mcs/class/corlib/System/MonoCustomAttrs.cs

   1 // System.MonoCustomAttrs.cs
   2 // Hooks into the runtime to get custom attributes for reflection handles
   3 //
   4 // Authors:
   5 //      Paolo Molaro (lupus@ximian.com)
   6 //      Gonzalo Paniagua Javier (gonzalo@ximian.com)
   7 //
   8 // (c) 2002,2003 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;
  35 using System.Reflection;
  36 using System.Collections;
  37 using System.Runtime.CompilerServices;
  38
  39 #if  NET_2_0
  40 using System.Collections.Generic;
  41 #endif
  42
  43 namespace System
  44 {
  45         internal class MonoCustomAttrs
  46         {
  47                 [MethodImplAttribute (MethodImplOptions.InternalCall)]
  48                 internal static extern object[] GetCustomAttributesInternal (ICustomAttributeProvider obj, Type attributeType, bool pseudoAttrs);
  49
  50                 internal static object[] GetPseudoCustomAttributes (ICustomAttributeProvider obj, Type attributeType) {
  51 #if NET_2_0 || BOOTSTRAP_NET_2_0
  52                         object[] pseudoAttrs = null;
  53
  54                         /* FIXME: Add other types */
  55                         if (obj is MonoMethod)
  56                                 pseudoAttrs = ((MonoMethod)obj).GetPseudoCustomAttributes ();
  57                         else if (obj is FieldInfo)
  58                                 pseudoAttrs = ((FieldInfo)obj).GetPseudoCustomAttributes ();
  59                         else if (obj is ParameterInfo)
  60                                 pseudoAttrs = ((ParameterInfo)obj).GetPseudoCustomAttributes ();
  61                         else if (obj is Type)
  62                                 pseudoAttrs = ((Type)obj).GetPseudoCustomAttributes ();
  63
  64                         if ((attributeType != null) && (pseudoAttrs != null)) {
  65                                 for (int i = 0; i < pseudoAttrs.Length; ++i)
  66                                         if (attributeType.IsAssignableFrom (pseudoAttrs [i].GetType ()))
  67                                                 if (pseudoAttrs.Length == 1)
  68                                                         return pseudoAttrs;
  69                                                 else
  70                                                         return new object [] { pseudoAttrs [i] };
  71                                 return new object [0];
  72                         }
  73                         else
  74                                 return pseudoAttrs;
  75 #else
  76                         return null;
  77 #endif
  78                 }
  79
  80                 internal static object[] GetCustomAttributesBase (ICustomAttributeProvider obj, Type attributeType)
  81                 {
  82                         object[] attrs = GetCustomAttributesInternal (obj, attributeType, false);
  83
  84                         object[] pseudoAttrs = GetPseudoCustomAttributes (obj, attributeType);
  85                         if (pseudoAttrs != null) {
  86                                 object[] res = new object [attrs.Length + pseudoAttrs.Length];
  87                                 System.Array.Copy (attrs, res, attrs.Length);
  88                                 System.Array.Copy (pseudoAttrs, 0, res, attrs.Length, pseudoAttrs.Length);
  89                                 return res;
  90                         }
  91                         else
  92                                 return attrs;
  93                 }
  94
  95                 internal static Attribute GetCustomAttribute (ICustomAttributeProvider obj,
  96                                                                 Type attributeType,
  97                                                                 bool inherit)
  98                 {
  99                         object[] res = GetCustomAttributes (obj, attributeType, inherit);
 100                         if (res.Length == 0)
 101                         {
 102                                 return null;
 103                         }
 104                         else if (res.Length > 1)
 105                         {
 106                                 string msg = "'{0}' has more than one attribute of type '{1}";
 107                                 msg = String.Format (msg, obj, attributeType);
 108                                 throw new AmbiguousMatchException (msg);
 109                         }
 110
 111                         return (Attribute) res[0];
 112                 }
 113
 114                 internal static object[] GetCustomAttributes (ICustomAttributeProvider obj, Type attributeType, bool inherit)
 115                 {
 116                         if (obj == null)
 117                                 throw new ArgumentNullException ("obj");
 118                         if (attributeType == null)
 119                                 throw new ArgumentNullException ("attributeType");
 120
 121                         if (attributeType == typeof (MonoCustomAttrs))
 122                                 attributeType = null;
 123
 124                         object[] r;
 125                         object[] res = GetCustomAttributesBase (obj, attributeType);
 126                         // shortcut
 127                         if (!inherit && res.Length == 1)
 128                         {
 129                                 if (attributeType != null)
 130                                 {
 131                                         if (attributeType.IsAssignableFrom (res[0].GetType ()))
 132                                         {
 133                                                 r = (object[]) Array.CreateInstance (attributeType, 1);
 134                                                 r[0] = res[0];
 135                                         }
 136                                         else
 137                                         {
 138                                                 r = (object[]) Array.CreateInstance (attributeType, 0);
 139                                         }
 140                                 }
 141                                 else
 142                                 {
 143                                         r = (object[]) Array.CreateInstance (res[0].GetType (), 1);
 144                                         r[0] = res[0];
 145                                 }
 146                                 return r;
 147                         }
 148
 149                         // if AttributeType is sealed, and Inherited is set to false, then
 150                         // there's no use in scanning base types
 151                         if ((attributeType != null && attributeType.IsSealed) && inherit)
 152                         {
 153                                 AttributeUsageAttribute usageAttribute = RetrieveAttributeUsage (
 154                                         attributeType);
 155                                 if (!usageAttribute.Inherited)
 156                                 {
 157                                         inherit = false;
 158                                 }
 159                         }
 160
 161                         int initialSize = res.Length < 16 ? res.Length : 16;
 162
 163                         Hashtable attributeInfos = new Hashtable (initialSize);
 164                         ArrayList a = new ArrayList (initialSize);
 165                         ICustomAttributeProvider btype = obj;
 166
 167                         int inheritanceLevel = 0;
 168
 169                         do
 170                         {
 171                                 foreach (object attr in res)
 172                                 {
 173                                         AttributeUsageAttribute usage;
 174
 175                                         Type attrType = attr.GetType ();
 176                                         if (attributeType != null)
 177                                         {
 178                                                 if (!attributeType.IsAssignableFrom (attrType))
 179                                                 {
 180                                                         continue;
 181                                                 }
 182                                         }
 183
 184                                         AttributeInfo firstAttribute = (AttributeInfo) attributeInfos[attrType];
 185                                         if (firstAttribute != null)
 186                                         {
 187                                                 usage = firstAttribute.Usage;
 188                                         }
 189                                         else
 190                                         {
 191                                                 usage = RetrieveAttributeUsage (attrType);
 192                                         }
 193
 194                                         // only add attribute to the list of attributes if
 195                                         // - we are on the first inheritance level, or the attribute can be inherited anyway
 196                                         // and (
 197                                         // - multiple attributes of the type are allowed
 198                                         // or (
 199                                         // - this is the first attribute we've discovered
 200                                         // or
 201                                         // - the attribute is on same inheritance level than the first
 202                                         //   attribute that was discovered for this attribute type ))
 203                                         if ((inheritanceLevel == 0 || usage.Inherited) && (usage.AllowMultiple ||
 204                                                 (firstAttribute == null || (firstAttribute != null
 205                                                         && firstAttribute.InheritanceLevel == inheritanceLevel))))
 206                                         {
 207                                                 a.Add (attr);
 208                                         }
 209
 210                                         if (firstAttribute == null)
 211                                         {
 212                                                 attributeInfos.Add (attrType, new AttributeInfo (usage, inheritanceLevel));
 213                                         }
 214                                 }
 215
 216                                 if ((btype = GetBase (btype)) != null)
 217                                 {
 218                                         inheritanceLevel++;
 219                                         res = GetCustomAttributesBase (btype, attributeType);
 220                                 }
 221                         } while (inherit && btype != null);
 222
 223                         object[] array = null;
 224                         if (attributeType == null || attributeType.IsValueType)
 225                         {
 226                                 array = (object[]) Array.CreateInstance (typeof(Attribute), a.Count);
 227                         }
 228                         else
 229                         {
 230                                 array = Array.CreateInstance (attributeType, a.Count) as object[];
 231                         }
 232
 233                         // copy attributes to array
 234                         a.CopyTo (array, 0);
 235
 236                         return array;
 237                 }
 238
 239                 internal static object[] GetCustomAttributes (ICustomAttributeProvider obj, bool inherit)
 240                 {
 241                         if (obj == null)
 242                                 throw new ArgumentNullException ("obj");
 243
 244                         if (!inherit)
 245                                 return (object[]) GetCustomAttributesBase (obj, null).Clone ();
 246
 247                         return GetCustomAttributes (obj, typeof (MonoCustomAttrs), inherit);
 248                 }
 249
 250 #if NET_2_0
 251                 [MethodImplAttribute (MethodImplOptions.InternalCall)]
 252                 static extern CustomAttributeData [] GetCustomAttributesDataInternal (ICustomAttributeProvider obj);
 253
 254                 internal static IList<CustomAttributeData> GetCustomAttributesData (ICustomAttributeProvider obj)
 255                 {
 256                         if (obj == null)
 257                                 throw new ArgumentNullException ("obj");
 258
 259                         CustomAttributeData [] attrs = GetCustomAttributesDataInternal (obj);
 260                         return Array.AsReadOnly<CustomAttributeData> (attrs);
 261                 }
 262 #endif
 263
 264                 internal static bool IsDefined (ICustomAttributeProvider obj, Type attributeType, bool inherit)
 265                 {
 266                         if (attributeType == null)
 267                                 throw new ArgumentNullException ("attributeType");
 268
 269                         if (obj.GetType ().Assembly != typeof (int).Assembly)
 270                                 // User types might overwrite GetCustomAttributes () but not
 271                                 // IsDefined ().
 272                                 return obj.GetCustomAttributes (attributeType, inherit).Length > 0;
 273
 274                         if (IsDefinedInternal (obj, attributeType))
 275                                 return true;
 276
 277                         object[] pseudoAttrs = GetPseudoCustomAttributes (obj, attributeType);
 278                         if (pseudoAttrs != null) {
 279                                 for (int i = 0; i < pseudoAttrs.Length; ++i)
 280                                         if (attributeType.IsAssignableFrom (pseudoAttrs [i].GetType ()))
 281                                                 return true;
 282                         }
 283
 284 #if ONLY_1_1
 285                         if (inherit) {
 286                                 AttributeUsageAttribute usage = RetrieveAttributeUsage (attributeType);
 287                                 if (!usage.Inherited)
 288                                         inherit = false;
 289                         }
 290 #endif
 291
 292                         // FIXME (bug #82431):
 293                         // on 2.0 profile we should always walk the inheritance
 294                         // chain and base the behavior on the inheritance level:
 295                         //
 296                         // 0  : return true if "attributeType" is assignable from
 297                         // any of the custom attributes
 298                         //
 299                         // > 0: return true if "attributeType" is assignable from
 300                         // any of the custom attributes and AttributeUsageAttribute
 301                         // .Inherited of the assignable attribute is true
 302
 303                         ICustomAttributeProvider btype;
 304                         if (inherit && ((btype = GetBase (obj)) != null))
 305                                 return IsDefined (btype, attributeType, inherit);
 306
 307                         return false;
 308                 }
 309
 310                 [MethodImplAttribute (MethodImplOptions.InternalCall)]
 311                 internal static extern bool IsDefinedInternal (ICustomAttributeProvider obj, Type AttributeType);
 312
 313                 static PropertyInfo GetBasePropertyDefinition (PropertyInfo property)
 314                 {
 315                         MethodInfo method = property.GetGetMethod (true);
 316                         if (method == null || !method.IsVirtual)
 317                                 method = property.GetSetMethod (true);
 318                         if (method == null || !method.IsVirtual)
 319                                 return null;
 320
 321                         MethodInfo baseMethod = method.GetBaseDefinition ();
 322                         if (baseMethod != null && baseMethod != method) {
 323                                 ParameterInfo[] parameters = property.GetIndexParameters ();
 324                                 if (parameters != null && parameters.Length > 0) {
 325                                         Type[] paramTypes = new Type[parameters.Length];
 326                                         for (int i=0; i < paramTypes.Length; i++)
 327                                                 paramTypes[i] = parameters[i].ParameterType;
 328                                         return baseMethod.DeclaringType.GetProperty (property.Name, property.PropertyType,
 329                                                                                      paramTypes);
 330                                 } else {
 331                                         return baseMethod.DeclaringType.GetProperty (property.Name, property.PropertyType);
 332                                 }
 333                         }
 334                         return null;
 335
 336                 }
 337
 338                 // Handles Type, MonoProperty and MonoMethod.
 339                 // The runtime has also cases for MonoEvent, MonoField, Assembly and ParameterInfo,
 340                 // but for those we return null here.
 341                 static ICustomAttributeProvider GetBase (ICustomAttributeProvider obj)
 342                 {
 343                         if (obj == null)
 344                                 return null;
 345
 346                         if (obj is Type)
 347                                 return ((Type) obj).BaseType;
 348
 349                         MethodInfo method = null;
 350                         if (obj is MonoProperty)
 351                                 return GetBasePropertyDefinition ((MonoProperty) obj);
 352                         else if (obj is MonoMethod)
 353                                 method = (MethodInfo) obj;
 354
 355                         /**
 356                          * ParameterInfo -> null
 357                          * Assembly -> null
 358                          * MonoEvent -> null
 359                          * MonoField -> null
 360                          */
 361                         if (method == null || !method.IsVirtual)
 362                                 return null;
 363
 364                         MethodInfo baseMethod = method.GetBaseDefinition ();
 365                         if (baseMethod == method)
 366                                 return null;
 367
 368                         return baseMethod;
 369                 }
 370
 371                 private static AttributeUsageAttribute RetrieveAttributeUsage (Type attributeType)
 372                 {
 373                         if (attributeType == typeof (AttributeUsageAttribute))
 374                                 /* Avoid endless recursion */
 375                                 return new AttributeUsageAttribute (AttributeTargets.Class);
 376
 377                         AttributeUsageAttribute usageAttribute = null;
 378                         object[] attribs = GetCustomAttributes (attributeType,
 379                                 MonoCustomAttrs.AttributeUsageType, false);
 380                         if (attribs.Length == 0)
 381                         {
 382                                 // if no AttributeUsage was defined on the attribute level, then
 383                                 // try to retrieve if from its base type
 384                                 if (attributeType.BaseType != null)
 385                                 {
 386                                         usageAttribute = RetrieveAttributeUsage (attributeType.BaseType);
 387
 388                                 }
 389                                 if (usageAttribute != null)
 390                                 {
 391                                         // return AttributeUsage of base class
 392                                         return usageAttribute;
 393
 394                                 }
 395                                 // return default AttributeUsageAttribute if no AttributeUsage
 396                                 // was defined on attribute, or its base class
 397                                 return DefaultAttributeUsage;
 398                         }
 399                         // check if more than one AttributeUsageAttribute has been specified
 400                         // on the type
 401                         // NOTE: compilers should prevent this, but that doesn't prevent
 402                         // anyone from using IL ofcourse
 403                         if (attribs.Length > 1)
 404                         {
 405                                 throw new FormatException ("Duplicate AttributeUsageAttribute cannot be specified on an attribute type.");
 406                         }
 407
 408                         return ((AttributeUsageAttribute) attribs[0]);
 409                 }
 410
 411                 private static readonly Type AttributeUsageType = typeof(AttributeUsageAttribute);
 412                 private static readonly AttributeUsageAttribute DefaultAttributeUsage =
 413                         new AttributeUsageAttribute (AttributeTargets.All);
 414
 415                 private class AttributeInfo
 416                 {
 417                         private AttributeUsageAttribute _usage;
 418                         private int _inheritanceLevel;
 419
 420                         public AttributeInfo (AttributeUsageAttribute usage, int inheritanceLevel)
 421                         {
 422                                 _usage = usage;
 423                                 _inheritanceLevel = inheritanceLevel;
 424                         }
 425
 426                         public AttributeUsageAttribute Usage
 427                         {
 428                                 get
 429                                 {
 430                                         return _usage;
 431                                 }
 432                         }
 433
 434                         public int InheritanceLevel
 435                         {
 436                                 get
 437                                 {
 438                                         return _inheritanceLevel;
 439                                 }
 440                         }
 441                 }
 442         }
 443 }
 444