summaryrefslogtreecommitdiff
path: root/mcs/class/corlib/System/Delegate.cs
blob: 507153c421aa2432b48f47c7eddacc499c4639ba (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
//
// System.Delegate.cs
//
// Authors:
//   Miguel de Icaza (miguel@ximian.com)
//   Daniel Stodden (stodden@in.tum.de)
//   Dietmar Maurer (dietmar@ximian.com)
//
// (C) Ximian, Inc.  http://www.ximian.com
//

//
// Copyright (C) 2004 Novell, Inc (http://www.novell.com)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//

using System.Reflection;
using System.Runtime.Remoting;
using System.Runtime.Serialization;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;

namespace System
{
	/* Contains the rarely used fields of Delegate */
	class DelegateData {
		public Type target_type;
		public string method_name;
	}

	[ClassInterface (ClassInterfaceType.AutoDual)]
	[System.Runtime.InteropServices.ComVisible (true)]
	[Serializable]
	[StructLayout (LayoutKind.Sequential)]
	public abstract class Delegate : ICloneable, ISerializable
	{
		#region Sync with object-internals.h
#pragma warning disable 169, 414, 649
		private IntPtr method_ptr;
		private IntPtr invoke_impl;
		private object m_target;
		private IntPtr method;
		private IntPtr delegate_trampoline;
		private IntPtr method_code;
		private MethodInfo method_info;

		// Keep a ref of the MethodInfo passed to CreateDelegate.
		// Used to keep DynamicMethods alive.
		private MethodInfo original_method_info;

		private DelegateData data;
#pragma warning restore 169, 414, 649
		#endregion

		protected Delegate (object target, string method)
		{
			if (target == null)
				throw new ArgumentNullException ("target");

			if (method == null)
				throw new ArgumentNullException ("method");

			this.m_target = target;
			this.data = new DelegateData ();
			this.data.method_name = method;
		}

		protected Delegate (Type target, string method)
		{
			if (target == null)
				throw new ArgumentNullException ("target");

			if (method == null)
				throw new ArgumentNullException ("method");

			this.data = new DelegateData ();
			this.data.method_name = method;
			this.data.target_type = target;
		}

		public MethodInfo Method {
			get {
				if (method_info != null) {
					return method_info;
				} else {
					if (method != IntPtr.Zero) {
						method_info = (MethodInfo)MethodBase.GetMethodFromHandleNoGenericCheck (new RuntimeMethodHandle (method));
					}
					return method_info;
				}
			}
		}

		public object Target {
			get {
				return m_target;
			}
		}

		//
		// Methods
		//

		[MethodImplAttribute (MethodImplOptions.InternalCall)]
		internal static extern Delegate CreateDelegate_internal (Type type, object target, MethodInfo info, bool throwOnBindFailure);

		[MethodImplAttribute (MethodImplOptions.InternalCall)]
		internal extern void SetMulticastInvoke ();

		private static bool arg_type_match (Type delArgType, Type argType) {
			bool match = delArgType == argType;

			// Delegate contravariance
			if (!match) {
				if (!argType.IsValueType && argType.IsAssignableFrom (delArgType))
					match = true;
			}
			// enum basetypes
			if (!match) {
				if (delArgType.IsEnum && Enum.GetUnderlyingType (delArgType) == argType)
					match = true;
			}

			return match;
		}

		private static bool arg_type_match_this (Type delArgType, Type argType, bool boxedThis) {
			bool match;
			if (argType.IsValueType)
				match = delArgType.IsByRef && delArgType.GetElementType () == argType ||
						(boxedThis && delArgType == argType);
			else
				match = delArgType == argType || argType.IsAssignableFrom (delArgType);

			return match;
		}
		private static bool return_type_match (Type delReturnType, Type returnType) {
			bool returnMatch = returnType == delReturnType;

			if (!returnMatch) {
				// Delegate covariance
				if (!returnType.IsValueType && delReturnType.IsAssignableFrom (returnType))
					returnMatch = true;
			}

			return returnMatch;
		}

		public static Delegate CreateDelegate (Type type, object firstArgument, MethodInfo method, bool throwOnBindFailure)
		{
			return CreateDelegate (type, firstArgument, method, throwOnBindFailure, true);
		}

		static Delegate CreateDelegate (Type type, object firstArgument, MethodInfo method, bool throwOnBindFailure, bool allowClosed)
		{
			// The name of the parameter changed in 2.0
			object target = firstArgument;

			if (type == null)
				throw new ArgumentNullException ("type");

			if (method == null)
				throw new ArgumentNullException ("method");

			if (!type.IsSubclassOf (typeof (MulticastDelegate)))
				throw new ArgumentException ("type is not a subclass of Multicastdelegate");

			MethodInfo invoke = type.GetMethod ("Invoke");

			if (!return_type_match (invoke.ReturnType, method.ReturnType))
				if (throwOnBindFailure)
					throw new ArgumentException ("method return type is incompatible");
				else
					return null;

			ParameterInfo[] delargs = invoke.GetParametersInternal ();
			ParameterInfo[] args = method.GetParametersInternal ();

			bool argLengthMatch;

			if (target != null) {
				// delegate closed over target
				if (!method.IsStatic)
					// target is passed as this
					argLengthMatch = (args.Length == delargs.Length);
				else
					// target is passed as the first argument to the static method
					argLengthMatch = (args.Length == delargs.Length + 1);
			} else {
				if (!method.IsStatic) {
					//
					// Net 2.0 feature. The first argument of the delegate is passed
					// as the 'this' argument to the method.
					//
					argLengthMatch = (args.Length + 1 == delargs.Length);

					if (!argLengthMatch)
						// closed over a null reference
						argLengthMatch = (args.Length == delargs.Length);
				} else {
					argLengthMatch = (args.Length == delargs.Length);

					if (!argLengthMatch)
						// closed over a null reference
						argLengthMatch = args.Length == delargs.Length + 1;
				}
			}
			if (!argLengthMatch)
				if (throwOnBindFailure)
					throw new ArgumentException ("method argument length mismatch");
				else
					return null;

			bool argsMatch;
			if (target != null) {
				if (!method.IsStatic) {
					argsMatch = arg_type_match_this (target.GetType (), method.DeclaringType, true);
					for (int i = 0; i < args.Length; i++)
						argsMatch &= arg_type_match (delargs [i].ParameterType, args [i].ParameterType);
				} else {
					argsMatch = arg_type_match (target.GetType (), args [0].ParameterType);
					for (int i = 1; i < args.Length; i++)
						argsMatch &= arg_type_match (delargs [i - 1].ParameterType, args [i].ParameterType);					
				}
			} else {
				if (!method.IsStatic) {
					if (args.Length + 1 == delargs.Length) {
						// The first argument should match this
						argsMatch = arg_type_match_this (delargs [0].ParameterType, method.DeclaringType, false);
						for (int i = 0; i < args.Length; i++)
							argsMatch &= arg_type_match (delargs [i + 1].ParameterType, args [i].ParameterType);
					} else {
						// closed over a null reference
						argsMatch = allowClosed;
						for (int i = 0; i < args.Length; i++)
							argsMatch &= arg_type_match (delargs [i].ParameterType, args [i].ParameterType);
					}
				} else {
					if (delargs.Length + 1 == args.Length) {
						// closed over a null reference
						argsMatch = !(args [0].ParameterType.IsValueType || args [0].ParameterType.IsByRef) && allowClosed;
						for (int i = 0; i < delargs.Length; i++)
							argsMatch &= arg_type_match (delargs [i].ParameterType, args [i + 1].ParameterType);
					} else {
						argsMatch = true;
						for (int i = 0; i < args.Length; i++)
							argsMatch &= arg_type_match (delargs [i].ParameterType, args [i].ParameterType);
					}
				}
			}

			if (!argsMatch)
				if (throwOnBindFailure)
					throw new ArgumentException ("method arguments are incompatible");
				else
					return null;

			Delegate d = CreateDelegate_internal (type, target, method, throwOnBindFailure);
			if (d != null)
				d.original_method_info = method;
			return d;
		}

		public static Delegate CreateDelegate (Type type, object firstArgument, MethodInfo method)
		{
			return CreateDelegate (type, firstArgument, method, true, true);
		}

		public static Delegate CreateDelegate (Type type, MethodInfo method, bool throwOnBindFailure)
		{
			return CreateDelegate (type, null, method, throwOnBindFailure, false);
		}

		public static Delegate CreateDelegate (Type type, MethodInfo method)
		{
			return CreateDelegate (type, method, true);
		}

		public static Delegate CreateDelegate (Type type, object target, string method)
		{
			return CreateDelegate (type, target, method, false);
		}

		static MethodInfo GetCandidateMethod (Type type, Type target, string method, BindingFlags bflags, bool ignoreCase, bool throwOnBindFailure)
		{
			if (type == null)
				throw new ArgumentNullException ("type");

			if (method == null)
				throw new ArgumentNullException ("method");

			if (!type.IsSubclassOf (typeof (MulticastDelegate)))
				throw new ArgumentException ("type is not subclass of MulticastDelegate.");

			MethodInfo invoke = type.GetMethod ("Invoke");
			ParameterInfo [] delargs = invoke.GetParametersInternal ();
			Type[] delargtypes = new Type [delargs.Length];

			for (int i=0; i<delargs.Length; i++)
				delargtypes [i] = delargs [i].ParameterType;

			/* 
			 * FIXME: we should check the caller has reflection permission
			 * or if it lives in the same assembly...
			 */

			/*
			 * since we need to walk the inheritance chain anyway to
			 * find private methods, adjust the bindingflags to ignore
			 * inherited methods
			 */
			BindingFlags flags = BindingFlags.ExactBinding |
				BindingFlags.Public | BindingFlags.NonPublic |
				BindingFlags.DeclaredOnly | bflags;

			if (ignoreCase)
				flags |= BindingFlags.IgnoreCase;

			MethodInfo info = null;

			for (Type targetType = target; targetType != null; targetType = targetType.BaseType) {
				MethodInfo mi = targetType.GetMethod (method, flags,
					null, delargtypes, EmptyArray<ParameterModifier>.Value);
				if (mi != null && return_type_match (invoke.ReturnType, mi.ReturnType)) {
					info = mi;
					break;
				}
			}

			if (info == null) {
				if (throwOnBindFailure)
					throw new ArgumentException ("Couldn't bind to method '" + method + "'.");
				else
					return null;
			}

			return info;
		}

 		public static Delegate CreateDelegate (Type type, Type target, string method, bool ignoreCase, bool throwOnBindFailure)
		{
			if (target == null)
				throw new ArgumentNullException ("target");

			MethodInfo info = GetCandidateMethod (type, target, method,
				BindingFlags.Static, ignoreCase, throwOnBindFailure);
			if (info == null)
				return null;

			return CreateDelegate_internal (type, null, info, throwOnBindFailure);
		}

 		public static Delegate CreateDelegate (Type type, Type target, string method) {
			return CreateDelegate (type, target, method, false, true);
		}

 		public static Delegate CreateDelegate (Type type, Type target, string method, bool ignoreCase) {
			return CreateDelegate (type, target, method, ignoreCase, true);
		}

		public static Delegate CreateDelegate (Type type, object target, string method, bool ignoreCase, bool throwOnBindFailure)
		{
			if (target == null)
				throw new ArgumentNullException ("target");

			MethodInfo info = GetCandidateMethod (type, target.GetType (), method,
				BindingFlags.Instance, ignoreCase, throwOnBindFailure);
			if (info == null)
				return null;

			return CreateDelegate_internal (type, target, info, throwOnBindFailure);
		}

		public static Delegate CreateDelegate (Type type, object target, string method, bool ignoreCase) {
			return CreateDelegate (type, target, method, ignoreCase, true);
		}

		public object DynamicInvoke (params object[] args)
		{
			return DynamicInvokeImpl (args);
		}

		protected virtual object DynamicInvokeImpl (object[] args)
		{
			if (Method == null) {
				Type[] mtypes = new Type [args.Length];
				for (int i = 0; i < args.Length; ++i) {
					mtypes [i] = args [i].GetType ();
				}
				method_info = m_target.GetType ().GetMethod (data.method_name, mtypes);
			}

			if (Method.IsStatic && (args != null ? args.Length : 0) == Method.GetParametersCount () - 1) {
				// The delegate is bound to m_target
				if (args != null) {
					object[] newArgs = new object [args.Length + 1];
					args.CopyTo (newArgs, 1);
					newArgs [0] = m_target;
					args = newArgs;
				} else {
					args = new object [] { m_target };
				}
				return Method.Invoke (null, args);
			}

			return Method.Invoke (m_target, args);
		}

		public virtual object Clone ()
		{
			return MemberwiseClone ();
		}

		internal bool Compare (Delegate d)
		{
			if (d == null)
				return false;
			
			// Do not compare method_ptr, since it can point to a trampoline
			if (d.m_target == m_target && d.method == method) {
				if (d.data != null || data != null) {
					/* Uncommon case */
					if (d.data != null && data != null)
						return (d.data.target_type == data.target_type && d.data.method_name == data.method_name);
					else
						return false;
				}
				return true;
			}

			return false;
		}

		public override bool Equals (object obj)
		{
			return Compare (obj as Delegate);
		}

		public override int GetHashCode ()
		{
			return method.GetHashCode () ^ (m_target != null ? m_target.GetHashCode () : 0);
		}

		protected virtual MethodInfo GetMethodImpl ()
		{
			return Method;
		}

		// This is from ISerializable
		public virtual void GetObjectData (SerializationInfo info, StreamingContext context)
		{
			DelegateSerializationHolder.GetDelegateData (this, info, context);
		}

		public virtual Delegate[] GetInvocationList()
		{
			return new Delegate[] { this };
		}

		/// <symmary>
		///   Returns a new MulticastDelegate holding the
		///   concatenated invocation lists of MulticastDelegates a and b
		/// </symmary>
		public static Delegate Combine (Delegate a, Delegate b)
		{
			if (a == null) {
				if (b == null)
					return null;
				return b;
			} else 
				if (b == null)
					return a;

			if (a.GetType () != b.GetType ())
				throw new ArgumentException (Locale.GetText ("Incompatible Delegate Types. First is {0} second is {1}.", a.GetType ().FullName, b.GetType ().FullName));
			
			return a.CombineImpl (b);
		}

		/// <symmary>
		///   Returns a new MulticastDelegate holding the
		///   concatenated invocation lists of an Array of MulticastDelegates
		/// </symmary>
		[System.Runtime.InteropServices.ComVisible (true)]
		public static Delegate Combine (params Delegate[] delegates)
		{
			if (delegates == null)
				return null;

			Delegate retval = null;

			foreach (Delegate next in delegates)
				retval = Combine (retval, next);

			return retval;
		}

		protected virtual Delegate CombineImpl (Delegate d)
		{
			throw new MulticastNotSupportedException (String.Empty);
		}

		public static Delegate Remove (Delegate source, Delegate value) 
		{
			if (source == null)
				return null;

			if (value == null)
				return source;

			if (source.GetType () != value.GetType ())
				throw new ArgumentException (Locale.GetText ("Incompatible Delegate Types. First is {0} second is {1}.", source.GetType ().FullName, value.GetType ().FullName));

			return source.RemoveImpl (value);
		}

		protected virtual Delegate RemoveImpl (Delegate d)
		{
			if (this.Equals (d))
				return null;

			return this;
		}

		public static Delegate RemoveAll (Delegate source, Delegate value)
		{
			Delegate tmp = source;
			while ((source = Delegate.Remove (source, value)) != tmp)
				tmp = source;

			return tmp;
		}

		public static bool operator == (Delegate d1, Delegate d2)
		{
			if ((object)d1 == null) {
				if ((object)d2 == null)
					return true;
				return false;
			} else if ((object) d2 == null)
				return false;
			
			return d1.Equals (d2);
		}

		public static bool operator != (Delegate d1, Delegate d2)
		{
			return !(d1 == d2);
		}

		internal bool IsTransparentProxy ()
		{
#if DISABLE_REMOTING
			return false;
#else
			return RemotingServices.IsTransparentProxy (m_target);
#endif
		}
	}
}