reactos/reactos/subsys/win32k/ntuser/msgqueue.c

/*
 *  ReactOS W32 Subsystem
 *  Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003 ReactOS Team
 *
 *  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; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
/* $Id: msgqueue.c,v 1.18 2003/08/25 23:55:46 weiden Exp $
 *
 * COPYRIGHT:        See COPYING in the top level directory
 * PROJECT:          ReactOS kernel
 * PURPOSE:          Message queues
 * FILE:             subsys/win32k/ntuser/msgqueue.c
 * PROGRAMER:        Casper S. Hornstrup ([email protected])
 * REVISION HISTORY:
 *       06-06-2001  CSH  Created
 */

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

#include <ddk/ntddk.h>
#include <win32k/win32k.h>
#include <include/msgqueue.h>
#include <include/callback.h>
#include <include/window.h>
#include <include/winpos.h>
#include <include/class.h>

#define NDEBUG
#include <debug.h>

/* GLOBALS *******************************************************************/

#define SYSTEM_MESSAGE_QUEUE_SIZE           (256)

static MSG SystemMessageQueue[SYSTEM_MESSAGE_QUEUE_SIZE];
static ULONG SystemMessageQueueHead = 0;
static ULONG SystemMessageQueueTail = 0;
static ULONG SystemMessageQueueCount = 0;
static KSPIN_LOCK SystemMessageQueueLock;

static ULONG HardwareMessageQueueStamp = 0;
static LIST_ENTRY HardwareMessageQueueHead;
static FAST_MUTEX HardwareMessageQueueLock;

static KEVENT HardwareMessageEvent;

static PAGED_LOOKASIDE_LIST MessageLookasideList;

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

/* check the queue status */
inline BOOL MsqIsSignaled( PUSER_MESSAGE_QUEUE Queue )
{
    return ((Queue->WakeBits & Queue->WakeMask) || (Queue->ChangedBits & Queue->ChangedMask));
}

/* set some queue bits */
inline VOID MsqSetQueueBits( PUSER_MESSAGE_QUEUE Queue, WORD Bits )
{
    Queue->WakeBits |= Bits;
    Queue->ChangedBits |= Bits;
    if (MsqIsSignaled( Queue )) KeSetEvent(&Queue->NewMessages, IO_NO_INCREMENT, FALSE);
}

/* clear some queue bits */
inline VOID MsqClearQueueBits( PUSER_MESSAGE_QUEUE Queue, WORD Bits )
{
    Queue->WakeBits &= ~Bits;
    Queue->ChangedBits &= ~Bits;
}

VOID FASTCALL
MsqIncPaintCountQueue(PUSER_MESSAGE_QUEUE Queue)
{
  ExAcquireFastMutex(&Queue->Lock);
  Queue->PaintCount++;
  Queue->PaintPosted = TRUE;
  KeSetEvent(&Queue->NewMessages, IO_NO_INCREMENT, FALSE);
  ExReleaseFastMutex(&Queue->Lock);
}

VOID FASTCALL
MsqDecPaintCountQueue(PUSER_MESSAGE_QUEUE Queue)
{
  ExAcquireFastMutex(&Queue->Lock);
  Queue->PaintCount--;
  if (Queue->PaintCount == 0)
    {
      Queue->PaintPosted = FALSE;
    }
  ExReleaseFastMutex(&Queue->Lock);
}


NTSTATUS FASTCALL
MsqInitializeImpl(VOID)
{
  /*CurrentFocusMessageQueue = NULL;*/
  InitializeListHead(&HardwareMessageQueueHead);
  KeInitializeEvent(&HardwareMessageEvent, NotificationEvent, 0);
  KeInitializeSpinLock(&SystemMessageQueueLock);
  ExInitializeFastMutex(&HardwareMessageQueueLock);

  ExInitializePagedLookasideList(&MessageLookasideList,
				 NULL,
				 NULL,
				 0,
				 sizeof(USER_MESSAGE),
				 0,
				 256);

  return(STATUS_SUCCESS);
}

ULONG FASTCALL
MsgFindSystemMouseMoveMessage()
{
  LPMSG Msg, Msg2;
  ULONG QueuePos;
  
  if(SystemMessageQueueCount > 0)
  {
    QueuePos = SystemMessageQueueTail;
    while(QueuePos >= SystemMessageQueueHead)
    {
      Msg = &SystemMessageQueue[QueuePos];
      if(Msg->message == WM_MOUSEMOVE)
      {
        if(SystemMessageQueueHead == QueuePos)
          return QueuePos;
          
        /* if there is one of the following messages after a 
           WM_MOUSEMOVE message then skip it */
        Msg2 = &SystemMessageQueue[QueuePos - 1];
        switch(Msg2->message)
        {
          case WM_LBUTTONDOWN:
          case WM_LBUTTONUP:
          case WM_RBUTTONDOWN:
          case WM_RBUTTONUP:
          case WM_MBUTTONDOWN:
          case WM_MBUTTONUP:
          #if 0
          case WM_XBUTTONDOWN:
          case WM_XBUTTONUP:
          #endif
            break;
          default:
            return QueuePos;
        }
      }
      QueuePos--;
    }
  }

  return (ULONG)-1;
}

VOID FASTCALL
MsqInsertSystemMessage(MSG* Msg)
{  
  KIRQL OldIrql;
  ULONG mmov = (ULONG)-1;

  KeAcquireSpinLock(&SystemMessageQueueLock, &OldIrql);
  
  /* only insert WM_MOUSEMOVE messages if not already in system message queue */
  if(Msg->message == WM_MOUSEMOVE)
    mmov = MsgFindSystemMouseMoveMessage();
    
  if(mmov != (ULONG)-1)
  {
    /* insert message at the queue head */
    while(mmov > SystemMessageQueueHead)
    {
      SystemMessageQueue[mmov] = SystemMessageQueue[mmov - 1];
      mmov--;
    }
    SystemMessageQueue[SystemMessageQueueHead] = *Msg;
  }
  else
  {
    if (SystemMessageQueueCount == SYSTEM_MESSAGE_QUEUE_SIZE)
    {
      KeReleaseSpinLock(&SystemMessageQueueLock, OldIrql);
      return;
    }
    SystemMessageQueue[SystemMessageQueueTail] = *Msg;
    SystemMessageQueueTail = 
      (SystemMessageQueueTail + 1) % SYSTEM_MESSAGE_QUEUE_SIZE;
    SystemMessageQueueCount++;
  }
  KeReleaseSpinLock(&SystemMessageQueueLock, OldIrql);
  KeSetEvent(&HardwareMessageEvent, IO_NO_INCREMENT, FALSE);
}

BOOL STATIC STDCALL
MsqTranslateMouseMessage(HWND hWnd, UINT FilterLow, UINT FilterHigh,
			 PUSER_MESSAGE Message, BOOL Remove, 
			 PWINDOW_OBJECT ScopeWin, PUSHORT HitTest,
			 PPOINT ScreenPoint, PBOOL MouseClick)
{
  static ULONG ClkTime = 0;
  static USHORT ClkMessage = 0;
  static HWND ClkWnd = 0;
  static POINT ClkPos = {0, 0};

  USHORT Msg = Message->Msg.message;
  PWINDOW_OBJECT Window;
  POINT Point;
  ULONG Click = 0;

  if ((Window = IntGetCaptureWindow()) == NULL)
    {
      *HitTest = WinPosWindowFromPoint(ScopeWin, Message->Msg.pt, &Window);
    }
  else
    {
      *HitTest = HTCLIENT;
    }
  
  if (Window == NULL)
    {
      ExFreePool(Message);
      return(FALSE);
    }
  if (Window->MessageQueue != PsGetWin32Thread()->MessageQueue)
    {      
      ExAcquireFastMutex(&Window->MessageQueue->Lock);
      InsertTailList(&Window->MessageQueue->HardwareMessagesListHead,
		     &Message->ListEntry);
      ExReleaseFastMutex(&Window->MessageQueue->Lock);
      KeSetEvent(&Window->MessageQueue->NewMessages, IO_NO_INCREMENT, FALSE);
      return(FALSE);
    }

  if (hWnd != NULL && Window->Self != hWnd && 
      !IntIsChildWindow(hWnd, Window->Self))
    {
      return(FALSE);
    }

  if (Msg == WM_LBUTTONDOWN || Msg == WM_RBUTTONDOWN || Msg == WM_MBUTTONDOWN)
    {
      (*MouseClick) = Click = 1;
    }
  if (Click)
    {
      if (IntGetClassLong(Window, GCL_STYLE, FALSE) & CS_DBLCLKS ||
	  (*HitTest) != HTCLIENT)
	{
	  if (Msg == ClkMessage &&
	      Window->Self == ClkWnd &&
	      (Message->Msg.time - ClkTime) < 452 &&
	      abs(Message->Msg.pt.x - ClkPos.x) < 2 &&
	      abs(Message->Msg.pt.y - ClkPos.y) < 2)
	    {
	      Msg += (WM_LBUTTONDBLCLK - WM_LBUTTONDOWN);
	      Click++;
	    }
	}
    }

  *ScreenPoint = Message->Msg.pt;

  if ((*HitTest) != HTCLIENT)
    {
      Msg += WM_NCMOUSEMOVE - WM_MOUSEMOVE;
      Message->Msg.wParam = *HitTest;
    }
  else
    {
      Point = Message->Msg.pt;

      Point.x -= Window->ClientRect.left;
      Point.y -= Window->ClientRect.top;
    }

  /* FIXME: Check message filter. */

  if (Remove && Click)
    {
      if (Click == 1)
	{
	  ClkTime = Message->Msg.time;
	  ClkMessage = Msg;
	  ClkWnd = Window->Self;
	  ClkPos = (*ScreenPoint);
	}
      else
	{
	  ClkTime = 0;
	  ClkWnd = NULL;
	}
    }

  if (Remove)
    {
      Message->Msg.hwnd = Window->Self;
      Message->Msg.message = Msg;
      Message->Msg.lParam = MAKELONG(Point.x, Point.y);
    }

  return(TRUE);
}

BOOL STDCALL
MsqPeekHardwareMessage(PUSER_MESSAGE_QUEUE MessageQueue, HWND hWnd, 
		       UINT FilterLow, UINT FilterHigh, BOOL Remove,
		       PUSER_MESSAGE* Message)
{
  KIRQL OldIrql;
  USHORT HitTest;
  POINT ScreenPoint;
  BOOL Accept;
  BOOL MouseClick;
  PLIST_ENTRY CurrentEntry;
  ULONG ActiveStamp;
  PWINDOW_OBJECT DesktopWindow;

  DesktopWindow = IntGetWindowObject(IntGetDesktopWindow());

  /* Process messages in the message queue itself. */
  ExAcquireFastMutex(&MessageQueue->Lock);
  CurrentEntry = MessageQueue->HardwareMessagesListHead.Flink;
  while (CurrentEntry != &MessageQueue->HardwareMessagesListHead)
    {
      PUSER_MESSAGE Current = 
	CONTAINING_RECORD(CurrentEntry, USER_MESSAGE, ListEntry);
      CurrentEntry = CurrentEntry->Flink;
      if (Current->Msg.message >= WM_MOUSEFIRST && 
	  Current->Msg.message <= WM_MOUSELAST)
	{
	  Accept = MsqTranslateMouseMessage(hWnd, FilterLow, FilterHigh,
					    Current, Remove, 
					    DesktopWindow, &HitTest,
					    &ScreenPoint, &MouseClick);
	  if (Accept)
	    {
	      if (Remove)
		{
		  RemoveEntryList(&Current->ListEntry);
		}
	      ExReleaseFastMutex(&MessageQueue->Lock);
	      *Message = Current;
	      IntReleaseWindowObject(DesktopWindow);
	      return(TRUE);
	    }
	}
    }
  ExReleaseFastMutex(&MessageQueue->Lock);

  /* Now try the global queue. */
  ExAcquireFastMutex(&HardwareMessageQueueLock);
  /* Transfer all messages from the DPC accessible queue to the main queue. */
  KeAcquireSpinLock(&SystemMessageQueueLock, &OldIrql);
  while (SystemMessageQueueCount > 0)
    {      
      PUSER_MESSAGE UserMsg;
      MSG Msg;

      Msg = SystemMessageQueue[SystemMessageQueueHead];
      SystemMessageQueueHead = 
	(SystemMessageQueueHead + 1) % SYSTEM_MESSAGE_QUEUE_SIZE;
      SystemMessageQueueCount--;
      KeReleaseSpinLock(&SystemMessageQueueLock, OldIrql);
      UserMsg = ExAllocateFromPagedLookasideList(&MessageLookasideList);
      UserMsg->Msg = Msg;
      InsertTailList(&HardwareMessageQueueHead, &UserMsg->ListEntry);
      KeAcquireSpinLock(&SystemMessageQueueLock, &OldIrql);
    }
  KeReleaseSpinLock(&SystemMessageQueueLock, OldIrql);
  HardwareMessageQueueStamp++;

  /* Process messages in the queue until we find one to return. */
  CurrentEntry = HardwareMessageQueueHead.Flink;
  while (CurrentEntry != &HardwareMessageQueueHead)
    {
      PUSER_MESSAGE Current = 
	CONTAINING_RECORD(CurrentEntry, USER_MESSAGE, ListEntry);
      CurrentEntry = CurrentEntry->Flink;
      RemoveEntryList(&Current->ListEntry);
      if (Current->Msg.message >= WM_MOUSEFIRST && 
	  Current->Msg.message <= WM_MOUSELAST)
	{
	  ActiveStamp = HardwareMessageQueueStamp;
	  ExReleaseFastMutex(&HardwareMessageQueueLock);
	  /* Translate the message. */
	  Accept = MsqTranslateMouseMessage(hWnd, FilterLow, FilterHigh,
					    Current, Remove,
					    DesktopWindow, &HitTest,
					    &ScreenPoint, &MouseClick);
	  ExAcquireFastMutex(&HardwareMessageQueueLock);
	  if (Accept)
	    {
	      /* Check for no more messages in the system queue. */
	      KeAcquireSpinLock(&SystemMessageQueueLock, &OldIrql);
	      if (SystemMessageQueueCount == 0 &&
		  IsListEmpty(&HardwareMessageQueueHead))
		{
		  KeClearEvent(&HardwareMessageEvent);
		}
	      KeReleaseSpinLock(&SystemMessageQueueLock, OldIrql);

	      /* 
		 If we aren't removing the message then add it to the private
		 queue.
	      */
	      if (!Remove)
		{
		  InsertTailList(&MessageQueue->HardwareMessagesListHead,
				 &Current->ListEntry);
		}
	      ExReleaseFastMutex(&HardwareMessageQueueLock);
	      *Message = Current;
	      IntReleaseWindowObject(DesktopWindow);
	      return(TRUE);
	    }
	  /* If the contents of the queue changed then restart processing. */
	  if (HardwareMessageQueueStamp != ActiveStamp)
	    {
	      CurrentEntry = HardwareMessageQueueHead.Flink;
	      continue;
	    }
	}      
    }
  /* Check if the system message queue is now empty. */
  KeAcquireSpinLock(&SystemMessageQueueLock, &OldIrql);
  if (SystemMessageQueueCount == 0 && IsListEmpty(&HardwareMessageQueueHead))
    {
      KeClearEvent(&HardwareMessageEvent);
    }
  KeReleaseSpinLock(&SystemMessageQueueLock, OldIrql);
  ExReleaseFastMutex(&HardwareMessageQueueLock);

  return(FALSE);
}

VOID STDCALL
MsqPostKeyboardMessage(UINT uMsg, WPARAM wParam, LPARAM lParam)
{
  PUSER_MESSAGE_QUEUE FocusMessageQueue;
  PUSER_MESSAGE Message;
  MSG Msg;

  DPRINT("MsqPostKeyboardMessage(uMsg 0x%x, wParam 0x%x, lParam 0x%x)\n",
    uMsg, wParam, lParam);

  FocusMessageQueue = IntGetFocusMessageQueue();
  if (FocusMessageQueue == NULL)
    {
      DPRINT("No focus message queue\n");
      return;
    }

  if (FocusMessageQueue->FocusWindow != (HWND)0)
    {
      Msg.hwnd = FocusMessageQueue->FocusWindow;
      Msg.message = uMsg;
      Msg.wParam = wParam;
      Msg.lParam = lParam;
      /* FIXME: Initialize time and point. */
    
      Message = MsqCreateMessage(&Msg);
      MsqPostMessage(FocusMessageQueue, Message);
    }
  else
    {
      DPRINT("Invalid focus window handle\n");
    }
}

VOID FASTCALL
MsqInitializeMessage(PUSER_MESSAGE Message,
		     LPMSG Msg)
{
  RtlMoveMemory(&Message->Msg, Msg, sizeof(MSG));
}

PUSER_MESSAGE FASTCALL
MsqCreateMessage(LPMSG Msg)
{
  PUSER_MESSAGE Message;
  
  Message = ExAllocateFromPagedLookasideList(&MessageLookasideList);
  if (!Message)
    {
      return NULL;
    }
  
  MsqInitializeMessage(Message, Msg);
  
  return Message;
}

VOID FASTCALL
MsqDestroyMessage(PUSER_MESSAGE Message)
{
  ExFreeToPagedLookasideList(&MessageLookasideList, Message);
}

VOID FASTCALL
MsqDispatchSentNotifyMessages(PUSER_MESSAGE_QUEUE MessageQueue)
{
  PLIST_ENTRY ListEntry;
  PUSER_SENT_MESSAGE_NOTIFY Message;

  while (!IsListEmpty(&MessageQueue->SentMessagesListHead))
  {
    ExAcquireFastMutex(&MessageQueue->Lock);
    ListEntry = RemoveHeadList(&MessageQueue->SentMessagesListHead);
    Message = CONTAINING_RECORD(ListEntry, USER_SENT_MESSAGE_NOTIFY, 
				ListEntry);
    ExReleaseFastMutex(&MessageQueue->Lock);

    IntCallSentMessageCallback(Message->CompletionCallback,
				Message->hWnd,
				Message->Msg,
				Message->CompletionCallbackContext,
				Message->Result);
  }
}

BOOLEAN FASTCALL
MsqPeekSentMessages(PUSER_MESSAGE_QUEUE MessageQueue)
{
  return(!IsListEmpty(&MessageQueue->SentMessagesListHead));
}

BOOLEAN FASTCALL
MsqDispatchOneSentMessage(PUSER_MESSAGE_QUEUE MessageQueue)
{
  PUSER_SENT_MESSAGE Message;
  PLIST_ENTRY Entry;
  LRESULT Result;
  PUSER_SENT_MESSAGE_NOTIFY NotifyMessage;

  ExAcquireFastMutex(&MessageQueue->Lock);
  if (IsListEmpty(&MessageQueue->SentMessagesListHead))
    {
      ExReleaseFastMutex(&MessageQueue->Lock);
      return(FALSE);
    }
  Entry = RemoveHeadList(&MessageQueue->SentMessagesListHead);
  Message = CONTAINING_RECORD(Entry, USER_SENT_MESSAGE, ListEntry);
  ExReleaseFastMutex(&MessageQueue->Lock);

  /* Call the window procedure. */
  Result = IntCallWindowProc(NULL,
			      Message->Msg.hwnd,
			      Message->Msg.message,
			      Message->Msg.wParam,
			      Message->Msg.lParam);

  /* Let the sender know the result. */
  if (Message->Result != NULL)
    {
      *Message->Result = Result;
    }

  /* Notify the sender. */
  if (Message->CompletionEvent != NULL)
    {
      KeSetEvent(Message->CompletionEvent, IO_NO_INCREMENT, FALSE);
    }

  /* Notify the sender if they specified a callback. */
  if (Message->CompletionCallback != NULL)
    {
      NotifyMessage = ExAllocatePool(NonPagedPool, 
				     sizeof(USER_SENT_MESSAGE_NOTIFY));
      NotifyMessage->CompletionCallback = 
	Message->CompletionCallback;
      NotifyMessage->CompletionCallbackContext =
	Message->CompletionCallbackContext;
      NotifyMessage->Result = Result;
      NotifyMessage->hWnd = Message->Msg.hwnd;
      NotifyMessage->Msg = Message->Msg.message;
      MsqSendNotifyMessage(Message->CompletionQueue, NotifyMessage);
    }

  ExFreePool(Message);
  return(TRUE);
}

VOID FASTCALL
MsqSendNotifyMessage(PUSER_MESSAGE_QUEUE MessageQueue,
		     PUSER_SENT_MESSAGE_NOTIFY NotifyMessage)
{
  ExAcquireFastMutex(&MessageQueue->Lock);
  InsertTailList(&MessageQueue->NotifyMessagesListHead, 
		 &NotifyMessage->ListEntry);
  KeSetEvent(&MessageQueue->NewMessages, IO_NO_INCREMENT, FALSE);
  ExReleaseFastMutex(&MessageQueue->Lock);
}

VOID FASTCALL
MsqSendMessage(PUSER_MESSAGE_QUEUE MessageQueue,
	       PUSER_SENT_MESSAGE Message)
{
  ExAcquireFastMutex(&MessageQueue->Lock);
  InsertTailList(&MessageQueue->SentMessagesListHead, &Message->ListEntry);
  KeSetEvent(&MessageQueue->NewMessages, IO_NO_INCREMENT, FALSE);
  ExReleaseFastMutex(&MessageQueue->Lock);
}

VOID FASTCALL
MsqPostMessage(PUSER_MESSAGE_QUEUE MessageQueue, PUSER_MESSAGE Message)
{
  ExAcquireFastMutex(&MessageQueue->Lock);
  InsertTailList(&MessageQueue->PostedMessagesListHead,
		 &Message->ListEntry);
  KeSetEvent(&MessageQueue->NewMessages, IO_NO_INCREMENT, FALSE);
  ExReleaseFastMutex(&MessageQueue->Lock);
}

VOID FASTCALL
MsqPostQuitMessage(PUSER_MESSAGE_QUEUE MessageQueue, ULONG ExitCode)
{
  ExAcquireFastMutex(&MessageQueue->Lock);
  MessageQueue->QuitPosted = TRUE;
  MessageQueue->QuitExitCode = ExitCode;
  KeSetEvent(&MessageQueue->NewMessages, IO_NO_INCREMENT, FALSE);
  ExReleaseFastMutex(&MessageQueue->Lock);
}

BOOLEAN STDCALL
MsqFindMessage(IN PUSER_MESSAGE_QUEUE MessageQueue,
	       IN BOOLEAN Hardware,
	       IN BOOLEAN Remove,
	       IN HWND Wnd,
	       IN UINT MsgFilterLow,
	       IN UINT MsgFilterHigh,
	       OUT PUSER_MESSAGE* Message)
{
  PLIST_ENTRY CurrentEntry;
  PUSER_MESSAGE CurrentMessage;
  PLIST_ENTRY ListHead;

  if (Hardware)
    {
      return(MsqPeekHardwareMessage(MessageQueue, Wnd,
				    MsgFilterLow, MsgFilterHigh,
				    Remove, Message));
    }
  
  ExAcquireFastMutex(&MessageQueue->Lock);
  CurrentEntry = MessageQueue->PostedMessagesListHead.Flink;
  ListHead = &MessageQueue->PostedMessagesListHead;
  while (CurrentEntry != ListHead)
    {
      CurrentMessage = CONTAINING_RECORD(CurrentEntry, USER_MESSAGE, 
					 ListEntry);
      if ((Wnd == 0 || Wnd == CurrentMessage->Msg.hwnd) &&
	  ((MsgFilterLow == 0 && MsgFilterHigh == 0) ||
	   (MsgFilterLow <= CurrentMessage->Msg.message &&
	    MsgFilterHigh >= CurrentMessage->Msg.message)))
	{
	  if (Remove)
	    {
	      RemoveEntryList(&CurrentMessage->ListEntry);
	    }
	  ExReleaseFastMutex(&MessageQueue->Lock);
	  *Message = CurrentMessage;
	  return(TRUE);
	}
      CurrentEntry = CurrentEntry->Flink;
    }
  ExReleaseFastMutex(&MessageQueue->Lock);
  return(FALSE);
}

NTSTATUS FASTCALL
MsqWaitForNewMessages(PUSER_MESSAGE_QUEUE MessageQueue)
{
  PVOID WaitObjects[2] = {&MessageQueue->NewMessages, &HardwareMessageEvent};
  return(KeWaitForMultipleObjects(2,
				  WaitObjects,
				  WaitAny,
				  Executive,
				  UserMode,
				  TRUE,
				  NULL,
				  NULL));
}

VOID FASTCALL
MsqInitializeMessageQueue(PUSER_MESSAGE_QUEUE MessageQueue)
{
  InitializeListHead(&MessageQueue->PostedMessagesListHead);
  InitializeListHead(&MessageQueue->SentMessagesListHead);
  InitializeListHead(&MessageQueue->HardwareMessagesListHead);
  ExInitializeFastMutex(&MessageQueue->Lock);
  MessageQueue->QuitPosted = FALSE;
  MessageQueue->QuitExitCode = 0;
  KeInitializeEvent(&MessageQueue->NewMessages, SynchronizationEvent, FALSE);
  MessageQueue->QueueStatus = 0;
  MessageQueue->FocusWindow = NULL;
}

VOID FASTCALL
MsqFreeMessageQueue(PUSER_MESSAGE_QUEUE MessageQueue)
{
  PLIST_ENTRY CurrentEntry;
  PUSER_MESSAGE CurrentMessage;
  
  CurrentEntry = MessageQueue->PostedMessagesListHead.Flink;
  while (CurrentEntry != &MessageQueue->PostedMessagesListHead)
    {
      CurrentMessage = CONTAINING_RECORD(CurrentEntry, USER_MESSAGE, 
					 ListEntry);
      CurrentEntry = CurrentEntry->Flink;
      MsqDestroyMessage(CurrentMessage);
    }
}

PUSER_MESSAGE_QUEUE FASTCALL
MsqCreateMessageQueue(VOID)
{
  PUSER_MESSAGE_QUEUE MessageQueue;

  MessageQueue = (PUSER_MESSAGE_QUEUE)ExAllocatePool(PagedPool, 
				   sizeof(USER_MESSAGE_QUEUE));
  if (!MessageQueue)
    {
      return NULL;
    }
  
  MsqInitializeMessageQueue(MessageQueue);
  
  return MessageQueue;
}

VOID FASTCALL
MsqDestroyMessageQueue(PUSER_MESSAGE_QUEUE MessageQueue)
{
  MsqFreeMessageQueue(MessageQueue);
  ExFreePool(MessageQueue);
}

/* EOF */