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