/// <summary>
/// Sets the <see cref="ShuttingDown"/> flag, and disposes of the MemoryMappedFile and MemoryMappedViewAccessor.<br />
/// Attempting to read/write to the buffer after closing will result in a <see cref="System.NullReferenceException"/>.
/// </summary>
public virtual void Close()
{
if (IsOwnerOfSharedMemory && View != null)
{
// Indicates to any open instances that the owner is no longer open
#pragma warning disable 0420 // ignore ref to volatile warning - Interlocked API
Interlocked.Exchange(ref Header->Shutdown, 1);
#pragma warning restore 0420
}
// Allow additional close logic
DoClose();
// Close the MemoryMappedFile and MemoryMappedViewAccessor
if (View != null)
{
View.SafeMemoryMappedViewHandle.ReleasePointer();
View.Dispose();
}
if (Mmf != null)
{
Mmf.Dispose();
}
Header = null;
ViewPtr = null;
BufferStartPtr = null;
View = null;
Mmf = null;
}
protected bool Open()
{
Close();
try
{
// Attempts to create or open the shared memory with a name of this.Name
if (IsOwnerOfSharedMemory)
{
// Create a new shared memory mapping
#if Windows
Mmf = MemoryMappedFile.CreateNew(Name, SharedMemorySize); //Linux not supported
#else
var path = System.IO.Path.Combine(System.IO.Path.GetTempPath(), Name);
Mmf = MemoryMappedFile.CreateFromFile(path, System.IO.FileMode.OpenOrCreate, null, SharedMemorySize);
Log.Debug($"MemoryMappedFile create at: {path}");
#endif
// Create a view to the entire region of the shared memory
View = Mmf.CreateViewAccessor(0, SharedMemorySize, MemoryMappedFileAccess.ReadWrite);
View.SafeMemoryMappedViewHandle.AcquirePointer(ref ViewPtr);
Header = (SharedHeader *)(ViewPtr + HeaderOffset);
BufferStartPtr = ViewPtr + BufferOffset;
// Initialise the header
InitialiseHeader();
}
else
{
// Open an existing shared memory mapping
#if Windows
Mmf = MemoryMappedFile.OpenExisting(Name); //Linux not supported
#else
var path = System.IO.Path.Combine(System.IO.Path.GetTempPath(), Name);
Mmf = MemoryMappedFile.CreateFromFile(path, System.IO.FileMode.Open, null);
Log.Debug($"MemoryMappedFile open at: {path}");
#endif
// Retrieve the header from the shared memory in order to initialise the correct size
using (var headerView = Mmf.CreateViewAccessor(0, HeaderOffset + Marshal.SizeOf(typeof(SharedHeader)), MemoryMappedFileAccess.Read))
{
byte *headerPtr = null;
headerView.SafeMemoryMappedViewHandle.AcquirePointer(ref headerPtr);
var header = (SharedHeader *)(headerPtr + HeaderOffset);
BufferSize = header->SharedMemorySize - Marshal.SizeOf(typeof(SharedHeader));
headerView.SafeMemoryMappedViewHandle.ReleasePointer();
}
// Create a view to the entire region of the shared memory
View = Mmf.CreateViewAccessor(0, SharedMemorySize, MemoryMappedFileAccess.ReadWrite);
View.SafeMemoryMappedViewHandle.AcquirePointer(ref ViewPtr);
Header = (SharedHeader *)(ViewPtr + HeaderOffset);
BufferStartPtr = ViewPtr + HeaderOffset + Marshal.SizeOf(typeof(SharedHeader));
}
}
catch
{
Close();
throw;
}
// Complete any additional open logic
try
{
if (!DoOpen())
{
Close();
return(false);
}
else
{
return(true);
}
}
catch
{
Close();
throw;
}
}
protected bool Open()
{
Close();
try
{
// Attempts to create or open the shared memory with a name of this.Name
if (IsOwnerOfSharedMemory)
{
// Create a new shared memory mapping
Mmf = MemoryMappedFile.CreateNew(Name, SharedMemorySize);
// Create a view to the entire region of the shared memory
View = Mmf.CreateViewAccessor(0, SharedMemorySize, MemoryMappedFileAccess.ReadWrite);
View.SafeMemoryMappedViewHandle.AcquirePointer(ref ViewPtr);
Header = (SharedHeader *)(ViewPtr + HeaderOffset);
BufferStartPtr = ViewPtr + BufferOffset;
// Initialise the header
InitialiseHeader();
}
else
{
// Open an existing shared memory mapping
Mmf = MemoryMappedFile.OpenExisting(Name);
// Retrieve the header from the shared memory in order to initialise the correct size
using (var headerView = Mmf.CreateViewAccessor(0, HeaderOffset + Marshal.SizeOf(typeof(SharedHeader)), MemoryMappedFileAccess.Read))
{
byte *headerPtr = null;
headerView.SafeMemoryMappedViewHandle.AcquirePointer(ref headerPtr);
var header = (SharedHeader *)(headerPtr + HeaderOffset);
BufferSize = header->SharedMemorySize - Marshal.SizeOf(typeof(SharedHeader));
headerView.SafeMemoryMappedViewHandle.ReleasePointer();
}
// Create a view to the entire region of the shared memory
View = Mmf.CreateViewAccessor(0, SharedMemorySize, MemoryMappedFileAccess.ReadWrite);
View.SafeMemoryMappedViewHandle.AcquirePointer(ref ViewPtr);
Header = (SharedHeader *)(ViewPtr + HeaderOffset);
BufferStartPtr = ViewPtr + HeaderOffset + Marshal.SizeOf(typeof(SharedHeader));
}
}
catch
{
Close();
throw;
}
// Complete any additional open logic
try
{
if (!DoOpen())
{
Close();
return(false);
}
else
{
return(true);
}
}
catch
{
Close();
throw;
}
}
protected bool Open()
{
Close();
try
{
// Attempts to create or open the shared memory with a name of this.Name
if (IsOwnerOfSharedMemory)
{
// Create a new shared memory mapping
#if NETFULL && !(NET35)
MemoryMappedFileSecurity memoryMappedFileSecurity = new MemoryMappedFileSecurity();
memoryMappedFileSecurity.SetSecurityDescriptorBinaryForm(BuildSecurityDescriptor(defaultAllowedList).GetSecurityDescriptorBinaryForm());
Mmf = MemoryMappedFile.CreateNew(Name, SharedMemorySize, MemoryMappedFileAccess.ReadWrite,
MemoryMappedFileOptions.DelayAllocatePages, memoryMappedFileSecurity, HandleInheritability.Inheritable);
#else
Mmf = MemoryMappedFile.CreateNew(Name, SharedMemorySize);
#endif
// Create a view to the entire region of the shared memory
View = Mmf.CreateViewAccessor(0, SharedMemorySize, MemoryMappedFileAccess.ReadWrite);
View.SafeMemoryMappedViewHandle.AcquirePointer(ref ViewPtr);
Header = (SharedHeader *)(ViewPtr + HeaderOffset);
BufferStartPtr = ViewPtr + BufferOffset;
// Initialise the header
InitialiseHeader();
}
else
{
// Open an existing shared memory mapping
Mmf = MemoryMappedFile.OpenExisting(Name);
// Retrieve the header from the shared memory in order to initialise the correct size
using (var headerView = Mmf.CreateViewAccessor(0, HeaderOffset + Marshal.SizeOf(typeof(SharedHeader)), MemoryMappedFileAccess.Read))
{
byte *headerPtr = null;
headerView.SafeMemoryMappedViewHandle.AcquirePointer(ref headerPtr);
var header = (SharedHeader *)(headerPtr + HeaderOffset);
BufferSize = header->SharedMemorySize - Marshal.SizeOf(typeof(SharedHeader));
headerView.SafeMemoryMappedViewHandle.ReleasePointer();
}
// Create a view to the entire region of the shared memory
View = Mmf.CreateViewAccessor(0, SharedMemorySize, MemoryMappedFileAccess.ReadWrite);
View.SafeMemoryMappedViewHandle.AcquirePointer(ref ViewPtr);
Header = (SharedHeader *)(ViewPtr + HeaderOffset);
BufferStartPtr = ViewPtr + HeaderOffset + Marshal.SizeOf(typeof(SharedHeader));
}
}
catch
{
Close();
throw;
}
// Complete any additional open logic
try
{
if (!DoOpen())
{
Close();
return(false);
}
else
{
return(true);
}
}
catch
{
Close();
throw;
}
}
