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                         if (IsUserCattrProvider (obj))
 286                                 return obj.IsDefined (attributeType, inherit);
 287
 288                         if (IsDefinedInternal (obj, attributeType))
 289                                 return true;
 290
 291                         object[] pseudoAttrs = GetPseudoCustomAttributes (obj, attributeType);
 292                         if (pseudoAttrs != null) {
 293                                 for (int i = 0; i < pseudoAttrs.Length; ++i)
 294                                         if (attributeType.IsAssignableFrom (pseudoAttrs [i].GetType ()))
 295                                                 return true;
 296                         }
 297
 298 #if ONLY_1_1
 299                         if (inherit) {
 300                                 AttributeUsageAttribute usage = RetrieveAttributeUsage (attributeType);
 301                                 if (!usage.Inherited)
 302                                         inherit = false;
 303                         }
 304 #endif
 305
 306                         // FIXME (bug #82431):
 307                         // on 2.0 profile we should always walk the inheritance
 308                         // chain and base the behavior on the inheritance level:
 309                         //
 310                         // 0  : return true if "attributeType" is assignable from
 311                         // any of the custom attributes
 312                         //
 313                         // > 0: return true if "attributeType" is assignable from
 314                         // any of the custom attributes and AttributeUsageAttribute
 315                         // .Inherited of the assignable attribute is true
 316
 317                         ICustomAttributeProvider btype;
 318                         if (inherit && ((btype = GetBase (obj)) != null))
 319                                 return IsDefined (btype, attributeType, inherit);
 320
 321                         return false;
 322                 }
 323
 324                 [MethodImplAttribute (MethodImplOptions.InternalCall)]
 325                 internal static extern bool IsDefinedInternal (ICustomAttributeProvider obj, Type AttributeType);
 326
 327                 static PropertyInfo GetBasePropertyDefinition (PropertyInfo property)
 328                 {
 329                         MethodInfo method = property.GetGetMethod (true);
 330                         if (method == null || !method.IsVirtual)
 331                                 method = property.GetSetMethod (true);
 332                         if (method == null || !method.IsVirtual)
 333                                 return null;
 334
 335                         MethodInfo baseMethod = method.GetBaseMethod ();
 336                         if (baseMethod != null && baseMethod != method) {
 337                                 ParameterInfo[] parameters = property.GetIndexParameters ();
 338                                 if (parameters != null && parameters.Length > 0) {
 339                                         Type[] paramTypes = new Type[parameters.Length];
 340                                         for (int i=0; i < paramTypes.Length; i++)
 341                                                 paramTypes[i] = parameters[i].ParameterType;
 342                                         return baseMethod.DeclaringType.GetProperty (property.Name, property.PropertyType,
 343                                                                                      paramTypes);
 344                                 } else {
 345                                         return baseMethod.DeclaringType.GetProperty (property.Name, property.PropertyType);
 346                                 }
 347                         }
 348                         return null;
 349
 350                 }
 351
 352                 // Handles Type, MonoProperty and MonoMethod.
 353                 // The runtime has also cases for MonoEvent, MonoField, Assembly and ParameterInfo,
 354                 // but for those we return null here.
 355                 static ICustomAttributeProvider GetBase (ICustomAttributeProvider obj)
 356                 {
 357                         if (obj == null)
 358                                 return null;
 359
 360                         if (obj is Type)
 361                                 return ((Type) obj).BaseType;
 362
 363                         MethodInfo method = null;
 364                         if (obj is MonoProperty)
 365                                 return GetBasePropertyDefinition ((MonoProperty) obj);
 366                         else if (obj is MonoMethod)
 367                                 method = (MethodInfo) obj;
 368
 369                         /**
 370                          * ParameterInfo -> null
 371                          * Assembly -> null
 372                          * MonoEvent -> null
 373                          * MonoField -> null
 374                          */
 375                         if (method == null || !method.IsVirtual)
 376                                 return null;
 377
 378                         MethodInfo baseMethod = method.GetBaseDefinition ();
 379                         if (baseMethod == method)
 380                                 return null;
 381
 382                         return baseMethod;
 383                 }
 384
 385                 private static AttributeUsageAttribute RetrieveAttributeUsage (Type attributeType)
 386                 {
 387                         if (attributeType == typeof (AttributeUsageAttribute))
 388                                 /* Avoid endless recursion */
 389                                 return new AttributeUsageAttribute (AttributeTargets.Class);
 390
 391                         AttributeUsageAttribute usageAttribute = null;
 392                         object[] attribs = GetCustomAttributes (attributeType,
 393                                 MonoCustomAttrs.AttributeUsageType, false);
 394                         if (attribs.Length == 0)
 395                         {
 396                                 // if no AttributeUsage was defined on the attribute level, then
 397                                 // try to retrieve if from its base type
 398                                 if (attributeType.BaseType != null)
 399                                 {
 400                                         usageAttribute = RetrieveAttributeUsage (attributeType.BaseType);
 401
 402                                 }
 403                                 if (usageAttribute != null)
 404                                 {
 405                                         // return AttributeUsage of base class
 406                                         return usageAttribute;
 407
 408                                 }
 409                                 // return default AttributeUsageAttribute if no AttributeUsage
 410                                 // was defined on attribute, or its base class
 411                                 return DefaultAttributeUsage;
 412                         }
 413                         // check if more than one AttributeUsageAttribute has been specified
 414                         // on the type
 415                         // NOTE: compilers should prevent this, but that doesn't prevent
 416                         // anyone from using IL ofcourse
 417                         if (attribs.Length > 1)
 418                         {
 419                                 throw new FormatException ("Duplicate AttributeUsageAttribute cannot be specified on an attribute type.");
 420                         }
 421
 422                         return ((AttributeUsageAttribute) attribs[0]);
 423                 }
 424
 425                 private static readonly Type AttributeUsageType = typeof(AttributeUsageAttribute);
 426                 private static readonly AttributeUsageAttribute DefaultAttributeUsage =
 427                         new AttributeUsageAttribute (AttributeTargets.All);
 428
 429                 private class AttributeInfo
 430                 {
 431                         private AttributeUsageAttribute _usage;
 432                         private int _inheritanceLevel;
 433
 434                         public AttributeInfo (AttributeUsageAttribute usage, int inheritanceLevel)
 435                         {
 436                                 _usage = usage;
 437                                 _inheritanceLevel = inheritanceLevel;
 438                         }
 439
 440                         public AttributeUsageAttribute Usage
 441                         {
 442                                 get
 443                                 {
 444                                         return _usage;
 445                                 }
 446                         }
 447
 448                         public int InheritanceLevel
 449                         {
 450                                 get
 451                                 {
 452                                         return _inheritanceLevel;
 453                                 }
 454                         }
 455                 }
 456         }
 457 }
 458