Attempt to fix hangs on MS-Windows due to C-g

* src/w32uniscribe.c (uniscribe_otf_capability): Set
inhibit-quit around calls to otf_features, because the latter
cons Lisp data structures while we are in a critical section.
* src/xdisp.c (ALLOCATE_HDC) [HAVE_NTGUI]: Set inhibit-quit.
(RELEASE_HDC) [HAVE_NTGUI]: Restore inhibit-quit.
(OPTIONAL_HDC, DECLARE_HDC): Remove macros, their job is now
done by ALLOCATE_HDC and by a single #ifdef.
(draw_glyphs): Adapt to the above changes in macros.
(Bug#34059)

1 files changed, 18 insertions, 13 deletions

diff --git a/src/xdisp.c b/src/xdisp.c
index 274ab8ddf51..94ce1c29a0c 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -25619,22 +25619,28 @@ dump_glyph_string (struct glyph_string *s)
    face-override for drawing S.  */
 
 #ifdef HAVE_NTGUI
-#define OPTIONAL_HDC(hdc)  HDC hdc,
-#define DECLARE_HDC(hdc)   HDC hdc;
-#define ALLOCATE_HDC(hdc, f) hdc = get_frame_dc ((f))
-#define RELEASE_HDC(hdc, f)  release_frame_dc ((f), (hdc))
-#endif
-
-#ifndef OPTIONAL_HDC
-#define OPTIONAL_HDC(hdc)
-#define DECLARE_HDC(hdc)
-#define ALLOCATE_HDC(hdc, f)
-#define RELEASE_HDC(hdc, f)
+/* We set inhibit-quit here due to paranoia: get_frame_dc acquires the
+   critical section, and we cannot QUIT while we hold the critical
+   section.  If any of the code run by callers of ALLOCATE_HDC happens
+   to call Lisp (might be possible due to all the hooks lying around),
+   we must prevent it from quitting.  */
+# define ALLOCATE_HDC(hdc, f)			\
+  Lisp_Object prev_quit = Vinhibit_quit;	\
+  Vinhibit_quit = Qt;				\
+  HDC hdc = get_frame_dc ((f))
+# define RELEASE_HDC(hdc, f)			\
+  release_frame_dc ((f), (hdc));		\
+  Vinhibit_quit = prev_quit
+#else
+# define ALLOCATE_HDC(hdc, f)
+# define RELEASE_HDC(hdc, f)
 #endif
 
 static void
 init_glyph_string (struct glyph_string *s,
-		   OPTIONAL_HDC (hdc)
+#ifdef HAVE_NTGUI
+		   HDC hdc,
+#endif
 		   XChar2b *char2b, struct window *w, struct glyph_row *row,
 		   enum glyph_row_area area, int start, enum draw_glyphs_face hl)
 {
@@ -26674,7 +26680,6 @@ draw_glyphs (struct window *w, int x, struct glyph_row *row,
   struct glyph_string *clip_head = NULL, *clip_tail = NULL;
   int i, j, x_reached, last_x, area_left = 0;
   struct frame *f = XFRAME (WINDOW_FRAME (w));
-  DECLARE_HDC (hdc);
 
   ALLOCATE_HDC (hdc, f);