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 MonoType and TypeBuilder */
  53                 static bool IsUserCattrProvider (object obj)
  54                 {
  55                         Type type = obj as Type;
  56 #if !FULL_AOT_RUNTIME
  57                         if ((type is MonoType) || (type is TypeBuilder))
  58 #else
  59                         if (type is MonoType)
  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 Attribute GetCustomAttribute (ICustomAttributeProvider obj,
 148                                                                 Type attributeType,
 149                                                                 bool inherit)
 150                 {
 151                         object[] res = GetCustomAttributes (obj, attributeType, inherit);
 152                         if (res.Length == 0)
 153                         {
 154                                 return null;
 155                         }
 156                         else if (res.Length > 1)
 157                         {
 158                                 string msg = "'{0}' has more than one attribute of type '{1}";
 159                                 msg = String.Format (msg, obj, attributeType);
 160                                 throw new AmbiguousMatchException (msg);
 161                         }
 162
 163                         return (Attribute) res[0];
 164                 }
 165
 166                 internal static object[] GetCustomAttributes (ICustomAttributeProvider obj, Type attributeType, bool inherit)
 167                 {
 168                         if (obj == null)
 169                                 throw new ArgumentNullException ("obj");
 170                         if (attributeType == null)
 171                                 throw new ArgumentNullException ("attributeType");
 172
 173                         if (attributeType == typeof (MonoCustomAttrs))
 174                                 attributeType = null;
 175
 176                         object[] r;
 177                         object[] res = GetCustomAttributesBase (obj, attributeType, false);
 178                         // shortcut
 179                         if (!inherit && res.Length == 1) {
 180                                 if (res [0] == null)
 181                                         throw new CustomAttributeFormatException ("Invalid custom attribute format");
 182
 183                                 if (attributeType != null) {
 184                                         if (attributeType.IsAssignableFrom (res[0].GetType ())) {
 185                                                 r = (object[]) Array.CreateInstance (attributeType, 1);
 186                                                 r[0] = res[0];
 187                                         } else {
 188                                                 r = (object[]) Array.CreateInstance (attributeType, 0);
 189                                         }
 190                                 } else {
 191                                         r = (object[]) Array.CreateInstance (res[0].GetType (), 1);
 192                                         r[0] = res[0];
 193                                 }
 194                                 return r;
 195                         }
 196
 197                         if (inherit && GetBase (obj) == null)
 198                                 inherit = false;
 199
 200                         // if AttributeType is sealed, and Inherited is set to false, then
 201                         // there's no use in scanning base types
 202                         if ((attributeType != null && attributeType.IsSealed) && inherit) {
 203                                 AttributeUsageAttribute usageAttribute = RetrieveAttributeUsage (
 204                                         attributeType);
 205                                 if (!usageAttribute.Inherited)
 206                                         inherit = false;
 207                         }
 208
 209                         var initialSize = Math.Max (res.Length, 16);
 210                         List<Object> a = null;
 211                         ICustomAttributeProvider btype = obj;
 212                         object[] array;
 213
 214                         /* Non-inherit case */
 215                         if (!inherit) {
 216                                 if (attributeType == null) {
 217                                         foreach (object attr in res) {
 218                                                 if (attr == null)
 219                                                         throw new CustomAttributeFormatException ("Invalid custom attribute format");
 220                                         }
 221                                         var result = new Attribute [res.Length];
 222                                         res.CopyTo (result, 0);
 223                                         return result;
 224                                 }
 225
 226                                 a = new List<object> (initialSize);
 227                                 foreach (object attr in res) {
 228                                         if (attr == null)
 229                                                 throw new CustomAttributeFormatException ("Invalid custom attribute format");
 230
 231                                         Type attrType = attr.GetType ();
 232                                         if (attributeType != null && !attributeType.IsAssignableFrom (attrType))
 233                                                 continue;
 234                                         a.Add (attr);
 235                                 }
 236
 237                                 if (attributeType == null || attributeType.IsValueType)
 238                                         array = new Attribute [a.Count];
 239                                 else
 240                                         array = Array.CreateInstance (attributeType, a.Count) as object[];
 241                                 a.CopyTo (array, 0);
 242                                 return array;
 243                         }
 244
 245                         /* Inherit case */
 246                         var attributeInfos = new Dictionary<Type, AttributeInfo> (initialSize);
 247                         int inheritanceLevel = 0;
 248                         a = new List<object> (initialSize);
 249
 250                         do {
 251                                 foreach (object attr in res) {
 252                                         AttributeUsageAttribute usage;
 253                                         if (attr == null)
 254                                                 throw new CustomAttributeFormatException ("Invalid custom attribute format");
 255
 256                                         Type attrType = attr.GetType ();
 257                                         if (attributeType != null) {
 258                                                 if (!attributeType.IsAssignableFrom (attrType))
 259                                                         continue;
 260                                         }
 261
 262                                         AttributeInfo firstAttribute;
 263                                         if (attributeInfos.TryGetValue (attrType, out firstAttribute))
 264                                                 usage = firstAttribute.Usage;
 265                                         else
 266                                                 usage = RetrieveAttributeUsage (attrType);
 267
 268                                         // only add attribute to the list of attributes if
 269                                         // - we are on the first inheritance level, or the attribute can be inherited anyway
 270                                         // and (
 271                                         // - multiple attributes of the type are allowed
 272                                         // or (
 273                                         // - this is the first attribute we've discovered
 274                                         // or
 275                                         // - the attribute is on same inheritance level than the first
 276                                         //   attribute that was discovered for this attribute type ))
 277                                         if ((inheritanceLevel == 0 || usage.Inherited) && (usage.AllowMultiple ||
 278                                                 (firstAttribute == null || (firstAttribute != null
 279                                                         && firstAttribute.InheritanceLevel == inheritanceLevel))))
 280                                                 a.Add (attr);
 281
 282                                         if (firstAttribute == null)
 283                                                 attributeInfos.Add (attrType, new AttributeInfo (usage, inheritanceLevel));
 284                                 }
 285
 286                                 if ((btype = GetBase (btype)) != null) {
 287                                         inheritanceLevel++;
 288                                         res = GetCustomAttributesBase (btype, attributeType, true);
 289                                 }
 290                         } while (inherit && btype != null);
 291
 292                         if (attributeType == null || attributeType.IsValueType)
 293                                 array = new Attribute [a.Count];
 294                         else
 295                                 array = Array.CreateInstance (attributeType, a.Count) as object[];
 296
 297                         // copy attributes to array
 298                         a.CopyTo (array, 0);
 299
 300                         return array;
 301                 }
 302
 303                 internal static object[] GetCustomAttributes (ICustomAttributeProvider obj, bool inherit)
 304                 {
 305                         if (obj == null)
 306                                 throw new ArgumentNullException ("obj");
 307
 308                         if (!inherit)
 309                                 return (object[]) GetCustomAttributesBase (obj, null, false).Clone ();
 310
 311                         return GetCustomAttributes (obj, typeof (MonoCustomAttrs), inherit);
 312                 }
 313
 314                 [MethodImplAttribute (MethodImplOptions.InternalCall)]
 315                 static extern CustomAttributeData [] GetCustomAttributesDataInternal (ICustomAttributeProvider obj);
 316
 317                 internal static IList<CustomAttributeData> GetCustomAttributesData (ICustomAttributeProvider obj)
 318                 {
 319                         if (obj == null)
 320                                 throw new ArgumentNullException ("obj");
 321
 322                         CustomAttributeData [] attrs = GetCustomAttributesDataInternal (obj);
 323                         return Array.AsReadOnly<CustomAttributeData> (attrs);
 324                 }
 325
 326                 internal static bool IsDefined (ICustomAttributeProvider obj, Type attributeType, bool inherit)
 327                 {
 328                         if (attributeType == null)
 329                                 throw new ArgumentNullException ("attributeType");
 330
 331                         AttributeUsageAttribute usage = null;
 332                         do {
 333                                 if (IsUserCattrProvider (obj))
 334                                         return obj.IsDefined (attributeType, inherit);
 335
 336                                 if (IsDefinedInternal (obj, attributeType))
 337                                         return true;
 338
 339                                 object[] pseudoAttrs = GetPseudoCustomAttributes (obj, attributeType);
 340                                 if (pseudoAttrs != null) {
 341                                         for (int i = 0; i < pseudoAttrs.Length; ++i)
 342                                                 if (attributeType.IsAssignableFrom (pseudoAttrs[i].GetType ()))
 343                                                         return true;
 344                                 }
 345
 346                                 if (usage == null) {
 347                                         if (!inherit)
 348                                                 return false;
 349
 350                                         usage = RetrieveAttributeUsage (attributeType);
 351                                         if (!usage.Inherited)
 352                                                 return false;
 353                                 }
 354
 355                                 obj = GetBase (obj);
 356                         } while (obj != null);
 357
 358                         return false;
 359                 }
 360
 361                 [MethodImplAttribute (MethodImplOptions.InternalCall)]
 362                 internal static extern bool IsDefinedInternal (ICustomAttributeProvider obj, Type AttributeType);
 363
 364                 static PropertyInfo GetBasePropertyDefinition (MonoProperty property)
 365                 {
 366                         MethodInfo method = property.GetGetMethod (true);
 367                         if (method == null || !method.IsVirtual)
 368                                 method = property.GetSetMethod (true);
 369                         if (method == null || !method.IsVirtual)
 370                                 return null;
 371
 372                         MethodInfo baseMethod = method.GetBaseMethod ();
 373                         if (baseMethod != null && baseMethod != method) {
 374                                 ParameterInfo[] parameters = property.GetIndexParameters ();
 375                                 if (parameters != null && parameters.Length > 0) {
 376                                         Type[] paramTypes = new Type[parameters.Length];
 377                                         for (int i=0; i < paramTypes.Length; i++)
 378                                                 paramTypes[i] = parameters[i].ParameterType;
 379                                         return baseMethod.DeclaringType.GetProperty (property.Name, property.PropertyType,
 380                                                                                      paramTypes);
 381                                 } else {
 382                                         return baseMethod.DeclaringType.GetProperty (property.Name, property.PropertyType);
 383                                 }
 384                         }
 385                         return null;
 386
 387                 }
 388
 389                 static EventInfo GetBaseEventDefinition (MonoEvent evt)
 390                 {
 391                         MethodInfo method = evt.GetAddMethod (true);
 392                         if (method == null || !method.IsVirtual)
 393                                 method = evt.GetRaiseMethod (true);
 394                         if (method == null || !method.IsVirtual)
 395                                 method = evt.GetRemoveMethod (true);
 396                         if (method == null || !method.IsVirtual)
 397                                 return null;
 398
 399                         MethodInfo baseMethod = method.GetBaseMethod ();
 400                         if (baseMethod != null && baseMethod != method) {
 401                                 BindingFlags flags = method.IsPublic ? BindingFlags.Public : BindingFlags.NonPublic;
 402                                 flags |= method.IsStatic ? BindingFlags.Static : BindingFlags.Instance;
 403
 404                                 return baseMethod.DeclaringType.GetEvent (evt.Name, flags);
 405                         }
 406                         return null;
 407                 }
 408
 409                 // Handles Type, MonoProperty and MonoMethod.
 410                 // The runtime has also cases for MonoEvent, MonoField, Assembly and ParameterInfo,
 411                 // but for those we return null here.
 412                 static ICustomAttributeProvider GetBase (ICustomAttributeProvider obj)
 413                 {
 414                         if (obj == null)
 415                                 return null;
 416
 417                         if (obj is Type)
 418                                 return ((Type) obj).BaseType;
 419
 420                         MethodInfo method = null;
 421                         if (obj is MonoProperty)
 422                                 return GetBasePropertyDefinition ((MonoProperty) obj);
 423                         else if (obj is MonoEvent)
 424                                 return GetBaseEventDefinition ((MonoEvent)obj);
 425                         else if (obj is MonoMethod)
 426                                 method = (MethodInfo) obj;
 427
 428                         /**
 429                          * ParameterInfo -> null
 430                          * Assembly -> null
 431                          * MonoEvent -> null
 432                          * MonoField -> null
 433                          */
 434                         if (method == null || !method.IsVirtual)
 435                                 return null;
 436
 437                         MethodInfo baseMethod = method.GetBaseMethod ();
 438                         if (baseMethod == method)
 439                                 return null;
 440
 441                         return baseMethod;
 442                 }
 443
 444                 private static AttributeUsageAttribute RetrieveAttributeUsageNoCache (Type attributeType)
 445                 {
 446                         if (attributeType == typeof (AttributeUsageAttribute))
 447                                 /* Avoid endless recursion */
 448                                 return new AttributeUsageAttribute (AttributeTargets.Class);
 449
 450                         AttributeUsageAttribute usageAttribute = null;
 451                         object[] attribs = GetCustomAttributes (attributeType, typeof(AttributeUsageAttribute), false);
 452                         if (attribs.Length == 0)
 453                         {
 454                                 // if no AttributeUsage was defined on the attribute level, then
 455                                 // try to retrieve if from its base type
 456                                 if (attributeType.BaseType != null)
 457                                 {
 458                                         usageAttribute = RetrieveAttributeUsage (attributeType.BaseType);
 459
 460                                 }
 461                                 if (usageAttribute != null)
 462                                 {
 463                                         // return AttributeUsage of base class
 464                                         return usageAttribute;
 465
 466                                 }
 467                                 // return default AttributeUsageAttribute if no AttributeUsage
 468                                 // was defined on attribute, or its base class
 469                                 return DefaultAttributeUsage;
 470                         }
 471                         // check if more than one AttributeUsageAttribute has been specified
 472                         // on the type
 473                         // NOTE: compilers should prevent this, but that doesn't prevent
 474                         // anyone from using IL ofcourse
 475                         if (attribs.Length > 1)
 476                         {
 477                                 throw new FormatException ("Duplicate AttributeUsageAttribute cannot be specified on an attribute type.");
 478                         }
 479
 480                         return ((AttributeUsageAttribute) attribs[0]);
 481                 }
 482
 483                 static AttributeUsageAttribute RetrieveAttributeUsage (Type attributeType)
 484                 {
 485                         AttributeUsageAttribute usageAttribute = null;
 486                         /* Usage a thread-local cache to speed this up, since it is called a lot from GetCustomAttributes () */
 487                         if (usage_cache == null)
 488                                 usage_cache = new Dictionary<Type, AttributeUsageAttribute> ();
 489                         if (usage_cache.TryGetValue (attributeType, out usageAttribute))
 490                                 return usageAttribute;
 491                         usageAttribute = RetrieveAttributeUsageNoCache (attributeType);
 492                         usage_cache [attributeType] = usageAttribute;
 493                         return usageAttribute;
 494                 }
 495
 496                 private static readonly AttributeUsageAttribute DefaultAttributeUsage =
 497                         new AttributeUsageAttribute (AttributeTargets.All);
 498
 499                 private class AttributeInfo
 500                 {
 501                         private AttributeUsageAttribute _usage;
 502                         private int _inheritanceLevel;
 503
 504                         public AttributeInfo (AttributeUsageAttribute usage, int inheritanceLevel)
 505                         {
 506                                 _usage = usage;
 507                                 _inheritanceLevel = inheritanceLevel;
 508                         }
 509
 510                         public AttributeUsageAttribute Usage
 511                         {
 512                                 get
 513                                 {
 514                                         return _usage;
 515                                 }
 516                         }
 517
 518                         public int InheritanceLevel
 519                         {
 520                                 get
 521                                 {
 522                                         return _inheritanceLevel;
 523                                 }
 524                         }
 525                 }
 526         }
 527 }
 528