// 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

// without restriction, including without limitation the rights to use, copy, modify, merge,

// 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

// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR

// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER

// 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;

}

}

}