source: branches/CodeEditor/HeuristicLab.ExtLibs/HeuristicLab.NRefactory/5.5.0/NRefactory-5.5.0/TypeSystem/TaskType.cs @ 11700

// Copyright (c) 2010-2014 AlphaSierraPapa for the SharpDevelop Team
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy of this
// software and associated documentation files (the "Software"), to deal in the Software
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// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
// to whom the Software is furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
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// DEALINGS IN THE SOFTWARE.

using System;

namespace ICSharpCode.NRefactory.TypeSystem
{
  /// <summary>
  /// Helper class for dealing with System.Threading.Tasks.Task.
  /// </summary>
  public static class TaskType
  {
    /// <summary>
    /// Gets the T in Task&lt;T&gt;.
    /// Returns void for non-generic Task.
    /// Any other type is returned unmodified.
    /// </summary>
    public static IType UnpackTask(ICompilation compilation, IType type)
    {
      if (!IsTask(type))
        return type;
      if (type.TypeParameterCount == 0)
        return compilation.FindType(KnownTypeCode.Void);
      else
        return type.TypeArguments[0];
    }
    
    /// <summary>
    /// Gets whether the specified type is Task or Task&lt;T&gt;.
    /// </summary>
    public static bool IsTask(IType type)
    {
      ITypeDefinition def = type.GetDefinition();
      if (def != null) {
        if (def.KnownTypeCode == KnownTypeCode.Task)
          return true;
        if (def.KnownTypeCode == KnownTypeCode.TaskOfT)
          return type is ParameterizedType;
      }
      return false;
    }
    
    /// <summary>
    /// Creates a task type.
    /// </summary>
    public static IType Create(ICompilation compilation, IType elementType)
    {
      if (compilation == null)
        throw new ArgumentNullException("compilation");
      if (elementType == null)
        throw new ArgumentNullException("elementType");
      
      if (elementType.Kind == TypeKind.Void)
        return compilation.FindType(KnownTypeCode.Task);
      IType taskType = compilation.FindType(KnownTypeCode.TaskOfT);
      ITypeDefinition taskTypeDef = taskType.GetDefinition();
      if (taskTypeDef != null)
        return new ParameterizedType(taskTypeDef, new [] { elementType });
      else
        return taskType;
    }
  }
}