103 lines
3.2 KiB
Plaintext
103 lines
3.2 KiB
Plaintext
////////////////////////////////////////////////////////////////////////////////
|
|
//
|
|
// Microsoft Research Singularity
|
|
//
|
|
// Copyright (c) Microsoft Corporation. All rights reserved.
|
|
//
|
|
// File: XRef.cs
|
|
//
|
|
// Note: File is part of Sing# runtime files and copied into Singularity tree
|
|
// whenever a new version of Sing# is dropped.
|
|
// Coordinate any changes with Sing# team.
|
|
//
|
|
|
|
using System;
|
|
using Microsoft.SingSharp;
|
|
using Microsoft.Singularity.Memory;
|
|
|
|
namespace Microsoft.Singularity.Channels
|
|
{
|
|
using System.Threading;
|
|
using Allocation = Microsoft.Singularity.Memory.SharedHeap.Allocation;
|
|
|
|
public sealed class ExRef<T> where T : unmanaged struct, ITracked
|
|
{
|
|
unsafe T* opt(ExHeap) obj;
|
|
Mutex mutex;
|
|
|
|
public ExRef([Claims] T* opt(ExHeap)! i_obj, bool synchronized)
|
|
{
|
|
if (i_obj == null) {
|
|
throw new ArgumentNullException("ExRef must be initialized with a non-null value!");
|
|
}
|
|
i_obj->Release();
|
|
obj = i_obj;
|
|
if (synchronized) {
|
|
this.mutex = new Mutex();
|
|
}
|
|
}
|
|
|
|
// invariant:
|
|
// If mutex is held, thread holding mutex is
|
|
// responsible for calling Release during that time,
|
|
// the obj slot is empty and if the thread tries to
|
|
// acquire it again, an exception is thrown.
|
|
|
|
/// <summary>
|
|
/// Will block until the ExRef is free.
|
|
/// </summary>
|
|
/// <returns>Acquired tracked type protected by ExRef</returns>
|
|
public T* opt(ExHeap)! Acquire()
|
|
{
|
|
if (this.mutex != null) {
|
|
this.mutex.WaitOne();
|
|
}
|
|
T* opt(ExHeap) elem = this.obj;
|
|
if (elem == null) {
|
|
throw new ApplicationException("thread already holds ExRef!");
|
|
}
|
|
elem->Acquire();
|
|
this.obj = null;
|
|
return elem;
|
|
}
|
|
|
|
/// <summary>
|
|
/// Releases tracked data into the ExRef so other
|
|
/// threads can access it.
|
|
/// </summary>
|
|
/// <param name="newObj">tracked data to be released</param>
|
|
public void Release([Claims] T* opt(ExHeap)! newObj)
|
|
{
|
|
if (newObj == null) {
|
|
throw new ArgumentNullException("ExRef must be released with a non-null value!");
|
|
}
|
|
|
|
T* opt(ExHeap) elem = this.obj;
|
|
if (elem != null) {
|
|
throw new ApplicationException("Releasing into occupied slot!");
|
|
}
|
|
|
|
newObj->Release();
|
|
obj = newObj;
|
|
if (this.mutex != null) {
|
|
this.mutex.ReleaseMutex();
|
|
}
|
|
}
|
|
|
|
/// <summary>
|
|
/// Finalizer to dispose of any left over contents
|
|
/// </summary>
|
|
~ExRef()
|
|
{
|
|
T* opt(ExHeap) toDelete = this.obj;
|
|
if (toDelete != null) {
|
|
this.obj = null;
|
|
unsafe {
|
|
toDelete->Dispose(); // Explicit call needed due to generics
|
|
}
|
|
delete toDelete;
|
|
}
|
|
}
|
|
}
|
|
}
|