///////////////////////////////////////////////////////////////////////////////
//
//  Microsoft Research Singularity
//
//  Copyright (c) Microsoft Corporation.  All rights reserved.
//
//  File:   ExHeap.sg
//
//  Note: This is the KERNEL version of the ExHeap custom allocator.
//


using System;
using System.Runtime.InteropServices;
using Microsoft.SingSharp;
using Microsoft.Singularity;

namespace Microsoft.Singularity.Channels {

    using Microsoft.Singularity.V1.Services;
    using Microsoft.Singularity.V1.Types;
    using EndpointCore = Microsoft.Singularity.V1.Services.EndpointCore;

    public class ExHeap : CustomAllocator {

        unsafe public static void*! in ExHeap Allocate(Type! type)
        {
            int size = Marshal.StructSize(type);
#if SINGULARITY
            SystemType st = type.GetSystemType();
            Tracing.Log(Tracing.Debug, "ExHeap.Allocate {0} size {1:x} type {2:x}",
                        type.FullName, (UIntPtr)unchecked((uint)size),
                        st.TypeId);
#else
            Console.WriteLine("ExHeap.Allocate {0} of size {1}", type.FullName, size);
            SystemType st = new SystemType();
#endif
            SharedHeapService.Allocation* ptr = SharedHeapService.Allocate((UIntPtr)size, st, 0);
#if SINGULARITY_KERNEL
            Tracing.Log(Tracing.Debug, "  result = {0:x8}", Kernel.AddressOf(ptr));
#elif SINGULARITY_PROCESS
            Tracing.Log(Tracing.Debug, "  result = {0:x8}", (UIntPtr)ptr);
#endif // SINGULARITY_PROCESS
            if (ptr == null) throw new OutOfMemoryException("SharedHeap.Allocate returned null");
            return (void* in ExHeap)ptr;
        }

        unsafe public static void* opt(ExHeap[])! AllocateVector(Type! type, int elems)
        {
            ulong elemSize = (ulong)Marshal.StructSize(type);
#if SINGULARITY
            SystemType st = type.GetSystemType();
            Tracing.Log(Tracing.Debug, "ExHeap.AllocateVector {0} size {1:x} type {2:x}",
                        type.FullName, (UIntPtr)unchecked(elemSize * (ulong)elems),
                        st.TypeId);
#else
            SystemType st = new SystemType();
#endif
            checked {
                SharedHeapService.Allocation* ptr =
                    SharedHeapService.Allocate( (UIntPtr)(elemSize * (ulong)elems), st, 0);

                if (ptr == null) throw new OutOfMemoryException("SharedHeap.Allocate returned null");
#if SINGULARITY
                Tracing.Log(Tracing.Debug, "  result = {0:x8}", (UIntPtr)ptr);
#endif
                return (void* opt(ExHeap[]))ptr;
            }
        }

        unsafe public static void Free([Claims] void* in ExHeap ptr)
        {
            // Should adhere to contract. ptr can be null.
            if (ptr == null) return;

#if SINGULARITY_KERNEL
            Tracing.Log(Tracing.Debug, "ExHeap.Free: {0:x8}", Kernel.AddressOf(ptr));
#elif SINGULARITY_PROCESS
            Tracing.Log(Tracing.Debug, "ExHeap.Free: {0:x8}", (UIntPtr)ptr);
#endif // SINGULARITY_PROCESS
            SharedHeapService.Allocation* alloc = (SharedHeapService.Allocation*)ptr;
            SystemType epType = typeof(Endpoint).GetSystemType();
            if (SystemType.IsSubtype(alloc, epType)) {
                EndpointCore.Free(alloc);
            }
            else {
                SharedHeapService.Free(alloc);
            }
        }

        unsafe public static bool IsInst(void* in ExHeap ptr, System.Type! targetType)
        {
#if SINGULARITY
            SystemType targetst = targetType.GetSystemType();
            SharedHeapService.Allocation* alloc = (SharedHeapService.Allocation*)ptr;
            return SystemType.IsSubtype(alloc, targetst);
#else
            return false;
#endif
        }

        unsafe public static UIntPtr GetSize(void* in ExHeap ptr)
        {
            SharedHeapService.Allocation* alloc = (SharedHeapService.Allocation*)ptr;
            return SharedHeapService.GetSize(alloc);
        }

        unsafe public static void* IndirectToData(void* in ExHeap ptr)
        {
            SharedHeapService.Allocation* alloc = (SharedHeapService.Allocation*)ptr;
            UIntPtr data = SharedHeapService.GetData(alloc);
#if DEBUG
            if (data == UIntPtr.Zero) throw new ApplicationException("SharedHeapService.GetData returned 0");
#endif
            void* result = (void*!)data;
            return result;
        }

        unsafe public static void*! in ExHeap Share(void* in ExHeap ptr) {
            SharedHeapService.Allocation* alloc = (SharedHeapService.Allocation*)ptr;
            UIntPtr size = SharedHeapService.GetSize(alloc);
            return (void*! in ExHeap)SharedHeapService.Share(alloc, (UIntPtr)0, size);
        }
    }

    /// <summary>
    /// Specialized entry point for allocating endpoints rather than other exchangeable objects
    /// </summary>
    class ChannelHeap : CustomAllocator {

        unsafe public static void*! in ExHeap Allocate(Type! type)
        {
            uint size = (uint)Marshal.StructSize(type);
            Tracing.Log(Tracing.Debug, "EndpointHeap.Allocate {0} with size {1:x}",
                        type.FullName, (UIntPtr)size);

            SystemType st = type.GetSystemType();
            SharedHeapService.Allocation* ptr = EndpointCore.Allocate(size, st);
            if (ptr == null) throw new OutOfMemoryException("EndpointCore.Allocate returned null");
            return (void* in ExHeap)ptr;
        }

    }
}