From d8977408fd48f0ab220e2897bbaa7456f23650a6 Mon Sep 17 00:00:00 2001
From: Richard Grenville <pyxlcy@gmail.com>
Date: Mon, 21 Oct 2013 22:17:01 +0800
Subject: [PATCH] Bug fix #153: Possible fix for a rare timing issue

Possible fix for a very rare timing issue in focus detection. Compton
may fail to detect the currently focused window, when a window newly
mapped gets focused, we failed to listen to events and get FocusIn from
it in time, and a series of focus change events before it happens stay
in the event queue and puzzled compton. My choice is to force focus
recheck on all focus-related events. More roundtrips to X, but not
necessarily worse performance, due to the high cost of focus flipping
especially when there's a lot of conditions. Thanks to SlackBox for
reporting.  (#153)
---
 Makefile      |  2 +-
 src/common.h  |  1 +
 src/compton.c | 20 ++++++++------------
 3 files changed, 10 insertions(+), 13 deletions(-)

diff --git a/Makefile b/Makefile
index 655c77da..701308b6 100644
--- a/Makefile
+++ b/Makefile
@@ -49,7 +49,7 @@ ifeq "$(NO_VSYNC_DRM)" ""
   CFG += -DCONFIG_VSYNC_DRM
 endif
 
-# ==== OpenGL VSync ====
+# ==== OpenGL ====
 ifeq "$(NO_VSYNC_OPENGL)" ""
   CFG += -DCONFIG_VSYNC_OPENGL
   # -lGL must precede some other libraries, or it segfaults on FreeBSD (#74)
diff --git a/src/common.h b/src/common.h
index eadaafd9..f8531bcb 100644
--- a/src/common.h
+++ b/src/common.h
@@ -30,6 +30,7 @@
 // #define DEBUG_GLX_GLSL   1
 // #define DEBUG_GLX_ERR    1
 // #define DEBUG_GLX_MARK   1
+// #define DEBUG_GLX_PAINTREG 1
 // #define MONITOR_REPAINT  1
 
 // Whether to enable PCRE regular expression support in blacklists, enabled
diff --git a/src/compton.c b/src/compton.c
index 68577f1e..0c985528 100644
--- a/src/compton.c
+++ b/src/compton.c
@@ -781,6 +781,12 @@ recheck_focus(session_t *ps) {
 
   win *w = find_win_all(ps, wid);
 
+#ifdef DEBUG_EVENTS
+  print_timestamp(ps);
+  printf_dbgf("(): %#010lx (%#010lx \"%s\") focused.\n", wid,
+      (w ? w->id: None), (w ? w->name: NULL));
+#endif
+
   // And we set the focus state here
   if (w) {
     win_set_focused(ps, w, true);
@@ -3815,12 +3821,7 @@ ev_focus_in(session_t *ps, XFocusChangeEvent *ev) {
   ev_focus_report(ev);
 #endif
 
-  if (!ev_focus_accept(ev))
-    return;
-
-  win *w = find_win_all(ps, ev->window);
-  if (w)
-    win_set_focused(ps, w, true);
+  recheck_focus(ps);
 }
 
 inline static void
@@ -3829,12 +3830,7 @@ ev_focus_out(session_t *ps, XFocusChangeEvent *ev) {
   ev_focus_report(ev);
 #endif
 
-  if (!ev_focus_accept(ev))
-    return;
-
-  win *w = find_win_all(ps, ev->window);
-  if (w)
-    win_set_focused(ps, w, false);
+  recheck_focus(ps);
 }
 
 inline static void