Fix creation of frames on MS-Windows: don't cons Lisp objects in input thread.

 src/w32fns.c (w32_createwindow): Accept an additional argument, an
 array of 2 values specifying the coordinates of the frame's
 top-left corner.  Use these values instead of calling x_get_arg,
 which can cons Lisp objects, and therefore cannot be called except
 from the main thread.  Remove redundant tests for the default
 values.
 (my_create_window): Move the calculation of the coordinates of the
 frame's top-left edge here.  Pass them to the input thread via the
 second parameter of the WM_EMACS_CREATEWINDOW message.  See
 http://lists.gnu.org/archive/html/emacs-devel/2014-09/msg00892.html
 for the details.

2 files changed, 44 insertions, 17 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index cc04e0cd826..fdc30da96b6 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,17 @@
+2014-09-30  Eli Zaretskii  <eliz@gnu.org>
+
+        * w32fns.c (w32_createwindow): Accept an additional argument, an
+        array of 2 values specifying the coordinates of the frame's
+        top-left corner.  Use these values instead of calling x_get_arg,
+        which can cons Lisp objects, and therefore cannot be called except
+        from the main thread.  Remove redundant tests for the default
+        values.
+        (my_create_window): Move the calculation of the coordinates of the
+        frame's top-left edge here.  Pass them to the input thread via the
+        second parameter of the WM_EMACS_CREATEWINDOW message.  See
+        http://lists.gnu.org/archive/html/emacs-devel/2014-09/msg00892.html
+        for the details.
+
 2014-09-29  Eli Zaretskii  <eliz@gnu.org>
 
         * xdisp.c (cursor_row_fully_visible_p): Update commentary.
diff --git a/src/w32fns.c b/src/w32fns.c
index 1c73cda469a..bc95005f52a 100644
--- a/src/w32fns.c
+++ b/src/w32fns.c
@@ -1911,13 +1911,12 @@ w32_createscrollbar (struct frame *f, struct scroll_bar * bar)
 }
 
 static void
-w32_createwindow (struct frame *f)
+w32_createwindow (struct frame *f, int *coords)
 {
   HWND hwnd;
   RECT rect;
-  Lisp_Object top = Qunbound;
-  Lisp_Object left = Qunbound;
-  struct w32_display_info *dpyinfo = &one_w32_display_info;
+  int top;
+  int left;
 
   rect.left = rect.top = 0;
   rect.right = FRAME_PIXEL_WIDTH (f);
@@ -1932,25 +1931,21 @@ w32_createwindow (struct frame *f)
 
   if (f->size_hint_flags & USPosition || f->size_hint_flags & PPosition)
     {
-      XSETINT (left, f->left_pos);
-      XSETINT (top, f->top_pos);
+      left = f->left_pos;
+      top = f->top_pos;
     }
-  else if (EQ (left, Qunbound) && EQ (top, Qunbound))
+  else
     {
-      /* When called with RES_TYPE_NUMBER, w32_get_arg will return zero
-         for anything that is not a number and is not Qunbound.  */
-      left = x_get_arg (dpyinfo, Qnil, Qleft, "left", "Left", RES_TYPE_NUMBER);
-      top = x_get_arg (dpyinfo, Qnil, Qtop, "top", "Top", RES_TYPE_NUMBER);
+      left = coords[0];
+      top = coords[1];
     }
 
   FRAME_W32_WINDOW (f) = hwnd
     = CreateWindow (EMACS_CLASS,
                     f->namebuf,
                     f->output_data.w32->dwStyle | WS_CLIPCHILDREN,
-                    EQ (left, Qunbound) ? CW_USEDEFAULT : XINT (left),
-                    EQ (top, Qunbound) ? CW_USEDEFAULT : XINT (top),
-                    rect.right - rect.left,
-                    rect.bottom - rect.top,
+                    left, top,
+                    rect.right - rect.left, rect.bottom - rect.top,
                     NULL,
                     NULL,
                     hinst,
@@ -2468,7 +2463,8 @@ w32_msg_pump (deferred_msg * msg_buf)
                  the patch for XP is not publicly available until XP SP3,
                  and older versions will never be patched.  */
               CoInitialize (NULL);
-              w32_createwindow ((struct frame *) msg.wParam);
+              w32_createwindow ((struct frame *) msg.wParam,
+                                (int *) msg.lParam);
               if (!PostThreadMessage (dwMainThreadId, WM_EMACS_DONE, 0, 0))
                 emacs_abort ();
               break;
@@ -4069,8 +4065,25 @@ static void
 my_create_window (struct frame * f)
 {
   MSG msg;
+  static int coords[2];
+  Lisp_Object left, top;
+  struct w32_display_info *dpyinfo = &one_w32_display_info;
+
+  /* When called with RES_TYPE_NUMBER, x_get_arg will return zero for
+     anything that is not a number and is not Qunbound.  */
+  left = x_get_arg (dpyinfo, Qnil, Qleft, "left", "Left", RES_TYPE_NUMBER);
+  top = x_get_arg (dpyinfo, Qnil, Qtop, "top", "Top", RES_TYPE_NUMBER);
+  if (EQ (left, Qunbound))
+    coords[0] = CW_USEDEFAULT;
+  else
+    coords[0] = XINT (left);
+  if (EQ (top, Qunbound))
+    coords[1] = CW_USEDEFAULT;
+  else
+    coords[1] = XINT (top);
 
-  if (!PostThreadMessage (dwWindowsThreadId, WM_EMACS_CREATEWINDOW, (WPARAM)f, 0))
+  if (!PostThreadMessage (dwWindowsThreadId, WM_EMACS_CREATEWINDOW,
+                          (WPARAM)f, (LPARAM)coords))
     emacs_abort ();
   GetMessage (&msg, NULL, WM_EMACS_DONE, WM_EMACS_DONE);
 }