src/Boo.Lang.Compiler/TypeSystem/AbstractExternalGenericInfo.cs

   1 #region license
   2 // Copyright (c) 2003, 2004, 2005 Rodrigo B. de Oliveira (rbo@acm.org)
   3 // All rights reserved.
   4 //
   5 // Redistribution and use in source and binary forms, with or without modification,
   6 // are permitted provided that the following conditions are met:
   7 //
   8 //     * Redistributions of source code must retain the above copyright notice,
   9 //     this list of conditions and the following disclaimer.
  10 //     * Redistributions in binary form must reproduce the above copyright notice,
  11 //     this list of conditions and the following disclaimer in the documentation
  12 //     and/or other materials provided with the distribution.
  13 //     * Neither the name of Rodrigo B. de Oliveira nor the names of its
  14 //     contributors may be used to endorse or promote products derived from this
  15 //     software without specific prior written permission.
  16 //
  17 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
  18 // ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  19 // WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  20 // DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
  21 // FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22 // DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  23 // SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  24 // CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  25 // OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26 // THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27 #endregion
  28
  29 namespace Boo.Lang.Compiler.TypeSystem
  30 {
  31         using System;
  32         using System.Collections.Generic;
  33
  34         public abstract class AbstractExternalGenericInfo<T> where T : IEntity
  35         {
  36                 protected TypeSystemServices _tss;
  37                 private IGenericParameter[] _parameters;
  38                 private Dictionary<IType[], T> _instances = new Dictionary<IType[], T>(ArrayEqualityComparer<IType>.Default);
  39
  40                 public AbstractExternalGenericInfo(TypeSystemServices tss)
  41                 {
  42                         _tss = tss;
  43                 }
  44
  45                 public IGenericParameter[] GenericParameters
  46                 {
  47                         get
  48                         {
  49                                 if (null == _parameters)
  50                                 {
  51                                         _parameters = Array.ConvertAll<Type, ExternalGenericParameter>(
  52                                                 GetActualGenericParameters(),
  53                                                 delegate(Type t) { return (ExternalGenericParameter)_tss.Map(t); });
  54                                 }
  55                                 return _parameters;
  56                         }
  57                 }
  58
  59                 protected T ConstructEntity(IType[] arguments)
  60                 {
  61                         if (Array.TrueForAll(arguments, IsExternal))
  62                         {
  63                                 Type[] actualTypes = Array.ConvertAll<IType, Type>(arguments, GetSystemType);
  64
  65                                 return ConstructExternalEntity(actualTypes);
  66                         }
  67                         else if (_instances.ContainsKey(arguments))
  68                         {
  69                                 return _instances[arguments];
  70                         }
  71                         else
  72                         {
  73                                 T instance = ConstructInternalEntity(arguments);
  74                                 _instances.Add(arguments, instance);
  75
  76                                 return instance;
  77                         }
  78                 }
  79
  80                 protected abstract Type[] GetActualGenericParameters();
  81                 protected abstract T ConstructInternalEntity(IType[] arguments);
  82                 protected abstract T ConstructExternalEntity(Type[] arguments);
  83
  84                 private bool IsExternal(IType type)
  85                 {
  86                         if (type is ExternalType)
  87                         {
  88                                 return true;
  89                         }
  90
  91                         if (type is ArrayType)
  92                         {
  93                                 return IsExternal(type.GetElementType());
  94                         }
  95
  96                         return false;
  97                 }
  98
  99                 private Type GetSystemType(IType type)
 100                 {
 101                         // Get system type from external types
 102                         if (type is ExternalType)
 103                         {
 104                                 return ((ExternalType)type).ActualType;
 105                         }
 106
 107                         // Get system array types from arrays of external types
 108                         ArrayType arrayType = type as ArrayType;
 109                         if (arrayType != null)
 110                         {
 111                                 Type elementType = GetSystemType(arrayType.GetElementType());
 112                                 int rank = arrayType.GetArrayRank();
 113
 114                                 // Calling MakeArrayType(1) gives a multi-dimensional array with 1 dimensions,
 115                                 // which is (surprisingly) not the same as calling MakeArrayType() which gives
 116                                 // a single-dimensional array
 117                                 return (rank == 1 ? elementType.MakeArrayType() : elementType.MakeArrayType(rank));
 118                         }
 119
 120                         // This shouldn't happen since we only call GetSystemType on external types or arrays of such
 121                         return null;
 122                 }
 123         }
 124 }