windows/dce.c

   1 /*
   2  * USER DCE functions
   3  *
   4  * Copyright 1993 Alexandre Julliard
   5  *           1996,1997 Alex Korobka
   6  *
   7  * This library is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * This library is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with this library; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  *
  21  *
  22  * Note: Visible regions of CS_OWNDC/CS_CLASSDC window DCs
  23  * have to be updated dynamically.
  24  *
  25  * Internal DCX flags:
  26  *
  27  * DCX_DCEEMPTY    - dce is uninitialized
  28  * DCX_DCEBUSY     - dce is in use
  29  * DCX_DCEDIRTY    - ReleaseDC() should wipe instead of caching
  30  * DCX_KEEPCLIPRGN - ReleaseDC() should not delete the clipping region
  31  * DCX_WINDOWPAINT - BeginPaint() is in effect
  32  */
  33
  34 #include <assert.h>
  35 #include "dce.h"
  36 #include "win.h"
  37 #include "gdi.h"
  38 #include "region.h"
  39 #include "user.h"
  40 #include "wine/debug.h"
  41 #include "windef.h"
  42 #include "wingdi.h"
  43 #include "wine/winbase16.h"
  44 #include "wine/winuser16.h"
  45
  46 WINE_DEFAULT_DEBUG_CHANNEL(dc);
  47
  48 static DCE *firstDCE;
  49 static HDC defaultDCstate;
  50
  51 static void DCE_DeleteClipRgn( DCE* );
  52 static INT DCE_ReleaseDC( DCE* );
  53
  54
  55 /***********************************************************************
  56  *           DCE_DumpCache
  57  */
  58 static void DCE_DumpCache(void)
  59 {
  60     DCE *dce;
  61
  62     USER_Lock();
  63     dce = firstDCE;
  64
  65     DPRINTF("DCE:\n");
  66     while( dce )
  67     {
  68         DPRINTF("\t[0x%08x] hWnd 0x%04x, dcx %08x, %s %s\n",
  69              (unsigned)dce, dce->hwndCurrent, (unsigned)dce->DCXflags,
  70              (dce->DCXflags & DCX_CACHE) ? "Cache" : "Owned",
  71              (dce->DCXflags & DCX_DCEBUSY) ? "InUse" : "" );
  72         dce = dce->next;
  73     }
  74
  75     USER_Unlock();
  76 }
  77
  78 /***********************************************************************
  79  *           DCE_AllocDCE
  80  *
  81  * Allocate a new DCE.
  82  */
  83 DCE *DCE_AllocDCE( HWND hWnd, DCE_TYPE type )
  84 {
  85     DCE * dce;
  86
  87     if (!(dce = HeapAlloc( GetProcessHeap(), 0, sizeof(DCE) ))) return NULL;
  88     if (!(dce->hDC = CreateDCA( "DISPLAY", NULL, NULL, NULL )))
  89     {
  90         HeapFree( GetProcessHeap(), 0, dce );
  91         return 0;
  92     }
  93     if (!defaultDCstate) defaultDCstate = GetDCState16( dce->hDC );
  94
  95     /* store DCE handle in DC hook data field */
  96
  97     SetDCHook( dce->hDC, DCHook16, (DWORD)dce );
  98
  99     dce->hwndCurrent = WIN_GetFullHandle( hWnd );
 100     dce->hClipRgn    = 0;
 101
 102     if( type != DCE_CACHE_DC ) /* owned or class DC */
 103     {
 104         dce->DCXflags = DCX_DCEBUSY;
 105         if( hWnd )
 106         {
 107             LONG style = GetWindowLongW( hWnd, GWL_STYLE );
 108             if (style & WS_CLIPCHILDREN) dce->DCXflags |= DCX_CLIPCHILDREN;
 109             if (style & WS_CLIPSIBLINGS) dce->DCXflags |= DCX_CLIPSIBLINGS;
 110         }
 111         SetHookFlags16(dce->hDC,DCHF_INVALIDATEVISRGN);
 112     }
 113     else dce->DCXflags = DCX_CACHE | DCX_DCEEMPTY;
 114
 115     USER_Lock();
 116     dce->next = firstDCE;
 117     firstDCE = dce;
 118     USER_Unlock();
 119     return dce;
 120 }
 121
 122
 123 /***********************************************************************
 124  *           DCE_FreeDCE
 125  */
 126 DCE* DCE_FreeDCE( DCE *dce )
 127 {
 128     DCE **ppDCE, *ret;
 129
 130     if (!dce) return NULL;
 131
 132     USER_Lock();
 133
 134     ppDCE = &firstDCE;
 135
 136     while (*ppDCE && (*ppDCE != dce)) ppDCE = &(*ppDCE)->next;
 137     if (*ppDCE == dce) *ppDCE = dce->next;
 138     ret = *ppDCE;
 139     USER_Unlock();
 140
 141     SetDCHook(dce->hDC, NULL, 0L);
 142
 143     DeleteDC( dce->hDC );
 144     if( dce->hClipRgn && !(dce->DCXflags & DCX_KEEPCLIPRGN) )
 145         DeleteObject(dce->hClipRgn);
 146     HeapFree( GetProcessHeap(), 0, dce );
 147
 148     return ret;
 149 }
 150
 151 /***********************************************************************
 152  *           DCE_FreeWindowDCE
 153  *
 154  * Remove owned DCE and reset unreleased cache DCEs.
 155  */
 156 void DCE_FreeWindowDCE( HWND hwnd )
 157 {
 158     DCE *pDCE;
 159     WND *pWnd = WIN_GetPtr( hwnd );
 160
 161     pDCE = firstDCE;
 162     while( pDCE )
 163     {
 164         if( pDCE->hwndCurrent == hwnd )
 165         {
 166             if( pDCE == pWnd->dce ) /* owned or Class DCE*/
 167             {
 168                 if (pWnd->clsStyle & CS_OWNDC)  /* owned DCE*/
 169                 {
 170                     pDCE = DCE_FreeDCE( pDCE );
 171                     pWnd->dce = NULL;
 172                     continue;
 173                 }
 174                 else if( pDCE->DCXflags & (DCX_INTERSECTRGN | DCX_EXCLUDERGN) ) /* Class DCE*/
 175                 {
 176                     DCE_DeleteClipRgn( pDCE );
 177                     pDCE->hwndCurrent = 0;
 178                 }
 179             }
 180             else
 181             {
 182                 if( pDCE->DCXflags & DCX_DCEBUSY ) /* shared cache DCE */
 183                 {
 184                     /* FIXME: AFAICS we are doing the right thing here so
 185                      * this should be a WARN. But this is best left as an ERR
 186                      * because the 'application error' is likely to come from
 187                      * another part of Wine (i.e. it's our fault after all).
 188                      * We should change this to WARN when Wine is more stable
 189                      * (for 1.0?).
 190                      */
 191                     ERR("[%08x] GetDC() without ReleaseDC()!\n",hwnd);
 192                     DCE_ReleaseDC( pDCE );
 193                 }
 194
 195                 pDCE->DCXflags &= DCX_CACHE;
 196                 pDCE->DCXflags |= DCX_DCEEMPTY;
 197                 pDCE->hwndCurrent = 0;
 198             }
 199         }
 200         pDCE = pDCE->next;
 201     }
 202     WIN_ReleasePtr( pWnd );
 203 }
 204
 205
 206 /***********************************************************************
 207  *   DCE_DeleteClipRgn
 208  */
 209 static void DCE_DeleteClipRgn( DCE* dce )
 210 {
 211     dce->DCXflags &= ~(DCX_EXCLUDERGN | DCX_INTERSECTRGN | DCX_WINDOWPAINT);
 212
 213     if( dce->DCXflags & DCX_KEEPCLIPRGN )
 214         dce->DCXflags &= ~DCX_KEEPCLIPRGN;
 215     else
 216         if( dce->hClipRgn > 1 )
 217             DeleteObject( dce->hClipRgn );
 218
 219     dce->hClipRgn = 0;
 220
 221     /* make it dirty so that the vis rgn gets recomputed next time */
 222     dce->DCXflags |= DCX_DCEDIRTY;
 223     SetHookFlags16( dce->hDC, DCHF_INVALIDATEVISRGN );
 224 }
 225
 226
 227 /***********************************************************************
 228  *   DCE_ReleaseDC
 229  */
 230 static INT DCE_ReleaseDC( DCE* dce )
 231 {
 232     if ((dce->DCXflags & (DCX_DCEEMPTY | DCX_DCEBUSY)) != DCX_DCEBUSY) return 0;
 233
 234     /* restore previous visible region */
 235
 236     if ((dce->DCXflags & (DCX_INTERSECTRGN | DCX_EXCLUDERGN)) &&
 237         (dce->DCXflags & (DCX_CACHE | DCX_WINDOWPAINT)) )
 238         DCE_DeleteClipRgn( dce );
 239
 240     if (dce->DCXflags & DCX_CACHE)
 241     {
 242         SetDCState16( dce->hDC, defaultDCstate );
 243         dce->DCXflags &= ~DCX_DCEBUSY;
 244         if (dce->DCXflags & DCX_DCEDIRTY)
 245         {
 246             /* don't keep around invalidated entries
 247              * because SetDCState() disables hVisRgn updates
 248              * by removing dirty bit. */
 249
 250             dce->hwndCurrent = 0;
 251             dce->DCXflags &= DCX_CACHE;
 252             dce->DCXflags |= DCX_DCEEMPTY;
 253         }
 254     }
 255     return 1;
 256 }
 257
 258
 259 /***********************************************************************
 260  *   DCE_InvalidateDCE
 261  *
 262  * It is called from SetWindowPos() and EVENT_MapNotify - we have to
 263  * mark as dirty all busy DCEs for windows that have pWnd->parent as
 264  * an ancestor and whose client rect intersects with specified update
 265  * rectangle. In addition, pWnd->parent DCEs may need to be updated if
 266  * DCX_CLIPCHILDREN flag is set.  */
 267 BOOL DCE_InvalidateDCE(HWND hwnd, const RECT* pRectUpdate)
 268 {
 269     HWND hwndScope = GetAncestor( hwnd, GA_PARENT );
 270     BOOL bRet = FALSE;
 271
 272     if( hwndScope )
 273     {
 274         DCE *dce;
 275
 276         TRACE("scope hwnd = %04x, (%i,%i - %i,%i)\n",
 277                      hwndScope, pRectUpdate->left,pRectUpdate->top,
 278                      pRectUpdate->right,pRectUpdate->bottom);
 279         if(TRACE_ON(dc))
 280           DCE_DumpCache();
 281
 282         /* walk all DCEs and fixup non-empty entries */
 283
 284         for (dce = firstDCE; (dce); dce = dce->next)
 285         {
 286             if (dce->DCXflags & DCX_DCEEMPTY) continue;
 287             if ((dce->hwndCurrent == hwndScope) && !(dce->DCXflags & DCX_CLIPCHILDREN))
 288                 continue;  /* child window positions don't bother us */
 289
 290             /* check if DCE window is within the z-order scope */
 291
 292             if (hwndScope == dce->hwndCurrent || IsChild( hwndScope, dce->hwndCurrent ))
 293             {
 294                 if (hwnd != dce->hwndCurrent)
 295                 {
 296                     /* check if the window rectangle intersects this DCE window */
 297                     RECT rect;
 298                     GetWindowRect( dce->hwndCurrent, &rect );
 299                     MapWindowPoints( 0, hwndScope, (POINT *)&rect, 2 );
 300                     if (!IntersectRect( &rect, &rect, pRectUpdate )) continue;
 301
 302                 }
 303                 if( !(dce->DCXflags & DCX_DCEBUSY) )
 304                 {
 305                     /* Don't bother with visible regions of unused DCEs */
 306
 307                     TRACE("\tpurged %p dce [%04x]\n", dce, dce->hwndCurrent);
 308                     dce->hwndCurrent = 0;
 309                     dce->DCXflags &= DCX_CACHE;
 310                     dce->DCXflags |= DCX_DCEEMPTY;
 311                 }
 312                 else
 313                 {
 314                     /* Set dirty bits in the hDC and DCE structs */
 315
 316                     TRACE("\tfixed up %p dce [%04x]\n", dce, dce->hwndCurrent);
 317                     dce->DCXflags |= DCX_DCEDIRTY;
 318                     SetHookFlags16(dce->hDC, DCHF_INVALIDATEVISRGN);
 319                     bRet = TRUE;
 320                 }
 321             }
 322         } /* dce list */
 323     }
 324     return bRet;
 325 }
 326
 327
 328 /***********************************************************************
 329  *           DCE_ExcludeRgn
 330  *
 331  *  Translate given region from the wnd client to the DC coordinates
 332  *  and add it to the clipping region.
 333  */
 334 INT DCE_ExcludeRgn( HDC hDC, HWND hwnd, HRGN hRgn )
 335 {
 336   POINT  pt = {0, 0};
 337   DCE     *dce = firstDCE;
 338
 339   while (dce && (dce->hDC != hDC)) dce = dce->next;
 340   if (!dce) return ERROR;
 341
 342   MapWindowPoints( hwnd, dce->hwndCurrent, &pt, 1);
 343   if( dce->DCXflags & DCX_WINDOW )
 344   {
 345       WND *wnd = WIN_FindWndPtr(dce->hwndCurrent);
 346       pt.x += wnd->rectClient.left - wnd->rectWindow.left;
 347       pt.y += wnd->rectClient.top - wnd->rectWindow.top;
 348       WIN_ReleaseWndPtr(wnd);
 349   }
 350   OffsetRgn(hRgn, pt.x, pt.y);
 351
 352   return ExtSelectClipRgn( hDC, hRgn, RGN_DIFF );
 353 }
 354
 355
 356 /***********************************************************************
 357  *              GetDCEx (USER32.@)
 358  *
 359  * Unimplemented flags: DCX_LOCKWINDOWUPDATE
 360  *
 361  * FIXME: Full support for hrgnClip == 1 (alias for entire window).
 362  */
 363 HDC WINAPI GetDCEx( HWND hwnd, HRGN hrgnClip, DWORD flags )
 364 {
 365     HDC         hdc = 0;
 366     DCE *       dce;
 367     WND *       wndPtr;
 368     DWORD       dcxFlags = 0;
 369     BOOL        bUpdateVisRgn = TRUE;
 370     BOOL        bUpdateClipOrigin = FALSE;
 371     HWND parent, full;
 372
 373     TRACE("hwnd %04x, hrgnClip %04x, flags %08x\n",
 374           hwnd, hrgnClip, (unsigned)flags);
 375
 376     if (!hwnd) hwnd = GetDesktopWindow();
 377     if (!(full = WIN_IsCurrentProcess( hwnd )))
 378     {
 379         FIXME( "not supported yet on other process window %x\n", hwnd );
 380         return 0;
 381     }
 382     hwnd = full;
 383     if (!(wndPtr = WIN_GetPtr( hwnd ))) return 0;
 384
 385     /* fixup flags */
 386
 387     if (flags & (DCX_WINDOW | DCX_PARENTCLIP)) flags |= DCX_CACHE;
 388
 389     if (flags & DCX_USESTYLE)
 390     {
 391         flags &= ~( DCX_CLIPCHILDREN | DCX_CLIPSIBLINGS | DCX_PARENTCLIP);
 392
 393         if( wndPtr->dwStyle & WS_CLIPSIBLINGS )
 394             flags |= DCX_CLIPSIBLINGS;
 395
 396         if ( !(flags & DCX_WINDOW) )
 397         {
 398             if (wndPtr->clsStyle & CS_PARENTDC) flags |= DCX_PARENTCLIP;
 399
 400             if (wndPtr->dwStyle & WS_CLIPCHILDREN &&
 401                      !(wndPtr->dwStyle & WS_MINIMIZE) ) flags |= DCX_CLIPCHILDREN;
 402             if (!wndPtr->dce) flags |= DCX_CACHE;
 403         }
 404     }
 405
 406     if (flags & DCX_WINDOW) flags &= ~DCX_CLIPCHILDREN;
 407
 408     parent = GetAncestor( hwnd, GA_PARENT );
 409     if (!parent || (parent == GetDesktopWindow()))
 410         flags = (flags & ~DCX_PARENTCLIP) | DCX_CLIPSIBLINGS;
 411
 412     /* it seems parent clip is ignored when clipping siblings or children */
 413     if (flags & (DCX_CLIPSIBLINGS | DCX_CLIPCHILDREN)) flags &= ~DCX_PARENTCLIP;
 414
 415     if( flags & DCX_PARENTCLIP )
 416     {
 417         LONG parent_style = GetWindowLongW( parent, GWL_STYLE );
 418         if( (wndPtr->dwStyle & WS_VISIBLE) && (parent_style & WS_VISIBLE) )
 419         {
 420             flags &= ~DCX_CLIPCHILDREN;
 421             if (parent_style & WS_CLIPSIBLINGS) flags |= DCX_CLIPSIBLINGS;
 422         }
 423     }
 424
 425     /* find a suitable DCE */
 426
 427     dcxFlags = flags & (DCX_PARENTCLIP | DCX_CLIPSIBLINGS | DCX_CLIPCHILDREN |
 428                         DCX_CACHE | DCX_WINDOW);
 429
 430     if (flags & DCX_CACHE)
 431     {
 432         DCE*    dceEmpty;
 433         DCE*    dceUnused;
 434
 435         dceEmpty = dceUnused = NULL;
 436
 437         /* Strategy: First, we attempt to find a non-empty but unused DCE with
 438          * compatible flags. Next, we look for an empty entry. If the cache is
 439          * full we have to purge one of the unused entries.
 440          */
 441
 442         for (dce = firstDCE; (dce); dce = dce->next)
 443         {
 444             if ((dce->DCXflags & (DCX_CACHE | DCX_DCEBUSY)) == DCX_CACHE )
 445             {
 446                 dceUnused = dce;
 447
 448                 if (dce->DCXflags & DCX_DCEEMPTY)
 449                     dceEmpty = dce;
 450                 else
 451                 if ((dce->hwndCurrent == hwnd) &&
 452                    ((dce->DCXflags & (DCX_CLIPSIBLINGS | DCX_CLIPCHILDREN |
 453                                       DCX_CACHE | DCX_WINDOW | DCX_PARENTCLIP)) == dcxFlags))
 454                 {
 455                     TRACE("\tfound valid %08x dce [%04x], flags %08x\n",
 456                                         (unsigned)dce, hwnd, (unsigned)dcxFlags );
 457                     bUpdateVisRgn = FALSE;
 458                     bUpdateClipOrigin = TRUE;
 459                     break;
 460                 }
 461             }
 462         }
 463
 464         if (!dce) dce = (dceEmpty) ? dceEmpty : dceUnused;
 465
 466         /* if there's no dce empty or unused, allocate a new one */
 467         if (!dce)
 468         {
 469             dce = DCE_AllocDCE( 0, DCE_CACHE_DC );
 470         }
 471     }
 472     else
 473     {
 474         dce = wndPtr->dce;
 475         if (dce && dce->hwndCurrent == hwnd)
 476         {
 477             TRACE("\tskipping hVisRgn update\n");
 478             bUpdateVisRgn = FALSE; /* updated automatically, via DCHook() */
 479         }
 480     }
 481     if (!dce)
 482     {
 483         hdc = 0;
 484         goto END;
 485     }
 486
 487     if (!(flags & (DCX_INTERSECTRGN | DCX_EXCLUDERGN))) hrgnClip = 0;
 488
 489     if (((flags ^ dce->DCXflags) & (DCX_INTERSECTRGN | DCX_EXCLUDERGN)) &&
 490         (dce->hClipRgn != hrgnClip))
 491     {
 492         /* if the extra clip region has changed, get rid of the old one */
 493         DCE_DeleteClipRgn( dce );
 494     }
 495
 496     dce->hwndCurrent = hwnd;
 497     dce->hClipRgn = hrgnClip;
 498     dce->DCXflags = flags & (DCX_PARENTCLIP | DCX_CLIPSIBLINGS | DCX_CLIPCHILDREN |
 499                              DCX_CACHE | DCX_WINDOW | DCX_WINDOWPAINT |
 500                              DCX_KEEPCLIPRGN | DCX_INTERSECTRGN | DCX_EXCLUDERGN);
 501     dce->DCXflags |= DCX_DCEBUSY;
 502     dce->DCXflags &= ~DCX_DCEDIRTY;
 503     hdc = dce->hDC;
 504
 505     if (bUpdateVisRgn) SetHookFlags16( hdc, DCHF_INVALIDATEVISRGN ); /* force update */
 506
 507     if (!USER_Driver.pGetDC( hwnd, hdc, hrgnClip, flags )) hdc = 0;
 508
 509     TRACE("(%04x,%04x,0x%lx): returning %04x\n", hwnd, hrgnClip, flags, hdc);
 510 END:
 511     WIN_ReleasePtr(wndPtr);
 512     return hdc;
 513 }
 514
 515
 516 /***********************************************************************
 517  *              GetDC (USER32.@)
 518  * RETURNS
 519  *      :Handle to DC
 520  *      NULL: Failure
 521  */
 522 HDC WINAPI GetDC(
 523              HWND hwnd /* [in] handle of window */
 524 ) {
 525     if (!hwnd)
 526         return GetDCEx( 0, 0, DCX_CACHE | DCX_WINDOW );
 527     return GetDCEx( hwnd, 0, DCX_USESTYLE );
 528 }
 529
 530
 531 /***********************************************************************
 532  *              GetWindowDC (USER32.@)
 533  */
 534 HDC WINAPI GetWindowDC( HWND hwnd )
 535 {
 536     return GetDCEx( hwnd, 0, DCX_USESTYLE | DCX_WINDOW );
 537 }
 538
 539
 540 /***********************************************************************
 541  *              ReleaseDC (USER32.@)
 542  *
 543  * RETURNS
 544  *      1: Success
 545  *      0: Failure
 546  */
 547 INT WINAPI ReleaseDC(
 548              HWND hwnd /* [in] Handle of window - ignored */,
 549              HDC hdc   /* [in] Handle of device context */
 550 ) {
 551     DCE * dce;
 552     INT nRet = 0;
 553
 554     USER_Lock();
 555     dce = firstDCE;
 556
 557     TRACE("%04x %04x\n", hwnd, hdc );
 558
 559     while (dce && (dce->hDC != hdc)) dce = dce->next;
 560
 561     if ( dce )
 562         if ( dce->DCXflags & DCX_DCEBUSY )
 563             nRet = DCE_ReleaseDC( dce );
 564
 565     USER_Unlock();
 566
 567     return nRet;
 568 }
 569
 570 /***********************************************************************
 571  *              DCHook (USER.362)
 572  *
 573  * See "Undoc. Windows" for hints (DC, SetDCHook, SetHookFlags)..
 574  */
 575 BOOL16 WINAPI DCHook16( HDC16 hDC, WORD code, DWORD data, LPARAM lParam )
 576 {
 577     BOOL retv = TRUE;
 578     DCE *dce = (DCE *)data;
 579
 580     TRACE("hDC = %04x, %i\n", hDC, code);
 581
 582     if (!dce) return 0;
 583     assert(dce->hDC == hDC);
 584
 585     /* Grab the windows lock before doing anything else  */
 586     USER_Lock();
 587
 588     switch( code )
 589     {
 590       case DCHC_INVALIDVISRGN:
 591            /* GDI code calls this when it detects that the
 592             * DC is dirty (usually after SetHookFlags()). This
 593             * means that we have to recompute the visible region.
 594             */
 595            if( dce->DCXflags & DCX_DCEBUSY )
 596            {
 597                /* Dirty bit has been cleared by caller, set it again so that
 598                 * pGetDC recomputes the visible region. */
 599                SetHookFlags16( dce->hDC, DCHF_INVALIDATEVISRGN );
 600                USER_Driver.pGetDC( dce->hwndCurrent, dce->hDC, dce->hClipRgn, dce->DCXflags );
 601            }
 602            else /* non-fatal but shouldn't happen */
 603              WARN("DC is not in use!\n");
 604            break;
 605
 606       case DCHC_DELETEDC:
 607            /*
 608             * Windows will not let you delete a DC that is busy
 609             * (between GetDC and ReleaseDC)
 610             */
 611
 612            if ( dce->DCXflags & DCX_DCEBUSY )
 613            {
 614                WARN("Application trying to delete a busy DC\n");
 615                retv = FALSE;
 616            }
 617            else DCE_FreeDCE( dce );
 618            break;
 619
 620       default:
 621            FIXME("unknown code\n");
 622     }
 623
 624   USER_Unlock();  /* Release the wnd lock */
 625   return retv;
 626 }
 627
 628
 629 /**********************************************************************
 630  *              WindowFromDC (USER32.@)
 631  */
 632 HWND WINAPI WindowFromDC( HDC hDC )
 633 {
 634     DCE *dce;
 635     HWND hwnd;
 636
 637     USER_Lock();
 638     dce = firstDCE;
 639
 640     while (dce && (dce->hDC != hDC)) dce = dce->next;
 641
 642     hwnd = dce ? dce->hwndCurrent : 0;
 643     USER_Unlock();
 644
 645     return hwnd;
 646 }
 647
 648
 649 /***********************************************************************
 650  *              LockWindowUpdate (USER32.@)
 651  */
 652 BOOL WINAPI LockWindowUpdate( HWND hwnd )
 653 {
 654     FIXME("(%x), stub!\n",hwnd);
 655     return TRUE;
 656 }