/* $Id$
 * reactos IO_WORKITEM handling by libcaptive
 * Copyright (C) 2002 Jan Kratochvil <project-captive@jankratochvil.net>
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; exactly version 2 of June 1991 is required
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */


#include "config.h"

#include "reactos/ddk/iofuncs.h"	/* self */
#include <glib/gmessages.h>
#include "captive/macros.h"
#include "reactos/ddk/obfuncs.h"	/* for ObDereferenceObject() */
#include <glib/gmain.h>


typedef struct _IO_WORKITEM {
	DEVICE_OBJECT *DeviceObject;
	PIO_WORKITEM_ROUTINE WorkerRoutine;
	VOID *Context;
} IO_WORKITEM;


/**
 * IoAllocateWorkItem:
 * @DeviceObject: Existing initialized #PDEVICE_OBJECT to bind with allocated #IO_WORKITEM.
 * %NULL value is forbidden.
 *
 * Allocates and initializes the memory for #IO_WORKITEM.
 * You may pass it to IoQueueWorkItem() later. At most one active IoQueueWorkItem()
 * request may be pending for this returned #IO_WORKITEM.
 *
 * Returns: Allocated #IO_WORKITEM ready to be used by IoQueueWorkItem().
 */
PIO_WORKITEM IoAllocateWorkItem(PDEVICE_OBJECT DeviceObject)
{
IO_WORKITEM *r;

	g_return_val_if_fail(DeviceObject!=NULL,NULL);
	
	captive_new(r);
  r->DeviceObject=DeviceObject;
	r->WorkerRoutine=NULL;

	return r;
}


/**
 * IoFreeWorkItem:
 * @IoWorkItem: #IO_WORKITEM allocated by IoAllocateWorkItem().
 * %NULL value is forbidden.
 *
 * Frees the resources allocated for @IoWorkItem.
 * No request by IoQueueWorkItem() may be pending.
 */
VOID IoFreeWorkItem(PIO_WORKITEM IoWorkItem)
{
	g_return_if_fail(IoWorkItem!=NULL);
	g_return_if_fail(IoWorkItem->WorkerRoutine==NULL);	/* no request should be pending */

	g_free(IoWorkItem);
}


static gboolean IoQueueWorkItem_idlefunc(IO_WORKITEM *IoWorkItem /* data */)
{
	g_return_val_if_fail(IoWorkItem!=NULL,FALSE);	/* false=>remove-me */
	g_return_val_if_fail(IoWorkItem->DeviceObject!=NULL,FALSE);	/* false=>remove-me */
	g_return_val_if_fail(IoWorkItem->WorkerRoutine!=NULL,FALSE);	/* false=>remove-me */

	(*IoWorkItem->WorkerRoutine)(IoWorkItem->DeviceObject,IoWorkItem->Context);
	ObDereferenceObject(IoWorkItem->DeviceObject);
	IoWorkItem->WorkerRoutine=NULL;	/* request is no longer pending */
	return FALSE;	/* remove-me */
}

/**
 * IoQueueWorkItem:
 * @IoWorkItem: Allocated space of #IO_WORKITEM to be initialize.
 * %NULL value is forbidden.
 * @WorkerRoutine: Function address to call in the idle time.
 * %NULL value is forbidden.
 * @QueueType: Queue priority.
 * @Context: Context pointer to pass to @WorkerRoutine during its invocation.
 * %NULL value is permitted.
 *
 * Inserts a work item in a queue for one of the system worker threads to
 * process. It will be processed through g_idle_add_full() with priority
 * range %G_PRIORITY_DEFAULT+10 ... %G_PRIORITY_DEFAULT+30.
 *
 * At most one active IoQueueWorkItem() request per one @IoWorkItem may be pending.
 */
VOID IoQueueWorkItem(IN PIO_WORKITEM IoWorkItem,
		IN PIO_WORKITEM_ROUTINE WorkerRoutine,IN WORK_QUEUE_TYPE QueueType,IN PVOID Context)
{
gint priority;

	g_return_if_fail(IoWorkItem!=NULL);
	g_return_if_fail(IoWorkItem->DeviceObject!=NULL);
	g_return_if_fail(IoWorkItem->WorkerRoutine==NULL);	/* no other request pending */
	g_return_if_fail(WorkerRoutine!=NULL);

	IoWorkItem->WorkerRoutine=WorkerRoutine;
	IoWorkItem->Context=Context;
	ObReferenceObjectByPointer(IoWorkItem->DeviceObject,FILE_ALL_ACCESS,NULL,KernelMode);

	switch (QueueType) {
		case DelayedWorkQueue:
			priority=G_PRIORITY_DEFAULT+30;	/* positive towards G_PRIORITY_HIGH_IDLE */
			break;
		case CriticalWorkQueue:
			priority=G_PRIORITY_DEFAULT+20;	/* positive towards G_PRIORITY_HIGH_IDLE */
			break;
		case HyperCriticalWorkQueue:
			priority=G_PRIORITY_DEFAULT+10;	/* positive towards G_PRIORITY_HIGH_IDLE */
			break;
		default:
			g_assert_not_reached();
			priority=G_PRIORITY_DEFAULT;
		}

	g_idle_add_full(
			priority,	/* priority */
			(GSourceFunc)IoQueueWorkItem_idlefunc,	/* function */
			IoWorkItem,	/* data */
			NULL);	/* notify */
}