Added global management of user handles in the server.
Very preliminary support for shared window handles.
diff --git a/server/window.c b/server/window.c
new file mode 100644
index 0000000..f6e853c
--- /dev/null
+++ b/server/window.c
@@ -0,0 +1,179 @@
+/*
+ * Server-side window handling
+ *
+ * Copyright (C) 2001 Alexandre Julliard
+ */
+
+#include <assert.h>
+
+#include "object.h"
+#include "request.h"
+#include "thread.h"
+#include "process.h"
+#include "user.h"
+
+struct window
+{
+ struct window *parent; /* parent window */
+ struct window *child; /* first child window */
+ struct window *next; /* next window in Z-order */
+ struct window *prev; /* prev window in Z-order */
+ user_handle_t handle; /* full handle for this window */
+ struct thread *thread; /* thread owning the window */
+};
+
+static struct window *top_window; /* top-level (desktop) window */
+
+/* link a window into the tree (or unlink it if the new parent is NULL) */
+static void link_window( struct window *win, struct window *parent, struct window *previous )
+{
+ if (win->parent) /* unlink it from the previous location */
+ {
+ if (win->next) win->next->prev = win->prev;
+ if (win->prev) win->prev->next = win->next;
+ else win->parent->child = win->next;
+ }
+ if ((win->parent = parent))
+ {
+ if ((win->prev = previous))
+ {
+ if ((win->next = previous->next)) win->next->prev = win;
+ win->prev->next = win;
+ }
+ else
+ {
+ if ((win->next = parent->child)) win->next->prev = win;
+ parent->child = win;
+ }
+ }
+ else win->next = win->prev = NULL;
+
+}
+
+/* free a window structure */
+static void free_window( struct window *win )
+{
+ assert( win != top_window );
+
+ while (win->child) free_window( win->child );
+ if (win->thread->queue) queue_cleanup_window( win->thread, win->handle );
+ free_user_handle( win->handle );
+ if (win->parent) link_window( win, NULL, NULL );
+ memset( win, 0x55, sizeof(*win) );
+ free( win );
+}
+
+/* create a new window structure */
+static struct window *create_window(void)
+{
+ struct window *win = mem_alloc( sizeof(*win) );
+ if (!win) return NULL;
+
+ if (!(win->handle = alloc_user_handle( win, USER_WINDOW )))
+ {
+ free( win );
+ return NULL;
+ }
+ win->parent = NULL;
+ win->child = NULL;
+ win->next = NULL;
+ win->prev = NULL;
+ win->thread = current;
+ return win;
+}
+
+/* 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;
+ free_window( win );
+ }
+}
+
+/* create a window */
+DECL_HANDLER(create_window)
+{
+ struct window *win;
+
+ req->handle = 0;
+ if ((win = create_window())) req->handle = win->handle;
+}
+
+
+/* create the desktop window */
+DECL_HANDLER(create_desktop_window)
+{
+ req->handle = 0;
+ if (!top_window)
+ {
+ if (!(top_window = create_window())) return;
+ top_window->thread = NULL; /* no thread owns the desktop */
+ }
+ req->handle = top_window->handle;
+}
+
+
+/* link a window into the tree */
+DECL_HANDLER(link_window)
+{
+ struct window *win, *parent = NULL, *previous = NULL;
+
+ if (!(win = get_user_object( req->handle, USER_WINDOW ))) return;
+ if (req->parent && !(parent = get_user_object( req->parent, USER_WINDOW ))) return;
+ if (parent && req->previous)
+ {
+ if (req->previous == 1) /* special case: HWND_BOTTOM */
+ {
+ if ((previous = parent->child))
+ {
+ /* make it the last of the list */
+ while (previous->next) previous = previous->next;
+ }
+ }
+ else if (!(previous = get_user_object( req->previous, USER_WINDOW ))) return;
+
+ if (previous && previous->parent != parent) /* previous must be a child of parent */
+ {
+ set_error( STATUS_INVALID_PARAMETER );
+ return;
+ }
+ }
+ link_window( win, parent, previous );
+}
+
+
+/* destroy a window */
+DECL_HANDLER(destroy_window)
+{
+ struct window *win = get_user_object( req->handle, USER_WINDOW );
+ if (win)
+ {
+ if (win != top_window) free_window( win );
+ else set_error( STATUS_ACCESS_DENIED );
+ }
+}
+
+
+/* Get information from a window handle */
+DECL_HANDLER(get_window_info)
+{
+ user_handle_t handle = req->handle;
+ struct window *win = get_user_object_handle( &handle, USER_WINDOW );
+
+ req->full_handle = 0;
+ req->tid = req->pid = 0;
+ if (win)
+ {
+ req->full_handle = handle;
+ if (win->thread)
+ {
+ req->tid = get_thread_id( win->thread );
+ req->pid = get_process_id( win->thread->process );
+ }
+ }
+}
