mcs/class/referencesource/mscorlib/system/runtime/interopservices/windowsruntime/dictionarytomapadapter.cs

   1 // ==++==
   2 //
   3 //   Copyright (c) Microsoft Corporation.  All rights reserved.
   4 //
   5 // ==--==
   6 //
   7 // <OWNER>GPaperin</OWNER>
   8 // <OWNER>Microsoft</OWNER>
   9
  10 using System;
  11 using System.Security;
  12 using System.Reflection;
  13 using System.Collections;
  14 using System.Collections.Generic;
  15 using System.Collections.ObjectModel;
  16 using System.Diagnostics.Contracts;
  17 using System.Runtime.InteropServices;
  18 using System.Runtime.CompilerServices;
  19
  20 namespace System.Runtime.InteropServices.WindowsRuntime
  21 {
  22     // This is a set of stub methods implementing the support for the IMap`2 interface on managed
  23     // objects that implement IDictionary`2. Used by the interop mashaling infrastructure.
  24     //
  25     // The methods on this class must be written VERY carefully to avoid introducing security holes.
  26     // That's because they are invoked with special "this"! The "this" object
  27     // for all of these methods are not DictionaryToMapAdapter objects. Rather, they are of type
  28     // IDictionary<K, V>. No actual DictionaryToMapAdapter object is ever instantiated. Thus, you will
  29     // see a lot of expressions that cast "this" to "IDictionary<K, V>".
  30     internal sealed class DictionaryToMapAdapter
  31     {
  32         private DictionaryToMapAdapter()
  33         {
  34             Contract.Assert(false, "This class is never instantiated");
  35         }
  36
  37         // V Lookup(K key)
  38         [SecurityCritical]
  39         internal V Lookup<K, V>(K key)
  40         {
  41             IDictionary<K, V> _this = JitHelpers.UnsafeCast<IDictionary<K, V>>(this);
  42             V value;
  43             bool keyFound = _this.TryGetValue(key, out value);
  44
  45             if (!keyFound)
  46             {
  47                 Exception e = new KeyNotFoundException(Environment.GetResourceString("Arg_KeyNotFound"));
  48                 e.SetErrorCode(__HResults.E_BOUNDS);
  49                 throw e;
  50             }
  51
  52             return value;
  53         }
  54
  55         // uint Size { get }
  56         [SecurityCritical]
  57         internal uint Size<K, V>()
  58         {
  59             IDictionary<K, V> _this = JitHelpers.UnsafeCast<IDictionary<K, V>>(this);
  60             return (uint)_this.Count;
  61         }
  62
  63         // bool HasKey(K key)
  64         [SecurityCritical]
  65         internal bool HasKey<K, V>(K key)
  66         {
  67             IDictionary<K, V> _this = JitHelpers.UnsafeCast<IDictionary<K, V>>(this);
  68             return _this.ContainsKey(key);
  69         }
  70
  71         // IMapView<K, V> GetView()
  72         [SecurityCritical]
  73         internal IReadOnlyDictionary<K, V> GetView<K, V>()
  74         {
  75             IDictionary<K, V> _this = JitHelpers.UnsafeCast<IDictionary<K, V>>(this);
  76             Contract.Assert(_this != null);
  77
  78             // Note: This dictionary is not really read-only - you could QI for a modifiable
  79             // dictionary.  We gain some perf by doing this.  We believe this is acceptable.
  80             IReadOnlyDictionary<K, V> roDictionary = _this as IReadOnlyDictionary<K, V>;
  81             if (roDictionary == null)
  82             {
  83                 roDictionary = new ReadOnlyDictionary<K, V>(_this);
  84             }
  85             return roDictionary;
  86         }
  87
  88         // bool Insert(K key, V value)
  89         [SecurityCritical]
  90         internal bool Insert<K, V>(K key, V value)
  91         {
  92             IDictionary<K, V> _this = JitHelpers.UnsafeCast<IDictionary<K, V>>(this);
  93             bool replacing = _this.ContainsKey(key);
  94             _this[key] = value;
  95             return replacing;
  96         }
  97
  98         // void Remove(K key)
  99         [SecurityCritical]
 100         internal void Remove<K, V>(K key)
 101         {
 102             IDictionary<K, V> _this = JitHelpers.UnsafeCast<IDictionary<K, V>>(this);
 103             bool removed = _this.Remove(key);
 104
 105             if (!removed)
 106             {
 107                 Exception e = new KeyNotFoundException(Environment.GetResourceString("Arg_KeyNotFound"));
 108                 e.SetErrorCode(__HResults.E_BOUNDS);
 109                 throw e;
 110             }
 111         }
 112
 113         // void Clear()
 114         [SecurityCritical]
 115         internal void Clear<K, V>()
 116         {
 117             IDictionary<K, V> _this = JitHelpers.UnsafeCast<IDictionary<K, V>>(this);
 118             _this.Clear();
 119         }
 120     }
 121 }