windows/dce.c

   1 /*
   2  * USER DCE functions
   3  *
   4  * Copyright 1993 Alexandre Julliard
   5  *           1996,1997 Alex Korobka
   6  *
   7  *
   8  * Note: Visible regions of CS_OWNDC/CS_CLASSDC window DCs
   9  * have to be updated dynamically.
  10  *
  11  * Internal DCX flags:
  12  *
  13  * DCX_DCEEMPTY    - dce is uninitialized
  14  * DCX_DCEBUSY     - dce is in use
  15  * DCX_DCEDIRTY    - ReleaseDC() should wipe instead of caching
  16  * DCX_KEEPCLIPRGN - ReleaseDC() should not delete the clipping region
  17  * DCX_WINDOWPAINT - BeginPaint() is in effect
  18  */
  19
  20 #include <assert.h>
  21 #include "dce.h"
  22 #include "win.h"
  23 #include "gdi.h"
  24 #include "region.h"
  25 #include "user.h"
  26 #include "debugtools.h"
  27 #include "windef.h"
  28 #include "wingdi.h"
  29 #include "wine/winbase16.h"
  30 #include "wine/winuser16.h"
  31
  32 DEFAULT_DEBUG_CHANNEL(dc);
  33
  34 static DCE *firstDCE;
  35 static HDC defaultDCstate;
  36
  37 static void DCE_DeleteClipRgn( DCE* );
  38 static INT DCE_ReleaseDC( DCE* );
  39
  40
  41 /***********************************************************************
  42  *           DCE_DumpCache
  43  */
  44 static void DCE_DumpCache(void)
  45 {
  46     DCE *dce;
  47
  48     USER_Lock();
  49     dce = firstDCE;
  50
  51     DPRINTF("DCE:\n");
  52     while( dce )
  53     {
  54         DPRINTF("\t[0x%08x] hWnd 0x%04x, dcx %08x, %s %s\n",
  55              (unsigned)dce, dce->hwndCurrent, (unsigned)dce->DCXflags,
  56              (dce->DCXflags & DCX_CACHE) ? "Cache" : "Owned",
  57              (dce->DCXflags & DCX_DCEBUSY) ? "InUse" : "" );
  58         dce = dce->next;
  59     }
  60
  61     USER_Unlock();
  62 }
  63
  64 /***********************************************************************
  65  *           DCE_AllocDCE
  66  *
  67  * Allocate a new DCE.
  68  */
  69 DCE *DCE_AllocDCE( HWND hWnd, DCE_TYPE type )
  70 {
  71     FARPROC16 hookProc;
  72     DCE * dce;
  73
  74     if (!(dce = HeapAlloc( GetProcessHeap(), 0, sizeof(DCE) ))) return NULL;
  75     if (!(dce->hDC = CreateDCA( "DISPLAY", NULL, NULL, NULL )))
  76     {
  77         HeapFree( GetProcessHeap(), 0, dce );
  78         return 0;
  79     }
  80     if (!defaultDCstate) defaultDCstate = GetDCState16( dce->hDC );
  81
  82     /* store DCE handle in DC hook data field */
  83
  84     hookProc = GetProcAddress16( GetModuleHandle16("USER"), (LPCSTR)362 );
  85     SetDCHook( dce->hDC, hookProc, (DWORD)dce );
  86
  87     dce->hwndCurrent = WIN_GetFullHandle( hWnd );
  88     dce->hClipRgn    = 0;
  89
  90     if( type != DCE_CACHE_DC ) /* owned or class DC */
  91     {
  92         dce->DCXflags = DCX_DCEBUSY;
  93         if( hWnd )
  94         {
  95             LONG style = GetWindowLongW( hWnd, GWL_STYLE );
  96             if (style & WS_CLIPCHILDREN) dce->DCXflags |= DCX_CLIPCHILDREN;
  97             if (style & WS_CLIPSIBLINGS) dce->DCXflags |= DCX_CLIPSIBLINGS;
  98         }
  99         SetHookFlags16(dce->hDC,DCHF_INVALIDATEVISRGN);
 100     }
 101     else dce->DCXflags = DCX_CACHE | DCX_DCEEMPTY;
 102
 103     USER_Lock();
 104     dce->next = firstDCE;
 105     firstDCE = dce;
 106     USER_Unlock();
 107     return dce;
 108 }
 109
 110
 111 /***********************************************************************
 112  *           DCE_FreeDCE
 113  */
 114 DCE* DCE_FreeDCE( DCE *dce )
 115 {
 116     DCE **ppDCE, *ret;
 117
 118     if (!dce) return NULL;
 119
 120     USER_Lock();
 121
 122     ppDCE = &firstDCE;
 123
 124     while (*ppDCE && (*ppDCE != dce)) ppDCE = &(*ppDCE)->next;
 125     if (*ppDCE == dce) *ppDCE = dce->next;
 126     ret = *ppDCE;
 127     USER_Unlock();
 128
 129     SetDCHook(dce->hDC, NULL, 0L);
 130
 131     DeleteDC( dce->hDC );
 132     if( dce->hClipRgn && !(dce->DCXflags & DCX_KEEPCLIPRGN) )
 133         DeleteObject(dce->hClipRgn);
 134     HeapFree( GetProcessHeap(), 0, dce );
 135
 136     return ret;
 137 }
 138
 139 /***********************************************************************
 140  *           DCE_FreeWindowDCE
 141  *
 142  * Remove owned DCE and reset unreleased cache DCEs.
 143  */
 144 void DCE_FreeWindowDCE( HWND hwnd )
 145 {
 146     DCE *pDCE;
 147     WND *pWnd = WIN_GetPtr( hwnd );
 148
 149     pDCE = firstDCE;
 150     while( pDCE )
 151     {
 152         if( pDCE->hwndCurrent == hwnd )
 153         {
 154             if( pDCE == pWnd->dce ) /* owned or Class DCE*/
 155             {
 156                 if (pWnd->clsStyle & CS_OWNDC)  /* owned DCE*/
 157                 {
 158                     pDCE = DCE_FreeDCE( pDCE );
 159                     pWnd->dce = NULL;
 160                     continue;
 161                 }
 162                 else if( pDCE->DCXflags & (DCX_INTERSECTRGN | DCX_EXCLUDERGN) ) /* Class DCE*/
 163                 {
 164                     DCE_DeleteClipRgn( pDCE );
 165                     pDCE->hwndCurrent = 0;
 166                 }
 167             }
 168             else
 169             {
 170                 if( pDCE->DCXflags & DCX_DCEBUSY ) /* shared cache DCE */
 171                 {
 172                     /* FIXME: AFAICS we are doing the right thing here so
 173                      * this should be a WARN. But this is best left as an ERR
 174                      * because the 'application error' is likely to come from
 175                      * another part of Wine (i.e. it's our fault after all).
 176                      * We should change this to WARN when Wine is more stable
 177                      * (for 1.0?).
 178                      */
 179                     ERR("[%08x] GetDC() without ReleaseDC()!\n",hwnd);
 180                     DCE_ReleaseDC( pDCE );
 181                 }
 182
 183                 pDCE->DCXflags &= DCX_CACHE;
 184                 pDCE->DCXflags |= DCX_DCEEMPTY;
 185                 pDCE->hwndCurrent = 0;
 186             }
 187         }
 188         pDCE = pDCE->next;
 189     }
 190     WIN_ReleasePtr( pWnd );
 191 }
 192
 193
 194 /***********************************************************************
 195  *   DCE_DeleteClipRgn
 196  */
 197 static void DCE_DeleteClipRgn( DCE* dce )
 198 {
 199     dce->DCXflags &= ~(DCX_EXCLUDERGN | DCX_INTERSECTRGN | DCX_WINDOWPAINT);
 200
 201     if( dce->DCXflags & DCX_KEEPCLIPRGN )
 202         dce->DCXflags &= ~DCX_KEEPCLIPRGN;
 203     else
 204         if( dce->hClipRgn > 1 )
 205             DeleteObject( dce->hClipRgn );
 206
 207     dce->hClipRgn = 0;
 208
 209     /* make it dirty so that the vis rgn gets recomputed next time */
 210     dce->DCXflags |= DCX_DCEDIRTY;
 211     SetHookFlags16( dce->hDC, DCHF_INVALIDATEVISRGN );
 212 }
 213
 214
 215 /***********************************************************************
 216  *   DCE_ReleaseDC
 217  */
 218 static INT DCE_ReleaseDC( DCE* dce )
 219 {
 220     if ((dce->DCXflags & (DCX_DCEEMPTY | DCX_DCEBUSY)) != DCX_DCEBUSY) return 0;
 221
 222     /* restore previous visible region */
 223
 224     if ((dce->DCXflags & (DCX_INTERSECTRGN | DCX_EXCLUDERGN)) &&
 225         (dce->DCXflags & (DCX_CACHE | DCX_WINDOWPAINT)) )
 226         DCE_DeleteClipRgn( dce );
 227
 228     if (dce->DCXflags & DCX_CACHE)
 229     {
 230         SetDCState16( dce->hDC, defaultDCstate );
 231         dce->DCXflags &= ~DCX_DCEBUSY;
 232         if (dce->DCXflags & DCX_DCEDIRTY)
 233         {
 234             /* don't keep around invalidated entries
 235              * because SetDCState() disables hVisRgn updates
 236              * by removing dirty bit. */
 237
 238             dce->hwndCurrent = 0;
 239             dce->DCXflags &= DCX_CACHE;
 240             dce->DCXflags |= DCX_DCEEMPTY;
 241         }
 242     }
 243     return 1;
 244 }
 245
 246
 247 /***********************************************************************
 248  *   DCE_InvalidateDCE
 249  *
 250  * It is called from SetWindowPos() and EVENT_MapNotify - we have to
 251  * mark as dirty all busy DCEs for windows that have pWnd->parent as
 252  * an ancestor and whose client rect intersects with specified update
 253  * rectangle. In addition, pWnd->parent DCEs may need to be updated if
 254  * DCX_CLIPCHILDREN flag is set.  */
 255 BOOL DCE_InvalidateDCE(HWND hwnd, const RECT* pRectUpdate)
 256 {
 257     HWND hwndScope = GetAncestor( hwnd, GA_PARENT );
 258     BOOL bRet = FALSE;
 259
 260     if( hwndScope )
 261     {
 262         DCE *dce;
 263
 264         TRACE("scope hwnd = %04x, (%i,%i - %i,%i)\n",
 265                      hwndScope, pRectUpdate->left,pRectUpdate->top,
 266                      pRectUpdate->right,pRectUpdate->bottom);
 267         if(TRACE_ON(dc))
 268           DCE_DumpCache();
 269
 270         /* walk all DCEs and fixup non-empty entries */
 271
 272         for (dce = firstDCE; (dce); dce = dce->next)
 273         {
 274             if (dce->DCXflags & DCX_DCEEMPTY) continue;
 275             if ((dce->hwndCurrent == hwndScope) && !(dce->DCXflags & DCX_CLIPCHILDREN))
 276                 continue;  /* child window positions don't bother us */
 277
 278             /* check if DCE window is within the z-order scope */
 279
 280             if (hwndScope == dce->hwndCurrent || IsChild( hwndScope, dce->hwndCurrent ))
 281             {
 282                 if (hwnd != dce->hwndCurrent)
 283                 {
 284                     /* check if the window rectangle intersects this DCE window */
 285                     RECT rect;
 286                     GetWindowRect( dce->hwndCurrent, &rect );
 287                     MapWindowPoints( 0, hwndScope, (POINT *)&rect, 2 );
 288                     if (!IntersectRect( &rect, &rect, pRectUpdate )) continue;
 289
 290                 }
 291                 if( !(dce->DCXflags & DCX_DCEBUSY) )
 292                 {
 293                     /* Don't bother with visible regions of unused DCEs */
 294
 295                     TRACE("\tpurged %p dce [%04x]\n", dce, dce->hwndCurrent);
 296                     dce->hwndCurrent = 0;
 297                     dce->DCXflags &= DCX_CACHE;
 298                     dce->DCXflags |= DCX_DCEEMPTY;
 299                 }
 300                 else
 301                 {
 302                     /* Set dirty bits in the hDC and DCE structs */
 303
 304                     TRACE("\tfixed up %p dce [%04x]\n", dce, dce->hwndCurrent);
 305                     dce->DCXflags |= DCX_DCEDIRTY;
 306                     SetHookFlags16(dce->hDC, DCHF_INVALIDATEVISRGN);
 307                     bRet = TRUE;
 308                 }
 309             }
 310         } /* dce list */
 311     }
 312     return bRet;
 313 }
 314
 315
 316 /***********************************************************************
 317  *           DCE_ExcludeRgn
 318  *
 319  *  Translate given region from the wnd client to the DC coordinates
 320  *  and add it to the clipping region.
 321  */
 322 INT DCE_ExcludeRgn( HDC hDC, HWND hwnd, HRGN hRgn )
 323 {
 324   POINT  pt = {0, 0};
 325   DCE     *dce = firstDCE;
 326
 327   while (dce && (dce->hDC != hDC)) dce = dce->next;
 328   if (!dce) return ERROR;
 329
 330   MapWindowPoints( hwnd, dce->hwndCurrent, &pt, 1);
 331   if( dce->DCXflags & DCX_WINDOW )
 332   {
 333       WND *wnd = WIN_FindWndPtr(dce->hwndCurrent);
 334       pt.x += wnd->rectClient.left - wnd->rectWindow.left;
 335       pt.y += wnd->rectClient.top - wnd->rectWindow.top;
 336       WIN_ReleaseWndPtr(wnd);
 337   }
 338   OffsetRgn(hRgn, pt.x, pt.y);
 339
 340   return ExtSelectClipRgn( hDC, hRgn, RGN_DIFF );
 341 }
 342
 343
 344 /***********************************************************************
 345  *              GetDCEx (USER32.@)
 346  *
 347  * Unimplemented flags: DCX_LOCKWINDOWUPDATE
 348  *
 349  * FIXME: Full support for hrgnClip == 1 (alias for entire window).
 350  */
 351 HDC WINAPI GetDCEx( HWND hwnd, HRGN hrgnClip, DWORD flags )
 352 {
 353     HDC         hdc = 0;
 354     DCE *       dce;
 355     WND *       wndPtr;
 356     DWORD       dcxFlags = 0;
 357     BOOL        bUpdateVisRgn = TRUE;
 358     BOOL        bUpdateClipOrigin = FALSE;
 359     HWND parent, full;
 360
 361     TRACE("hwnd %04x, hrgnClip %04x, flags %08x\n",
 362           hwnd, hrgnClip, (unsigned)flags);
 363
 364     if (!hwnd) hwnd = GetDesktopWindow();
 365     if (!(full = WIN_IsCurrentProcess( hwnd )))
 366     {
 367         FIXME( "not supported yet on other process window %x\n", hwnd );
 368         return 0;
 369     }
 370     hwnd = full;
 371     if (!(wndPtr = WIN_GetPtr( hwnd ))) return 0;
 372
 373     /* fixup flags */
 374
 375     if (flags & (DCX_WINDOW | DCX_PARENTCLIP)) flags |= DCX_CACHE;
 376
 377     if (flags & DCX_USESTYLE)
 378     {
 379         flags &= ~( DCX_CLIPCHILDREN | DCX_CLIPSIBLINGS | DCX_PARENTCLIP);
 380
 381         if( wndPtr->dwStyle & WS_CLIPSIBLINGS )
 382             flags |= DCX_CLIPSIBLINGS;
 383
 384         if ( !(flags & DCX_WINDOW) )
 385         {
 386             if (wndPtr->clsStyle & CS_PARENTDC) flags |= DCX_PARENTCLIP;
 387
 388             if (wndPtr->dwStyle & WS_CLIPCHILDREN &&
 389                      !(wndPtr->dwStyle & WS_MINIMIZE) ) flags |= DCX_CLIPCHILDREN;
 390             if (!wndPtr->dce) flags |= DCX_CACHE;
 391         }
 392     }
 393
 394     if (flags & DCX_WINDOW) flags &= ~DCX_CLIPCHILDREN;
 395
 396     parent = GetAncestor( hwnd, GA_PARENT );
 397     if (!parent || (parent == GetDesktopWindow()))
 398         flags = (flags & ~DCX_PARENTCLIP) | DCX_CLIPSIBLINGS;
 399
 400     /* it seems parent clip is ignored when clipping siblings or children */
 401     if (flags & (DCX_CLIPSIBLINGS | DCX_CLIPCHILDREN)) flags &= ~DCX_PARENTCLIP;
 402
 403     if( flags & DCX_PARENTCLIP )
 404     {
 405         LONG parent_style = GetWindowLongW( parent, GWL_STYLE );
 406         if( (wndPtr->dwStyle & WS_VISIBLE) && (parent_style & WS_VISIBLE) )
 407         {
 408             flags &= ~DCX_CLIPCHILDREN;
 409             if (parent_style & WS_CLIPSIBLINGS) flags |= DCX_CLIPSIBLINGS;
 410         }
 411     }
 412
 413     /* find a suitable DCE */
 414
 415     dcxFlags = flags & (DCX_PARENTCLIP | DCX_CLIPSIBLINGS | DCX_CLIPCHILDREN |
 416                         DCX_CACHE | DCX_WINDOW);
 417
 418     if (flags & DCX_CACHE)
 419     {
 420         DCE*    dceEmpty;
 421         DCE*    dceUnused;
 422
 423         dceEmpty = dceUnused = NULL;
 424
 425         /* Strategy: First, we attempt to find a non-empty but unused DCE with
 426          * compatible flags. Next, we look for an empty entry. If the cache is
 427          * full we have to purge one of the unused entries.
 428          */
 429
 430         for (dce = firstDCE; (dce); dce = dce->next)
 431         {
 432             if ((dce->DCXflags & (DCX_CACHE | DCX_DCEBUSY)) == DCX_CACHE )
 433             {
 434                 dceUnused = dce;
 435
 436                 if (dce->DCXflags & DCX_DCEEMPTY)
 437                     dceEmpty = dce;
 438                 else
 439                 if ((dce->hwndCurrent == hwnd) &&
 440                    ((dce->DCXflags & (DCX_CLIPSIBLINGS | DCX_CLIPCHILDREN |
 441                                       DCX_CACHE | DCX_WINDOW | DCX_PARENTCLIP)) == dcxFlags))
 442                 {
 443                     TRACE("\tfound valid %08x dce [%04x], flags %08x\n",
 444                                         (unsigned)dce, hwnd, (unsigned)dcxFlags );
 445                     bUpdateVisRgn = FALSE;
 446                     bUpdateClipOrigin = TRUE;
 447                     break;
 448                 }
 449             }
 450         }
 451
 452         if (!dce) dce = (dceEmpty) ? dceEmpty : dceUnused;
 453
 454         /* if there's no dce empty or unused, allocate a new one */
 455         if (!dce)
 456         {
 457             dce = DCE_AllocDCE( 0, DCE_CACHE_DC );
 458         }
 459     }
 460     else
 461     {
 462         dce = wndPtr->dce;
 463         if (dce && dce->hwndCurrent == hwnd)
 464         {
 465             TRACE("\tskipping hVisRgn update\n");
 466             bUpdateVisRgn = FALSE; /* updated automatically, via DCHook() */
 467         }
 468     }
 469     if (!dce)
 470     {
 471         hdc = 0;
 472         goto END;
 473     }
 474
 475     if (!(flags & (DCX_INTERSECTRGN | DCX_EXCLUDERGN))) hrgnClip = 0;
 476
 477     if (((flags ^ dce->DCXflags) & (DCX_INTERSECTRGN | DCX_EXCLUDERGN)) &&
 478         (dce->hClipRgn != hrgnClip))
 479     {
 480         /* if the extra clip region has changed, get rid of the old one */
 481         DCE_DeleteClipRgn( dce );
 482     }
 483
 484     dce->hwndCurrent = hwnd;
 485     dce->hClipRgn = hrgnClip;
 486     dce->DCXflags = flags & (DCX_PARENTCLIP | DCX_CLIPSIBLINGS | DCX_CLIPCHILDREN |
 487                              DCX_CACHE | DCX_WINDOW | DCX_WINDOWPAINT |
 488                              DCX_KEEPCLIPRGN | DCX_INTERSECTRGN | DCX_EXCLUDERGN);
 489     dce->DCXflags |= DCX_DCEBUSY;
 490     dce->DCXflags &= ~DCX_DCEDIRTY;
 491     hdc = dce->hDC;
 492
 493     if (bUpdateVisRgn) SetHookFlags16( hdc, DCHF_INVALIDATEVISRGN ); /* force update */
 494
 495     if (!USER_Driver.pGetDC( hwnd, hdc, hrgnClip, flags )) hdc = 0;
 496
 497     TRACE("(%04x,%04x,0x%lx): returning %04x\n", hwnd, hrgnClip, flags, hdc);
 498 END:
 499     WIN_ReleasePtr(wndPtr);
 500     return hdc;
 501 }
 502
 503
 504 /***********************************************************************
 505  *              GetDC (USER32.@)
 506  * RETURNS
 507  *      :Handle to DC
 508  *      NULL: Failure
 509  */
 510 HDC WINAPI GetDC(
 511              HWND hwnd /* [in] handle of window */
 512 ) {
 513     if (!hwnd)
 514         return GetDCEx( 0, 0, DCX_CACHE | DCX_WINDOW );
 515     return GetDCEx( hwnd, 0, DCX_USESTYLE );
 516 }
 517
 518
 519 /***********************************************************************
 520  *              GetWindowDC (USER32.@)
 521  */
 522 HDC WINAPI GetWindowDC( HWND hwnd )
 523 {
 524     return GetDCEx( hwnd, 0, DCX_USESTYLE | DCX_WINDOW );
 525 }
 526
 527
 528 /***********************************************************************
 529  *              ReleaseDC (USER32.@)
 530  *
 531  * RETURNS
 532  *      1: Success
 533  *      0: Failure
 534  */
 535 INT WINAPI ReleaseDC(
 536              HWND hwnd /* [in] Handle of window - ignored */,
 537              HDC hdc   /* [in] Handle of device context */
 538 ) {
 539     DCE * dce;
 540     INT nRet = 0;
 541
 542     USER_Lock();
 543     dce = firstDCE;
 544
 545     TRACE("%04x %04x\n", hwnd, hdc );
 546
 547     while (dce && (dce->hDC != hdc)) dce = dce->next;
 548
 549     if ( dce )
 550         if ( dce->DCXflags & DCX_DCEBUSY )
 551             nRet = DCE_ReleaseDC( dce );
 552
 553     USER_Unlock();
 554
 555     return nRet;
 556 }
 557
 558 /***********************************************************************
 559  *              DCHook (USER.362)
 560  *
 561  * See "Undoc. Windows" for hints (DC, SetDCHook, SetHookFlags)..
 562  */
 563 BOOL16 WINAPI DCHook16( HDC16 hDC, WORD code, DWORD data, LPARAM lParam )
 564 {
 565     BOOL retv = TRUE;
 566     DCE *dce = (DCE *)data;
 567
 568     TRACE("hDC = %04x, %i\n", hDC, code);
 569
 570     if (!dce) return 0;
 571     assert(dce->hDC == hDC);
 572
 573     /* Grab the windows lock before doing anything else  */
 574     USER_Lock();
 575
 576     switch( code )
 577     {
 578       case DCHC_INVALIDVISRGN:
 579            /* GDI code calls this when it detects that the
 580             * DC is dirty (usually after SetHookFlags()). This
 581             * means that we have to recompute the visible region.
 582             */
 583            if( dce->DCXflags & DCX_DCEBUSY )
 584            {
 585                /* Dirty bit has been cleared by caller, set it again so that
 586                 * pGetDC recomputes the visible region. */
 587                SetHookFlags16( dce->hDC, DCHF_INVALIDATEVISRGN );
 588                USER_Driver.pGetDC( dce->hwndCurrent, dce->hDC, dce->hClipRgn, dce->DCXflags );
 589            }
 590            else /* non-fatal but shouldn't happen */
 591              WARN("DC is not in use!\n");
 592            break;
 593
 594       case DCHC_DELETEDC:
 595            /*
 596             * Windows will not let you delete a DC that is busy
 597             * (between GetDC and ReleaseDC)
 598             */
 599
 600            if ( dce->DCXflags & DCX_DCEBUSY )
 601            {
 602                WARN("Application trying to delete a busy DC\n");
 603                retv = FALSE;
 604            }
 605            else DCE_FreeDCE( dce );
 606            break;
 607
 608       default:
 609            FIXME("unknown code\n");
 610     }
 611
 612   USER_Unlock();  /* Release the wnd lock */
 613   return retv;
 614 }
 615
 616
 617 /**********************************************************************
 618  *              WindowFromDC (USER32.@)
 619  */
 620 HWND WINAPI WindowFromDC( HDC hDC )
 621 {
 622     DCE *dce;
 623     HWND hwnd;
 624
 625     USER_Lock();
 626     dce = firstDCE;
 627
 628     while (dce && (dce->hDC != hDC)) dce = dce->next;
 629
 630     hwnd = dce ? dce->hwndCurrent : 0;
 631     USER_Unlock();
 632
 633     return hwnd;
 634 }
 635
 636
 637 /***********************************************************************
 638  *              LockWindowUpdate (USER32.@)
 639  */
 640 BOOL WINAPI LockWindowUpdate( HWND hwnd )
 641 {
 642     FIXME("(%x), stub!\n",hwnd);
 643     return TRUE;
 644 }