server: Keep a list of threads connected to each desktop.

server/thread.h

@@ -51,6 +51,7 @@ struct thread
     struct object          obj;           /* object header */
     struct list            entry;         /* entry in system-wide thread list */
     struct list            proc_entry;    /* entry in per-process thread list */
+    struct list            desktop_entry; /* entry in per-desktop thread list */
     struct process        *process;
     thread_id_t            id;            /* thread id */
     struct list            mutex_list;    /* list of currently owned mutexes */

server/user.h

@@ -70,6 +70,7 @@ struct desktop
     struct winstation   *winstation;       /* winstation this desktop belongs to */
     timeout_t            input_time;       /* last time this desktop had the input */
     struct list          entry;            /* entry in winstation list of desktops */
+    struct list          threads;          /* list of threads connected to this desktop */
     struct window       *top_window;       /* desktop window for this desktop */
     struct window       *msg_window;       /* HWND_MESSAGE top window */
     struct hook_table   *global_hooks;     /* table of global hooks on this desktop */

server/winstation.c

@@ -273,6 +273,7 @@ static struct desktop *create_desktop( const struct unicode_str *name, unsigned
             desktop->close_timeout = NULL;
             desktop->foreground_input = NULL;
             desktop->users = 0;
+            list_init( &desktop->threads );
             memset( &desktop->cursor, 0, sizeof(desktop->cursor) );
             memset( desktop->keystate, 0, sizeof(desktop->keystate) );
             list_add_tail( &winstation->desktops, &desktop->entry );
@@ -362,26 +363,37 @@ static void close_desktop_timeout( void *private )
 }
 
 /* add a user of the desktop and cancel the close timeout */
-static void add_desktop_user( struct desktop *desktop )
+static void add_desktop_thread( struct desktop *desktop, struct thread *thread )
 {
+    list_add_tail( &desktop->threads, &thread->desktop_entry );
+
+    if (!thread->process->is_system)
+    {
         desktop->users++;
         if (desktop->close_timeout)
         {
             remove_timeout_user( desktop->close_timeout );
             desktop->close_timeout = NULL;
         }
+    }
 }
 
 /* remove a user of the desktop and start the close timeout if necessary */
-static void remove_desktop_user( struct desktop *desktop )
+static void remove_desktop_thread( struct desktop *desktop, struct thread *thread )
 {
     struct process *process;
+
+    list_remove( &thread->desktop_entry );
+
+    if (!thread->process->is_system)
+    {
         assert( desktop->users > 0 );
         desktop->users--;
 
         /* if we have one remaining user, it has to be the manager of the desktop window */
         if ((process = get_top_window_owner( desktop )) && desktop->users == process->running_threads && !desktop->close_timeout)
             desktop->close_timeout = add_timeout_user( -TICKS_PER_SEC, close_desktop_timeout, desktop );
+    }
 }
 
 /* set the thread default desktop handle */
@@ -390,7 +402,7 @@ void set_thread_default_desktop( struct thread *thread, struct desktop *desktop,
     if (thread->desktop) return;  /* nothing to do */
 
     thread->desktop = handle;
-    if (!thread->process->is_system) add_desktop_user( desktop );
+    add_desktop_thread( desktop, thread );
 }
 
 /* set the process default desktop handle */
@@ -500,15 +512,12 @@ void release_thread_desktop( struct thread *thread, int close )
 
     if (!(handle = thread->desktop)) return;
 
-    if (!thread->process->is_system)
-    {
     if (!(desktop = get_desktop_obj( thread->process, handle, 0 ))) clear_error();  /* ignore errors */
     else
     {
-            remove_desktop_user( desktop );
+        remove_desktop_thread( desktop, thread );
         release_object( desktop );
     }
-    }
 
     if (close)
     {
@@ -730,10 +739,10 @@ DECL_HANDLER(set_thread_desktop)
     else
     {
         current->desktop = req->handle;  /* FIXME: should we close the old one? */
-        if (!current->process->is_system && old_desktop != new_desktop)
+        if (old_desktop != new_desktop)
         {
-            add_desktop_user( new_desktop );
-            if (old_desktop) remove_desktop_user( old_desktop );
+            if (old_desktop) remove_desktop_thread( old_desktop, current );
+            add_desktop_thread( new_desktop, current );
         }
     }