mcs/class/corlib/System/MonoCustomAttrs.cs

   1 //
   2 // MonoCustomAttrs.cs: 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 //      Marek Safar (marek.safar@gmail.com)
   8 //
   9 // (c) 2002,2003 Ximian, Inc. (http://www.ximian.com)
  10 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)
  11 // Copyright (C) 2013 Xamarin, Inc (http://www.xamarin.com)
  12 //
  13 // Permission is hereby granted, free of charge, to any person obtaining
  14 // a copy of this software and associated documentation files (the
  15 // "Software"), to deal in the Software without restriction, including
  16 // without limitation the rights to use, copy, modify, merge, publish,
  17 // distribute, sublicense, and/or sell copies of the Software, and to
  18 // permit persons to whom the Software is furnished to do so, subject to
  19 // the following conditions:
  20 //
  21 // The above copyright notice and this permission notice shall be
  22 // included in all copies or substantial portions of the Software.
  23 //
  24 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  25 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  26 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  27 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  28 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  29 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  30 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  31 //
  32
  33 using System;
  34 using System.Reflection;
  35 using System.Collections;
  36 using System.Runtime.CompilerServices;
  37 using System.Runtime.InteropServices;
  38 #if !FULL_AOT_RUNTIME
  39 using System.Reflection.Emit;
  40 #endif
  41
  42 using System.Collections.Generic;
  43
  44 namespace System
  45 {
  46         static class MonoCustomAttrs
  47         {
  48                 static Assembly corlib;
  49                 [ThreadStatic]
  50                 static Dictionary<Type, AttributeUsageAttribute> usage_cache;
  51
  52                 /* Treat as user types all corlib types extending System.Type that are not RuntimeType and TypeBuilder */
  53                 static bool IsUserCattrProvider (object obj)
  54                 {
  55                         Type type = obj as Type;
  56 #if !FULL_AOT_RUNTIME
  57                         if ((type is RuntimeType) || (type is TypeBuilder))
  58 #else
  59                         if (type is RuntimeType)
  60 #endif
  61                                 return false;
  62                         if ((obj is Type))
  63                                 return true;
  64                         if (corlib == null)
  65                                  corlib = typeof (int).Assembly;
  66                         return obj.GetType ().Assembly != corlib;
  67                 }
  68
  69                 [MethodImplAttribute (MethodImplOptions.InternalCall)]
  70                 internal static extern object[] GetCustomAttributesInternal (ICustomAttributeProvider obj, Type attributeType, bool pseudoAttrs);
  71
  72                 internal static object[] GetPseudoCustomAttributes (ICustomAttributeProvider obj, Type attributeType) {
  73                         object[] pseudoAttrs = null;
  74
  75                         /* FIXME: Add other types */
  76                         if (obj is MonoMethod)
  77                                 pseudoAttrs = ((MonoMethod)obj).GetPseudoCustomAttributes ();
  78                         else if (obj is FieldInfo)
  79                                 pseudoAttrs = ((FieldInfo)obj).GetPseudoCustomAttributes ();
  80                         else if (obj is ParameterInfo)
  81                                 pseudoAttrs = ((ParameterInfo)obj).GetPseudoCustomAttributes ();
  82                         else if (obj is Type)
  83                                 pseudoAttrs = GetPseudoCustomAttributes (((Type)obj));
  84
  85                         if ((attributeType != null) && (pseudoAttrs != null)) {
  86                                 for (int i = 0; i < pseudoAttrs.Length; ++i)
  87                                         if (attributeType.IsAssignableFrom (pseudoAttrs [i].GetType ()))
  88                                                 if (pseudoAttrs.Length == 1)
  89                                                         return pseudoAttrs;
  90                                                 else
  91                                                         return new object [] { pseudoAttrs [i] };
  92                                 return EmptyArray<object>.Value;
  93                         }
  94
  95                         return pseudoAttrs;
  96                 }
  97
  98                 static object[] GetPseudoCustomAttributes (Type type)
  99                 {
 100                         int count = 0;
 101                         var Attributes = type.Attributes;
 102
 103                         /* IsSerializable returns true for delegates/enums as well */
 104                         if ((Attributes & TypeAttributes.Serializable) != 0)
 105                                 count ++;
 106                         if ((Attributes & TypeAttributes.Import) != 0)
 107                                 count ++;
 108
 109                         if (count == 0)
 110                                 return null;
 111                         object[] attrs = new object [count];
 112                         count = 0;
 113
 114                         if ((Attributes & TypeAttributes.Serializable) != 0)
 115                                 attrs [count ++] = new SerializableAttribute ();
 116                         if ((Attributes & TypeAttributes.Import) != 0)
 117                                 attrs [count ++] = new ComImportAttribute ();
 118
 119                         return attrs;
 120                 }
 121
 122                 internal static object[] GetCustomAttributesBase (ICustomAttributeProvider obj, Type attributeType, bool inheritedOnly)
 123                 {
 124                         object[] attrs;
 125                         if (IsUserCattrProvider (obj))
 126                                 attrs = obj.GetCustomAttributes (attributeType, true);
 127                         else
 128                                 attrs = GetCustomAttributesInternal (obj, attributeType, false);
 129
 130                         //
 131                         // All pseudo custom attributes are Inherited = false hence we can avoid
 132                         // building attributes array which would be discarded by inherited checks
 133                         //
 134                         if (!inheritedOnly) {
 135                                 object[] pseudoAttrs = GetPseudoCustomAttributes (obj, attributeType);
 136                                 if (pseudoAttrs != null) {
 137                                         object[] res = new object [attrs.Length + pseudoAttrs.Length];
 138                                         System.Array.Copy (attrs, res, attrs.Length);
 139                                         System.Array.Copy (pseudoAttrs, 0, res, attrs.Length, pseudoAttrs.Length);
 140                                         return res;
 141                                 }
 142                         }
 143
 144                         return attrs;
 145                 }
 146
 147                 internal static object[] GetCustomAttributes (ICustomAttributeProvider obj, Type attributeType, bool inherit)
 148                 {
 149                         if (obj == null)
 150                                 throw new ArgumentNullException ("obj");
 151                         if (attributeType == null)
 152                                 throw new ArgumentNullException ("attributeType");
 153
 154                         if (attributeType == typeof (MonoCustomAttrs))
 155                                 attributeType = null;
 156
 157                         object[] r;
 158                         object[] res = GetCustomAttributesBase (obj, attributeType, false);
 159                         // shortcut
 160                         if (!inherit && res.Length == 1) {
 161                                 if (res [0] == null)
 162                                         throw new CustomAttributeFormatException ("Invalid custom attribute format");
 163
 164                                 if (attributeType != null) {
 165                                         if (attributeType.IsAssignableFrom (res[0].GetType ())) {
 166                                                 r = (object[]) Array.CreateInstance (attributeType, 1);
 167                                                 r[0] = res[0];
 168                                         } else {
 169                                                 r = (object[]) Array.CreateInstance (attributeType, 0);
 170                                         }
 171                                 } else {
 172                                         r = (object[]) Array.CreateInstance (res[0].GetType (), 1);
 173                                         r[0] = res[0];
 174                                 }
 175                                 return r;
 176                         }
 177
 178                         if (inherit && GetBase (obj) == null)
 179                                 inherit = false;
 180
 181                         // if AttributeType is sealed, and Inherited is set to false, then
 182                         // there's no use in scanning base types
 183                         if ((attributeType != null && attributeType.IsSealed) && inherit) {
 184                                 AttributeUsageAttribute usageAttribute = RetrieveAttributeUsage (
 185                                         attributeType);
 186                                 if (!usageAttribute.Inherited)
 187                                         inherit = false;
 188                         }
 189
 190                         var initialSize = Math.Max (res.Length, 16);
 191                         List<Object> a = null;
 192                         ICustomAttributeProvider btype = obj;
 193                         object[] array;
 194
 195                         /* Non-inherit case */
 196                         if (!inherit) {
 197                                 if (attributeType == null) {
 198                                         foreach (object attr in res) {
 199                                                 if (attr == null)
 200                                                         throw new CustomAttributeFormatException ("Invalid custom attribute format");
 201                                         }
 202                                         var result = new Attribute [res.Length];
 203                                         res.CopyTo (result, 0);
 204                                         return result;
 205                                 }
 206
 207                                 a = new List<object> (initialSize);
 208                                 foreach (object attr in res) {
 209                                         if (attr == null)
 210                                                 throw new CustomAttributeFormatException ("Invalid custom attribute format");
 211
 212                                         Type attrType = attr.GetType ();
 213                                         if (attributeType != null && !attributeType.IsAssignableFrom (attrType))
 214                                                 continue;
 215                                         a.Add (attr);
 216                                 }
 217
 218                                 if (attributeType == null || attributeType.IsValueType)
 219                                         array = new Attribute [a.Count];
 220                                 else
 221                                         array = Array.CreateInstance (attributeType, a.Count) as object[];
 222                                 a.CopyTo (array, 0);
 223                                 return array;
 224                         }
 225
 226                         /* Inherit case */
 227                         var attributeInfos = new Dictionary<Type, AttributeInfo> (initialSize);
 228                         int inheritanceLevel = 0;
 229                         a = new List<object> (initialSize);
 230
 231                         do {
 232                                 foreach (object attr in res) {
 233                                         AttributeUsageAttribute usage;
 234                                         if (attr == null)
 235                                                 throw new CustomAttributeFormatException ("Invalid custom attribute format");
 236
 237                                         Type attrType = attr.GetType ();
 238                                         if (attributeType != null) {
 239                                                 if (!attributeType.IsAssignableFrom (attrType))
 240                                                         continue;
 241                                         }
 242
 243                                         AttributeInfo firstAttribute;
 244                                         if (attributeInfos.TryGetValue (attrType, out firstAttribute))
 245                                                 usage = firstAttribute.Usage;
 246                                         else
 247                                                 usage = RetrieveAttributeUsage (attrType);
 248
 249                                         // only add attribute to the list of attributes if
 250                                         // - we are on the first inheritance level, or the attribute can be inherited anyway
 251                                         // and (
 252                                         // - multiple attributes of the type are allowed
 253                                         // or (
 254                                         // - this is the first attribute we've discovered
 255                                         // or
 256                                         // - the attribute is on same inheritance level than the first
 257                                         //   attribute that was discovered for this attribute type ))
 258                                         if ((inheritanceLevel == 0 || usage.Inherited) && (usage.AllowMultiple ||
 259                                                 (firstAttribute == null || (firstAttribute != null
 260                                                         && firstAttribute.InheritanceLevel == inheritanceLevel))))
 261                                                 a.Add (attr);
 262
 263                                         if (firstAttribute == null)
 264                                                 attributeInfos.Add (attrType, new AttributeInfo (usage, inheritanceLevel));
 265                                 }
 266
 267                                 if ((btype = GetBase (btype)) != null) {
 268                                         inheritanceLevel++;
 269                                         res = GetCustomAttributesBase (btype, attributeType, true);
 270                                 }
 271                         } while (inherit && btype != null);
 272
 273                         if (attributeType == null || attributeType.IsValueType)
 274                                 array = new Attribute [a.Count];
 275                         else
 276                                 array = Array.CreateInstance (attributeType, a.Count) as object[];
 277
 278                         // copy attributes to array
 279                         a.CopyTo (array, 0);
 280
 281                         return array;
 282                 }
 283
 284                 internal static object[] GetCustomAttributes (ICustomAttributeProvider obj, bool inherit)
 285                 {
 286                         if (obj == null)
 287                                 throw new ArgumentNullException ("obj");
 288
 289                         if (!inherit)
 290                                 return (object[]) GetCustomAttributesBase (obj, null, false).Clone ();
 291
 292                         return GetCustomAttributes (obj, typeof (MonoCustomAttrs), inherit);
 293                 }
 294
 295                 [MethodImplAttribute (MethodImplOptions.InternalCall)]
 296                 static extern CustomAttributeData [] GetCustomAttributesDataInternal (ICustomAttributeProvider obj);
 297
 298                 internal static IList<CustomAttributeData> GetCustomAttributesData (ICustomAttributeProvider obj)
 299                 {
 300                         if (obj == null)
 301                                 throw new ArgumentNullException ("obj");
 302
 303                         CustomAttributeData [] attrs = GetCustomAttributesDataInternal (obj);
 304                         return Array.AsReadOnly<CustomAttributeData> (attrs);
 305                 }
 306
 307                 internal static bool IsDefined (ICustomAttributeProvider obj, Type attributeType, bool inherit)
 308                 {
 309                         if (attributeType == null)
 310                                 throw new ArgumentNullException ("attributeType");
 311
 312                         AttributeUsageAttribute usage = null;
 313                         do {
 314                                 if (IsUserCattrProvider (obj))
 315                                         return obj.IsDefined (attributeType, inherit);
 316
 317                                 if (IsDefinedInternal (obj, attributeType))
 318                                         return true;
 319
 320                                 object[] pseudoAttrs = GetPseudoCustomAttributes (obj, attributeType);
 321                                 if (pseudoAttrs != null) {
 322                                         for (int i = 0; i < pseudoAttrs.Length; ++i)
 323                                                 if (attributeType.IsAssignableFrom (pseudoAttrs[i].GetType ()))
 324                                                         return true;
 325                                 }
 326
 327                                 if (usage == null) {
 328                                         if (!inherit)
 329                                                 return false;
 330
 331                                         usage = RetrieveAttributeUsage (attributeType);
 332                                         if (!usage.Inherited)
 333                                                 return false;
 334                                 }
 335
 336                                 obj = GetBase (obj);
 337                         } while (obj != null);
 338
 339                         return false;
 340                 }
 341
 342                 [MethodImplAttribute (MethodImplOptions.InternalCall)]
 343                 internal static extern bool IsDefinedInternal (ICustomAttributeProvider obj, Type AttributeType);
 344
 345                 static PropertyInfo GetBasePropertyDefinition (MonoProperty property)
 346                 {
 347                         MethodInfo method = property.GetGetMethod (true);
 348                         if (method == null || !method.IsVirtual)
 349                                 method = property.GetSetMethod (true);
 350                         if (method == null || !method.IsVirtual)
 351                                 return null;
 352
 353                         MethodInfo baseMethod = method.GetBaseMethod ();
 354                         if (baseMethod != null && baseMethod != method) {
 355                                 ParameterInfo[] parameters = property.GetIndexParameters ();
 356                                 if (parameters != null && parameters.Length > 0) {
 357                                         Type[] paramTypes = new Type[parameters.Length];
 358                                         for (int i=0; i < paramTypes.Length; i++)
 359                                                 paramTypes[i] = parameters[i].ParameterType;
 360                                         return baseMethod.DeclaringType.GetProperty (property.Name, property.PropertyType,
 361                                                                                      paramTypes);
 362                                 } else {
 363                                         return baseMethod.DeclaringType.GetProperty (property.Name, property.PropertyType);
 364                                 }
 365                         }
 366                         return null;
 367
 368                 }
 369
 370                 static EventInfo GetBaseEventDefinition (MonoEvent evt)
 371                 {
 372                         MethodInfo method = evt.GetAddMethod (true);
 373                         if (method == null || !method.IsVirtual)
 374                                 method = evt.GetRaiseMethod (true);
 375                         if (method == null || !method.IsVirtual)
 376                                 method = evt.GetRemoveMethod (true);
 377                         if (method == null || !method.IsVirtual)
 378                                 return null;
 379
 380                         MethodInfo baseMethod = method.GetBaseMethod ();
 381                         if (baseMethod != null && baseMethod != method) {
 382                                 BindingFlags flags = method.IsPublic ? BindingFlags.Public : BindingFlags.NonPublic;
 383                                 flags |= method.IsStatic ? BindingFlags.Static : BindingFlags.Instance;
 384
 385                                 return baseMethod.DeclaringType.GetEvent (evt.Name, flags);
 386                         }
 387                         return null;
 388                 }
 389
 390                 // Handles Type, MonoProperty and MonoMethod.
 391                 // The runtime has also cases for MonoEvent, MonoField, Assembly and ParameterInfo,
 392                 // but for those we return null here.
 393                 static ICustomAttributeProvider GetBase (ICustomAttributeProvider obj)
 394                 {
 395                         if (obj == null)
 396                                 return null;
 397
 398                         if (obj is Type)
 399                                 return ((Type) obj).BaseType;
 400
 401                         MethodInfo method = null;
 402                         if (obj is MonoProperty)
 403                                 return GetBasePropertyDefinition ((MonoProperty) obj);
 404                         else if (obj is MonoEvent)
 405                                 return GetBaseEventDefinition ((MonoEvent)obj);
 406                         else if (obj is MonoMethod)
 407                                 method = (MethodInfo) obj;
 408
 409                         /**
 410                          * ParameterInfo -> null
 411                          * Assembly -> null
 412                          * MonoEvent -> null
 413                          * MonoField -> null
 414                          */
 415                         if (method == null || !method.IsVirtual)
 416                                 return null;
 417
 418                         MethodInfo baseMethod = method.GetBaseMethod ();
 419                         if (baseMethod == method)
 420                                 return null;
 421
 422                         return baseMethod;
 423                 }
 424
 425                 private static AttributeUsageAttribute RetrieveAttributeUsageNoCache (Type attributeType)
 426                 {
 427                         if (attributeType == typeof (AttributeUsageAttribute))
 428                                 /* Avoid endless recursion */
 429                                 return new AttributeUsageAttribute (AttributeTargets.Class);
 430
 431                         AttributeUsageAttribute usageAttribute = null;
 432                         object[] attribs = GetCustomAttributes (attributeType, typeof(AttributeUsageAttribute), false);
 433                         if (attribs.Length == 0)
 434                         {
 435                                 // if no AttributeUsage was defined on the attribute level, then
 436                                 // try to retrieve if from its base type
 437                                 if (attributeType.BaseType != null)
 438                                 {
 439                                         usageAttribute = RetrieveAttributeUsage (attributeType.BaseType);
 440
 441                                 }
 442                                 if (usageAttribute != null)
 443                                 {
 444                                         // return AttributeUsage of base class
 445                                         return usageAttribute;
 446
 447                                 }
 448                                 // return default AttributeUsageAttribute if no AttributeUsage
 449                                 // was defined on attribute, or its base class
 450                                 return DefaultAttributeUsage;
 451                         }
 452                         // check if more than one AttributeUsageAttribute has been specified
 453                         // on the type
 454                         // NOTE: compilers should prevent this, but that doesn't prevent
 455                         // anyone from using IL ofcourse
 456                         if (attribs.Length > 1)
 457                         {
 458                                 throw new FormatException ("Duplicate AttributeUsageAttribute cannot be specified on an attribute type.");
 459                         }
 460
 461                         return ((AttributeUsageAttribute) attribs[0]);
 462                 }
 463
 464                 static AttributeUsageAttribute RetrieveAttributeUsage (Type attributeType)
 465                 {
 466                         AttributeUsageAttribute usageAttribute = null;
 467                         /* Usage a thread-local cache to speed this up, since it is called a lot from GetCustomAttributes () */
 468                         if (usage_cache == null)
 469                                 usage_cache = new Dictionary<Type, AttributeUsageAttribute> ();
 470                         if (usage_cache.TryGetValue (attributeType, out usageAttribute))
 471                                 return usageAttribute;
 472                         usageAttribute = RetrieveAttributeUsageNoCache (attributeType);
 473                         usage_cache [attributeType] = usageAttribute;
 474                         return usageAttribute;
 475                 }
 476
 477                 private static readonly AttributeUsageAttribute DefaultAttributeUsage =
 478                         new AttributeUsageAttribute (AttributeTargets.All);
 479
 480                 private class AttributeInfo
 481                 {
 482                         private AttributeUsageAttribute _usage;
 483                         private int _inheritanceLevel;
 484
 485                         public AttributeInfo (AttributeUsageAttribute usage, int inheritanceLevel)
 486                         {
 487                                 _usage = usage;
 488                                 _inheritanceLevel = inheritanceLevel;
 489                         }
 490
 491                         public AttributeUsageAttribute Usage
 492                         {
 493                                 get
 494                                 {
 495                                         return _usage;
 496                                 }
 497                         }
 498
 499                         public int InheritanceLevel
 500                         {
 501                                 get
 502                                 {
 503                                         return _inheritanceLevel;
 504                                 }
 505                         }
 506                 }
 507         }
 508 }
 509