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 using System.Reflection.Emit;
  39 using System.Collections.Generic;
  40
  41 namespace System
  42 {
  43         internal class MonoCustomAttrs
  44         {
  45                 static Assembly corlib;
  46
  47                 /* Treat as user types all corlib types extending System.Type that are not MonoType and TypeBuilder */
  48                 static bool IsUserCattrProvider (object obj)
  49                 {
  50                         Type type = obj as Type;
  51                         if ((type is MonoType) || (type is TypeBuilder))
  52                                 return false;
  53                         if ((obj is Type))
  54                                 return true;
  55                         if (corlib == null)
  56                                  corlib = typeof (int).Assembly;
  57                         return obj.GetType ().Assembly != corlib;
  58                 }
  59
  60                 [MethodImplAttribute (MethodImplOptions.InternalCall)]
  61                 internal static extern object[] GetCustomAttributesInternal (ICustomAttributeProvider obj, Type attributeType, bool pseudoAttrs);
  62
  63                 internal static object[] GetPseudoCustomAttributes (ICustomAttributeProvider obj, Type attributeType) {
  64                         object[] pseudoAttrs = null;
  65
  66                         /* FIXME: Add other types */
  67                         if (obj is MonoMethod)
  68                                 pseudoAttrs = ((MonoMethod)obj).GetPseudoCustomAttributes ();
  69                         else if (obj is FieldInfo)
  70                                 pseudoAttrs = ((FieldInfo)obj).GetPseudoCustomAttributes ();
  71                         else if (obj is ParameterInfo)
  72                                 pseudoAttrs = ((ParameterInfo)obj).GetPseudoCustomAttributes ();
  73                         else if (obj is Type)
  74                                 pseudoAttrs = ((Type)obj).GetPseudoCustomAttributes ();
  75
  76                         if ((attributeType != null) && (pseudoAttrs != null)) {
  77                                 for (int i = 0; i < pseudoAttrs.Length; ++i)
  78                                         if (attributeType.IsAssignableFrom (pseudoAttrs [i].GetType ()))
  79                                                 if (pseudoAttrs.Length == 1)
  80                                                         return pseudoAttrs;
  81                                                 else
  82                                                         return new object [] { pseudoAttrs [i] };
  83                                 return new object [0];
  84                         }
  85                         else
  86                                 return pseudoAttrs;
  87                 }
  88
  89                 internal static object[] GetCustomAttributesBase (ICustomAttributeProvider obj, Type attributeType)
  90                 {
  91                         object[] attrs;
  92                         if (IsUserCattrProvider (obj))
  93                                 attrs = obj.GetCustomAttributes (attributeType, true);
  94                         else
  95                                 attrs = GetCustomAttributesInternal (obj, attributeType, false);
  96
  97                         object[] pseudoAttrs = GetPseudoCustomAttributes (obj, attributeType);
  98                         if (pseudoAttrs != null) {
  99                                 object[] res = new object [attrs.Length + pseudoAttrs.Length];
 100                                 System.Array.Copy (attrs, res, attrs.Length);
 101                                 System.Array.Copy (pseudoAttrs, 0, res, attrs.Length, pseudoAttrs.Length);
 102                                 return res;
 103                         }
 104                         else
 105                                 return attrs;
 106                 }
 107
 108                 internal static Attribute GetCustomAttribute (ICustomAttributeProvider obj,
 109                                                                 Type attributeType,
 110                                                                 bool inherit)
 111                 {
 112                         object[] res = GetCustomAttributes (obj, attributeType, inherit);
 113                         if (res.Length == 0)
 114                         {
 115                                 return null;
 116                         }
 117                         else if (res.Length > 1)
 118                         {
 119                                 string msg = "'{0}' has more than one attribute of type '{1}";
 120                                 msg = String.Format (msg, obj, attributeType);
 121                                 throw new AmbiguousMatchException (msg);
 122                         }
 123
 124                         return (Attribute) res[0];
 125                 }
 126
 127                 internal static object[] GetCustomAttributes (ICustomAttributeProvider obj, Type attributeType, bool inherit)
 128                 {
 129                         if (obj == null)
 130                                 throw new ArgumentNullException ("obj");
 131                         if (attributeType == null)
 132                                 throw new ArgumentNullException ("attributeType");
 133
 134                         if (attributeType == typeof (MonoCustomAttrs))
 135                                 attributeType = null;
 136
 137                         object[] r;
 138                         object[] res = GetCustomAttributesBase (obj, attributeType);
 139                         // shortcut
 140                         if (!inherit && res.Length == 1)
 141                         {
 142                                 if (res [0] == null)
 143                                         throw new CustomAttributeFormatException ("Invalid custom attribute format");
 144
 145                                 if (attributeType != null)
 146                                 {
 147                                         if (attributeType.IsAssignableFrom (res[0].GetType ()))
 148                                         {
 149                                                 r = (object[]) Array.CreateInstance (attributeType, 1);
 150                                                 r[0] = res[0];
 151                                         }
 152                                         else
 153                                         {
 154                                                 r = (object[]) Array.CreateInstance (attributeType, 0);
 155                                         }
 156                                 }
 157                                 else
 158                                 {
 159                                         r = (object[]) Array.CreateInstance (res[0].GetType (), 1);
 160                                         r[0] = res[0];
 161                                 }
 162                                 return r;
 163                         }
 164
 165                         // if AttributeType is sealed, and Inherited is set to false, then
 166                         // there's no use in scanning base types
 167                         if ((attributeType != null && attributeType.IsSealed) && inherit)
 168                         {
 169                                 AttributeUsageAttribute usageAttribute = RetrieveAttributeUsage (
 170                                         attributeType);
 171                                 if (!usageAttribute.Inherited)
 172                                 {
 173                                         inherit = false;
 174                                 }
 175                         }
 176
 177                         int initialSize = res.Length < 16 ? res.Length : 16;
 178
 179                         Hashtable attributeInfos = new Hashtable (initialSize);
 180                         ArrayList a = new ArrayList (initialSize);
 181                         ICustomAttributeProvider btype = obj;
 182
 183                         int inheritanceLevel = 0;
 184
 185                         do
 186                         {
 187                                 foreach (object attr in res)
 188                                 {
 189                                         AttributeUsageAttribute usage;
 190                                         if (attr == null)
 191                                                 throw new CustomAttributeFormatException ("Invalid custom attribute format");
 192
 193                                         Type attrType = attr.GetType ();
 194                                         if (attributeType != null)
 195                                         {
 196                                                 if (!attributeType.IsAssignableFrom (attrType))
 197                                                 {
 198                                                         continue;
 199                                                 }
 200                                         }
 201
 202                                         AttributeInfo firstAttribute = (AttributeInfo) attributeInfos[attrType];
 203                                         if (firstAttribute != null)
 204                                         {
 205                                                 usage = firstAttribute.Usage;
 206                                         }
 207                                         else
 208                                         {
 209                                                 usage = RetrieveAttributeUsage (attrType);
 210                                         }
 211
 212                                         // only add attribute to the list of attributes if
 213                                         // - we are on the first inheritance level, or the attribute can be inherited anyway
 214                                         // and (
 215                                         // - multiple attributes of the type are allowed
 216                                         // or (
 217                                         // - this is the first attribute we've discovered
 218                                         // or
 219                                         // - the attribute is on same inheritance level than the first
 220                                         //   attribute that was discovered for this attribute type ))
 221                                         if ((inheritanceLevel == 0 || usage.Inherited) && (usage.AllowMultiple ||
 222                                                 (firstAttribute == null || (firstAttribute != null
 223                                                         && firstAttribute.InheritanceLevel == inheritanceLevel))))
 224                                         {
 225                                                 a.Add (attr);
 226                                         }
 227
 228                                         if (firstAttribute == null)
 229                                         {
 230                                                 attributeInfos.Add (attrType, new AttributeInfo (usage, inheritanceLevel));
 231                                         }
 232                                 }
 233
 234                                 if ((btype = GetBase (btype)) != null)
 235                                 {
 236                                         inheritanceLevel++;
 237                                         res = GetCustomAttributesBase (btype, attributeType);
 238                                 }
 239                         } while (inherit && btype != null);
 240
 241                         object[] array = null;
 242                         if (attributeType == null || attributeType.IsValueType)
 243                         {
 244                                 array = (object[]) Array.CreateInstance (typeof(Attribute), a.Count);
 245                         }
 246                         else
 247                         {
 248                                 array = Array.CreateInstance (attributeType, a.Count) as object[];
 249                         }
 250
 251                         // copy attributes to array
 252                         a.CopyTo (array, 0);
 253
 254                         return array;
 255                 }
 256
 257                 internal static object[] GetCustomAttributes (ICustomAttributeProvider obj, bool inherit)
 258                 {
 259                         if (obj == null)
 260                                 throw new ArgumentNullException ("obj");
 261
 262                         if (!inherit)
 263                                 return (object[]) GetCustomAttributesBase (obj, null).Clone ();
 264
 265                         return GetCustomAttributes (obj, typeof (MonoCustomAttrs), inherit);
 266                 }
 267
 268                 [MethodImplAttribute (MethodImplOptions.InternalCall)]
 269                 static extern CustomAttributeData [] GetCustomAttributesDataInternal (ICustomAttributeProvider obj);
 270
 271                 internal static IList<CustomAttributeData> GetCustomAttributesData (ICustomAttributeProvider obj)
 272                 {
 273                         if (obj == null)
 274                                 throw new ArgumentNullException ("obj");
 275
 276                         CustomAttributeData [] attrs = GetCustomAttributesDataInternal (obj);
 277                         return Array.AsReadOnly<CustomAttributeData> (attrs);
 278                 }
 279
 280                 internal static bool IsDefined (ICustomAttributeProvider obj, Type attributeType, bool inherit)
 281                 {
 282                         if (attributeType == null)
 283                                 throw new ArgumentNullException ("attributeType");
 284
 285                         AttributeUsageAttribute usage = null;
 286                         do {
 287                                 if (IsUserCattrProvider (obj))
 288                                         return obj.IsDefined (attributeType, inherit);
 289
 290                                 if (IsDefinedInternal (obj, attributeType))
 291                                         return true;
 292
 293                                 object[] pseudoAttrs = GetPseudoCustomAttributes (obj, attributeType);
 294                                 if (pseudoAttrs != null) {
 295                                         for (int i = 0; i < pseudoAttrs.Length; ++i)
 296                                                 if (attributeType.IsAssignableFrom (pseudoAttrs[i].GetType ()))
 297                                                         return true;
 298                                 }
 299
 300                                 if (usage == null) {
 301                                         if (!inherit)
 302                                                 return false;
 303
 304                                         usage = RetrieveAttributeUsage (attributeType);
 305                                         if (!usage.Inherited)
 306                                                 return false;
 307                                 }
 308
 309                                 obj = GetBase (obj);
 310                         } while (obj != null);
 311
 312                         return false;
 313                 }
 314
 315                 [MethodImplAttribute (MethodImplOptions.InternalCall)]
 316                 internal static extern bool IsDefinedInternal (ICustomAttributeProvider obj, Type AttributeType);
 317
 318                 static PropertyInfo GetBasePropertyDefinition (PropertyInfo property)
 319                 {
 320                         MethodInfo method = property.GetGetMethod (true);
 321                         if (method == null || !method.IsVirtual)
 322                                 method = property.GetSetMethod (true);
 323                         if (method == null || !method.IsVirtual)
 324                                 return null;
 325
 326                         MethodInfo baseMethod = method.GetBaseMethod ();
 327                         if (baseMethod != null && baseMethod != method) {
 328                                 ParameterInfo[] parameters = property.GetIndexParameters ();
 329                                 if (parameters != null && parameters.Length > 0) {
 330                                         Type[] paramTypes = new Type[parameters.Length];
 331                                         for (int i=0; i < paramTypes.Length; i++)
 332                                                 paramTypes[i] = parameters[i].ParameterType;
 333                                         return baseMethod.DeclaringType.GetProperty (property.Name, property.PropertyType,
 334                                                                                      paramTypes);
 335                                 } else {
 336                                         return baseMethod.DeclaringType.GetProperty (property.Name, property.PropertyType);
 337                                 }
 338                         }
 339                         return null;
 340
 341                 }
 342
 343                 static EventInfo GetBaseEventDefinition (EventInfo evt)
 344                 {
 345                         MethodInfo method = evt.GetAddMethod (true);
 346                         if (method == null || !method.IsVirtual)
 347                                 method = evt.GetRaiseMethod (true);
 348                         if (method == null || !method.IsVirtual)
 349                                 method = evt.GetRemoveMethod (true);
 350                         if (method == null || !method.IsVirtual)
 351                                 return null;
 352
 353                         MethodInfo baseMethod = method.GetBaseMethod ();
 354                         if (baseMethod != null && baseMethod != method) {
 355                                 BindingFlags flags = method.IsPublic ? BindingFlags.Public : BindingFlags.NonPublic;
 356                                 flags |= method.IsStatic ? BindingFlags.Static : BindingFlags.Instance;
 357
 358                                 return baseMethod.DeclaringType.GetEvent (evt.Name, flags);
 359                         }
 360                         return null;
 361                 }
 362
 363                 // Handles Type, MonoProperty and MonoMethod.
 364                 // The runtime has also cases for MonoEvent, MonoField, Assembly and ParameterInfo,
 365                 // but for those we return null here.
 366                 static ICustomAttributeProvider GetBase (ICustomAttributeProvider obj)
 367                 {
 368                         if (obj == null)
 369                                 return null;
 370
 371                         if (obj is Type)
 372                                 return ((Type) obj).BaseType;
 373
 374                         MethodInfo method = null;
 375                         if (obj is MonoProperty)
 376                                 return GetBasePropertyDefinition ((MonoProperty) obj);
 377                         else if (obj is MonoEvent)
 378                                 return GetBaseEventDefinition ((MonoEvent)obj);
 379                         else if (obj is MonoMethod)
 380                                 method = (MethodInfo) obj;
 381
 382                         /**
 383                          * ParameterInfo -> null
 384                          * Assembly -> null
 385                          * MonoEvent -> null
 386                          * MonoField -> null
 387                          */
 388                         if (method == null || !method.IsVirtual)
 389                                 return null;
 390
 391                         MethodInfo baseMethod = method.GetBaseMethod ();
 392                         if (baseMethod == method)
 393                                 return null;
 394
 395                         return baseMethod;
 396                 }
 397
 398                 private static AttributeUsageAttribute RetrieveAttributeUsage (Type attributeType)
 399                 {
 400                         if (attributeType == typeof (AttributeUsageAttribute))
 401                                 /* Avoid endless recursion */
 402                                 return new AttributeUsageAttribute (AttributeTargets.Class);
 403
 404                         AttributeUsageAttribute usageAttribute = null;
 405                         object[] attribs = GetCustomAttributes (attributeType,
 406                                 MonoCustomAttrs.AttributeUsageType, false);
 407                         if (attribs.Length == 0)
 408                         {
 409                                 // if no AttributeUsage was defined on the attribute level, then
 410                                 // try to retrieve if from its base type
 411                                 if (attributeType.BaseType != null)
 412                                 {
 413                                         usageAttribute = RetrieveAttributeUsage (attributeType.BaseType);
 414
 415                                 }
 416                                 if (usageAttribute != null)
 417                                 {
 418                                         // return AttributeUsage of base class
 419                                         return usageAttribute;
 420
 421                                 }
 422                                 // return default AttributeUsageAttribute if no AttributeUsage
 423                                 // was defined on attribute, or its base class
 424                                 return DefaultAttributeUsage;
 425                         }
 426                         // check if more than one AttributeUsageAttribute has been specified
 427                         // on the type
 428                         // NOTE: compilers should prevent this, but that doesn't prevent
 429                         // anyone from using IL ofcourse
 430                         if (attribs.Length > 1)
 431                         {
 432                                 throw new FormatException ("Duplicate AttributeUsageAttribute cannot be specified on an attribute type.");
 433                         }
 434
 435                         return ((AttributeUsageAttribute) attribs[0]);
 436                 }
 437
 438                 private static readonly Type AttributeUsageType = typeof(AttributeUsageAttribute);
 439                 private static readonly AttributeUsageAttribute DefaultAttributeUsage =
 440                         new AttributeUsageAttribute (AttributeTargets.All);
 441
 442                 private class AttributeInfo
 443                 {
 444                         private AttributeUsageAttribute _usage;
 445                         private int _inheritanceLevel;
 446
 447                         public AttributeInfo (AttributeUsageAttribute usage, int inheritanceLevel)
 448                         {
 449                                 _usage = usage;
 450                                 _inheritanceLevel = inheritanceLevel;
 451                         }
 452
 453                         public AttributeUsageAttribute Usage
 454                         {
 455                                 get
 456                                 {
 457                                         return _usage;
 458                                 }
 459                         }
 460
 461                         public int InheritanceLevel
 462                         {
 463                                 get
 464                                 {
 465                                         return _inheritanceLevel;
 466                                 }
 467                         }
 468                 }
 469         }
 470 }
 471