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 
AccessPathFilter()38 		private AccessPathFilter ()
39 		{
40 			this.flags = Flags.AllowLocals;
41 			this.member_filter = MemberFilter.NoFilter;
42 		}
43 
AccessPathFilter(TMember member, MemberFilter memberFilter)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 
FromPrecondition(TMember member)65 		public static AccessPathFilter<TMember> FromPrecondition (TMember member)
66 		{
67 			return new AccessPathFilter<TMember> (member, MemberFilter.FromPrecondition);
68 		}
69 
FromPostcondition(TMember member)70 		public static AccessPathFilter<TMember> FromPostcondition (TMember member)
71 		{
72 			return new AccessPathFilter<TMember> (member, MemberFilter.FromPostcondition);
73 		}
74 
IsVisibleFrom(TMember member)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 }
113