master f3481f21f7 1/2: Find a way to make restacking frames work on Haiku

[Po Lu]

branch: master
commit f3481f21f710ab41980623728917704bb25b3ae5
Author: Po Lu <luangruo@yahoo.com>
Commit: Po Lu <luangruo@yahoo.com>

    Find a way to make restacking frames work on Haiku
    
    * doc/lispref/frames.texi (Raising and Lowering): Update
    documentation to reflect that restacking frames is now
    supported on Haiku.
    * lisp/frame.el (haiku-frame-restack): New declaration.
    (frame-restack): Use `haiku-frame-restack' on Haiku.
    
    * src/haiku_support.cc (BWindow_send_behind):
    * src/haiku_support.h (BWindow_send_behind):
    * src/haikufns.c (Fhaiku_frame_restack): New functions.
    (syms_of_haikufns): New subr `haiku-frame-restack'.
---
 doc/lispref/frames.texi |  3 +--
 lisp/frame.el           |  3 +++
 src/haiku_support.cc    | 12 ++++++++++++
 src/haiku_support.h     |  3 +++
 src/haikufns.c          | 34 ++++++++++++++++++++++++++++++++++
 5 files changed, 53 insertions(+), 2 deletions(-)

diff --git a/doc/lispref/frames.texi b/doc/lispref/frames.texi
index bb5d4bf291..ceaa11529f 100644
--- a/doc/lispref/frames.texi
+++ b/doc/lispref/frames.texi
@@ -3165,8 +3165,7 @@ that if both frames are visible and their display areas 
overlap,
 third argument @var{above} is non-@code{nil}, this function restacks
 @var{frame1} above @var{frame2}.  This means that if both frames are
 visible and their display areas overlap, @var{frame1} will (partially)
-obscure @var{frame2}.@footnote{Restacking frames is not supported on
-Haiku, due to limitations imposed by the system.}
+obscure @var{frame2}.
 
 Technically, this function may be thought of as an atomic action
 performed in two steps: The first step removes @var{frame1}'s
diff --git a/lisp/frame.el b/lisp/frame.el
index 60ef563e59..62b73f3157 100644
--- a/lisp/frame.el
+++ b/lisp/frame.el
@@ -2019,6 +2019,7 @@ Return nil if DISPLAY contains no Emacs frame."
 (declare-function w32-frame-restack "w32fns.c" (frame1 frame2 &optional above))
 (declare-function ns-frame-restack "nsfns.m" (frame1 frame2 &optional above))
 (declare-function pgtk-frame-restack "pgtkfns.c" (frame1 frame2 &optional 
above))
+(declare-function haiku-frame-restack "haikufns.c" (frame1 frame2 &optional 
above))
 
 (defun frame-restack (frame1 frame2 &optional above)
   "Restack FRAME1 below FRAME2.
@@ -2049,6 +2050,8 @@ Some window managers may refuse to restack windows."
           (w32-frame-restack frame1 frame2 above))
          ((eq frame-type 'ns)
           (ns-frame-restack frame1 frame2 above))
+         ((eq frame-type 'haiku)
+          (haiku-frame-restack frame1 frame2 above))
          ((eq frame-type 'pgtk)
           (pgtk-frame-restack frame1 frame2 above))))
     (error "Cannot restack frames")))
diff --git a/src/haiku_support.cc b/src/haiku_support.cc
index 74e9765903..effd4c33a9 100644
--- a/src/haiku_support.cc
+++ b/src/haiku_support.cc
@@ -2990,3 +2990,15 @@ BWindow_set_size_alignment (void *window, int 
align_width, int align_height)
 #endif
   w->UnlockLooper ();
 }
+
+void
+BWindow_send_behind (void *window, void *other_window)
+{
+  BWindow *w = (BWindow *) window;
+  BWindow *other = (BWindow *) other_window;
+
+  if (!w->LockLooper ())
+    gui_abort ("Failed to lock window in order to send it behind another");
+  w->SendBehind (other);
+  w->UnlockLooper ();
+}
diff --git a/src/haiku_support.h b/src/haiku_support.h
index dd5e168d14..2b61ec1ac1 100644
--- a/src/haiku_support.h
+++ b/src/haiku_support.h
@@ -823,6 +823,9 @@ extern "C"
   extern void
   BWindow_sync (void *window);
 
+  extern void
+  BWindow_send_behind (void *window, void *other_window);
+
 #ifdef __cplusplus
   extern void *
   find_appropriate_view_for_draw (void *vw);
diff --git a/src/haikufns.c b/src/haikufns.c
index 6cd12f129c..0b7972f945 100644
--- a/src/haikufns.c
+++ b/src/haikufns.c
@@ -2321,6 +2321,39 @@ DEFUN ("x-display-save-under", Fx_display_save_under,
   return Qnil;
 }
 
+DEFUN ("haiku-frame-restack", Fhaiku_frame_restack, Shaiku_frame_restack, 2, 
3, 0,
+       doc: /* Restack FRAME1 below FRAME2.
+This means that if both frames are visible and the display areas of
+these frames overlap, FRAME2 (partially) obscures FRAME1.  If optional
+third argument ABOVE is non-nil, restack FRAME1 above FRAME2.  This
+means that if both frames are visible and the display areas of these
+frames overlap, FRAME1 (partially) obscures FRAME2.
+
+Some window managers may refuse to restack windows.  */)
+     (Lisp_Object frame1, Lisp_Object frame2, Lisp_Object above)
+{
+  struct frame *f1 = decode_live_frame (frame1);
+  struct frame *f2 = decode_live_frame (frame2);
+
+  check_window_system (f1);
+  check_window_system (f2);
+
+  block_input ();
+
+  if (NILP (above))
+    BWindow_send_behind (FRAME_HAIKU_WINDOW (f1),
+                        FRAME_HAIKU_WINDOW (f2));
+  else
+    BWindow_send_behind (FRAME_HAIKU_WINDOW (f2),
+                        FRAME_HAIKU_WINDOW (f1));
+  BWindow_sync (FRAME_HAIKU_WINDOW (f1));
+  BWindow_sync (FRAME_HAIKU_WINDOW (f2));
+
+  unblock_input ();
+
+  return Qnil;
+}
+
 frame_parm_handler haiku_frame_parm_handlers[] =
   {
     gui_set_autoraise,
@@ -2415,6 +2448,7 @@ syms_of_haikufns (void)
   defsubr (&Shaiku_put_resource);
   defsubr (&Shaiku_frame_list_z_order);
   defsubr (&Sx_display_save_under);
+  defsubr (&Shaiku_frame_restack);
 
   tip_timer = Qnil;
   staticpro (&tip_timer);