/*
 * Message queues related functions
 *
 * Copyright 1993, 1994 Alexandre Julliard
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <string.h>
#include <signal.h>
#include <assert.h>
#include "windef.h"
#include "wingdi.h"
#include "winerror.h"
#include "wine/winbase16.h"
#include "wine/winuser16.h"
#include "queue.h"
#include "win.h"
#include "user.h"
#include "hook.h"
#include "thread.h"
#include "wine/debug.h"
#include "wine/server.h"
#include "spy.h"

WINE_DEFAULT_DEBUG_CHANNEL(msg);


/***********************************************************************
 *	     QUEUE_Lock
 *
 * Function for getting a 32 bit pointer on queue structure. For thread
 * safeness programmers should use this function instead of GlobalLock to
 * retrieve a pointer on the structure. QUEUE_Unlock should also be called
 * when access to the queue structure is not required anymore.
 */
MESSAGEQUEUE *QUEUE_Lock( HQUEUE16 hQueue )
{
    MESSAGEQUEUE *queue;

    HeapLock( GetProcessHeap() );  /* FIXME: a bit overkill */
    queue = GlobalLock16( hQueue );
    if ( !queue || (queue->magic != QUEUE_MAGIC) )
    {
        HeapUnlock( GetProcessHeap() );
        return NULL;
    }

    queue->lockCount++;
    HeapUnlock( GetProcessHeap() );
    return queue;
}


/***********************************************************************
 *	     QUEUE_Current
 *
 * Get the current thread queue, creating it if required.
 * QUEUE_Unlock is not needed since the queue can only be deleted by
 * the current thread anyway.
 */
MESSAGEQUEUE *QUEUE_Current(void)
{
    MESSAGEQUEUE *queue;
    HQUEUE16 hQueue;

    if (!(hQueue = GetThreadQueue16(0)))
    {
        if (!(hQueue = InitThreadInput16( 0, 0 ))) return NULL;
    }

    if ((queue = GlobalLock16( hQueue )))
    {
        if (queue->magic != QUEUE_MAGIC) queue = NULL;
    }
    return queue;
}


/***********************************************************************
 *	     QUEUE_Unlock
 *
 * Use with QUEUE_Lock to get a thread safe access to message queue
 * structure
 */
void QUEUE_Unlock( MESSAGEQUEUE *queue )
{
    if (queue)
    {
        HeapLock( GetProcessHeap() );  /* FIXME: a bit overkill */

        if ( --queue->lockCount == 0 )
        {
            if (queue->server_queue)
                CloseHandle( queue->server_queue );
            GlobalFree16( queue->self );
        }

        HeapUnlock( GetProcessHeap() );
    }
}


/***********************************************************************
 *           QUEUE_CreateMsgQueue
 *
 * Creates a message queue. Doesn't link it into queue list!
 */
static HQUEUE16 QUEUE_CreateMsgQueue( BOOL16 bCreatePerQData )
{
    HQUEUE16 hQueue;
    HANDLE handle;
    MESSAGEQUEUE * msgQueue;

    TRACE_(msg)("(): Creating message queue...\n");

    if (!(hQueue = GlobalAlloc16( GMEM_FIXED | GMEM_ZEROINIT,
                                  sizeof(MESSAGEQUEUE) )))
        return 0;

    msgQueue = (MESSAGEQUEUE *) GlobalLock16( hQueue );
    if ( !msgQueue )
        return 0;

    if (bCreatePerQData)
    {
        SERVER_START_REQ( get_msg_queue )
        {
            wine_server_call_err( req );
            handle = reply->handle;
        }
        SERVER_END_REQ;
        if (!handle)
        {
            ERR_(msg)("Cannot get thread queue");
            GlobalFree16( hQueue );
            return 0;
        }
        msgQueue->server_queue = handle;
    }

    msgQueue->self = hQueue;
    msgQueue->lockCount = 1;
    msgQueue->magic = QUEUE_MAGIC;
    return hQueue;
}


/***********************************************************************
 *	     QUEUE_DeleteMsgQueue
 *
 * Unlinks and deletes a message queue.
 *
 * Note: We need to mask asynchronous events to make sure PostMessage works
 * even in the signal handler.
 */
void QUEUE_DeleteMsgQueue(void)
{
    HQUEUE16 hQueue = GetThreadQueue16(0);
    MESSAGEQUEUE * msgQueue;

    if (!hQueue) return;  /* thread doesn't have a queue */

    TRACE("(): Deleting message queue %04x\n", hQueue);

    if (!(msgQueue = QUEUE_Lock(hQueue)))
    {
        ERR("invalid thread queue\n");
        return;
    }

    msgQueue->magic = 0;
    msgQueue->self = 0;
    SetThreadQueue16( 0, 0 );

    /* free up resource used by MESSAGEQUEUE structure */
    msgQueue->lockCount--;
    QUEUE_Unlock( msgQueue );
}


/***********************************************************************
 *		GetWindowTask (USER.224)
 */
HTASK16 WINAPI GetWindowTask16( HWND16 hwnd )
{
    HTASK16 retvalue;
    MESSAGEQUEUE *queue;

    WND *wndPtr = WIN_FindWndPtr16( hwnd );
    if (!wndPtr) return 0;

    queue = QUEUE_Lock( wndPtr->hmemTaskQ );
    WIN_ReleaseWndPtr(wndPtr);

    if (!queue) return 0;

    retvalue = queue->teb->htask16;
    QUEUE_Unlock( queue );

    return retvalue;
}

/***********************************************************************
 *		InitThreadInput   (USER.409)
 */
HQUEUE16 WINAPI InitThreadInput16( WORD unknown, WORD flags )
{
    MESSAGEQUEUE *queuePtr;
    HQUEUE16 hQueue = NtCurrentTeb()->queue;

    if ( !hQueue )
    {
        /* Create thread message queue */
        if( !(hQueue = QUEUE_CreateMsgQueue( TRUE )))
        {
            ERR_(msg)("failed!\n");
            return FALSE;
	}

        /* Link new queue into list */
        queuePtr = QUEUE_Lock( hQueue );
        queuePtr->teb = NtCurrentTeb();

        HeapLock( GetProcessHeap() );  /* FIXME: a bit overkill */
        SetThreadQueue16( 0, hQueue );
        NtCurrentTeb()->queue = hQueue;
        HeapUnlock( GetProcessHeap() );

        QUEUE_Unlock( queuePtr );
    }

    return hQueue;
}

/***********************************************************************
 *		GetQueueStatus (USER32.@)
 */
DWORD WINAPI GetQueueStatus( UINT flags )
{
    DWORD ret = 0;

    SERVER_START_REQ( get_queue_status )
    {
        req->clear = 1;
        wine_server_call( req );
        ret = MAKELONG( reply->changed_bits & flags, reply->wake_bits & flags );
    }
    SERVER_END_REQ;
    return ret;
}


/***********************************************************************
 *		GetInputState   (USER32.@)
 */
BOOL WINAPI GetInputState(void)
{
    DWORD ret = 0;

    SERVER_START_REQ( get_queue_status )
    {
        req->clear = 0;
        wine_server_call( req );
        ret = reply->wake_bits & (QS_KEY | QS_MOUSEBUTTON);
    }
    SERVER_END_REQ;
    return ret;
}

/***********************************************************************
 *		GetMessagePos (USER.119)
 *		GetMessagePos (USER32.@)
 *
 * The GetMessagePos() function returns a long value representing a
 * cursor position, in screen coordinates, when the last message
 * retrieved by the GetMessage() function occurs. The x-coordinate is
 * in the low-order word of the return value, the y-coordinate is in
 * the high-order word. The application can use the MAKEPOINT()
 * macro to obtain a POINT structure from the return value.
 *
 * For the current cursor position, use GetCursorPos().
 *
 * RETURNS
 *
 * Cursor position of last message on success, zero on failure.
 *
 * CONFORMANCE
 *
 * ECMA-234, Win32
 *
 */
DWORD WINAPI GetMessagePos(void)
{
    MESSAGEQUEUE *queue;

    if (!(queue = QUEUE_Current())) return 0;
    return queue->GetMessagePosVal;
}


/***********************************************************************
 *		GetMessageTime (USER.120)
 *		GetMessageTime (USER32.@)
 *
 * GetMessageTime() returns the message time for the last message
 * retrieved by the function. The time is measured in milliseconds with
 * the same offset as GetTickCount().
 *
 * Since the tick count wraps, this is only useful for moderately short
 * relative time comparisons.
 *
 * RETURNS
 *
 * Time of last message on success, zero on failure.
 *
 * CONFORMANCE
 *
 * ECMA-234, Win32
 *
 */
LONG WINAPI GetMessageTime(void)
{
    MESSAGEQUEUE *queue;

    if (!(queue = QUEUE_Current())) return 0;
    return queue->GetMessageTimeVal;
}


/***********************************************************************
 *		GetMessageExtraInfo (USER.288)
 *		GetMessageExtraInfo (USER32.@)
 */
LONG WINAPI GetMessageExtraInfo(void)
{
    MESSAGEQUEUE *queue;

    if (!(queue = QUEUE_Current())) return 0;
    return queue->GetMessageExtraInfoVal;
}