UXP-elim-gtk2 revision 2 from Gord

1 files changed, 69 insertions, 1 deletions

diff --git a/newmoon/debian/patches/UXP-eliminate-need-for-GTK-2.patch b/newmoon/debian/patches/UXP-eliminate-need-for-GTK-2.patch
index c266f78..f28fd10 100644
--- a/newmoon/debian/patches/UXP-eliminate-need-for-GTK-2.patch
+++ b/newmoon/debian/patches/UXP-eliminate-need-for-GTK-2.patch
@@ -1,4 +1,4 @@
-# This patch was created by Gordon N. Squash.
+# This patch and its previous revision were created by Gordon N. Squash.
 #
 # This patch can be used to eliminate the Unified XUL Platform's need for both
 # GTK+ 2 and GTK+ 3, even when you are compiling UXP only to use GTK+ 3.
@@ -6,6 +6,14 @@
 # This patch is still highly experimental.  The author of this patch has not
 # yet encountered any issues with this patch, but there are no guarantees.
 #
+# This is revision 2 of the patch.  The previous revisions eliminated a stub
+# function from mozgtk which disabled the X Shared Memory (X MIT-SHM) extension
+# from getting used by Cairo.  Unfortunately, that function, while overly
+# simplistic, was necessary to ensure the guaranteed operability of UXP; in
+# other words, UXP crashed sometimes if this function wasn't present.
+# This revision re-introduces this function into the codebase -- but part of
+# libxul this time, not libmozgtk.
+#
 # WARNING!  This is not an official patch in any way, shape or form!  Do not
 #           contact the original authors of UXP for support of this patch!
 #
@@ -312,3 +320,63 @@ diff -uprN palemoon-28.12.0-original/palemoon/installer/package-manifest.in pale
  
  [browser]
  ; [Base Browser Files]
+# CHANGES MADE IN REVISION 2
+#
+# Hooray GTK+ 3 users!  UXP does not play well with Cairo!  Therefore we
+# need this separate file.  This code was borrowed from mozgtk.c.
+# According to bug #  1271100, basically if you scroll (or do almost anything)
+# while UXP is rendering something on the page, UXP is not designed properly
+# to handle this situation and a race condition results.  The race condition
+# ends up with the scratch buffer drawable UXP uses getting deleted.  When
+# this happens, the next operation UXP performs is a CopyArea request, to
+# copy the drawable to the actual window where this stuff is getting displayed.
+# The X server recognizes that the drawable has been deleted, signals an
+# error condition, and GTK, which catches the error, throws up its hands and
+# kills the whole #$@% application.
+#
+# This all apparently has something to do with the usage of the X MIT-SHM
+# extension.  Apparently by disabling Cairo's, and ultimately GTK's, use
+# of the SHM extension, this bug does not occur.  It turns out that the
+# dynamic linker will load this function first and the real function second;
+# Cairo will use this function and failures will be no more.  UXP however
+# uses XCB instead of XLib, so UXP still uses SHM.
+#
+# In other words, the Mozilla codebase does not play well with other libraries.
+# Now, the Mozilla and UXP people can say that the other libraries should play
+# well with Mozilla and UXP, but the fact is code should always adapt to error
+# conditions if possible -- error conditions should not adapt to code.
+#
+# But at the very least this stuff works!
+#
+diff -uprN palemoon-28.12.0-original/platform/widget/gtk/gtk3frictionworkarounds.c palemoon-28.12.0-patched/platform/widget/gtk/gtk3frictionworkarounds.c
+--- palemoon-28.12.0-original/platform/widget/gtk/gtk3frictionworkarounds.c     1969-12-31 19:00:00.000000000 -0500
++++ palemoon-28.12.0-patched/platform/widget/gtk/gtk3frictionworkarounds.c      2020-08-21 20:30:01.616049093 -0400
+@@ -0,0 +1,16 @@
++/*
++ * This file was added by Gordon N. Squash.  Please see his original patch
++ * for details on what this code is for.  If you have not received his patch
++ * then at least understand that THIS IS NOT THE OFFICIAL UXP SOURCE CODE IN
++ * ANY WAY, SHAPE OR FORM:  IT IS A PATCHED VERSION.  DO NOT CONTACT THE
++ * ORIGINAL DEVELOPERS OF UXP OR MOZILLA FOR SUPPORT OF THIS CODE.
++ */
++
++#include "mozilla/Types.h"
++#include <X11/Xlib.h>
++
++MOZ_EXPORT Bool
++XShmQueryExtension(Display* aDisplay)
++{
++  return False;
++}
+diff -uprN palemoon-28.12.0-original/platform/widget/gtk/moz.build palemoon-28.12.0-patched/platform/widget/gtk/moz.build
+--- palemoon-28.12.0-original/platform/widget/gtk/moz.build     2020-08-20 21:24:39.148073190 -0400
++++ palemoon-28.12.0-patched/platform/widget/gtk/moz.build      2020-08-21 20:31:09.660050615 -0400
+@@ -104,6 +104,7 @@ if CONFIG['MOZ_WIDGET_TOOLKIT'] == 'gtk2
+ else:
+     UNIFIED_SOURCES += [
+         'gtk3drawing.cpp',
++        'gtk3frictionworkarounds.c',
+         'nsApplicationChooser.cpp',
+         'WidgetStyleCache.cpp',
+     ]
+