/* ****************************************************************************
 *
 * Copyright (c) Microsoft Corporation.
 *
 * This source code is subject to terms and conditions of the Apache License, Version 2.0. A
 * copy of the license can be found in the License.html file at the root of this distribution. If
 * you cannot locate the Apache License, Version 2.0, please send an email to
 * dlr@microsoft.com. By using this source code in any fashion, you are agreeing to be bound
 * by the terms of the Apache License, Version 2.0.
 *
 * You must not remove this notice, or any other, from this software.
 *
 *
 * ***************************************************************************/

using System.Diagnostics;
using System.Reflection;

namespace System.Management.Automation.Interpreter
{
    internal sealed class LoadStaticFieldInstruction : Instruction
    {
        private readonly FieldInfo _field;

        public LoadStaticFieldInstruction(FieldInfo field)
        {
            Debug.Assert(field.IsStatic);
            _field = field;
        }

        public override int ProducedStack { get { return 1; } }

        public override int Run(InterpretedFrame frame)
        {
            frame.Push(_field.GetValue(null));
            return +1;
        }
    }

    internal sealed class LoadFieldInstruction : Instruction
    {
        private readonly FieldInfo _field;

        public LoadFieldInstruction(FieldInfo field)
        {
            Assert.NotNull(field);
            _field = field;
        }

        public override int ConsumedStack { get { return 1; } }

        public override int ProducedStack { get { return 1; } }

        public override int Run(InterpretedFrame frame)
        {
            frame.Push(_field.GetValue(frame.Pop()));
            return +1;
        }
    }

    internal sealed class StoreFieldInstruction : Instruction
    {
        private readonly FieldInfo _field;

        public StoreFieldInstruction(FieldInfo field)
        {
            Assert.NotNull(field);
            _field = field;
        }

        public override int ConsumedStack { get { return 2; } }

        public override int ProducedStack { get { return 0; } }

        public override int Run(InterpretedFrame frame)
        {
            object value = frame.Pop();
            object self = frame.Pop();
            _field.SetValue(self, value);
            return +1;
        }
    }

    internal sealed class StoreStaticFieldInstruction : Instruction
    {
        private readonly FieldInfo _field;

        public StoreStaticFieldInstruction(FieldInfo field)
        {
            Assert.NotNull(field);
            _field = field;
        }

        public override int ConsumedStack { get { return 1; } }

        public override int ProducedStack { get { return 0; } }

        public override int Run(InterpretedFrame frame)
        {
            object value = frame.Pop();
            _field.SetValue(null, value);
            return +1;
        }
    }
}