//

// GenericParameter.cs

//

// Author:

//   Jb Evain (jbevain@gmail.com)

//

// Copyright (c) 2008 - 2011 Jb Evain

//

// 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;



using Mono.Collections.Generic;



using Mono.Cecil.Metadata;



namespace Mono.Cecil {



	public sealed class GenericParameter : TypeReference, ICustomAttributeProvider {



		readonly IGenericParameterProvider owner;



		ushort attributes;

		Collection<TypeReference> constraints;

		Collection<CustomAttribute> custom_attributes;



		public GenericParameterAttributes Attributes {

			get { return (GenericParameterAttributes) attributes; }

			set { attributes = (ushort) value; }

		}



		public int Position {

			get {

				if (owner == null)

					return -1;



				return owner.GenericParameters.IndexOf (this);

			}

		}



		public IGenericParameterProvider Owner {

			get { return owner; }

		}



		public bool HasConstraints {

			get {

				if (constraints != null)

					return constraints.Count > 0;



				if (HasImage)

					return Module.Read (this, (generic_parameter, reader) => reader.HasGenericConstraints (generic_parameter));



				return false;

			}

		}



		public Collection<TypeReference> Constraints {

			get {

				if (constraints != null)

					return constraints;



				if (HasImage)

					return constraints = Module.Read (this, (generic_parameter, reader) => reader.ReadGenericConstraints (generic_parameter));



				return constraints = new Collection<TypeReference> ();

			}

		}



		public bool HasCustomAttributes {

			get {

				if (custom_attributes != null)

					return custom_attributes.Count > 0;



				return this.GetHasCustomAttributes (Module);

			}

		}



		public Collection<CustomAttribute> CustomAttributes {

			get {

				if (custom_attributes != null)

					return custom_attributes;



				return custom_attributes = this.GetCustomAttributes (Module);

			}

		}



		public override IMetadataScope Scope {

			get {

				if (owner.GenericParameterType == GenericParameterType.Method)

					return ((MethodReference) owner).DeclaringType.Scope;



				return ((TypeReference) owner).Scope;

			}

		}



		public override ModuleDefinition Module {

			get { return ((MemberReference) owner).Module; }

		}



		public override string Name {

			get {

				if (!string.IsNullOrEmpty (base.Name))

					return base.Name; 



				return base.Name = (owner.GenericParameterType == GenericParameterType.Type ? "!" : "!!") + Position;

			}

		}



		public override string Namespace {

			get { return string.Empty; }

			set { throw new InvalidOperationException (); }

		}



		public override string FullName {

            get { return (owner.GenericParameterType == GenericParameterType.Type ? "!" : "!!") + Position; }

		}



		public override bool IsGenericParameter {

			get { return true; }

		}



		internal override bool ContainsGenericParameter {

			get { return true; }

		}



		public override MetadataType MetadataType {

			get { return (MetadataType) etype; }

		}



		#region GenericParameterAttributes



		public bool IsNonVariant {

			get { return attributes.GetMaskedAttributes ((ushort) GenericParameterAttributes.VarianceMask, (ushort) GenericParameterAttributes.NonVariant); }

			set { attributes = attributes.SetMaskedAttributes ((ushort) GenericParameterAttributes.VarianceMask, (ushort) GenericParameterAttributes.NonVariant, value); }

		}



		public bool IsCovariant {

			get { return attributes.GetMaskedAttributes ((ushort) GenericParameterAttributes.VarianceMask, (ushort) GenericParameterAttributes.Covariant); }

			set { attributes = attributes.SetMaskedAttributes ((ushort) GenericParameterAttributes.VarianceMask, (ushort) GenericParameterAttributes.Covariant, value); }

		}



		public bool IsContravariant {

			get { return attributes.GetMaskedAttributes ((ushort) GenericParameterAttributes.VarianceMask, (ushort) GenericParameterAttributes.Contravariant); }

			set { attributes = attributes.SetMaskedAttributes ((ushort) GenericParameterAttributes.VarianceMask, (ushort) GenericParameterAttributes.Contravariant, value); }

		}



		public bool HasReferenceTypeConstraint {

			get { return attributes.GetAttributes ((ushort) GenericParameterAttributes.ReferenceTypeConstraint); }

			set { attributes = attributes.SetAttributes ((ushort) GenericParameterAttributes.ReferenceTypeConstraint, value); }

		}



		public bool HasNotNullableValueTypeConstraint {

			get { return attributes.GetAttributes ((ushort) GenericParameterAttributes.NotNullableValueTypeConstraint); }

			set { attributes = attributes.SetAttributes ((ushort) GenericParameterAttributes.NotNullableValueTypeConstraint, value); }

		}



		public bool HasDefaultConstructorConstraint {

			get { return attributes.GetAttributes ((ushort) GenericParameterAttributes.DefaultConstructorConstraint); }

			set { attributes = attributes.SetAttributes ((ushort) GenericParameterAttributes.DefaultConstructorConstraint, value); }

		}



		#endregion



		public GenericParameter (IGenericParameterProvider owner)

			: this (string.Empty, owner)

		{

		}



		public GenericParameter (string name, IGenericParameterProvider owner)

			: base (string.Empty, name)

		{

			if (owner == null)

				throw new ArgumentNullException ();



			this.owner = owner;

			this.etype = owner.GenericParameterType == GenericParameterType.Type ? ElementType.Var : ElementType.MVar;

		}



		public override TypeDefinition Resolve ()

		{

			return null;

		}

	}

}