if (d == null)
  89                                 return false;
  90
  91                         if (this.prev == null) {
  92                                 if (d.prev == null)
  93                                         return true;
  94                                 else
  95                                         return false;
  96                         }
  97
  98                         return this.prev.Equals (d.prev);
  99                 }
 100
 101                 //
 102                 // FIXME: This could use some improvements.
 103                 //
 104                 public sealed override int GetHashCode ()
 105                 {
 106                         return base.GetHashCode ();
 107                 }
 108
 109                 // <summary>
 110                 //   Return, in order of invocation, the invocation list
 111                 //   of a MulticastDelegate
 112                 // </summary>
 113                 public sealed override Delegate[] GetInvocationList ()
 114                 {
 115                         MulticastDelegate d;
 116                         d = (MulticastDelegate) this.Clone ();
 117                         for (d.kpm_next = null; d.prev != null; d = d.prev)
 118                                 d.prev.kpm_next = d;
 119
 120                         if (d.kpm_next == null) {
 121                                 MulticastDelegate other = (MulticastDelegate) d.Clone ();
 122                                 other.prev = null;
 123                                 other.kpm_next = null;
 124                                 return new Delegate [1] { other };
 125                         }
 126
 127                         var list = new List<Delegate> ();
 128                         for (; d != null; d = d.kpm_next) {
 129                                 MulticastDelegate other = (MulticastDelegate) d.Clone ();
 130                                 other.prev = null;
 131                                 other.kpm_next = null;
 132                                 list.Add (other);
 133                         }
 134
 135                         return list.ToArray ();
 136                 }
 137
 138                 // <summary>
 139                 //   Combines this MulticastDelegate with the (Multicast)Delegate `follow'.
 140                 //   This does _not_ combine with Delegates. ECMA states the whole delegate
 141                 //   thing should have better been a simple System.Delegate class.
 142                 //   Compiler generated delegates are always MulticastDelegates.
 143                 // </summary>
 144                 protected sealed override Delegate CombineImpl (Delegate follow)
 145                 {
 146                         MulticastDelegate combined, orig, clone;
 147
 148                         if (this.GetType() != follow.GetType ())
 149                                 throw new ArgumentException (Locale.GetText ("Incompatible Delegate Types. First is {0} second is {1}.", this.GetType ().FullName, follow.GetType ().FullName));
 150
 151                         combined = (MulticastDelegate)follow.Clone ();
 152                         combined.SetMulticastInvoke ();
 153
 154                         for (clone = combined, orig = ((MulticastDelegate)follow).prev; orig != null; orig = orig.prev) {
 155
 156                                 clone.prev = (MulticastDelegate)orig.Clone ();
 157                                 clone = clone.prev;
 158                         }
 159
 160                         clone.prev = (MulticastDelegate)this.Clone ();
 161
 162                         for (clone = clone.prev, orig = this.prev; orig != null; orig = orig.prev) {
 163
 164                                 clone.prev = (MulticastDelegate)orig.Clone ();
 165                                 clone = clone.prev;
 166                         }
 167
 168                         return combined;
 169                 }
 170
 171                 private bool BaseEquals (MulticastDelegate value)
 172                 {
 173                         return base.Equals (value);
 174                 }
 175
 176                 /*
 177                  * Perform a slightly crippled version of
 178                  * Knuth-Pratt-Morris over MulticastDelegate chains.
 179                  * Border values are set as pointers in kpm_next;
 180                  * Generally, KPM border arrays are length n+1 for
 181                  * strings of n. This one works with length n at the
 182                  * expense of a few additional comparisions.
 183                  */
 184                 private static MulticastDelegate KPM (MulticastDelegate needle, MulticastDelegate haystack,
 185                                                       out MulticastDelegate tail)
 186                 {
 187                         MulticastDelegate nx, hx;
 188
 189                         // preprocess
 190                         hx = needle;
 191                         nx = needle.kpm_next = null;
 192                         do {
 193                                 while ((nx != null) && (!nx.BaseEquals (hx)))
 194                                         nx = nx.kpm_next;
 195
 196                                 hx = hx.prev;
 197                                 if (hx == null)
 198                                         break;
 199
 200                                 nx = nx == null ? needle : nx.prev;
 201                                 if (hx.BaseEquals (nx))
 202                                         hx.kpm_next = nx.kpm_next;
 203                                 else
 204                                         hx.kpm_next = nx;
 205
 206                         } while (true);
 207
 208                         // match
 209                         MulticastDelegate match = haystack;
 210                         nx = needle;
 211                         hx = haystack;
 212                         do {
 213                                 while (nx != null && !nx.BaseEquals (hx)) {
 214                                         nx = nx.kpm_next;
 215                                         match = match.prev;
 216                                 }
 217
 218                                 nx = nx == null ? needle : nx.prev;
 219                                 if (nx == null) {
 220                                         // bingo
 221                                         tail = hx.prev;
 222                                         return match;
 223                                 }
 224
 225                                 hx = hx.prev;
 226                         } while (hx != null);
 227
 228                         tail = null;
 229                         return null;
 230                 }
 231
 232                 protected sealed override Delegate RemoveImpl (Delegate value)
 233                 {
 234                         if (value == null)
 235                                 return this;
 236
 237                         // match this with value
 238                         MulticastDelegate head, tail;
 239                         head = KPM ((MulticastDelegate)value, this, out tail);
 240                         if (head == null)
 241                                 return this;
 242
 243                         // duplicate chain without head..tail
 244                         MulticastDelegate prev = null, retval = null, orig;
 245                         for (orig = this; (object)orig != (object)head; orig = orig.prev) {
 246                                 MulticastDelegate clone = (MulticastDelegate)orig.Clone ();
 247                                 if (prev != null)
 248                                         prev.prev = clone;
 249                                 else
 250                                         retval = clone;
 251                                 prev = clone;
 252                         }
 253                         for (orig = tail; (object)orig != null; orig = orig.prev) {
 254                                 MulticastDelegate clone = (MulticastDelegate)orig.Clone ();
 255                                 if (prev != null)
 256                                         prev.prev = clone;
 257                                 else
 258                                         retval = clone;
 259                                 prev = clone;
 260                         }
 261                         if (prev != null)
 262                                 prev.prev = null;
 263
 264                         return retval;
 265                 }
 266
 267                 public static bool operator == (MulticastDelegate d1, MulticastDelegate d2)
 268                 {
 269                         if (d1 == null)
 270                                 return d2 == null;
 271
 272                         return d1.Equals (d2);
 273                 }
 274
 275                 public static bool operator != (MulticastDelegate d1, MulticastDelegate d2)
 276                 {
 277                         if (d1 == null)
 278                                 return d2 != null;
 279
 280                         return !d1.Equals (d2);
 281                 }
 282         }
 283 }