text: /*
   * Server-side window handling
   *
   * Copyright (C) 2001 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
   */
  
  #include "config.h"
  #include "wine/port.h"
  
  #include <assert.h>
  #include <stdarg.h>
  
  #include "ntstatus.h"
  #define WIN32_NO_STATUS
  #include "windef.h"
  #include "winbase.h"
  #include "wingdi.h"
  #include "winuser.h"
  #include "winternl.h"
  
  #include "object.h"
  #include "request.h"
  #include "thread.h"
  #include "process.h"
  #include "user.h"
  #include "handle.h"
  #include "file.h"
  #include "unicode.h"
  
  /* a window property */
  struct property
  {
      unsigned short type;     /* property type (see below) */
      atom_t         atom;     /* property atom */
      lparam_t       data;     /* property data (user-defined storage) */
  };
  
  enum property_type
  {
      PROP_TYPE_FREE,   /* free entry */
      PROP_TYPE_STRING, /* atom that was originally a string */
      PROP_TYPE_ATOM    /* plain atom */
  };
  
  
  struct window
  {
      struct window   *parent;          /* parent window */
      user_handle_t    owner;           /* owner of this window */
      struct list      children;        /* list of children in Z-order */
      struct list      unlinked;        /* list of children not linked in the Z-order list */
      struct list      entry;           /* entry in parent's children list */
      user_handle_t    handle;          /* full handle for this window */
      struct thread   *thread;          /* thread owning the window */
      struct desktop  *desktop;         /* desktop that the window belongs to */
      struct window_class *class;       /* window class */
      atom_t           atom;            /* class atom */
      user_handle_t    last_active;     /* last active popup */
      rectangle_t      window_rect;     /* window rectangle (relative to parent client area) */
      rectangle_t      visible_rect;    /* visible part of window rect (relative to parent client area) */
      rectangle_t      surface_rect;    /* window surface rectangle (relative to parent client area) */
      rectangle_t      client_rect;     /* client rectangle (relative to parent client area) */
      struct region   *win_region;      /* region for shaped windows (relative to window rect) */
      struct region   *update_region;   /* update region (relative to window rect) */
      unsigned int     style;           /* window style */
      unsigned int     ex_style;        /* window extended style */
      unsigned int     id;              /* window id */
      mod_handle_t     instance;        /* creator instance */
      unsigned int     is_unicode : 1;  /* ANSI or unicode */
      unsigned int     is_linked : 1;   /* is it linked into the parent z-order list? */
      unsigned int     is_layered : 1;  /* has layered info been set? */
      unsigned int     color_key;       /* color key for a layered window */
      unsigned int     alpha;           /* alpha value for a layered window */
      unsigned int     layered_flags;   /* flags for a layered window */
      unsigned int     dpi;             /* window DPI or 0 if per-monitor aware */
      DPI_AWARENESS    dpi_awareness;   /* DPI awareness mode */
      lparam_t         user_data;       /* user-specific data */
      WCHAR           *text;            /* window caption text */
      unsigned int     paint_flags;     /* various painting flags */
      int              prop_inuse;      /* number of in-use window properties */
      int              prop_alloc;      /* number of allocated window properties */
      struct property *properties;      /* window properties array */
      int              nb_extra_bytes;  /* number of extra bytes */
      char             extra_bytes[1];  /* extra bytes storage */
  };
  
  static void shm_surface_dump( struct object *obj, int verbose );
  static int shm_surface_signaled( struct object *obj, struct wait_queue_entry *entry );
  static void shm_surface_destroy( struct object *obj );
  
  struct shm_surface
  {
      struct object    obj;             /* object header */
      user_handle_t    window;          /* window handle */
      unsigned int     lock_cnt;        /* recursive lock count */
      unsigned int     lock_tid;        /* locking thread id (0 if locked for flush) */
      rectangle_t      bounds;          /* bounds of region requiring flush */
      struct process  *process;         /* flushing process */
      struct object   *mapping;         /* mapping of surface data */
      obj_handle_t     mapping_handle;  /* handle of mapping in flushing process */
      struct list      entry;           /* entry in process list */
  };
  
  static const struct object_ops shm_surface_ops =
  {
      sizeof(struct shm_surface),  /* size */
      shm_surface_dump,            /* dump */
      no_get_type,                 /* get_type */
      add_queue,                   /* add_queue */
      remove_queue,                /* remove_queue */
      shm_surface_signaled,        /* signaled */
      no_satisfied,                /* satisfied */
      no_signal,                   /* signal */
      no_get_fd,                   /* get_fd */
      no_map_access,               /* map_access */
      default_get_sd,              /* get_sd */
      default_set_sd,              /* set_sd */
      no_lookup_name,              /* lookup_name */
      no_link_name,                /* link_name */
      NULL,                        /* unlink_name */
      no_open_file,                /* open_file */
      no_kernel_obj_list,          /* get_kernel_obj_list */
      no_close_handle,             /* close_handle */
      shm_surface_destroy          /* destroy */
  };
  
  /* flags that can be set by the client */
  #define PAINT_HAS_SURFACE        SET_WINPOS_PAINT_SURFACE
  #define PAINT_HAS_PIXEL_FORMAT   SET_WINPOS_PIXEL_FORMAT
  #define PAINT_CLIENT_FLAGS       (PAINT_HAS_SURFACE | PAINT_HAS_PIXEL_FORMAT)
  /* flags only manipulated by the server */
  #define PAINT_INTERNAL           0x0010  /* internal WM_PAINT pending */
  #define PAINT_ERASE              0x0020  /* needs WM_ERASEBKGND */
  #define PAINT_NONCLIENT          0x0040  /* needs WM_NCPAINT */
  #define PAINT_DELAYED_ERASE      0x0080  /* still needs erase after WM_ERASEBKGND */
  #define PAINT_PIXEL_FORMAT_CHILD 0x0100  /* at least one child has a custom pixel format */
  
  /* growable array of user handles */
  struct user_handle_array
  {
      user_handle_t *handles;
      int            count;
      int            total;
  };
  
  static const rectangle_t empty_rect;
  
  /* global window pointers */
  static struct window *shell_window;
  static struct window *shell_listview;
  static struct window *progman_window;
  static struct window *taskman_window;
  
  /* magic HWND_TOP etc. pointers */
  #define WINPTR_TOP       ((struct window *)1L)
  #define WINPTR_BOTTOM    ((struct window *)2L)
  #define WINPTR_TOPMOST   ((struct window *)3L)
  #define WINPTR_NOTOPMOST ((struct window *)4L)
  
  /* retrieve a pointer to a window from its handle */
  static inline struct window *get_window( user_handle_t handle )
  {
      struct window *ret = get_user_object( handle, USER_WINDOW );
      if (!ret) set_win32_error( ERROR_INVALID_WINDOW_HANDLE );
      return ret;
  }
  
  /* check if window is the desktop */
  static inline int is_desktop_window( const struct window *win )
  {
      return !win->parent;  /* only desktop windows have no parent */
  }
  
  /* get next window in Z-order list */
  static inline struct window *get_next_window( struct window *win )
  {
      struct list *ptr = list_next( &win->parent->children, &win->entry );
      return ptr ? LIST_ENTRY( ptr, struct window, entry ) : NULL;
  }
  
  /* get previous window in Z-order list */
  static inline struct window *get_prev_window( struct window *win )
  {
      struct list *ptr = list_prev( &win->parent->children, &win->entry );
      return ptr ? LIST_ENTRY( ptr, struct window, entry ) : NULL;
  }
  
  /* get first child in Z-order list */
  static inline struct window *get_first_child( struct window *win )
  {
      struct list *ptr = list_head( &win->children );
      return ptr ? LIST_ENTRY( ptr, struct window, entry ) : NULL;
  }
  
  /* get last child in Z-order list */
  static inline struct window *get_last_child( struct window *win )
  {
      struct list *ptr = list_tail( &win->children );
      return ptr ? LIST_ENTRY( ptr, struct window, entry ) : NULL;
  }
  
  /* set the PAINT_PIXEL_FORMAT_CHILD flag on all the parents */
  /* note: we never reset the flag, it's just a heuristic */
  static inline void update_pixel_format_flags( struct window *win )
  {
      for (win = win->parent; win && win->parent; win = win->parent)
          win->paint_flags |= PAINT_PIXEL_FORMAT_CHILD;
  }
  
  /* get the per-monitor DPI for a window */
  static unsigned int get_monitor_dpi( struct window *win )
  {
      /* FIXME: we return the desktop window DPI for now */
      while (!is_desktop_window( win )) win = win->parent;
      return win->dpi ? win->dpi : USER_DEFAULT_SCREEN_DPI;
  }
  
  static rectangle_t union_rect( const rectangle_t *src1, const rectangle_t *src2 )
  {
      rectangle_t r;
      if (is_rect_empty( src1 )) return *src2;
      if (is_rect_empty( src2 )) return *src1;
      r.left   = min( src1->left, src2->left );
      r.top    = min( src1->top, src2->top );
      r.right  = max( src1->right, src2->right );
      r.bottom = max( src1->bottom, src2->bottom );
      return r;
  }
  
  /* link a window at the right place in the siblings list */
  static void link_window( struct window *win, struct window *previous )
  {
      if (previous == WINPTR_NOTOPMOST)
      {
          if (!(win->ex_style & WS_EX_TOPMOST) && win->is_linked) return;  /* nothing to do */
          win->ex_style &= ~WS_EX_TOPMOST;
          previous = WINPTR_TOP;  /* fallback to the HWND_TOP case */
      }
  
      list_remove( &win->entry );  /* unlink it from the previous location */
  
      if (previous == WINPTR_BOTTOM)
      {
          list_add_tail( &win->parent->children, &win->entry );
          win->ex_style &= ~WS_EX_TOPMOST;
      }
      else if (previous == WINPTR_TOPMOST)
      {
          list_add_head( &win->parent->children, &win->entry );
          win->ex_style |= WS_EX_TOPMOST;
      }
      else if (previous == WINPTR_TOP)
      {
          struct list *entry = win->parent->children.next;
          if (!(win->ex_style & WS_EX_TOPMOST))  /* put it above the first non-topmost window */
          {
              while (entry != &win->parent->children)
              {
                  struct window *next = LIST_ENTRY( entry, struct window, entry );
                  if (!(next->ex_style & WS_EX_TOPMOST)) break;
                  if (next->handle == win->owner)  /* keep it above owner */
                  {
                      win->ex_style |= WS_EX_TOPMOST;
                      break;
                  }
                  entry = entry->next;
              }
          }
          list_add_before( entry, &win->entry );
      }
      else
      {
          list_add_after( &previous->entry, &win->entry );
          if (!(previous->ex_style & WS_EX_TOPMOST)) win->ex_style &= ~WS_EX_TOPMOST;
          else
          {
              struct window *next = get_next_window( win );
              if (next && (next->ex_style & WS_EX_TOPMOST)) win->ex_style |= WS_EX_TOPMOST;
          }
      }
  
      win->is_linked = 1;
  }
  
  /* change the parent of a window (or unlink the window if the new parent is NULL) */
  static int set_parent_window( struct window *win, struct window *parent )
  {
      struct window *ptr;
  
      /* make sure parent is not a child of window */
      for (ptr = parent; ptr; ptr = ptr->parent)
      {
          if (ptr == win)
          {
              set_error( STATUS_INVALID_PARAMETER );
              return 0;
          }
      }
  
      if (parent)
      {
          win->parent = parent;
          link_window( win, WINPTR_TOP );
  
          if (!is_desktop_window( parent ))
          {
              win->dpi = parent->dpi;
              win->dpi_awareness = parent->dpi_awareness;
          }
  
          /* if parent belongs to a different thread and the window isn't */
          /* top-level, attach the two threads */
          if (parent->thread && parent->thread != win->thread && !is_desktop_window(parent))
              attach_thread_input( win->thread, parent->thread );
  
          if (win->paint_flags & (PAINT_HAS_PIXEL_FORMAT | PAINT_PIXEL_FORMAT_CHILD))
              update_pixel_format_flags( win );
      }
      else  /* move it to parent unlinked list */
      {
          list_remove( &win->entry );  /* unlink it from the previous location */
          list_add_head( &win->parent->unlinked, &win->entry );
          win->is_linked = 0;
      }
      return 1;
  }
  
  /* append a user handle to a handle array */
  static int add_handle_to_array( struct user_handle_array *array, user_handle_t handle )
  {
      if (array->count >= array->total)
      {
          int new_total = max( array->total * 2, 32 );
          user_handle_t *new_array = realloc( array->handles, new_total * sizeof(*new_array) );
          if (!new_array)
          {
              free( array->handles );
              set_error( STATUS_NO_MEMORY );
              return 0;
          }
          array->handles = new_array;
          array->total = new_total;
      }
      array->handles[array->count++] = handle;
      return 1;
  }
  
  /* set a window property */
  static void set_property( struct window *win, atom_t atom, lparam_t data, enum property_type type )
  {
      int i, free = -1;
      struct property *new_props;
  
      /* check if it exists already */
      for (i = 0; i < win->prop_inuse; i++)
      {
          if (win->properties[i].type == PROP_TYPE_FREE)
          {
              free = i;
              continue;
          }
          if (win->properties[i].atom == atom)
          {
              win->properties[i].type = type;
              win->properties[i].data = data;
              return;
          }
      }
  
      /* need to add an entry */
      if (!grab_global_atom( NULL, atom )) return;
      if (free == -1)
      {
          /* no free entry */
          if (win->prop_inuse >= win->prop_alloc)
          {
              /* need to grow the array */
              if (!(new_props = realloc( win->properties,
                                         sizeof(*new_props) * (win->prop_alloc + 16) )))
              {
                  set_error( STATUS_NO_MEMORY );
                  release_global_atom( NULL, atom );
                  return;
              }
              win->prop_alloc += 16;
              win->properties = new_props;
          }
          free = win->prop_inuse++;
      }
      win->properties[free].atom = atom;
      win->properties[free].type = type;
      win->properties[free].data = data;
  }
  
  /* remove a window property */
  static lparam_t remove_property( struct window *win, atom_t atom )
  {
      int i;
  
      for (i = 0; i < win->prop_inuse; i++)
      {
          if (win->properties[i].type == PROP_TYPE_FREE) continue;
          if (win->properties[i].atom == atom)
          {
              release_global_atom( NULL, atom );
              win->properties[i].type = PROP_TYPE_FREE;
              return win->properties[i].data;
          }
      }
      /* FIXME: last error? */
      return 0;
  }
  
  /* find a window property */
  static lparam_t get_property( struct window *win, atom_t atom )
  {
      int i;
  
      for (i = 0; i < win->prop_inuse; i++)
      {
          if (win->properties[i].type == PROP_TYPE_FREE) continue;
          if (win->properties[i].atom == atom) return win->properties[i].data;
      }
      /* FIXME: last error? */
      return 0;
  }
  
  /* destroy all properties of a window */
  static inline void destroy_properties( struct window *win )
  {
      int i;
  
      if (!win->properties) return;
      for (i = 0; i < win->prop_inuse; i++)
      {
          if (win->properties[i].type == PROP_TYPE_FREE) continue;
          release_global_atom( NULL, win->properties[i].atom );
      }
      free( win->properties );
  }
  
  /* detach a window from its owner thread but keep the window around */
  static void detach_window_thread( struct window *win )
  {
      struct thread *thread = win->thread;
  
      if (!thread) return;
      if (thread->queue)
      {
          if (win->update_region) inc_queue_paint_count( thread, -1 );
          if (win->paint_flags & PAINT_INTERNAL) inc_queue_paint_count( thread, -1 );
          queue_cleanup_window( thread, win->handle );
      }
      assert( thread->desktop_users > 0 );
      thread->desktop_users--;
      release_class( win->class );
      win->class = NULL;
  
      /* don't hold a reference to the desktop so that the desktop window can be */
      /* destroyed when the desktop ref count reaches zero */
      release_object( win->desktop );
      win->thread = NULL;
  }
  
  /* get the process owning the top window of a given desktop */
  struct process *get_top_window_owner( struct desktop *desktop )
  {
      struct window *win = desktop->top_window;
      if (!win || !win->thread) return NULL;
      return win->thread->process;
  }
  
  /* get the top window size of a given desktop */
  void get_top_window_rectangle( struct desktop *desktop, rectangle_t *rect )
  {
      struct window *win = desktop->top_window;
      *rect = win ? win->window_rect : empty_rect;
  }
  
  /* post a message to the desktop window */
  void post_desktop_message( struct desktop *desktop, unsigned int message,
                             lparam_t wparam, lparam_t lparam )
  {
      struct window *win = desktop->top_window;
      if (win && win->thread) post_message( win->handle, message, wparam, lparam );
  }
  
  /* create a new window structure (note: the window is not linked in the window tree) */
  static struct window *create_window( struct window *parent, struct window *owner,
                                       atom_t atom, mod_handle_t instance )
  {
      int extra_bytes;
      struct window *win = NULL;
      struct desktop *desktop;
      struct window_class *class;
  
      if (!(desktop = get_thread_desktop( current, DESKTOP_CREATEWINDOW ))) return NULL;
  
      if (!(class = grab_class( current->process, atom, instance, &extra_bytes )))
      {
          release_object( desktop );
          return NULL;
      }
  
      if (!parent)  /* null parent is only allowed for desktop or HWND_MESSAGE top window */
      {
          if (is_desktop_class( class ))
              parent = desktop->top_window;  /* use existing desktop if any */
          else if (is_hwnd_message_class( class ))
              /* use desktop window if message window is already created */
              parent = desktop->msg_window ? desktop->top_window : NULL;
          else if (!(parent = desktop->top_window))  /* must already have a desktop then */
          {
              set_error( STATUS_ACCESS_DENIED );
              goto failed;
          }
      }
  
      /* parent must be on the same desktop */
      if (parent && parent->desktop != desktop)
      {
          set_error( STATUS_ACCESS_DENIED );
          goto failed;
      }
  
      if (!(win = mem_alloc( sizeof(*win) + extra_bytes - 1 ))) goto failed;
      if (!(win->handle = alloc_user_handle( win, USER_WINDOW ))) goto failed;
  
      win->parent         = parent;
      win->owner          = owner ? owner->handle : 0;
      win->thread         = current;
      win->desktop        = desktop;
      win->class          = class;
      win->atom           = atom;
      win->last_active    = win->handle;
      win->win_region     = NULL;
      win->update_region  = NULL;
      win->style          = 0;
      win->ex_style       = 0;
      win->id             = 0;
      win->instance       = 0;
      win->is_unicode     = 1;
      win->is_linked      = 0;
      win->is_layered     = 0;
      win->dpi_awareness  = DPI_AWARENESS_PER_MONITOR_AWARE;
      win->dpi            = 0;
      win->user_data      = 0;
      win->text           = NULL;
      win->paint_flags    = 0;
      win->prop_inuse     = 0;
      win->prop_alloc     = 0;
      win->properties     = NULL;
      win->nb_extra_bytes = extra_bytes;
      win->window_rect = win->visible_rect = win->surface_rect = win->client_rect = empty_rect;
      memset( win->extra_bytes, 0, extra_bytes );
      list_init( &win->children );
      list_init( &win->unlinked );
  
      /* if parent belongs to a different thread and the window isn't */
      /* top-level, attach the two threads */
      if (parent && parent->thread && parent->thread != current && !is_desktop_window(parent))
      {
          if (!attach_thread_input( current, parent->thread )) goto failed;
      }
      else  /* otherwise just make sure that the thread has a message queue */
      {
          if (!current->queue && !init_thread_queue( current )) goto failed;
      }
  
      /* put it on parent unlinked list */
      if (parent) list_add_head( &parent->unlinked, &win->entry );
      else
      {
          list_init( &win->entry );
          if (is_desktop_class( class ))
          {
              assert( !desktop->top_window );
              desktop->top_window = win;
              set_process_default_desktop( current->process, desktop, current->desktop );
          }
          else
          {
              assert( !desktop->msg_window );
              desktop->msg_window = win;
          }
      }
  
      current->desktop_users++;
      return win;
  
  failed:
      if (win)
      {
          if (win->handle) free_user_handle( win->handle );
          free( win );
      }
      release_object( desktop );
      release_class( class );
      return NULL;
  }
  
  /* destroy all windows belonging to a given thread */
  void destroy_thread_windows( struct thread *thread )
  {
      user_handle_t handle = 0;
      struct window *win;
  
      while ((win = next_user_handle( &handle, USER_WINDOW )))
      {
          if (win->thread != thread) continue;
          if (is_desktop_window( win )) detach_window_thread( win );
          else destroy_window( win );
      }
  }
  
  /* get the desktop window */
  static struct window *get_desktop_window( struct thread *thread )
  {
      struct window *top_window;
      struct desktop *desktop = get_thread_desktop( thread, 0 );
  
      if (!desktop) return NULL;
      top_window = desktop->top_window;
      release_object( desktop );
      return top_window;
  }
  
  /* check whether child is a descendant of parent */
  int is_child_window( user_handle_t parent, user_handle_t child )
  {
      struct window *child_ptr = get_user_object( child, USER_WINDOW );
      struct window *parent_ptr = get_user_object( parent, USER_WINDOW );
  
      if (!child_ptr || !parent_ptr) return 0;
      while (child_ptr->parent)
      {
          if (child_ptr->parent == parent_ptr) return 1;
          child_ptr = child_ptr->parent;
      }
      return 0;
  }
  
  /* check if window can be set as foreground window */
  int is_valid_foreground_window( user_handle_t window )
  {
      struct window *win = get_user_object( window, USER_WINDOW );
      return win && (win->style & (WS_POPUP|WS_CHILD)) != WS_CHILD;
  }
  
  /* make a window active if possible */
  int make_window_active( user_handle_t window )
  {
      struct window *owner, *win = get_window( window );
  
      if (!win) return 0;
  
      /* set last active for window and its owners */
      owner = win;
      while (owner)
      {
          owner->last_active = win->handle;
          owner = get_user_object( owner->owner, USER_WINDOW );
      }
      return 1;
  }
  
  /* increment (or decrement) the window paint count */
  static inline void inc_window_paint_count( struct window *win, int incr )
  {
      if (win->thread) inc_queue_paint_count( win->thread, incr );
  }
  
  /* map a point between different DPI scaling levels */
  static void map_dpi_point( struct window *win, int *x, int *y, unsigned int from, unsigned int to )
  {
      if (!from) from = get_monitor_dpi( win );
      if (!to) to = get_monitor_dpi( win );
      if (from == to) return;
      *x = scale_dpi( *x, from, to );
      *y = scale_dpi( *y, from, to );
  }
  
  /* map a window rectangle between different DPI scaling levels */
  static void map_dpi_rect( struct window *win, rectangle_t *rect, unsigned int from, unsigned int to )
  {
      if (!from) from = get_monitor_dpi( win );
      if (!to) to = get_monitor_dpi( win );
      if (from == to) return;
      scale_dpi_rect( rect, from, to );
  }
  
  /* map a region between different DPI scaling levels */
  static void map_dpi_region( struct window *win, struct region *region, unsigned int from, unsigned int to )
  {
      if (!from) from = get_monitor_dpi( win );
      if (!to) to = get_monitor_dpi( win );
      if (from == to) return;
      scale_region( region, from, to );
  }
  
  /* convert coordinates from client to screen coords */
  static inline void client_to_screen( struct window *win, int *x, int *y )
  {
      for ( ; win && !is_desktop_window(win); win = win->parent)
      {
          *x += win->client_rect.left;
          *y += win->client_rect.top;
      }
  }
  
  /* convert coordinates from screen to client coords and dpi */
  static void screen_to_client( struct window *win, int *x, int *y, unsigned int dpi )
  {
      int offset_x = 0, offset_y = 0;
  
      if (is_desktop_window( win )) return;
  
      client_to_screen( win, &offset_x, &offset_y );
      map_dpi_point( win, x, y, dpi, win->dpi );
      *x -= offset_x;
      *y -= offset_y;
  }
  
  /* check if window and all its ancestors are visible */
  static int is_visible( const struct window *win )
  {
      while (win)
      {
          if (!(win->style & WS_VISIBLE)) return 0;
          win = win->parent;
          /* if parent is minimized children are not visible */
          if (win && (win->style & WS_MINIMIZE)) return 0;
      }
      return 1;
  }
  
  /* same as is_visible but takes a window handle */
  int is_window_visible( user_handle_t window )
  {
      struct window *win = get_user_object( window, USER_WINDOW );
      if (!win) return 0;
      return is_visible( win );
  }
  
  int is_window_transparent( user_handle_t window )
  {
      struct window *win = get_user_object( window, USER_WINDOW );
      if (!win) return 0;
      return (win->ex_style & (WS_EX_LAYERED|WS_EX_TRANSPARENT)) == (WS_EX_LAYERED|WS_EX_TRANSPARENT);
  }
  
  /* check if point is inside the window, and map to window dpi */
  static int is_point_in_window( struct window *win, int *x, int *y, unsigned int dpi )
  {
      if (!(win->style & WS_VISIBLE)) return 0; /* not visible */
      if ((win->style & (WS_POPUP|WS_CHILD|WS_DISABLED)) == (WS_CHILD|WS_DISABLED))
          return 0;  /* disabled child */
      if ((win->ex_style & (WS_EX_LAYERED|WS_EX_TRANSPARENT)) == (WS_EX_LAYERED|WS_EX_TRANSPARENT))
          return 0;  /* transparent */
      map_dpi_point( win, x, y, dpi, win->dpi );
      if (!point_in_rect( &win->visible_rect, *x, *y ))
          return 0;  /* not in window */
      if (win->win_region &&
          !point_in_region( win->win_region, *x - win->window_rect.left, *y - win->window_rect.top ))
          return 0;  /* not in window region */
      return 1;
  }
  
  /* fill an array with the handles of the children of a specified window */
  static unsigned int get_children_windows( struct window *parent, atom_t atom, thread_id_t tid,
                                            user_handle_t *handles, unsigned int max_count )
  {
      struct window *ptr;
      unsigned int count = 0;
  
      if (!parent) return 0;
  
      LIST_FOR_EACH_ENTRY( ptr, &parent->children, struct window, entry )
      {
          if (atom && get_class_atom(ptr->class) != atom) continue;
          if (tid && get_thread_id(ptr->thread) != tid) continue;
          if (handles)
          {
              if (count >= max_count) break;
              handles[count] = ptr->handle;
          }
          count++;
      }
      return count;
  }
  
  /* find child of 'parent' that contains the given point (in parent-relative coords) */
  static struct window *child_window_from_point( struct window *parent, int x, int y )
  {
      struct window *ptr;
  
      LIST_FOR_EACH_ENTRY( ptr, &parent->children, struct window, entry )
      {
          int x_child = x, y_child = y;
  
          if (!is_point_in_window( ptr, &x_child, &y_child, parent->dpi )) continue;  /* skip it */
  
          /* if window is minimized or disabled, return at once */
          if (ptr->style & (WS_MINIMIZE|WS_DISABLED)) return ptr;
  
          /* if point is not in client area, return at once */
          if (!point_in_rect( &ptr->client_rect, x_child, y_child )) return ptr;
  
          return child_window_from_point( ptr, x_child - ptr->client_rect.left,
                                          y_child - ptr->client_rect.top );
      }
      return parent;  /* not found any child */
  }
  
  /* find all children of 'parent' that contain the given point */
  static int get_window_children_from_point( struct window *parent, int x, int y,
                                             struct user_handle_array *array )
  {
      struct window *ptr;
  
      LIST_FOR_EACH_ENTRY( ptr, &parent->children, struct window, entry )
      {
          int x_child = x, y_child = y;
  
          if (!is_point_in_window( ptr, &x_child, &y_child, parent->dpi )) continue;  /* skip it */
  
          /* if point is in client area, and window is not minimized or disabled, check children */
          if (!(ptr->style & (WS_MINIMIZE|WS_DISABLED)) && point_in_rect( &ptr->client_rect, x_child, y_child ))
          {
              if (!get_window_children_from_point( ptr, x_child - ptr->client_rect.left,
                                                   y_child - ptr->client_rect.top, array ))
                  return 0;
          }
  
          /* now add window to the array */
          if (!add_handle_to_array( array, ptr->handle )) return 0;
      }
      return 1;
  }
  
  /* get handle of root of top-most window containing point */
  user_handle_t shallow_window_from_point( struct desktop *desktop, int x, int y )
  {
      struct window *ptr;
  
      if (!desktop->top_window) return 0;
  
      LIST_FOR_EACH_ENTRY( ptr, &desktop->top_window->children, struct window, entry )
      {
          int x_child = x, y_child = y;
  
          if (!is_point_in_window( ptr, &x_child, &y_child, 0 )) continue;  /* skip it */
          return ptr->handle;
      }
      return desktop->top_window->handle;
  }
  
  /* return thread of top-most window containing point (in absolute coords) */
  struct thread *window_thread_from_point( user_handle_t scope, int x, int y )
  {
      struct window *win = get_user_object( scope, USER_WINDOW );
  
      if (!win) return NULL;
  
      screen_to_client( win, &x, &y, 0 );
      win = child_window_from_point( win, x, y );
      if (!win->thread) return NULL;
      return (struct thread *)grab_object( win->thread );
  }
  
  /* return list of all windows containing point (in absolute coords) */
  static int all_windows_from_point( struct window *top, int x, int y, unsigned int dpi,
                                     struct user_handle_array *array )
  {
      if (!is_desktop_window( top ) && !is_desktop_window( top->parent ))
      {
          screen_to_client( top->parent, &x, &y, dpi );
          dpi = top->parent->dpi;
      }
  
      if (!is_point_in_window( top, &x, &y, dpi )) return 1;
      /* if point is in client area, and window is not minimized or disabled, check children */
      if (!(top->style & (WS_MINIMIZE|WS_DISABLED)) && point_in_rect( &top->client_rect, x, y ))
      {
          if (!is_desktop_window(top))
          {
              x -= top->client_rect.left;
              y -= top->client_rect.top;
          }
          if (!get_window_children_from_point( top, x, y, array )) return 0;
      }
      /* now add window to the array */
      if (!add_handle_to_array( array, top->handle )) return 0;
      return 1;
  }
  
  
  /* return the thread owning a window */
  struct thread *get_window_thread( user_handle_t handle )
  {
      struct window *win = get_user_object( handle, USER_WINDOW );
      if (!win || !win->thread) return NULL;
      return (struct thread *)grab_object( win->thread );
  }
  
  
  /* check if any area of a window needs repainting */
  static inline int win_needs_repaint( struct window *win )
  {
      return win->update_region || (win->paint_flags & PAINT_INTERNAL);
  }
  
  
  /* find a child of the specified window that needs repainting */
  static struct window *find_child_to_repaint( struct window *parent, struct thread *thread )
  {
      struct window *ptr, *ret = NULL;
  
      LIST_FOR_EACH_ENTRY( ptr, &parent->children, struct window, entry )
      {
          if (!(ptr->style & WS_VISIBLE)) continue;
          if (ptr->thread == thread && win_needs_repaint( ptr ))
              ret = ptr;
          else if (!(ptr->style & WS_MINIMIZE)) /* explore its children */
              ret = find_child_to_repaint( ptr, thread );
          if (ret) break;
      }
  
      if (ret && (ret->ex_style & WS_EX_TRANSPARENT))
      {
          /* transparent window, check for non-transparent sibling to paint first */
          for (ptr = get_next_window(ret); ptr; ptr = get_next_window(ptr))
          {
              if (!(ptr->style & WS_VISIBLE)) continue;
              if (ptr->ex_style & WS_EX_TRANSPARENT) continue;
              if (ptr->thread != thread) continue;
              if (win_needs_repaint( ptr )) return ptr;
          }
      }
      return ret;
  }
  
  
  /* find a window that needs to receive a WM_PAINT; also clear its internal paint flag */
  user_handle_t find_window_to_repaint( user_handle_t parent, struct thread *thread )
  {
      struct window *ptr, *win, *top_window = get_desktop_window( thread );
  
      if (!top_window) return 0;
  
      if (top_window->thread == thread && win_needs_repaint( top_window )) win = top_window;
      else win = find_child_to_repaint( top_window, thread );
  
      if (win && parent)
      {
          /* check that it is a child of the specified parent */
          for (ptr = win; ptr; ptr = ptr->parent)
              if (ptr->handle == parent) break;
          /* otherwise don't return any window, we don't repaint a child before its parent */
          if (!ptr) win = NULL;
      }
      if (!win) return 0;
      win->paint_flags &= ~PAINT_INTERNAL;
      return win->handle;
  }
  
  
  /* intersect the window region with the specified region, relative to the window parent */
  static struct region *intersect_window_region( struct region *region, struct window *win )
  {
      /* make region relative to window rect */
      offset_region( region, -win->window_rect.left, -win->window_rect.top );
      if (!intersect_region( region, region, win->win_region )) return NULL;
      /* make region relative to parent again */
      offset_region( region, win->window_rect.left, win->window_rect.top );
      return region;
  }
  
  
  /* convert coordinates from client to screen coords */
  static inline void client_to_screen_rect( struct window *win, rectangle_t *rect )
  {
      for ( ; win && !is_desktop_window(win); win = win->parent)
          offset_rect( rect, win->client_rect.left, win->client_rect.top );
  }
  
  /* map the region from window to screen coordinates */
  static inline void map_win_region_to_screen( struct window *win, struct region *region )
  {
      if (!is_desktop_window(win))
      {
          int x = win->window_rect.left;
          int y = win->window_rect.top;
          client_to_screen( win->parent, &x, &y );
          offset_region( region, x, y );
      }
  }
  
  
  /* clip all children of a given window out of the visible region */
  static struct region *clip_children( struct window *parent, struct window *last,
                                       struct region *region, int offset_x, int offset_y )
  {
      struct window *ptr;
      struct region *tmp = create_empty_region();
  
      if (!tmp) return NULL;
      LIST_FOR_EACH_ENTRY( ptr, &parent->children, struct window, entry )
      {
          if (ptr == last) break;
          if (!(ptr->style & WS_VISIBLE)) continue;
          if (ptr->ex_style & WS_EX_TRANSPARENT) continue;
          set_region_rect( tmp, &ptr->visible_rect );
          if (ptr->win_region && !intersect_window_region( tmp, ptr ))
          {
              free_region( tmp );
              return NULL;
          }
          offset_region( tmp, offset_x, offset_y );
          if (!(region = subtract_region( region, region, tmp ))) break;
          if (is_region_empty( region )) break;
      }
      free_region( tmp );
      return region;
  }
  
  
  /* set the region to the client rect clipped by the window rect, in parent-relative coordinates */
  static void set_region_client_rect( struct region *region, struct window *win )
  {
      rectangle_t rect;
  
      intersect_rect( &rect, &win->window_rect, &win->client_rect );
      intersect_rect( &rect, &rect, &win->surface_rect );
      set_region_rect( region, &rect );
  }
  
  
  /* set the region to the visible rect clipped by the window surface, in parent-relative coordinates */
  static void set_region_visible_rect( struct region *region, struct window *win )
  {
      rectangle_t rect;
  
      intersect_rect( &rect, &win->visible_rect, &win->surface_rect );
      set_region_rect( region, &rect );
  }
  
  
  /* get the top-level window to clip against for a given window */
  static inline struct window *get_top_clipping_window( struct window *win )
  {
      while ((!(win->paint_flags & PAINT_HAS_SURFACE) || !win->thread || win->thread->process != current->process)
             && win->parent && !is_desktop_window(win->parent))
          win = win->parent;
      return win;
  }
  
  
  /* compute the visible region of a window, in window coordinates */
  static struct region *get_visible_region( struct window *win, unsigned int flags )
  {
      struct region *tmp = NULL, *region;
      int offset_x, offset_y;
  
      if (!(region = create_empty_region())) return NULL;
  
      /* first check if all ancestors are visible */
  
      if (!is_visible( win )) return region;  /* empty region */
  
      if (is_desktop_window( win ))
      {
          set_region_rect( region, &win->window_rect );
          return region;
      }
  
      /* create a region relative to the window itself */
  
      if ((flags & DCX_PARENTCLIP) && !is_desktop_window( win->parent ))
      {
          set_region_client_rect( region, win->parent );
          offset_region( region, -win->parent->client_rect.left, -win->parent->client_rect.top );
      }
      else if (flags & DCX_WINDOW)
      {
          set_region_visible_rect( region, win );
          if (win->win_region && !intersect_window_region( region, win )) goto error;
      }
      else
      {
          set_region_client_rect( region, win );
          if (win->win_region && !intersect_window_region( region, win )) goto error;
      }
  
      /* clip children */
  
      if (flags & DCX_CLIPCHILDREN)
      {
          if (!clip_children( win, NULL, region, win->client_rect.left, win->client_rect.top )) goto error;
      }
  
      /* clip siblings of ancestors */
  
      offset_x = win->window_rect.left;
      offset_y = win->window_rect.top;
  
      if ((tmp = create_empty_region()) != NULL)
      {
          while (!is_desktop_window( win->parent ))
          {
              /* we don't clip out top-level siblings as that's up to the native windowing system */
              if (win->style & WS_CLIPSIBLINGS)
              {
                  if (!clip_children( win->parent, win, region, 0, 0 )) goto error;
                  if (is_region_empty( region )) break;
              }
              /* clip to parent client area */
              win = win->parent;
              offset_x += win->client_rect.left;
              offset_y += win->client_rect.top;
              offset_region( region, win->client_rect.left, win->client_rect.top );
              set_region_client_rect( tmp, win );
              if (win->win_region && !intersect_window_region( tmp, win )) goto error;
              if (!intersect_region( region, region, tmp )) goto error;
              if (is_region_empty( region )) break;
          }
          free_region( tmp );
      }
      offset_region( region, -offset_x, -offset_y );  /* make it relative to target window */
      return region;
  
  error:
      if (tmp) free_region( tmp );
      free_region( region );
      return NULL;
  }
  
  
  /* clip all children with a custom pixel format out of the visible region */
  static struct region *clip_pixel_format_children( struct window *parent, struct region *parent_clip,
                                                    struct region *region, int offset_x, int offset_y )
  {
      struct window *ptr;
      struct region *clip = create_empty_region();
  
      if (!clip) return NULL;
  
      LIST_FOR_EACH_ENTRY_REV( ptr, &parent->children, struct window, entry )
      {
          if (!(ptr->style & WS_VISIBLE)) continue;
          if (ptr->ex_style & WS_EX_TRANSPARENT) continue;
  
          /* add the visible rect */
          set_region_rect( clip, &ptr->visible_rect );
          if (ptr->win_region && !intersect_window_region( clip, ptr )) break;
          offset_region( clip, offset_x, offset_y );
          if (!intersect_region( clip, clip, parent_clip )) break;
          if (!union_region( region, region, clip )) break;
          if (!(ptr->paint_flags & (PAINT_HAS_PIXEL_FORMAT | PAINT_PIXEL_FORMAT_CHILD))) continue;
  
          /* subtract the client rect if it uses a custom pixel format */
          set_region_rect( clip, &ptr->client_rect );
          if (ptr->win_region && !intersect_window_region( clip, ptr )) break;
          offset_region( clip, offset_x, offset_y );
          if (!intersect_region( clip, clip, parent_clip )) break;
          if ((ptr->paint_flags & PAINT_HAS_PIXEL_FORMAT) && !subtract_region( region, region, clip ))
              break;
  
          if (!clip_pixel_format_children( ptr, clip, region, offset_x + ptr->client_rect.left,
                                           offset_y + ptr->client_rect.top ))
              break;
      }
      free_region( clip );
      return region;
  }
  
  
  /* compute the visible surface region of a window, in parent coordinates */
  static struct region *get_surface_region( struct window *win )
  {
      struct region *region, *clip;
      int offset_x, offset_y;
  
      /* create a region relative to the window itself */
  
      if (!(region = create_empty_region())) return NULL;
      if (!(clip = create_empty_region())) goto error;
      set_region_rect( region, &win->visible_rect );
      if (win->win_region && !intersect_window_region( region, win )) goto error;
      set_region_rect( clip, &win->client_rect );
      if (win->win_region && !intersect_window_region( clip, win )) goto error;
  
      if ((win->paint_flags & PAINT_HAS_PIXEL_FORMAT) && !subtract_region( region, region, clip ))
          goto error;
  
      /* clip children */
  
      if (!is_desktop_window(win))
      {
          offset_x = win->client_rect.left;
          offset_y = win->client_rect.top;
      }
      else offset_x = offset_y = 0;
  
      if (!clip_pixel_format_children( win, clip, region, offset_x, offset_y )) goto error;
  
      free_region( clip );
      return region;
  
  error:
      if (clip) free_region( clip );
      free_region( region );
      return NULL;
  }
  
  
  /* get the window class of a window */
  struct window_class* get_window_class( user_handle_t window )
  {
      struct window *win;
      if (!(win = get_window( window ))) return NULL;
      if (!win->class) set_error( STATUS_ACCESS_DENIED );
      return win->class;
  }
  
  /* determine the window visible rectangle, i.e. window or client rect cropped by parent rects */
  /* the returned rectangle is in window coordinates; return 0 if rectangle is empty */
  static int get_window_visible_rect( struct window *win, rectangle_t *rect, int frame )
  {
      int offset_x = win->window_rect.left, offset_y = win->window_rect.top;
  
      *rect = frame ? win->window_rect : win->client_rect;
  
      if (!(win->style & WS_VISIBLE)) return 0;
      if (is_desktop_window( win )) return 1;
  
      while (!is_desktop_window( win->parent ))
      {
          win = win->parent;
          if (!(win->style & WS_VISIBLE) || win->style & WS_MINIMIZE) return 0;
          offset_x += win->client_rect.left;
          offset_y += win->client_rect.top;
          offset_rect( rect, win->client_rect.left, win->client_rect.top );
          if (!intersect_rect( rect, rect, &win->client_rect )) return 0;
          if (!intersect_rect( rect, rect, &win->window_rect )) return 0;
      }
      offset_rect( rect, -offset_x, -offset_y );
      return 1;
  }
  
  /* return a copy of the specified region cropped to the window client or frame rectangle, */
  /* and converted from client to window coordinates. Helper for (in)validate_window. */
  static struct region *crop_region_to_win_rect( struct window *win, struct region *region, int frame )
  {
      rectangle_t rect;
      struct region *tmp;
  
      if (!get_window_visible_rect( win, &rect, frame )) return NULL;
      if (!(tmp = create_empty_region())) return NULL;
      set_region_rect( tmp, &rect );
  
      if (region)
      {
          /* map it to client coords */
          offset_region( tmp, win->window_rect.left - win->client_rect.left,
                         win->window_rect.top - win->client_rect.top );
  
          /* intersect specified region with bounding rect */
          if (!intersect_region( tmp, region, tmp )) goto done;
          if (is_region_empty( tmp )) goto done;
  
          /* map it back to window coords */
          offset_region( tmp, win->client_rect.left - win->window_rect.left,
                         win->client_rect.top - win->window_rect.top );
      }
      return tmp;
  
  done:
      free_region( tmp );
      return NULL;
  }
  
  
  /* set a region as new update region for the window */
  static void set_update_region( struct window *win, struct region *region )
  {
      if (region && !is_region_empty( region ))
      {
          if (!win->update_region) inc_window_paint_count( win, 1 );
          else free_region( win->update_region );
          win->update_region = region;
      }
      else
      {
          if (win->update_region)
          {
              inc_window_paint_count( win, -1 );
              free_region( win->update_region );
          }
          win->paint_flags &= ~(PAINT_ERASE | PAINT_DELAYED_ERASE | PAINT_NONCLIENT);
          win->update_region = NULL;
          if (region) free_region( region );
      }
  }
  
  
  /* add a region to the update region; the passed region is freed or reused */
  static int add_update_region( struct window *win, struct region *region )
  {
      if (win->update_region && !union_region( region, win->update_region, region ))
      {
          free_region( region );
          return 0;
      }
      set_update_region( win, region );
      return 1;
  }
  
  
  /* crop the update region of children to the specified rectangle, in client coords */
  static void crop_children_update_region( struct window *win, rectangle_t *rect )
  {
      struct window *child;
      struct region *tmp;
      rectangle_t child_rect;
  
      LIST_FOR_EACH_ENTRY( child, &win->children, struct window, entry )
      {
          if (!(child->style & WS_VISIBLE)) continue;
          if (!rect)  /* crop everything out */
          {
              crop_children_update_region( child, NULL );
              set_update_region( child, NULL );
              continue;
          }
  
          /* nothing to do if child is completely inside rect */
          if (child->window_rect.left >= rect->left &&
              child->window_rect.top >= rect->top &&
              child->window_rect.right <= rect->right &&
              child->window_rect.bottom <= rect->bottom) continue;
  
          /* map to child client coords and crop grand-children */
          child_rect = *rect;
          offset_rect( &child_rect, -child->client_rect.left, -child->client_rect.top );
          crop_children_update_region( child, &child_rect );
  
          /* now crop the child itself */
          if (!child->update_region) continue;
          if (!(tmp = create_empty_region())) continue;
          set_region_rect( tmp, rect );
          offset_region( tmp, -child->window_rect.left, -child->window_rect.top );
          if (intersect_region( tmp, child->update_region, tmp )) set_update_region( child, tmp );
          else free_region( tmp );
      }
  }
  
  
  /* validate the non client area of a window */
  static void validate_non_client( struct window *win )
  {
      struct region *tmp;
      rectangle_t rect;
  
      if (!win->update_region) return;  /* nothing to do */
  
      /* get client rect in window coords */
      rect.left   = win->client_rect.left - win->window_rect.left;
      rect.top    = win->client_rect.top - win->window_rect.top;
      rect.right  = win->client_rect.right - win->window_rect.left;
      rect.bottom = win->client_rect.bottom - win->window_rect.top;
  
      if ((tmp = create_empty_region()))
      {
          set_region_rect( tmp, &rect );
          if (intersect_region( tmp, win->update_region, tmp ))
              set_update_region( win, tmp );
          else
              free_region( tmp );
      }
      win->paint_flags &= ~PAINT_NONCLIENT;
  }
  
  
  /* validate a window completely so that we don't get any further paint messages for it */
  static void validate_whole_window( struct window *win )
  {
      set_update_region( win, NULL );
  
      if (win->paint_flags & PAINT_INTERNAL)
      {
          win->paint_flags &= ~PAINT_INTERNAL;
          inc_window_paint_count( win, -1 );
      }
  }
  
  
  /* validate a window's children so that we don't get any further paint messages for it */
  static void validate_children( struct window *win )
  {
      struct window *child;
  
      LIST_FOR_EACH_ENTRY( child, &win->children, struct window, entry )
      {
          if (!(child->style & WS_VISIBLE)) continue;
          validate_children(child);
          validate_whole_window(child);
      }
  }
  
  
  /* validate the update region of a window on all parents; helper for get_update_region */
  static void validate_parents( struct window *child )
  {
      int offset_x = 0, offset_y = 0;
      struct window *win = child;
      struct region *tmp = NULL;
  
      if (!child->update_region) return;
  
      while (win->parent)
      {
          /* map to parent client coords */
          offset_x += win->window_rect.left;
          offset_y += win->window_rect.top;
  
          win = win->parent;
  
          /* and now map to window coords */
          offset_x += win->client_rect.left - win->window_rect.left;
          offset_y += win->client_rect.top - win->window_rect.top;
  
          if (win->update_region && !(win->style & WS_CLIPCHILDREN))
          {
              if (!tmp && !(tmp = create_empty_region())) return;
              offset_region( child->update_region, offset_x, offset_y );
              if (subtract_region( tmp, win->update_region, child->update_region ))
              {
                  set_update_region( win, tmp );
                  tmp = NULL;
              }
              /* restore child coords */
              offset_region( child->update_region, -offset_x, -offset_y );
          }
      }
      if (tmp) free_region( tmp );
  }
  
  
  /* add/subtract a region (in client coordinates) to the update region of the window */
  static void redraw_window( struct window *win, struct region *region, int frame, unsigned int flags )
  {
      struct region *child_rgn, *tmp;
      struct window *child;
  
      if (flags & RDW_INVALIDATE)
      {
          if (!(tmp = crop_region_to_win_rect( win, region, frame ))) return;
  
          if (!add_update_region( win, tmp )) return;
  
          if (flags & RDW_FRAME) win->paint_flags |= PAINT_NONCLIENT;
          if (flags & RDW_ERASE) win->paint_flags |= PAINT_ERASE;
      }
      else if (flags & RDW_VALIDATE)
      {
          if (!region && (flags & RDW_NOFRAME))  /* shortcut: validate everything */
          {
              set_update_region( win, NULL );
          }
          else if (win->update_region)
          {
              if ((tmp = crop_region_to_win_rect( win, region, frame )))
              {
                  if (!subtract_region( tmp, win->update_region, tmp ))
                  {
                      free_region( tmp );
                      return;
                  }
                  set_update_region( win, tmp );
              }
              if (flags & RDW_NOFRAME) validate_non_client( win );
              if (flags & RDW_NOERASE) win->paint_flags &= ~(PAINT_ERASE | PAINT_DELAYED_ERASE);
          }
      }
  
      if ((flags & RDW_INTERNALPAINT) && !(win->paint_flags & PAINT_INTERNAL))
      {
          win->paint_flags |= PAINT_INTERNAL;
          inc_window_paint_count( win, 1 );
      }
      else if ((flags & RDW_NOINTERNALPAINT) && (win->paint_flags & PAINT_INTERNAL))
      {
          win->paint_flags &= ~PAINT_INTERNAL;
          inc_window_paint_count( win, -1 );
      }
  
      /* now process children recursively */
  
      if (flags & RDW_NOCHILDREN) return;
      if (win->style & WS_MINIMIZE) return;
      if ((win->style & WS_CLIPCHILDREN) && !(flags & RDW_ALLCHILDREN)) return;
  
      if (!(tmp = crop_region_to_win_rect( win, region, 0 ))) return;
  
      /* map to client coordinates */
      offset_region( tmp, win->window_rect.left - win->client_rect.left,
                     win->window_rect.top - win->client_rect.top );
  
      if (flags & RDW_INVALIDATE) flags |= RDW_FRAME | RDW_ERASE;
  
      LIST_FOR_EACH_ENTRY( child, &win->children, struct window, entry )
      {
          if (!(child->style & WS_VISIBLE)) continue;
          if (!(child_rgn = create_empty_region())) continue;
          if (copy_region( child_rgn, tmp ))
          {
              map_dpi_region( child, child_rgn, win->dpi, child->dpi );
              if (rect_in_region( child_rgn, &child->window_rect ))
              {
                  offset_region( child_rgn, -child->client_rect.left, -child->client_rect.top );
                  redraw_window( child, child_rgn, 1, flags );
              }
          }
          free_region( child_rgn );
      }
  
      free_region( tmp );
  }
  
  
  /* retrieve the update flags for a window depending on the state of the update region */
  static unsigned int get_update_flags( struct window *win, unsigned int flags )
  {
      unsigned int ret = 0;
  
      if (flags & UPDATE_NONCLIENT)
      {
          if ((win->paint_flags & PAINT_NONCLIENT) && win->update_region) ret |= UPDATE_NONCLIENT;
      }
      if (flags & UPDATE_ERASE)
      {
          if ((win->paint_flags & PAINT_ERASE) && win->update_region) ret |= UPDATE_ERASE;
      }
      if (flags & UPDATE_PAINT)
      {
          if (win->update_region)
          {
              if (win->paint_flags & PAINT_DELAYED_ERASE) ret |= UPDATE_DELAYED_ERASE;
              ret |= UPDATE_PAINT;
          }
      }
      if (flags & UPDATE_INTERNALPAINT)
      {
          if (win->paint_flags & PAINT_INTERNAL)
          {
              ret |= UPDATE_INTERNALPAINT;
              if (win->paint_flags & PAINT_DELAYED_ERASE) ret |= UPDATE_DELAYED_ERASE;
          }
      }
      return ret;
  }
  
  
  /* iterate through the children of the given window until we find one with some update flags */
  static unsigned int get_child_update_flags( struct window *win, struct window *from_child,
                                              unsigned int flags, struct window **child )
  {
      struct window *ptr;
      unsigned int ret = 0;
  
      /* first make sure we want to iterate children at all */
  
      if (win->style & WS_MINIMIZE) return 0;
  
      /* note: the WS_CLIPCHILDREN test is the opposite of the invalidation case,
       * here we only want to repaint children of windows that clip them, others
       * need to wait for WM_PAINT to be done in the parent first.
       */
      if (!(flags & UPDATE_ALLCHILDREN) && !(win->style & WS_CLIPCHILDREN)) return 0;
  
      LIST_FOR_EACH_ENTRY( ptr, &win->children, struct window, entry )
      {
          if (from_child)  /* skip all children until from_child is found */
          {
              if (ptr == from_child) from_child = NULL;
              continue;
          }
          if (!(ptr->style & WS_VISIBLE)) continue;
          if ((ret = get_update_flags( ptr, flags )) != 0)
          {
              *child = ptr;
              break;
          }
          if ((ret = get_child_update_flags( ptr, NULL, flags, child ))) break;
      }
      return ret;
  }
  
  /* iterate through children and siblings of the given window until we find one with some update flags */
  static unsigned int get_window_update_flags( struct window *win, struct window *from_child,
                                               unsigned int flags, struct window **child )
  {
      unsigned int ret;
      struct window *ptr, *from_sibling = NULL;
  
      /* if some parent is not visible start from the next sibling */
  
      if (!is_visible( win )) return 0;
      for (ptr = from_child; ptr; ptr = ptr->parent)
      {
          if (!(ptr->style & WS_VISIBLE) || (ptr->style & WS_MINIMIZE)) from_sibling = ptr;
          if (ptr == win) break;
      }
  
      /* non-client painting must be delayed if one of the parents is going to
       * be repainted and doesn't clip children */
  
      if ((flags & UPDATE_NONCLIENT) && !(flags & (UPDATE_PAINT|UPDATE_INTERNALPAINT)))
      {
          for (ptr = win->parent; ptr; ptr = ptr->parent)
          {
              if (!(ptr->style & WS_CLIPCHILDREN) && win_needs_repaint( ptr ))
                  return 0;
          }
          if (from_child && !(flags & UPDATE_ALLCHILDREN))
          {
              for (ptr = from_sibling ? from_sibling : from_child; ptr; ptr = ptr->parent)
              {
                  if (!(ptr->style & WS_CLIPCHILDREN) && win_needs_repaint( ptr )) from_sibling = ptr;
                  if (ptr == win) break;
              }
          }
      }
  
  
      /* check window itself (only if not restarting from a child) */
  
      if (!from_child)
      {
          if ((ret = get_update_flags( win, flags )))
          {
              *child = win;
              return ret;
          }
          from_child = win;
      }
  
      /* now check children */
  
      if (flags & UPDATE_NOCHILDREN) return 0;
      if (!from_sibling)
      {
          if ((ret = get_child_update_flags( from_child, NULL, flags, child ))) return ret;
          from_sibling = from_child;
      }
  
      /* then check siblings and parent siblings */
  
      while (from_sibling->parent && from_sibling != win)
      {
          if ((ret = get_child_update_flags( from_sibling->parent, from_sibling, flags, child )))
              return ret;
          from_sibling = from_sibling->parent;
      }
      return 0;
  }
  
  
  /* expose the areas revealed by a vis region change on the window parent */
  /* returns the region exposed on the window itself (in client coordinates) */
  static struct region *expose_window( struct window *win, const rectangle_t *old_window_rect,
                                       struct region *old_vis_rgn )
  {
      struct region *new_vis_rgn, *exposed_rgn;
  
      if (!(new_vis_rgn = get_visible_region( win, DCX_WINDOW ))) return NULL;
  
      if ((exposed_rgn = create_empty_region()))
      {
          if (subtract_region( exposed_rgn, new_vis_rgn, old_vis_rgn ) && !is_region_empty( exposed_rgn ))
          {
              /* make it relative to the new client area */
              offset_region( exposed_rgn, win->window_rect.left - win->client_rect.left,
                             win->window_rect.top - win->client_rect.top );
          }
          else
          {
              free_region( exposed_rgn );
              exposed_rgn = NULL;
          }
      }
  
      if (win->parent && !is_desktop_window( win->parent ))
      {
          /* make it relative to the old window pos for subtracting */
          offset_region( new_vis_rgn, win->window_rect.left - old_window_rect->left,
                         win->window_rect.top - old_window_rect->top  );
  
          if ((win->parent->style & WS_CLIPCHILDREN) ?
              subtract_region( new_vis_rgn, old_vis_rgn, new_vis_rgn ) :
              xor_region( new_vis_rgn, old_vis_rgn, new_vis_rgn ))
          {
              if (!is_region_empty( new_vis_rgn ))
              {
                  /* make it relative to parent */
                  offset_region( new_vis_rgn, old_window_rect->left, old_window_rect->top );
                  redraw_window( win->parent, new_vis_rgn, 0, RDW_INVALIDATE | RDW_ERASE | RDW_ALLCHILDREN );
              }
          }
      }
      free_region( new_vis_rgn );
      return exposed_rgn;
  }
  
  
  /* set the window and client rectangles, updating the update region if necessary */
  static void set_window_pos( struct window *win, struct window *previous,
                              unsigned int swp_flags, const rectangle_t *window_rect,
                              const rectangle_t *client_rect, const rectangle_t *visible_rect,
                              const rectangle_t *surface_rect, const rectangle_t *valid_rect )
  {
      struct region *old_vis_rgn = NULL, *exposed_rgn = NULL;
      const rectangle_t old_window_rect = win->window_rect;
      const rectangle_t old_visible_rect = win->visible_rect;
      const rectangle_t old_client_rect = win->client_rect;
      rectangle_t rect;
      int client_changed, frame_changed;
      int visible = (win->style & WS_VISIBLE) || (swp_flags & SWP_SHOWWINDOW);
  
      if (win->parent && !is_visible( win->parent )) visible = 0;
  
      if (visible && !(old_vis_rgn = get_visible_region( win, DCX_WINDOW ))) return;
  
      /* set the new window info before invalidating anything */
  
      win->window_rect  = *window_rect;
      win->visible_rect = *visible_rect;
      win->surface_rect = *surface_rect;
      win->client_rect  = *client_rect;
      if (!(swp_flags & SWP_NOZORDER) && win->parent) link_window( win, previous );
      if (swp_flags & SWP_SHOWWINDOW) win->style |= WS_VISIBLE;
      else if (swp_flags & SWP_HIDEWINDOW) win->style &= ~WS_VISIBLE;
  
      /* keep children at the same position relative to top right corner when the parent is mirrored */
      if (win->ex_style & WS_EX_LAYOUTRTL)
      {
          struct window *child;
          int old_size = old_client_rect.right - old_client_rect.left;
          int new_size = win->client_rect.right - win->client_rect.left;
  
          if (old_size != new_size) LIST_FOR_EACH_ENTRY( child, &win->children, struct window, entry )
          {
              offset_rect( &child->window_rect, new_size - old_size, 0 );
              offset_rect( &child->visible_rect, new_size - old_size, 0 );
              offset_rect( &child->surface_rect, new_size - old_size, 0 );
              offset_rect( &child->client_rect, new_size - old_size, 0 );
          }
      }
  
      /* reset cursor clip rectangle when the desktop changes size */
      if (win == win->desktop->top_window) win->desktop->cursor.clip = *window_rect;
  
      /* if the window is not visible, everything is easy */
      if (!visible) return;
  
      /* expose anything revealed by the change */
  
      if (!(swp_flags & SWP_NOREDRAW))
          exposed_rgn = expose_window( win, &old_window_rect, old_vis_rgn );
  
      if (!(win->style & WS_VISIBLE))
      {
          /* clear the update region since the window is no longer visible */
          validate_whole_window( win );
          validate_children( win );
          goto done;
      }
  
      /* crop update region to the new window rect */
  
      if (win->update_region)
      {
          if (get_window_visible_rect( win, &rect, 1 ))
          {
              struct region *tmp = create_empty_region();
              if (tmp)
              {
                  set_region_rect( tmp, &rect );
                  if (intersect_region( tmp, win->update_region, tmp ))
                      set_update_region( win, tmp );
                  else
                      free_region( tmp );
              }
          }
          else set_update_region( win, NULL ); /* visible rect is empty */
      }
  
      /* crop children regions to the new window rect */
  
      if (get_window_visible_rect( win, &rect, 0 ))
      {
          /* map to client coords */
          offset_rect( &rect, win->window_rect.left - win->client_rect.left,
                       win->window_rect.top - win->client_rect.top );
          crop_children_update_region( win, &rect );
      }
      else crop_children_update_region( win, NULL );
  
      if (swp_flags & SWP_NOREDRAW) goto done;  /* do not repaint anything */
  
      /* expose the whole non-client area if it changed in any way */
  
      if (swp_flags & SWP_NOCOPYBITS)
      {
          frame_changed = ((swp_flags & SWP_FRAMECHANGED) ||
                           memcmp( window_rect, &old_window_rect, sizeof(old_window_rect) ) ||
                           memcmp( visible_rect, &old_visible_rect, sizeof(old_visible_rect) ));
          client_changed = memcmp( client_rect, &old_client_rect, sizeof(old_client_rect) );
      }
      else
      {
          /* assume the bits have been moved to follow the window rect */
          int x_offset = window_rect->left - old_window_rect.left;
          int y_offset = window_rect->top - old_window_rect.top;
          frame_changed = ((swp_flags & SWP_FRAMECHANGED) ||
                           window_rect->right  - old_window_rect.right != x_offset ||
                           window_rect->bottom - old_window_rect.bottom != y_offset ||
                           visible_rect->left   - old_visible_rect.left   != x_offset ||
                           visible_rect->right  - old_visible_rect.right  != x_offset ||
                           visible_rect->top    - old_visible_rect.top    != y_offset ||
                           visible_rect->bottom - old_visible_rect.bottom != y_offset);
          client_changed = (client_rect->left   - old_client_rect.left   != x_offset ||
                            client_rect->right  - old_client_rect.right  != x_offset ||
                            client_rect->top    - old_client_rect.top    != y_offset ||
                            client_rect->bottom - old_client_rect.bottom != y_offset ||
                            memcmp( valid_rect, client_rect, sizeof(*client_rect) ));
      }
  
      if (frame_changed || client_changed)
      {
          struct region *win_rgn = old_vis_rgn;  /* reuse previous region */
  
          set_region_rect( win_rgn, window_rect );
          if (!is_rect_empty( valid_rect ))
          {
              /* subtract the valid portion of client rect from the total region */
              struct region *tmp = create_empty_region();
              if (tmp)
              {
                  set_region_rect( tmp, valid_rect );
                  /* subtract update region since invalid parts of the valid rect won't be copied */
                  if (win->update_region)
                  {
                      offset_region( tmp, -window_rect->left, -window_rect->top );
                      subtract_region( tmp, tmp, win->update_region );
                      offset_region( tmp, window_rect->left, window_rect->top );
                  }
                  if (subtract_region( tmp, win_rgn, tmp )) win_rgn = tmp;
                  else free_region( tmp );
              }
          }
          if (!is_desktop_window(win))
              offset_region( win_rgn, -client_rect->left, -client_rect->top );
          if (exposed_rgn)
          {
              union_region( exposed_rgn, exposed_rgn, win_rgn );
              if (win_rgn != old_vis_rgn) free_region( win_rgn );
          }
          else
          {
              exposed_rgn = win_rgn;
              if (win_rgn == old_vis_rgn) old_vis_rgn = NULL;
          }
      }
  
      if (exposed_rgn)
          redraw_window( win, exposed_rgn, 1, RDW_INVALIDATE | RDW_ERASE | RDW_FRAME | RDW_ALLCHILDREN );
  
  done:
      if (old_vis_rgn) free_region( old_vis_rgn );
      if (exposed_rgn) free_region( exposed_rgn );
      clear_error();  /* we ignore out of memory errors once the new rects have been set */
  }
  
  
  /* set the window region, updating the update region if necessary */
  static void set_window_region( struct window *win, struct region *region, int redraw )
  {
      struct region *old_vis_rgn = NULL, *exposed_rgn;
  
      /* no need to redraw if window is not visible */
      if (redraw && !is_visible( win )) redraw = 0;
  
      if (redraw) old_vis_rgn = get_visible_region( win, DCX_WINDOW );
  
      if (win->win_region) free_region( win->win_region );
      win->win_region = region;
  
      /* expose anything revealed by the change */
      if (old_vis_rgn && ((exposed_rgn = expose_window( win, &win->window_rect, old_vis_rgn ))))
      {
          redraw_window( win, exposed_rgn, 1, RDW_INVALIDATE | RDW_ERASE | RDW_FRAME | RDW_ALLCHILDREN );
          free_region( exposed_rgn );
      }
  
      if (old_vis_rgn) free_region( old_vis_rgn );
      clear_error();  /* we ignore out of memory errors since the region has been set */
  }
  
  
  /* destroy a window */
  void destroy_window( struct window *win )
  {
      /* hide the window */
      if (is_visible(win))
      {
          struct region *vis_rgn = get_visible_region( win, DCX_WINDOW );
          win->style &= ~WS_VISIBLE;
          if (vis_rgn)
          {
              struct region *exposed_rgn = expose_window( win, &win->window_rect, vis_rgn );
              if (exposed_rgn) free_region( exposed_rgn );
              free_region( vis_rgn );
          }
          validate_whole_window( win );
          validate_children( win );
      }
  
      /* destroy all children */
      while (!list_empty(&win->children))
          destroy_window( LIST_ENTRY( list_head(&win->children), struct window, entry ));
      while (!list_empty(&win->unlinked))
          destroy_window( LIST_ENTRY( list_head(&win->unlinked), struct window, entry ));
  
      /* reset global window pointers, if the corresponding window is destroyed */
      if (win == shell_window) shell_window = NULL;
      if (win == shell_listview) shell_listview = NULL;
      if (win == progman_window) progman_window = NULL;
      if (win == taskman_window) taskman_window = NULL;
      free_hotkeys( win->desktop, win->handle );
      cleanup_clipboard_window( win->desktop, win->handle );
      free_user_handle( win->handle );
      destroy_properties( win );
      list_remove( &win->entry );
      if (is_desktop_window(win))
      {
          struct desktop *desktop = win->desktop;
          assert( desktop->top_window == win || desktop->msg_window == win );
          if (desktop->top_window == win) desktop->top_window = NULL;
          else desktop->msg_window = NULL;
      }
      else if (is_desktop_window( win->parent ))
      {
          post_message( win->parent->handle, WM_PARENTNOTIFY, WM_DESTROY, win->handle );
      }
  
      detach_window_thread( win );
      if (win->win_region) free_region( win->win_region );
      if (win->update_region) free_region( win->update_region );
      if (win->class) release_class( win->class );
      free( win->text );
      memset( win, 0x55, sizeof(*win) + win->nb_extra_bytes - 1 );
      free( win );
  }
  
  
  static void shm_surface_dump( struct object *obj, int verbose )
  {
      struct shm_surface *surface = (struct shm_surface *)obj;
      assert( obj->ops == &shm_surface_ops );
      fprintf( stderr, "shm surface of window %x\n", surface->window );
  }
  
  
  static int shm_surface_signaled( struct object *obj, struct wait_queue_entry *entry )
  {
      struct shm_surface *surface = (struct shm_surface *)obj;
      assert( obj->ops == &shm_surface_ops );
      return !surface->lock_cnt;
  }
  
  
  static void shm_surface_destroy( struct object *obj )
  {
      struct shm_surface *surface = (struct shm_surface *)obj;
      assert( obj->ops == &shm_surface_ops );
      if (surface->mapping) release_object( surface->mapping );
      if (surface->process)
      {
          if (surface->mapping_handle) close_handle( surface->process, surface->mapping_handle );
          list_remove( &surface->entry );
      }
  }
  
  
  struct shm_surface *find_pending_surface( struct process *process, user_handle_t *win,
                                            lparam_t *lparam, rectangle_t *bounds )
  {
      struct shm_surface *surface;
      LIST_FOR_EACH_ENTRY( surface, &process->surfaces, struct shm_surface, entry )
      {
          if (surface->lock_cnt || is_rect_empty( &surface->bounds )) continue;
  
          *win    = surface->window;
          *lparam = surface->mapping_handle;
          *bounds = surface->bounds;
  
          surface->bounds = empty_rect;
          surface->lock_cnt++;
          return (struct shm_surface *)grab_object( surface );
      }
      return NULL;
  }
  
  
  void unlock_surface( struct shm_surface *surface )
  {
      assert( surface->lock_cnt );
      if (--surface->lock_cnt) return;
  
      surface->lock_tid = 0;
      wake_up( &surface->obj, 0 );
      if (surface->process && !is_rect_empty( &surface->bounds ))
          wake_queue_for_surface( surface->process );
  }
  
  
  void remove_process_surfaces( struct process *process )
  {
      struct shm_surface *surface;
  
      while (!list_empty( &process->surfaces ))
      {
          surface = LIST_ENTRY( list_head( &process->surfaces ), struct shm_surface, entry );
          list_remove( &surface->entry );
          surface->process = NULL;
      }
  }
  
  
  static struct shm_surface *create_shm_surface( data_size_t mapping_size, struct process *process,
                                                 user_handle_t window )
  {
      struct shm_surface *surface;
  
      if (!(surface = alloc_object( &shm_surface_ops ))) return NULL;
  
      surface->window         = window;
      surface->lock_cnt       = 0;
      surface->lock_tid       = 0;
      surface->bounds         = empty_rect;
      surface->mapping_handle = 0;
      surface->process        = process;
      surface->mapping_handle = 0;
      list_add_head( &process->surfaces, &surface->entry );
  
      surface->mapping = create_mapping( NULL, NULL, 0, mapping_size, SEC_RESERVE, 0,
                                         SECTION_MAP_READ | SECTION_MAP_WRITE, NULL );
      if (!surface->mapping)
      {
          release_object( surface );
          return NULL;
      }
  
      surface->mapping_handle = alloc_handle( process, surface->mapping, SECTION_MAP_READ, 0 );
      if (!surface->mapping_handle)
      {
          release_object( surface );
          return NULL;
      }
  
      return surface;
  }
  
  
  /* create a window */
  DECL_HANDLER(create_window)
  {
      struct window *win, *parent = NULL, *owner = NULL;
      struct unicode_str cls_name = get_req_unicode_str();
      atom_t atom;
  
      reply->handle = 0;
      if (req->parent && !(parent = get_window( req->parent ))) return;
  
      if (req->owner)
      {
          if (!(owner = get_window( req->owner ))) return;
          if (is_desktop_window(owner)) owner = NULL;
          else if (parent && !is_desktop_window(parent))
          {
              /* an owned window must be created as top-level */
              set_error( STATUS_ACCESS_DENIED );
              return;
          }
          else /* owner must be a top-level window */
              while ((owner->style & (WS_POPUP|WS_CHILD)) == WS_CHILD && !is_desktop_window(owner->parent))
                  owner = owner->parent;
      }
  
      atom = cls_name.len ? find_global_atom( NULL, &cls_name ) : req->atom;
  
      if (!(win = create_window( parent, owner, atom, req->instance ))) return;
  
      if (parent && !is_desktop_window( parent ))
      {
          win->dpi_awareness = parent->dpi_awareness;
          win->dpi = parent->dpi;
      }
      else if (!parent || req->awareness != DPI_AWARENESS_PER_MONITOR_AWARE)
      {
          win->dpi_awareness = req->awareness;
          win->dpi = req->dpi;
      }
  
      reply->handle    = win->handle;
      reply->parent    = win->parent ? win->parent->handle : 0;
      reply->owner     = win->owner;
      reply->extra     = win->nb_extra_bytes;
      reply->dpi       = win->dpi;
      reply->awareness = win->dpi_awareness;
      reply->class_ptr = get_class_client_ptr( win->class );
  }
  
  
  /* set the parent of a window */
  DECL_HANDLER(set_parent)
  {
      struct window *win, *parent = NULL;
  
      if (!(win = get_window( req->handle ))) return;
      if (req->parent && !(parent = get_window( req->parent ))) return;
  
      if (is_desktop_window(win))
      {
          set_error( STATUS_INVALID_PARAMETER );
          return;
      }
      reply->old_parent  = win->parent->handle;
      reply->full_parent = parent ? parent->handle : 0;
      set_parent_window( win, parent );
      reply->dpi       = win->dpi;
      reply->awareness = win->dpi_awareness;
  }
  
  
  /* destroy a window */
  DECL_HANDLER(destroy_window)
  {
      struct window *win = get_window( req->handle );
      if (win)
      {
          if (!is_desktop_window(win)) destroy_window( win );
          else if (win->thread == current) detach_window_thread( win );
          else set_error( STATUS_ACCESS_DENIED );
      }
  }
  
  
  /* retrieve the desktop window for the current thread */
  DECL_HANDLER(get_desktop_window)
  {
      struct desktop *desktop = get_thread_desktop( current, 0 );
      int force;
  
      if (!desktop) return;
  
      /* if winstation is invisible, then avoid roundtrip */
      force = req->force || !(desktop->winstation->flags & WSF_VISIBLE);
  
      if (!desktop->top_window && force)  /* create it */
      {
          if ((desktop->top_window = create_window( NULL, NULL, DESKTOP_ATOM, 0 )))
          {
              detach_window_thread( desktop->top_window );
              desktop->top_window->style  = WS_POPUP | WS_VISIBLE | WS_CLIPSIBLINGS | WS_CLIPCHILDREN;
          }
      }
  
      if (!desktop->msg_window && force)  /* create it */
      {
          static const WCHAR messageW[] = {'M','e','s','s','a','g','e'};
          static const struct unicode_str name = { messageW, sizeof(messageW) };
          atom_t atom = add_global_atom( NULL, &name );
          if (atom && (desktop->msg_window = create_window( NULL, NULL, atom, 0 )))
          {
              detach_window_thread( desktop->msg_window );
              desktop->msg_window->style = WS_POPUP | WS_CLIPSIBLINGS | WS_CLIPCHILDREN;
          }
      }
  
      reply->top_window = desktop->top_window ? desktop->top_window->handle : 0;
      reply->msg_window = desktop->msg_window ? desktop->msg_window->handle : 0;
      release_object( desktop );
  }
  
  
  /* set a window owner */
  DECL_HANDLER(set_window_owner)
  {
      struct window *win = get_window( req->handle );
      struct window *owner = NULL, *ptr;
  
      if (!win) return;
      if (req->owner && !(owner = get_window( req->owner ))) return;
      if (is_desktop_window(win))
      {
          set_error( STATUS_ACCESS_DENIED );
          return;
      }
  
      /* make sure owner is not a successor of window */
      for (ptr = owner; ptr; ptr = ptr->owner ? get_window( ptr->owner ) : NULL)
      {
          if (ptr == win)
          {
              set_error( STATUS_INVALID_PARAMETER );
              return;
          }
      }
  
      reply->prev_owner = win->owner;
      reply->full_owner = win->owner = owner ? owner->handle : 0;
  }
  
  
  /* get information from a window handle */
  DECL_HANDLER(get_window_info)
  {
      struct window *win = get_window( req->handle );
  
      if (!win) return;
  
      reply->full_handle = win->handle;
      reply->last_active = win->handle;
      reply->is_unicode  = win->is_unicode;
      reply->awareness   = win->dpi_awareness;
      reply->dpi         = win->dpi ? win->dpi : get_monitor_dpi( win );
      if (get_user_object( win->last_active, USER_WINDOW )) reply->last_active = win->last_active;
      if (win->thread)
      {
          reply->tid  = get_thread_id( win->thread );
          reply->pid  = get_process_id( win->thread->process );
          reply->atom = win->class ? get_class_atom( win->class ) : DESKTOP_ATOM;
      }
  }
  
  
  /* set some information in a window */
  DECL_HANDLER(set_window_info)
  {
      struct window *win = get_window( req->handle );
  
      if (!win) return;
      if (req->flags && is_desktop_window(win) && win->thread != current)
      {
          set_error( STATUS_ACCESS_DENIED );
          return;
      }
      if (req->extra_size > sizeof(req->extra_value) ||
          req->extra_offset < -1 ||
          req->extra_offset > win->nb_extra_bytes - (int)req->extra_size)
      {
          set_win32_error( ERROR_INVALID_INDEX );
          return;
      }
      if (req->extra_offset != -1)
      {
          memcpy( &reply->old_extra_value, win->extra_bytes + req->extra_offset, req->extra_size );
      }
      else if (req->flags & SET_WIN_EXTRA)
      {
          set_win32_error( ERROR_INVALID_INDEX );
          return;
      }
      reply->old_style     = win->style;
      reply->old_ex_style  = win->ex_style;
      reply->old_id        = win->id;
      reply->old_instance  = win->instance;
      reply->old_user_data = win->user_data;
      if (req->flags & SET_WIN_STYLE) win->style = req->style;
      if (req->flags & SET_WIN_EXSTYLE)
      {
          /* WS_EX_TOPMOST can only be changed for unlinked windows */
          if (!win->is_linked) win->ex_style = req->ex_style;
          else win->ex_style = (req->ex_style & ~WS_EX_TOPMOST) | (win->ex_style & WS_EX_TOPMOST);
          if (!(win->ex_style & WS_EX_LAYERED)) win->is_layered = 0;
      }
      if (req->flags & SET_WIN_ID) win->id = req->id;
      if (req->flags & SET_WIN_INSTANCE) win->instance = req->instance;
      if (req->flags & SET_WIN_UNICODE) win->is_unicode = req->is_unicode;
      if (req->flags & SET_WIN_USERDATA) win->user_data = req->user_data;
      if (req->flags & SET_WIN_EXTRA) memcpy( win->extra_bytes + req->extra_offset,
                                              &req->extra_value, req->extra_size );
  
      /* changing window style triggers a non-client paint */
      if (req->flags & SET_WIN_STYLE) win->paint_flags |= PAINT_NONCLIENT;
  }
  
  
  /* get a list of the window parents, up to the root of the tree */
  DECL_HANDLER(get_window_parents)
  {
      struct window *ptr, *win = get_window( req->handle );
      int total = 0;
      user_handle_t *data;
      data_size_t len;
  
      if (win) for (ptr = win->parent; ptr; ptr = ptr->parent) total++;
  
      reply->count = total;
      len = min( get_reply_max_size(), total * sizeof(user_handle_t) );
      if (len && ((data = set_reply_data_size( len ))))
      {
          for (ptr = win->parent; ptr && len; ptr = ptr->parent, len -= sizeof(*data))
              *data++ = ptr->handle;
      }
  }
  
  
  /* get a list of the window children */
  DECL_HANDLER(get_window_children)
  {
      struct window *parent = NULL;
      unsigned int total;
      user_handle_t *data;
      data_size_t len;
      struct unicode_str cls_name = get_req_unicode_str();
      atom_t atom = req->atom;
      struct desktop *desktop = NULL;
  
      if (cls_name.len && !(atom = find_global_atom( NULL, &cls_name ))) return;
  
      if (req->desktop)
      {
          if (!(desktop = get_desktop_obj( current->process, req->desktop, DESKTOP_ENUMERATE ))) return;
          parent = desktop->top_window;
      }
      else
      {
          if (req->parent && !(parent = get_window( req->parent ))) return;
          if (!parent && !(desktop = get_thread_desktop( current, 0 ))) return;
      }
  
      if (parent)
          total = get_children_windows( parent, atom, req->tid, NULL, 0 );
      else
          total = get_children_windows( desktop->top_window, atom, req->tid, NULL, 0 ) +
                  get_children_windows( desktop->msg_window, atom, req->tid, NULL, 0 );
  
      reply->count = total;
      len = min( get_reply_max_size(), total * sizeof(user_handle_t) );
      if (len && ((data = set_reply_data_size( len ))))
      {
          if (parent) get_children_windows( parent, atom, req->tid, data, len / sizeof(user_handle_t) );
          else
          {
              total = get_children_windows( desktop->top_window, atom, req->tid,
                                            data, len / sizeof(user_handle_t) );
              data += total;
              len -= total * sizeof(user_handle_t);
              if (len >= sizeof(user_handle_t))
                  get_children_windows( desktop->msg_window, atom, req->tid,
                                        data, len / sizeof(user_handle_t) );
          }
      }
      if (desktop) release_object( desktop );
  }
  
  
  /* get a list of the window children that contain a given point */
  DECL_HANDLER(get_window_children_from_point)
  {
      struct user_handle_array array;
      struct window *parent = get_window( req->parent );
      data_size_t len;
  
      if (!parent) return;
  
      array.handles = NULL;
      array.count = 0;
      array.total = 0;
      if (!all_windows_from_point( parent, req->x, req->y, req->dpi, &array )) return;
  
      reply->count = array.count;
      len = min( get_reply_max_size(), array.count * sizeof(user_handle_t) );
      if (len) set_reply_data_ptr( array.handles, len );
      else free( array.handles );
  }
  
  
  /* get window tree information from a window handle */
  DECL_HANDLER(get_window_tree)
  {
      struct window *ptr, *win = get_window( req->handle );
  
      if (!win) return;
  
      reply->parent        = 0;
      reply->owner         = 0;
      reply->next_sibling  = 0;
      reply->prev_sibling  = 0;
      reply->first_sibling = 0;
      reply->last_sibling  = 0;
      reply->first_child   = 0;
      reply->last_child    = 0;
  
      if (win->parent)
      {
          struct window *parent = win->parent;
          reply->parent = parent->handle;
          reply->owner  = win->owner;
          if (win->is_linked)
          {
              if ((ptr = get_next_window( win ))) reply->next_sibling = ptr->handle;
              if ((ptr = get_prev_window( win ))) reply->prev_sibling = ptr->handle;
          }
          if ((ptr = get_first_child( parent ))) reply->first_sibling = ptr->handle;
          if ((ptr = get_last_child( parent ))) reply->last_sibling = ptr->handle;
      }
      if ((ptr = get_first_child( win ))) reply->first_child = ptr->handle;
      if ((ptr = get_last_child( win ))) reply->last_child = ptr->handle;
  }
  
  
  /* set the position and Z order of a window */
  DECL_HANDLER(set_window_pos)
  {
      rectangle_t window_rect, client_rect, visible_rect, surface_rect, valid_rect;
      const rectangle_t *extra_rects = get_req_data();
      struct window *previous = NULL;
      struct window *top, *win = get_window( req->handle );
      unsigned int flags = req->swp_flags;
  
      if (!win) return;
      if (!win->parent) flags |= SWP_NOZORDER;  /* no Z order for the desktop */
  
      if (!(flags & SWP_NOZORDER))
      {
          switch ((int)req->previous)
          {
          case 0:   /* HWND_TOP */
              previous = WINPTR_TOP;
              break;
          case 1:   /* HWND_BOTTOM */
              previous = WINPTR_BOTTOM;
              break;
          case -1:  /* HWND_TOPMOST */
              previous = WINPTR_TOPMOST;
              break;
          case -2:  /* HWND_NOTOPMOST */
              previous = WINPTR_NOTOPMOST;
              break;
          default:
              if (!(previous = get_window( req->previous ))) return;
              /* previous must be a sibling */
              if (previous->parent != win->parent)
              {
                  set_error( STATUS_INVALID_PARAMETER );
                  return;
              }
              break;
          }
          if (previous == win) flags |= SWP_NOZORDER;  /* nothing to do */
      }
  
      /* windows that use UpdateLayeredWindow don't trigger repaints */
      if ((win->ex_style & WS_EX_LAYERED) && !win->is_layered) flags |= SWP_NOREDRAW;
  
      /* window rectangle must be ordered properly */
      if (req->window.right < req->window.left || req->window.bottom < req->window.top)
      {
          set_error( STATUS_INVALID_PARAMETER );
          return;
      }
  
      window_rect = req->window;
      client_rect = req->client;
      if (get_req_data_size() >= sizeof(rectangle_t)) visible_rect = extra_rects[0];
      else visible_rect = window_rect;
      if (get_req_data_size() >= 2 * sizeof(rectangle_t)) surface_rect = extra_rects[1];
      else surface_rect = visible_rect;
      if (get_req_data_size() >= 3 * sizeof(rectangle_t)) valid_rect = extra_rects[2];
      else valid_rect = empty_rect;
      if (win->parent && win->parent->ex_style & WS_EX_LAYOUTRTL)
      {
          mirror_rect( &win->parent->client_rect, &window_rect );
          mirror_rect( &win->parent->client_rect, &visible_rect );
          mirror_rect( &win->parent->client_rect, &client_rect );
          mirror_rect( &win->parent->client_rect, &surface_rect );
          mirror_rect( &win->parent->client_rect, &valid_rect );
      }
  
      win->paint_flags = (win->paint_flags & ~PAINT_CLIENT_FLAGS) | (req->paint_flags & PAINT_CLIENT_FLAGS);
      if (win->paint_flags & PAINT_HAS_PIXEL_FORMAT) update_pixel_format_flags( win );
  
      set_window_pos( win, previous, flags, &window_rect, &client_rect,
                      &visible_rect, &surface_rect, &valid_rect );
  
      reply->new_style = win->style;
      reply->new_ex_style = win->ex_style;
  
      top = get_top_clipping_window( win );
      if (is_visible( top ) && (top->paint_flags & PAINT_HAS_SURFACE))
      {
          reply->surface_win = top->handle;
          reply->needs_update = !!(top->paint_flags & (PAINT_HAS_PIXEL_FORMAT | PAINT_PIXEL_FORMAT_CHILD));
      }
  }
  
  
  /* get the window and client rectangles of a window */
  DECL_HANDLER(get_window_rectangles)
  {
      struct window *win = get_window( req->handle );
  
      if (!win) return;
  
      reply->window  = win->window_rect;
      reply->client  = win->client_rect;
  
      switch (req->relative)
      {
      case COORDS_CLIENT:
          offset_rect( &reply->window, -win->client_rect.left, -win->client_rect.top );
          offset_rect( &reply->client, -win->client_rect.left, -win->client_rect.top );
          if (win->ex_style & WS_EX_LAYOUTRTL) mirror_rect( &win->client_rect, &reply->window );
          break;
      case COORDS_WINDOW:
          offset_rect( &reply->window, -win->window_rect.left, -win->window_rect.top );
          offset_rect( &reply->client, -win->window_rect.left, -win->window_rect.top );
          if (win->ex_style & WS_EX_LAYOUTRTL) mirror_rect( &win->window_rect, &reply->client );
          break;
      case COORDS_PARENT:
          if (win->parent && win->parent->ex_style & WS_EX_LAYOUTRTL)
          {
              mirror_rect( &win->parent->client_rect, &reply->window );
              mirror_rect( &win->parent->client_rect, &reply->client );
          }
          break;
      case COORDS_SCREEN:
          client_to_screen_rect( win->parent, &reply->window );
          client_to_screen_rect( win->parent, &reply->client );
          break;
      default:
          set_error( STATUS_INVALID_PARAMETER );
          break;
      }
      map_dpi_rect( win, &reply->window, win->dpi, req->dpi );
      map_dpi_rect( win, &reply->client, win->dpi, req->dpi );
  }
  
  
  /* get the window text */
  DECL_HANDLER(get_window_text)
  {
      struct window *win = get_window( req->handle );
  
      if (win && win->text)
      {
          reply->length = strlenW( win->text );
          set_reply_data( win->text, min( reply->length * sizeof(WCHAR), get_reply_max_size() ));
      }
  }
  
  
  /* set the window text */
  DECL_HANDLER(set_window_text)
  {
      struct window *win = get_window( req->handle );
  
      if (win)
      {
          WCHAR *text = NULL;
          data_size_t len = get_req_data_size() / sizeof(WCHAR);
          if (len)
          {
              if (!(text = mem_alloc( (len+1) * sizeof(WCHAR) ))) return;
              memcpy( text, get_req_data(), len * sizeof(WCHAR) );
              text[len] = 0;
          }
          free( win->text );
          win->text = text;
      }
  }
  
  
  /* get the coordinates offset between two windows */
  DECL_HANDLER(get_windows_offset)
  {
      struct window *win;
      int x, y, mirror_from = 0, mirror_to = 0;
  
      reply->x = reply->y = 0;
      if (req->from)
      {
          if (!(win = get_window( req->from ))) return;
          if (win->ex_style & WS_EX_LAYOUTRTL) mirror_from = 1;
          x = mirror_from ? win->client_rect.right - win->client_rect.left : 0;
          y = 0;
          client_to_screen( win, &x, &y );
          map_dpi_point( win, &x, &y, win->dpi, req->dpi );
          reply->x += x;
          reply->y += y;
      }
      if (req->to)
      {
          if (!(win = get_window( req->to ))) return;
          if (win->ex_style & WS_EX_LAYOUTRTL) mirror_to = 1;
          x = mirror_to ? win->client_rect.right - win->client_rect.left : 0;
          y = 0;
          client_to_screen( win, &x, &y );
          map_dpi_point( win, &x, &y, win->dpi, req->dpi );
          reply->x -= x;
          reply->y -= y;
      }
      if (mirror_from) reply->x = -reply->x;
      reply->mirror = mirror_from ^ mirror_to;
  }
  
  
  /* get the visible region of a window */
  DECL_HANDLER(get_visible_region)
  {
      struct region *region;
      struct window *top, *win = get_window( req->window );
  
      if (!win) return;
  
      top = get_top_clipping_window( win );
      if ((region = get_visible_region( win, req->flags )))
      {
          rectangle_t *data;
          map_win_region_to_screen( win, region );
          data = get_region_data_and_free( region, get_reply_max_size(), &reply->total_size );
          if (data) set_reply_data_ptr( data, reply->total_size );
      }
      reply->top_win  = top->handle;
      reply->top_rect = top->surface_rect;
  
      if (!is_desktop_window(win))
      {
          reply->win_rect = (req->flags & DCX_WINDOW) ? win->window_rect : win->client_rect;
          client_to_screen_rect( top->parent, &reply->top_rect );
          client_to_screen_rect( win->parent, &reply->win_rect );
      }
      else
      {
          reply->win_rect.left   = 0;
          reply->win_rect.top    = 0;
          reply->win_rect.right  = win->client_rect.right - win->client_rect.left;
          reply->win_rect.bottom = win->client_rect.bottom - win->client_rect.top;
      }
      reply->paint_flags = win->paint_flags & PAINT_CLIENT_FLAGS;
  }
  
  
  /* get the surface visible region of a window */
  DECL_HANDLER(get_surface_region)
  {
      struct region *region;
      struct window *win = get_window( req->window );
  
      if (!win || !is_visible( win )) return;
  
      if ((region = get_surface_region( win )))
      {
          rectangle_t *data = get_region_data_and_free( region, get_reply_max_size(), &reply->total_size );
          if (data) set_reply_data_ptr( data, reply->total_size );
      }
      reply->visible_rect = win->visible_rect;
  }
  
  
  /* get the window region */
  DECL_HANDLER(get_window_region)
  {
      rectangle_t *data;
      struct window *win = get_window( req->window );
  
      if (!win) return;
      if (!win->win_region) return;
  
      if (win->ex_style & WS_EX_LAYOUTRTL)
      {
          struct region *region = create_empty_region();
  
          if (!region) return;
          if (!copy_region( region, win->win_region ))
          {
              free_region( region );
              return;
          }
          mirror_region( &win->window_rect, region );
          data = get_region_data_and_free( region, get_reply_max_size(), &reply->total_size );
      }
      else data = get_region_data( win->win_region, get_reply_max_size(), &reply->total_size );
  
      if (data) set_reply_data_ptr( data, reply->total_size );
  }
  
  
  /* set the window region */
  DECL_HANDLER(set_window_region)
  {
      struct region *region = NULL;
      struct window *win = get_window( req->window );
  
      if (!win) return;
  
      if (get_req_data_size())  /* no data means remove the region completely */
      {
          if (!(region = create_region_from_req_data( get_req_data(), get_req_data_size() )))
              return;
          if (win->ex_style & WS_EX_LAYOUTRTL) mirror_region( &win->window_rect, region );
      }
      set_window_region( win, region, req->redraw );
  }
  
  
  /* get a window update region */
  DECL_HANDLER(get_update_region)
  {
      rectangle_t *data;
      unsigned int flags = req->flags;
      struct window *from_child = NULL;
      struct window *win = get_window( req->window );
  
      reply->flags = 0;
      if (!win) return;
  
      if (req->from_child)
      {
          struct window *ptr;
  
          if (!(from_child = get_window( req->from_child ))) return;
  
          /* make sure from_child is a child of win */
          ptr = from_child;
          while (ptr && ptr != win) ptr = ptr->parent;
          if (!ptr)
          {
              set_error( STATUS_INVALID_PARAMETER );
              return;
          }
      }
  
      if (flags & UPDATE_DELAYED_ERASE)  /* this means that the previous call didn't erase */
      {
          if (from_child) from_child->paint_flags |= PAINT_DELAYED_ERASE;
          else win->paint_flags |= PAINT_DELAYED_ERASE;
      }
  
      reply->flags = get_window_update_flags( win, from_child, flags, &win );
      reply->child = win->handle;
  
      if (flags & UPDATE_NOREGION) return;
  
      if (win->update_region)
      {
          /* convert update region to screen coordinates */
          struct region *region = create_empty_region();
  
          if (!region) return;
          if (!copy_region( region, win->update_region ))
          {
              free_region( region );
              return;
          }
          if ((flags & UPDATE_CLIPCHILDREN) && (win->style & WS_CLIPCHILDREN))
              clip_children( win, NULL, region, win->client_rect.left - win->window_rect.left,
                             win->client_rect.top - win->window_rect.top );
          map_win_region_to_screen( win, region );
          if (!(data = get_region_data_and_free( region, get_reply_max_size(),
                                                 &reply->total_size ))) return;
          set_reply_data_ptr( data, reply->total_size );
      }
  
      if (reply->flags & (UPDATE_PAINT|UPDATE_INTERNALPAINT)) /* validate everything */
      {
          validate_parents( win );
          validate_whole_window( win );
      }
      else
      {
          if (reply->flags & UPDATE_NONCLIENT) validate_non_client( win );
          if (reply->flags & UPDATE_ERASE)
          {
              win->paint_flags &= ~(PAINT_ERASE | PAINT_DELAYED_ERASE);
              /* desktop window only gets erased, not repainted */
              if (is_desktop_window(win)) validate_whole_window( win );
          }
      }
  }
  
  
  /* update the z order of a window so that a given rectangle is fully visible */
  DECL_HANDLER(update_window_zorder)
  {
      rectangle_t tmp, rect = req->rect;
      struct window *ptr, *win = get_window( req->window );
  
      if (!win || !win->parent || !is_visible( win )) return;  /* nothing to do */
  
      LIST_FOR_EACH_ENTRY( ptr, &win->parent->children, struct window, entry )
      {
          if (ptr == win) break;
          if (!(ptr->style & WS_VISIBLE)) continue;
          if (ptr->ex_style & WS_EX_TRANSPARENT) continue;
          if (ptr->is_layered && (ptr->layered_flags & LWA_COLORKEY)) continue;
          tmp = rect;
          map_dpi_rect( win, &tmp, win->parent->dpi, win->dpi );
          if (!intersect_rect( &tmp, &tmp, &ptr->visible_rect )) continue;
          if (ptr->win_region)
          {
              offset_rect( &tmp, -ptr->window_rect.left, -ptr->window_rect.top );
              if (!rect_in_region( ptr->win_region, &tmp )) continue;
          }
          /* found a window obscuring the rectangle, now move win above this one */
          /* making sure to not violate the topmost rule */
          if (!(ptr->ex_style & WS_EX_TOPMOST) || (win->ex_style & WS_EX_TOPMOST))
          {
              list_remove( &win->entry );
              list_add_before( &ptr->entry, &win->entry );
          }
          break;
      }
  }
  
  
  /* mark parts of a window as needing a redraw */
  DECL_HANDLER(redraw_window)
  {
      unsigned int flags = req->flags;
      struct region *region = NULL;
      struct window *win;
  
      if (!req->window)
      {
          if (!(win = get_desktop_window( current ))) return;
      }
      else
      {
          if (!(win = get_window( req->window ))) return;
          if (is_desktop_window( win )) flags &= ~RDW_ALLCHILDREN;
      }
  
      if (!is_visible( win )) return;  /* nothing to do */
  
      if (flags & (RDW_VALIDATE|RDW_INVALIDATE))
      {
          if (get_req_data_size())  /* no data means whole rectangle */
          {
              if (!(region = create_region_from_req_data( get_req_data(), get_req_data_size() )))
                  return;
              if (win->ex_style & WS_EX_LAYOUTRTL) mirror_region( &win->client_rect, region );
          }
      }
  
      redraw_window( win, region, (flags & RDW_INVALIDATE) && (flags & RDW_FRAME), flags );
      if (region) free_region( region );
  }
  
  
  /* set a window property */
  DECL_HANDLER(set_window_property)
  {
      struct unicode_str name = get_req_unicode_str();
      struct window *win = get_window( req->window );
  
      if (!win) return;
  
      if (name.len)
      {
          atom_t atom = add_global_atom( NULL, &name );
          if (atom)
          {
              set_property( win, atom, req->data, PROP_TYPE_STRING );
              release_global_atom( NULL, atom );
          }
      }
      else set_property( win, req->atom, req->data, PROP_TYPE_ATOM );
  }
  
  
  /* remove a window property */
  DECL_HANDLER(remove_window_property)
  {
      struct unicode_str name = get_req_unicode_str();
      struct window *win = get_window( req->window );
  
      if (win)
      {
          atom_t atom = name.len ? find_global_atom( NULL, &name ) : req->atom;
          if (atom) reply->data = remove_property( win, atom );
      }
  }
  
  
  /* get a window property */
  DECL_HANDLER(get_window_property)
  {
      struct unicode_str name = get_req_unicode_str();
      struct window *win = get_window( req->window );
  
      if (win)
      {
          atom_t atom = name.len ? find_global_atom( NULL, &name ) : req->atom;
          if (atom) reply->data = get_property( win, atom );
      }
  }
  
  
  /* get the list of properties of a window */
  DECL_HANDLER(get_window_properties)
  {
      property_data_t *data;
      int i, count, max = get_reply_max_size() / sizeof(*data);
      struct window *win = get_window( req->window );
  
      reply->total = 0;
      if (!win) return;
  
      for (i = count = 0; i < win->prop_inuse; i++)
          if (win->properties[i].type != PROP_TYPE_FREE) count++;
      reply->total = count;
  
      if (count > max) count = max;
      if (!count || !(data = set_reply_data_size( count * sizeof(*data) ))) return;
  
      for (i = 0; i < win->prop_inuse && count; i++)
      {
          if (win->properties[i].type == PROP_TYPE_FREE) continue;
          data->atom   = win->properties[i].atom;
          data->string = (win->properties[i].type == PROP_TYPE_STRING);
          data->data   = win->properties[i].data;
          data++;
          count--;
      }
  }
  
  
  /* get the new window pointer for a global window, checking permissions */
  /* helper for set_global_windows request */
  static int get_new_global_window( struct window **win, user_handle_t handle )
  {
      if (!handle)
      {
          *win = NULL;
          return 1;
      }
      else if (*win)
      {
          set_error( STATUS_ACCESS_DENIED );
          return 0;
      }
      *win = get_window( handle );
      return (*win != NULL);
  }
  
  /* Set/get the global windows */
  DECL_HANDLER(set_global_windows)
  {
      struct window *new_shell_window   = shell_window;
      struct window *new_shell_listview = shell_listview;
      struct window *new_progman_window = progman_window;
      struct window *new_taskman_window = taskman_window;
  
      reply->old_shell_window   = shell_window ? shell_window->handle : 0;
      reply->old_shell_listview = shell_listview ? shell_listview->handle : 0;
      reply->old_progman_window = progman_window ? progman_window->handle : 0;
      reply->old_taskman_window = taskman_window ? taskman_window->handle : 0;
  
      if (req->flags & SET_GLOBAL_SHELL_WINDOWS)
      {
          if (!get_new_global_window( &new_shell_window, req->shell_window )) return;
          if (!get_new_global_window( &new_shell_listview, req->shell_listview )) return;
      }
      if (req->flags & SET_GLOBAL_PROGMAN_WINDOW)
      {
          if (!get_new_global_window( &new_progman_window, req->progman_window )) return;
      }
      if (req->flags & SET_GLOBAL_TASKMAN_WINDOW)
      {
          if (!get_new_global_window( &new_taskman_window, req->taskman_window )) return;
      }
      shell_window   = new_shell_window;
      shell_listview = new_shell_listview;
      progman_window = new_progman_window;
      taskman_window = new_taskman_window;
  }
  
  /* retrieve layered info for a window */
  DECL_HANDLER(get_window_layered_info)
  {
      struct window *win = get_window( req->handle );
  
      if (!win) return;
  
      if (win->is_layered)
      {
          reply->color_key = win->color_key;
          reply->alpha     = win->alpha;
          reply->flags     = win->layered_flags;
      }
      else set_win32_error( ERROR_INVALID_WINDOW_HANDLE );
  }
  
  
  /* set layered info for a window */
  DECL_HANDLER(set_window_layered_info)
  {
      struct window *win = get_window( req->handle );
  
      if (!win) return;
  
      if (win->ex_style & WS_EX_LAYERED)
      {
          int was_layered = win->is_layered;
  
          if (req->flags & LWA_ALPHA) win->alpha = req->alpha;
          else if (!win->is_layered) win->alpha = 0;  /* alpha init value is 0 */
  
          win->color_key     = req->color_key;
          win->layered_flags = req->flags;
          win->is_layered    = 1;
          /* repaint since we know now it's not going to use UpdateLayeredWindow */
          if (!was_layered) redraw_window( win, 0, 1, RDW_ALLCHILDREN | RDW_INVALIDATE | RDW_ERASE | RDW_FRAME );
      }
      else set_win32_error( ERROR_INVALID_WINDOW_HANDLE );
  }
  
  
  /* lock or unlock the surface */
  DECL_HANDLER(lock_shm_surface)
  {
      struct shm_surface *surface;
      surface = (struct shm_surface *)get_handle_obj( current->process, req->surface,
                                                      0, &shm_surface_ops );
      if (!surface) return;
  
      if (req->lock)
      {
          if (!surface->lock_cnt || surface->lock_tid == current->id)
          {
              surface->lock_cnt++;
              surface->lock_tid = current->id;
          }
          else set_error( STATUS_PENDING );
      }
      else if (surface->lock_cnt)
      {
          unlock_surface( surface );
      }
      else set_error( STATUS_INVALID_DEVICE_STATE );
      release_object( surface );
  }
  
  
  /* flush the surface */
  DECL_HANDLER(flush_shm_surface)
  {
      struct shm_surface *surface;
      surface = (struct shm_surface *)get_handle_obj( current->process, req->surface,
                                                      0, &shm_surface_ops );
      if (!surface) return;
  
      if (surface->process)
      {
          surface->bounds = union_rect( &surface->bounds, &req->bounds );
          wake_queue_for_surface( surface->process );
      }
      else set_error( STATUS_INVALID_DEVICE_STATE );
      release_object( surface );
  }
  
  
  /* create shared memory surface object */
  DECL_HANDLER(create_shm_surface)
  {
      struct shm_surface *surface;
      struct window *win;
  
      if (!(win = get_window( req->window ))) return;
      if (!win->parent || !win->parent->thread)
      {
          set_error( STATUS_INVALID_PARAMETER );
          return;
      }
  
      surface = create_shm_surface( req->mapping_size, win->parent->thread->process, req->window );
      if (surface)
      {
          reply->mapping = alloc_handle( current->process, surface->mapping,
                                         SECTION_MAP_READ | SECTION_MAP_WRITE, 0 );
          if (reply->mapping) reply->handle = alloc_handle( current->process, surface, SYNCHRONIZE, 0 );
          release_object( surface );
      }
  }
  