mcs/class/corlib/System/MonoCustomAttrs.cs

   1 // System.MonoCustomAttrs.cs
   2 // Hooks into the runtime to get custom attributes for reflection handles
   3 //
   4 // Paolo Molaro (lupus@ximian.com)
   5 //
   6 // (c) 2002 Ximian, Inc.
   7
   8 using System;
   9 using System.Reflection;
  10 using System.Collections;
  11 using System.Runtime.CompilerServices;
  12
  13 namespace System {
  14         internal class MonoCustomAttrs {
  15
  16                 static Hashtable handle_to_attrs = new Hashtable ();
  17
  18                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
  19                 internal static extern object[] GetCustomAttributes (ICustomAttributeProvider obj);
  20
  21                 private static object[] from_cache (ICustomAttributeProvider obj) {
  22                         object[] res = (object[])handle_to_attrs [obj];
  23                         if (res != null)
  24                                 return res;
  25                         res = GetCustomAttributes (obj);
  26                         handle_to_attrs.Add (obj, res);
  27                         return res;
  28                 }
  29
  30                 internal static object[] GetCustomAttributes (ICustomAttributeProvider obj, Type attributeType, bool inherit) {
  31                         object[] res = from_cache (obj);
  32                         // shortcut
  33                         if (res.Length == 1 && (res[0].GetType () == attributeType || res[0].GetType().IsSubclassOf(attributeType)))
  34                                 return (object[])res.Clone ();
  35                         ArrayList a = new ArrayList ();
  36                         Type btype = obj as Type;
  37                         do {
  38                                 foreach (object attr in res) {
  39                                         if (attributeType.Equals (attr.GetType ()) || attr.GetType().IsSubclassOf(attributeType))
  40                                                 a.Add (attr);
  41                                 }
  42                                 if (btype != null && ((btype = btype.BaseType) != null)) {
  43                                         res = from_cache (btype);
  44                                 } else {
  45                                         break;
  46                                 }
  47                         } while (inherit && btype != null && ((btype = btype.BaseType) != null));
  48                         Attribute[] r = new Attribute [a.Count];
  49                         a.CopyTo (r);
  50                         return r;
  51                 }
  52
  53                 internal static object[] GetCustomAttributes (ICustomAttributeProvider obj, bool inherit) {
  54                         Type btype = obj as Type;
  55                         if (!inherit || btype == null) {
  56                                 return (Object[])from_cache (obj).Clone ();
  57                         } else {
  58                                 ArrayList a = new ArrayList ();
  59                                 a.AddRange (from_cache (obj));
  60                                 while ((btype = btype.BaseType) != null) {
  61                                         a.AddRange (from_cache (btype));
  62                                 }
  63                                 Attribute[] r = new Attribute [a.Count];
  64                                 a.CopyTo (r);
  65                                 return (object[])r;
  66                         }
  67                 }
  68                 internal static bool IsDefined (ICustomAttributeProvider obj, Type attributeType, bool inherit) {
  69                         object[] res = from_cache (obj);
  70                         foreach (object attr in res) {
  71                                 if (attributeType.Equals (attr.GetType ()))
  72                                         return true;
  73                         }
  74                         Type btype = obj as Type;
  75                         if (inherit && (btype != null) && ((btype = btype.BaseType) != null))
  76                                 return IsDefined (btype, attributeType, inherit);
  77                         return false;
  78                 }
  79         }
  80 }