mcs/class/System/System.Net/DnsPermission.cs

   1 //\r
   2 // System.Net.DnsPermission.cs\r
   3 //\r
   4 // Author:\r
   5 //   Lawrence Pit (loz@cable.a2000.nl)\r
   6 //\r
   7 \r
   8 using System;\r
   9 using System.Collections;\r
  10 using System.Security;\r
  11 using System.Security.Permissions;\r
  12 \r
  13 namespace System.Net\r
  14 {\r
  15         [Serializable]\r
  16         public sealed class DnsPermission : CodeAccessPermission, IUnrestrictedPermission\r
  17         {\r
  18                 // Fields\r
  19                 bool m_noRestriction;\r
  20                 \r
  21                 // Constructors\r
  22                 public DnsPermission (PermissionState state) : base () \r
  23                 {                                               \r
  24                         m_noRestriction = (state == PermissionState.Unrestricted);\r
  25                 }\r
  26                 \r
  27                 // Methods\r
  28                                 \r
  29                 public override IPermission Copy ()\r
  30                 {\r
  31                         // this is immutable.\r
  32                         return this;            \r
  33                 }\r
  34                 \r
  35                 public override IPermission Intersect (IPermission target)\r
  36                 {\r
  37                         // LAMESPEC: says to throw an exception when null\r
  38                         // but at same time it says to return null. We'll\r
  39                         // follow MS behaviour.\r
  40                         if (target == null) \r
  41                                 return null;\r
  42                         \r
  43                         DnsPermission perm = target as DnsPermission;\r
  44                         \r
  45                         if (perm == null)\r
  46                                 throw new ArgumentException ("Argument not of type DnsPermission");\r
  47                                 \r
  48                         if (this.m_noRestriction && perm.m_noRestriction)\r
  49                                 return this;\r
  50                         \r
  51                         return this.m_noRestriction ? perm : this;\r
  52                 }\r
  53                 \r
  54                 public override bool IsSubsetOf (IPermission target) \r
  55                 {\r
  56                         if (target == null)\r
  57                                 return !m_noRestriction;\r
  58                         \r
  59                         DnsPermission perm = target as DnsPermission;\r
  60                         \r
  61                         if (perm == null)\r
  62                                 throw new ArgumentException ("Argument not of type DnsPermission");\r
  63                         \r
  64                         return !this.m_noRestriction || perm.m_noRestriction;\r
  65                 }\r
  66 \r
  67                 public bool IsUnrestricted () \r
  68                 {\r
  69                         return this.m_noRestriction;\r
  70                 }\r
  71 \r
  72                 /*\r
  73                 \r
  74                 DnsPermission dns1 = new DnsPermission (PermissionState.None);\r
  75                 Console.WriteLine (dns1.ToXml ().ToString ());\r
  76 \r
  77                 DnsPermission dns2 = new DnsPermission (PermissionState.Unrestricted);\r
  78                 Console.WriteLine (dns2.ToXml ().ToString ());\r
  79                 \r
  80                 This is the sample xml output:\r
  81 \r
  82                 <IPermission class="System.Net.DnsPermission, System, Version=1.0.3300.0, Cultur\r
  83                 e=neutral, PublicKeyToken=b77a5c561934e089"\r
  84                              version="1"/>\r
  85 \r
  86                 <IPermission class="System.Net.DnsPermission, System, Version=1.0.3300.0, Cultur\r
  87                 e=neutral, PublicKeyToken=b77a5c561934e089"\r
  88                              version="1"\r
  89                              Unrestricted="true"/>\r
  90                 */\r
  91                 public override SecurityElement ToXml ()\r
  92                 {\r
  93              \r
  94                         SecurityElement root = new SecurityElement ("IPermission");\r
  95                         root.AddAttribute ("class", this.GetType ().AssemblyQualifiedName);\r
  96                         root.AddAttribute ("version", "1");\r
  97                         if (m_noRestriction)\r
  98                                 root.AddAttribute ("Unrestricted", "true");                             \r
  99 \r
 100                         return root;\r
 101                 }\r
 102                 \r
 103                 public override void FromXml (SecurityElement securityElement)\r
 104                 {\r
 105                         if (securityElement == null)\r
 106                                 throw new ArgumentNullException ("securityElement");\r
 107                                 \r
 108                         // LAMESPEC: it says to throw an ArgumentNullException in this case                             \r
 109                         if (securityElement.Tag != "IPermission")\r
 110                                 throw new ArgumentException ("securityElement");\r
 111                                 \r
 112                         string classStr = securityElement.Attribute ("class");\r
 113                         if (classStr == null || !classStr.StartsWith (this.GetType ().FullName + ","))\r
 114                                 throw new ArgumentException ("securityElement");\r
 115                                 \r
 116                         string unrestricted = securityElement.Attribute ("Unrestricted");\r
 117                         if (unrestricted != null) \r
 118                                 this.m_noRestriction = (String.Compare (unrestricted, "true", true) == 0);\r
 119                 }               \r
 120                 \r
 121                 public override IPermission Union (IPermission target) \r
 122                 {\r
 123                         // LAMESPEC: according to spec we should throw an \r
 124                         // exception when target is null. We'll follow the\r
 125                         // behaviour of MS.Net instead of the spec.\r
 126                         if (target == null)\r
 127                                 return this;\r
 128                                 // throw new ArgumentNullException ("target");\r
 129                                 \r
 130                         DnsPermission perm = target as DnsPermission;\r
 131                         \r
 132                         if (perm == null)\r
 133                                 throw new ArgumentException ("Argument not of type DnsPermission");\r
 134                         \r
 135                         return this.m_noRestriction ? this : perm;\r
 136                 }\r
 137 \r
 138         }\r
 139 }\r