// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System.Runtime.CompilerServices;
using System.Runtime.Versioning;
 
namespace System.Runtime.InteropServices.Java
{
    [CLSCompliant(false)]
    [SupportedOSPlatform("android")]
    public static partial class JavaMarshal
    {
        public static unsafe void Initialize(delegate* unmanaged<MarkCrossReferencesArgs*, void> markCrossReferences)
        {
            ArgumentNullException.ThrowIfNull(markCrossReferences);
 
            if (!InitializeInternal((IntPtr)markCrossReferences))
            {
                throw new InvalidOperationException(SR.InvalidOperation_ReinitializeJavaMarshal);
            }
        }
 
        public static unsafe GCHandle CreateReferenceTrackingHandle(object obj, void* context)
        {
            ArgumentNullException.ThrowIfNull(obj);
 
            IntPtr handle = CreateReferenceTrackingHandleInternal(ObjectHandleOnStack.Create(ref obj), context);
            return GCHandle.FromIntPtr(handle);
        }
 
        public static unsafe void* GetContext(GCHandle obj)
        {
            IntPtr handle = GCHandle.ToIntPtr(obj);
            if (handle == IntPtr.Zero
                || !GetContextInternal(handle, out void* context))
            {
                throw new InvalidOperationException(SR.InvalidOperation_IncorrectGCHandleType);
            }
 
            return context;
        }
 
        public static unsafe void FinishCrossReferenceProcessing(
            MarkCrossReferencesArgs* crossReferences,
            ReadOnlySpan<GCHandle> unreachableObjectHandles)
        {
            fixed (GCHandle* pHandles = unreachableObjectHandles)
            {
                FinishCrossReferenceProcessing(
                    crossReferences,
                    (nuint)unreachableObjectHandles.Length,
                    pHandles);
            }
        }
 
        [LibraryImport(RuntimeHelpers.QCall, EntryPoint = "JavaMarshal_Initialize")]
        [return: MarshalAs(UnmanagedType.Bool)]
        private static partial bool InitializeInternal(IntPtr callback);
 
        [LibraryImport(RuntimeHelpers.QCall, EntryPoint = "JavaMarshal_CreateReferenceTrackingHandle")]
        private static unsafe partial IntPtr CreateReferenceTrackingHandleInternal(ObjectHandleOnStack obj, void* context);
 
        [LibraryImport(RuntimeHelpers.QCall, EntryPoint = "JavaMarshal_FinishCrossReferenceProcessing")]
        private static unsafe partial void FinishCrossReferenceProcessing(MarkCrossReferencesArgs* crossReferences, nuint length, void* unreachableObjectHandles);
 
        [LibraryImport(RuntimeHelpers.QCall, EntryPoint = "JavaMarshal_GetContext")]
        [SuppressGCTransition]
        [return: MarshalAs(UnmanagedType.Bool)]
        private static unsafe partial bool GetContextInternal(IntPtr handle, out void* context);
    }
}