/*
* COPYRIGHT:  See COPYING in the top level directory
* PROJECT:    ReactOS kernel
* FILE:       drivers/fs/np/rw.c
* PURPOSE:    Named pipe filesystem
* PROGRAMMER: David Welch <welch@cwcom.net>
*/

/* INCLUDES ******************************************************************/

#include "npfs.h"

#define NDEBUG
#include <debug.h>

/* FUNCTIONS *****************************************************************/

#ifndef NDEBUG
VOID HexDump(PUCHAR Buffer, ULONG Length)
{
	CHAR Line[65];
	UCHAR ch;
	const char Hex[] = "0123456789ABCDEF";
	int i, j;

	DbgPrint("---------------\n");

	for (i = 0; i < Length; i+= 16)
	{
		memset(Line, ' ', 64);
		Line[64] = 0;

		for (j = 0; j < 16 && j + i < Length; j++)
		{
			ch = Buffer[i + j];
			Line[3*j + 0] = Hex[ch >> 4];
			Line[3*j + 1] = Hex[ch & 0x0f];
			Line[48 + j] = isprint(ch) ? ch : '.';
		}
		DbgPrint("%s\n", Line);
	}
	DbgPrint("---------------\n");
}
#endif

static VOID STDCALL
NpfsReadWriteCancelRoutine(IN PDEVICE_OBJECT DeviceObject,
						   IN PIRP Irp)
{
	PNPFS_CONTEXT Context;
	PNPFS_DEVICE_EXTENSION DeviceExt;
	PIO_STACK_LOCATION IoStack;
	PNPFS_CCB Ccb;
	BOOLEAN Complete = FALSE;

	DPRINT("NpfsReadWriteCancelRoutine(DeviceObject %x, Irp %x)\n", DeviceObject, Irp);

	IoReleaseCancelSpinLock(Irp->CancelIrql);

	Context = (PNPFS_CONTEXT)&Irp->Tail.Overlay.DriverContext;
	DeviceExt = (PNPFS_DEVICE_EXTENSION)DeviceObject->DeviceExtension;
	IoStack = IoGetCurrentIrpStackLocation(Irp);
	Ccb = IoStack->FileObject->FsContext2;

	KeLockMutex(&DeviceExt->PipeListLock);
	ExAcquireFastMutex(&Ccb->DataListLock);
	switch(IoStack->MajorFunction)
	{
	case IRP_MJ_READ:
		if (Ccb->ReadRequestListHead.Flink != &Context->ListEntry)
		{
			/* we are not the first in the list, remove an complete us */
			RemoveEntryList(&Context->ListEntry);
			Complete = TRUE;
		}
		else
		{
			KeSetEvent(&Ccb->ReadEvent, IO_NO_INCREMENT, FALSE);
		}
		break;
	default:
		KEBUGCHECK(0);
	}
	ExReleaseFastMutex(&Ccb->DataListLock);
	KeUnlockMutex(&DeviceExt->PipeListLock);
	if (Complete)
	{
		Irp->IoStatus.Status = STATUS_CANCELLED;
		Irp->IoStatus.Information = 0;
		IoCompleteRequest(Irp, IO_NO_INCREMENT);
	}
}

static VOID STDCALL
NpfsWaiterThread(PVOID InitContext)
{
	PNPFS_THREAD_CONTEXT ThreadContext = (PNPFS_THREAD_CONTEXT) InitContext;
	ULONG CurrentCount;
	ULONG Count = 0;
	PIRP Irp = NULL;
	PIRP NextIrp;
	NTSTATUS Status;
	BOOLEAN Terminate = FALSE;
	BOOLEAN Cancel = FALSE;
	PIO_STACK_LOCATION IoStack = NULL;
	PNPFS_CONTEXT Context;
	PNPFS_CONTEXT NextContext;
	PNPFS_CCB Ccb;

	KeLockMutex(&ThreadContext->DeviceExt->PipeListLock);

	while (1)
	{
		CurrentCount = ThreadContext->Count;
		KeUnlockMutex(&ThreadContext->DeviceExt->PipeListLock);
		if (Irp)
		{
			if (Cancel)
			{
				Irp->IoStatus.Status = STATUS_CANCELLED;
				Irp->IoStatus.Information = 0;
				IoCompleteRequest(Irp, IO_NO_INCREMENT);
			}
			else
			{
				switch (IoStack->MajorFunction)
				{
				case IRP_MJ_READ:
					NpfsRead(IoStack->DeviceObject, Irp);
					break;
				default:
					KEBUGCHECK(0);
				}
			}
		}
		if (Terminate)
		{
			break;
		}
		Status = KeWaitForMultipleObjects(CurrentCount,
			ThreadContext->WaitObjectArray,
			WaitAny,
			Executive,
			KernelMode,
			FALSE,
			NULL,
			ThreadContext->WaitBlockArray);
		if (!NT_SUCCESS(Status))
		{
			KEBUGCHECK(0);
		}
		KeLockMutex(&ThreadContext->DeviceExt->PipeListLock);
		Count = Status - STATUS_SUCCESS;
		ASSERT (Count < CurrentCount);
		if (Count > 0)
		{
			Irp = ThreadContext->WaitIrpArray[Count];
			ThreadContext->Count--;
			ThreadContext->DeviceExt->EmptyWaiterCount++;
			ThreadContext->WaitObjectArray[Count] = ThreadContext->WaitObjectArray[ThreadContext->Count];
			ThreadContext->WaitIrpArray[Count] = ThreadContext->WaitIrpArray[ThreadContext->Count];

			Cancel = (NULL == IoSetCancelRoutine(Irp, NULL));
			Context = (PNPFS_CONTEXT)&Irp->Tail.Overlay.DriverContext;
			IoStack = IoGetCurrentIrpStackLocation(Irp);

			if (Cancel)
			{
				Ccb = IoStack->FileObject->FsContext2;
				ExAcquireFastMutex(&Ccb->DataListLock);
				RemoveEntryList(&Context->ListEntry);
				switch (IoStack->MajorFunction)
				{
				case IRP_MJ_READ:
					if (!IsListEmpty(&Ccb->ReadRequestListHead))
					{
						/* put the next request on the wait list */
						NextContext = CONTAINING_RECORD(Ccb->ReadRequestListHead.Flink, NPFS_CONTEXT, ListEntry);
						ThreadContext->WaitObjectArray[ThreadContext->Count] = NextContext->WaitEvent;
						NextIrp = CONTAINING_RECORD(NextContext, IRP, Tail.Overlay.DriverContext);
						ThreadContext->WaitIrpArray[ThreadContext->Count] = NextIrp;
						ThreadContext->Count++;
						ThreadContext->DeviceExt->EmptyWaiterCount--;
					}
					break;
				default:
					KEBUGCHECK(0);
				}
				ExReleaseFastMutex(&Ccb->DataListLock);
			}
		}
		else
		{
			/* someone has add a new wait request */
			Irp = NULL;
		}
		if (ThreadContext->Count == 1 && ThreadContext->DeviceExt->EmptyWaiterCount >= MAXIMUM_WAIT_OBJECTS)
		{
			/* it exist an other thread with empty wait slots, we can remove our thread from the list */
			RemoveEntryList(&ThreadContext->ListEntry);
			ThreadContext->DeviceExt->EmptyWaiterCount -= MAXIMUM_WAIT_OBJECTS - 1;
			Terminate = TRUE;
		}
	}
	ExFreePool(ThreadContext);
}

static NTSTATUS
NpfsAddWaitingReadWriteRequest(IN PDEVICE_OBJECT DeviceObject,
							   IN PIRP Irp)
{
	PLIST_ENTRY ListEntry;
	PNPFS_THREAD_CONTEXT ThreadContext = NULL;
	NTSTATUS Status;
	HANDLE hThread;
	KIRQL oldIrql;

	PNPFS_CONTEXT Context = (PNPFS_CONTEXT)&Irp->Tail.Overlay.DriverContext;
	PNPFS_DEVICE_EXTENSION DeviceExt = (PNPFS_DEVICE_EXTENSION)DeviceObject->DeviceExtension;

	DPRINT("NpfsAddWaitingReadWriteRequest(DeviceObject %p, Irp %p)\n", DeviceObject, Irp);

	KeLockMutex(&DeviceExt->PipeListLock);

	ListEntry = DeviceExt->ThreadListHead.Flink;
	while (ListEntry != &DeviceExt->ThreadListHead)
	{
		ThreadContext = CONTAINING_RECORD(ListEntry, NPFS_THREAD_CONTEXT, ListEntry);
		if (ThreadContext->Count < MAXIMUM_WAIT_OBJECTS)
		{
			break;
		}
		ListEntry = ListEntry->Flink;
	}
	if (ListEntry == &DeviceExt->ThreadListHead)
	{
		ThreadContext = ExAllocatePool(NonPagedPool, sizeof(NPFS_THREAD_CONTEXT));
		if (ThreadContext == NULL)
		{
			KeUnlockMutex(&DeviceExt->PipeListLock);
			return STATUS_NO_MEMORY;
		}
		ThreadContext->DeviceExt = DeviceExt;
		KeInitializeEvent(&ThreadContext->Event, SynchronizationEvent, FALSE);
		ThreadContext->Count = 1;
		ThreadContext->WaitObjectArray[0] = &ThreadContext->Event;


		DPRINT("Creating a new system thread for waiting read/write requests\n");

		Status = PsCreateSystemThread(&hThread,
			THREAD_ALL_ACCESS,
			NULL,
			NULL,
			NULL,
			NpfsWaiterThread,
			(PVOID)ThreadContext);
		if (!NT_SUCCESS(Status))
		{
			ExFreePool(ThreadContext);
			KeUnlockMutex(&DeviceExt->PipeListLock);
			return Status;
		}
		InsertHeadList(&DeviceExt->ThreadListHead, &ThreadContext->ListEntry);
		DeviceExt->EmptyWaiterCount += MAXIMUM_WAIT_OBJECTS - 1;
	}
	IoMarkIrpPending(Irp);

	IoAcquireCancelSpinLock(&oldIrql);
	if (Irp->Cancel)
	{
		IoReleaseCancelSpinLock(oldIrql);
		Status = STATUS_CANCELLED;
	}
	else
	{
		(void)IoSetCancelRoutine(Irp, NpfsReadWriteCancelRoutine);
		IoReleaseCancelSpinLock(oldIrql);
		ThreadContext->WaitObjectArray[ThreadContext->Count] = Context->WaitEvent;
		ThreadContext->WaitIrpArray[ThreadContext->Count] = Irp;
		ThreadContext->Count++;
		DeviceExt->EmptyWaiterCount--;
		KeSetEvent(&ThreadContext->Event, IO_NO_INCREMENT, FALSE);
		Status = STATUS_SUCCESS;
	}
	KeUnlockMutex(&DeviceExt->PipeListLock);
	return Status;
}

NTSTATUS STDCALL
NpfsRead(IN PDEVICE_OBJECT DeviceObject,
		 IN PIRP Irp)
{
	PFILE_OBJECT FileObject;
	NTSTATUS Status;
	NTSTATUS OriginalStatus = STATUS_SUCCESS;
	PNPFS_CCB Ccb;
	PNPFS_CONTEXT Context;
	KEVENT Event;
	ULONG Length;
	ULONG Information = 0;
	ULONG CopyLength;
	ULONG TempLength;
	BOOLEAN IsOriginalRequest = TRUE;
	PVOID Buffer;

	DPRINT("NpfsRead(DeviceObject %p, Irp %p)\n", DeviceObject, Irp);

	if (Irp->MdlAddress == NULL)
	{
		DPRINT("Irp->MdlAddress == NULL\n");
		Status = STATUS_UNSUCCESSFUL;
		Irp->IoStatus.Information = 0;
		goto done;
	}

	FileObject = IoGetCurrentIrpStackLocation(Irp)->FileObject;
	Ccb = FileObject->FsContext2;
	Context = (PNPFS_CONTEXT)&Irp->Tail.Overlay.DriverContext;

	if (Ccb->OtherSide == NULL)
	{
		DPRINT("Pipe is NOT connected!\n");
		if (Ccb->PipeState == FILE_PIPE_LISTENING_STATE)
			Status = STATUS_PIPE_LISTENING;
		else if (Ccb->PipeState == FILE_PIPE_DISCONNECTED_STATE)
			Status = STATUS_PIPE_DISCONNECTED;
		else
			Status = STATUS_UNSUCCESSFUL;
		Irp->IoStatus.Information = 0;
		goto done;
	}

	if (Ccb->Data == NULL)
	{
		DPRINT1("Pipe is NOT readable!\n");
		Status = STATUS_UNSUCCESSFUL;
		Irp->IoStatus.Information = 0;
		goto done;
	}

	ExAcquireFastMutex(&Ccb->DataListLock);

	if (IoIsOperationSynchronous(Irp))
	{
		InsertTailList(&Ccb->ReadRequestListHead, &Context->ListEntry);
		if (Ccb->ReadRequestListHead.Flink != &Context->ListEntry)
		{
			KeInitializeEvent(&Event, SynchronizationEvent, FALSE);
			Context->WaitEvent = &Event;
			ExReleaseFastMutex(&Ccb->DataListLock);
			Status = KeWaitForSingleObject(&Event,
				Executive,
				KernelMode,
				FALSE,
				NULL);
			if (!NT_SUCCESS(Status))
			{
				KEBUGCHECK(0);
			}
			ExAcquireFastMutex(&Ccb->DataListLock);
		}
		Irp->IoStatus.Information = 0;
	}
	else
	{
		KIRQL oldIrql;
		if (IsListEmpty(&Ccb->ReadRequestListHead) ||
			Ccb->ReadRequestListHead.Flink != &Context->ListEntry)
		{
			/* this is a new request */
			Irp->IoStatus.Information = 0;
			Context->WaitEvent = &Ccb->ReadEvent;
			InsertTailList(&Ccb->ReadRequestListHead, &Context->ListEntry);
			if (Ccb->ReadRequestListHead.Flink != &Context->ListEntry)
			{
				/* there was already a request on the list */
				IoAcquireCancelSpinLock(&oldIrql);
				if (Irp->Cancel)
				{
					IoReleaseCancelSpinLock(oldIrql);
					RemoveEntryList(&Context->ListEntry);
					ExReleaseFastMutex(&Ccb->DataListLock);
					Status = STATUS_CANCELLED;
					goto done;
				}
				(void)IoSetCancelRoutine(Irp, NpfsReadWriteCancelRoutine);
				IoReleaseCancelSpinLock(oldIrql);
				ExReleaseFastMutex(&Ccb->DataListLock);
				IoMarkIrpPending(Irp);