// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
 
using System;
using System.Diagnostics;
using Roslyn.Utilities;
 
namespace Microsoft.CodeAnalysis.ExpressionEvaluator
{
    /// <summary>
    /// Module metadata block
    /// </summary>
    [DebuggerDisplay("{GetDebuggerDisplay(), nq}")]
    internal readonly struct MetadataBlock(ModuleId moduleId, Guid generationId, IntPtr pointer, int size) : IEquatable<MetadataBlock>
    {
        /// <summary>
        /// Module id.
        /// </summary>
        internal readonly ModuleId ModuleId = moduleId;
 
        /// <summary>
        /// Module generation id.
        /// </summary>
        internal readonly Guid GenerationId = generationId;
 
        /// <summary>
        /// Pointer to memory block managed by the caller.
        /// </summary>
        internal readonly IntPtr Pointer = pointer;
 
        /// <summary>
        /// Size of memory block.
        /// </summary>
        internal readonly int Size = size;
 
        // Used by VS debugger (/src/debugger/ProductionDebug/CodeAnalysis/CodeAnalysis/ExpressionEvaluator.cs)
        internal MetadataBlock(Guid moduleId, Guid generationId, IntPtr pointer, int size)
            : this(new ModuleId(moduleId, "<unknown>"), generationId, pointer, size)
        {
        }
 
        public bool Equals(MetadataBlock other)
        {
            return Pointer == other.Pointer &&
                   Size == other.Size &&
                   ModuleId.Id == other.ModuleId.Id &&
                   GenerationId == other.GenerationId;
        }
 
        public override bool Equals(object obj)
        {
            if (!(obj is MetadataBlock))
            {
                return false;
            }
            return Equals((MetadataBlock)obj);
        }
 
        public override int GetHashCode()
        {
            return Hash.Combine(
                Hash.Combine(Pointer.GetHashCode(), Size),
                Hash.Combine(ModuleId.GetHashCode(), GenerationId.GetHashCode()));
        }
 
        private string GetDebuggerDisplay()
        {
            return string.Format("MetadataBlock {{ Mvid = {{{0}}}, Address = {1}, Size = {2} }}", ModuleId, Pointer, Size);
        }
    }
}