mcs/class/Mono.CodeContracts/Mono.CodeContracts.Static.Analysis.HeapAnalysis.Paths/AccessPathFilter.cs

   1 //
   2 // AccessPathFilter.cs
   3 //
   4 // Authors:
   5 //      Alexander Chebaturkin (chebaturkin@gmail.com)
   6 //
   7 // Copyright (C) 2011 Alexander Chebaturkin
   8 //
   9 // Permission is hereby granted, free of charge, to any person obtaining
  10 // a copy of this software and associated documentation files (the
  11 // "Software"), to deal in the Software without restriction, including
  12 // without limitation the rights to use, copy, modify, merge, publish,
  13 // distribute, sublicense, and/or sell copies of the Software, and to
  14 // permit persons to whom the Software is furnished to do so, subject to
  15 // the following conditions:
  16 //
  17 // The above copyright notice and this permission notice shall be
  18 // included in all copies or substantial portions of the Software.
  19 //
  20 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  21 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  22 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  23 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  24 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  25 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  26 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  27 //
  28
  29 using System;
  30
  31 namespace Mono.CodeContracts.Static.Analysis.HeapAnalysis.Paths {
  32         class AccessPathFilter<TMember> {
  33                 public static AccessPathFilter<TMember> NoFilter = new AccessPathFilter<TMember> ();
  34                 private readonly Flags flags;
  35                 private readonly TMember member;
  36                 private readonly MemberFilter member_filter;
  37
  38                 private AccessPathFilter ()
  39                 {
  40                         this.flags = Flags.AllowLocals;
  41                         this.member_filter = MemberFilter.NoFilter;
  42                 }
  43
  44                 private AccessPathFilter (TMember member, MemberFilter memberFilter)
  45                 {
  46                         this.member_filter = memberFilter;
  47                         this.member = member;
  48                 }
  49
  50                 public bool AllowLocal
  51                 {
  52                         get { return (this.flags & Flags.AllowLocals) == Flags.AllowLocals; }
  53                 }
  54
  55                 public bool HasVisibilityMember
  56                 {
  57                         get { return this.member_filter != MemberFilter.NoFilter; }
  58                 }
  59
  60                 public TMember VisibilityMember
  61                 {
  62                         get { return this.member; }
  63                 }
  64
  65                 public static AccessPathFilter<TMember> FromPrecondition (TMember member)
  66                 {
  67                         return new AccessPathFilter<TMember> (member, MemberFilter.FromPrecondition);
  68                 }
  69
  70                 public static AccessPathFilter<TMember> FromPostcondition (TMember member)
  71                 {
  72                         return new AccessPathFilter<TMember> (member, MemberFilter.FromPostcondition);
  73                 }
  74
  75                 public static AccessPathFilter<TMember> IsVisibleFrom (TMember member)
  76                 {
  77                         return new AccessPathFilter<TMember> (member, MemberFilter.FromMethodBody);
  78                 }
  79
  80                 public bool FilterOutPathElement<P> (P element)
  81                         where P : IVisibilityCheck<TMember>
  82                 {
  83                         switch (this.member_filter) {
  84                         case MemberFilter.FromPrecondition:
  85                                 return !element.IsAsVisibleAs (this.member);
  86                         case MemberFilter.FromPostcondition:
  87                                 return !element.IfRootIsParameter || !element.IsVisibleFrom (this.member);
  88                         case MemberFilter.FromMethodBody:
  89                                 return !element.IsVisibleFrom (this.member);
  90                         default:
  91                                 return false;
  92                         }
  93                 }
  94
  95                 #region Nested type: Flags
  96                 [Flags]
  97                 private enum Flags {
  98                         AllowLocals = 1,
  99                         RequireParameter = 2
 100                 }
 101                 #endregion
 102
 103                 #region Nested type: MemberFilter
 104                 private enum MemberFilter {
 105                         NoFilter = 0,
 106                         FromPrecondition,
 107                         FromPostcondition,
 108                         FromMethodBody
 109                 }
 110                 #endregion
 111         }
 112 }