gui-libs/gtk: add a "poison" macro support to disable X/wayland

Many packages perform automagic dependencies on gdk's backend
implementations by checking if the macro is defined and then using the
code it unlocks, rather than having a buildsystem option such as
-Dwayland=true.

It's unfeasible to patch every such package's source code to add
configure options and respect them. Instead add a truly filthy hack and
permit gtk itself to selectively show or hide the windowing system in
use.

Bug: https://bugs.gentoo.org/624960
Signed-off-by: Eli Schwartz <eschwartz93@gmail.com>
Part-of: https://github.com/gentoo/gentoo/pull/37259
Signed-off-by: Eli Schwartz <eschwartz@gentoo.org>

4 files changed, 347 insertions, 0 deletions

diff --git a/gui-libs/gtk/files/0001-gdk-add-a-poison-macro-to-hide-GDK_WINDOWING_.patch b/gui-libs/gtk/files/0001-gdk-add-a-poison-macro-to-hide-GDK_WINDOWING_.patch
new file mode 100644
index 000000000000..652e9e116339
--- /dev/null
+++ b/gui-libs/gtk/files/0001-gdk-add-a-poison-macro-to-hide-GDK_WINDOWING_.patch
@@ -0,0 +1,91 @@
+From 0537043f72ea1a634b101efa9e11cc0a22baaf71 Mon Sep 17 00:00:00 2001
+From: Eli Schwartz <eschwartz93@gmail.com>
+Date: Wed, 19 Jun 2024 21:28:31 -0400
+Subject: [PATCH] gdk: add a "poison" macro to hide GDK_WINDOWING_*
+
+Many packages perform automagic dependencies on gdk's backend
+implementations by checking if the macro is defined and then using the
+code it unlocks, rather than having a buildsystem option such as
+-Dwayland=true.
+
+It's unfeasible to patch every such package's source code to add
+configure options and respect them. Instead add a truly filthy hack and
+permit gtk itself to selectively show or hide the windowing system in
+use.
+
+By default, we assume this macro is never defined. It should only ever
+be defined inside an ebuild, as such:
+
+```
+use wayland || append-cflags -DGENTOO_GTK_HIDE_WAYLAND
+use X || append-cflags -DGENTOO_GTK_HIDE_X11
+```
+
+When seen, this will prevent code using "#ifdef GDK_WINDOWING_*" from
+seeing the define, so the automagic dependency won't be picked up. It
+will also cause any attempt to #include the backend-specific headers to
+bug out.
+
+Bug: https://bugs.gentoo.org/624960
+Signed-off-by: Eli Schwartz <eschwartz93@gmail.com>
+---
+ gdk/gdkconfig.h.meson    | 7 +++++++
+ gdk/wayland/gdkwayland.h | 4 ++++
+ gdk/x11/gdkx.h           | 4 ++++
+ 3 files changed, 15 insertions(+)
+
+diff --git a/gdk/gdkconfig.h.meson b/gdk/gdkconfig.h.meson
+index d5b48f3184..22baab52ae 100644
+--- a/gdk/gdkconfig.h.meson
++++ b/gdk/gdkconfig.h.meson
+@@ -10,10 +10,17 @@
+ G_BEGIN_DECLS
+ 
+ 
++#ifndef GENTOO_GTK_HIDE_X11
+ #mesondefine GDK_WINDOWING_X11
++#endif
++
+ #mesondefine GDK_WINDOWING_BROADWAY
+ #mesondefine GDK_WINDOWING_MACOS
++
++#ifndef GENTOO_GTK_HIDE_WAYLAND
+ #mesondefine GDK_WINDOWING_WAYLAND
++#endif
++
+ #mesondefine GDK_WINDOWING_WIN32
+ 
+ #mesondefine GDK_RENDERING_CAIRO
+diff --git a/gdk/wayland/gdkwayland.h b/gdk/wayland/gdkwayland.h
+index 846445910e..5d84619295 100644
+--- a/gdk/wayland/gdkwayland.h
++++ b/gdk/wayland/gdkwayland.h
+@@ -24,6 +24,10 @@
+ 
+ #pragma once
+ 
++#ifdef GENTOO_GTK_HIDE_WAYLAND
++  #error "A Gentoo ebuild has hidden wayland and it cannot be used in this compilation unit. Please file a bug if you see this error."
++#endif
++
+ #include <gdk/gdk.h>
+ 
+ #define __GDKWAYLAND_H_INSIDE__
+diff --git a/gdk/x11/gdkx.h b/gdk/x11/gdkx.h
+index 6bef6b6de8..d4f8b94550 100644
+--- a/gdk/x11/gdkx.h
++++ b/gdk/x11/gdkx.h
+@@ -24,6 +24,10 @@
+ 
+ #pragma once
+ 
++#ifdef GENTOO_GTK_HIDE_X11
++  #error "A Gentoo ebuild has hidden x11 and it cannot be used in this compilation unit. Please file a bug if you see this error."
++#endif
++
+ #include <gdk/gdk.h>
+ 
+ #include <X11/Xlib.h>
+-- 
+2.44.2
+
diff --git a/gui-libs/gtk/gtk-4.12.5-r2.ebuild b/gui-libs/gtk/gtk-4.12.5-r2.ebuild
new file mode 100644
index 000000000000..aaf7a773087e
--- /dev/null
+++ b/gui-libs/gtk/gtk-4.12.5-r2.ebuild
@@ -0,0 +1,240 @@
+# Copyright 2023-2024 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+PYTHON_COMPAT=( python3_{10..12} )
+inherit gnome.org gnome2-utils meson optfeature python-any-r1 toolchain-funcs virtualx xdg
+
+DESCRIPTION="GTK is a multi-platform toolkit for creating graphical user interfaces"
+HOMEPAGE="https://www.gtk.org/ https://gitlab.gnome.org/GNOME/gtk/"
+
+LICENSE="LGPL-2+"
+SLOT="4"
+IUSE="aqua broadway cloudproviders colord cups examples ffmpeg gstreamer +introspection sysprof test vulkan wayland +X cpu_flags_x86_f16c"
+REQUIRED_USE="
+	|| ( aqua wayland X )
+	test? ( introspection )
+"
+
+KEYWORDS="~alpha ~amd64 ~arm ~arm64 ~ia64 ~loong ~ppc ~ppc64 ~riscv ~sparc ~x86"
+
+COMMON_DEPEND="
+	>=dev-libs/glib-2.76.0:2
+	>=x11-libs/cairo-1.17.6[aqua?,glib,svg(+),X?]
+	>=x11-libs/pango-1.50.0[introspection?]
+	>=dev-libs/fribidi-1.0.6
+	>=media-libs/harfbuzz-2.6.0:=
+	>=x11-libs/gdk-pixbuf-2.30:2[introspection?]
+	media-libs/libpng:=
+	media-libs/tiff:=
+	media-libs/libjpeg-turbo:=
+	>=media-libs/libepoxy-1.4[egl(+),X(+)?]
+	>=media-libs/graphene-1.10.0[introspection?]
+	app-text/iso-codes
+	x11-misc/shared-mime-info
+
+	cloudproviders? ( net-libs/libcloudproviders )
+	colord? ( >=x11-misc/colord-0.1.9:0= )
+	cups? ( >=net-print/cups-2.0 )
+	ffmpeg? ( media-video/ffmpeg:= )
+	gstreamer? (
+		>=media-libs/gst-plugins-bad-1.12.3:1.0
+		>=media-libs/gst-plugins-base-1.12.3:1.0[opengl]
+	)
+	introspection? ( >=dev-libs/gobject-introspection-1.76:= )
+	vulkan? ( media-libs/vulkan-loader:= )
+	wayland? (
+		>=dev-libs/wayland-1.21.0
+		>=dev-libs/wayland-protocols-1.31
+		media-libs/mesa[wayland]
+		>=x11-libs/libxkbcommon-0.2
+	)
+	X? (
+		>=app-accessibility/at-spi2-core-2.46.0
+		media-libs/fontconfig
+		media-libs/mesa[X(+)]
+		x11-libs/libX11
+		>=x11-libs/libXi-1.8
+		x11-libs/libXext
+		>=x11-libs/libXrandr-1.5
+		x11-libs/libXcursor
+		x11-libs/libXfixes
+		x11-libs/libXdamage
+		x11-libs/libXinerama
+	)
+"
+DEPEND="${COMMON_DEPEND}
+	sysprof? ( >=dev-util/sysprof-capture-3.40.1:4 )
+	X? ( x11-base/xorg-proto )
+"
+RDEPEND="${COMMON_DEPEND}
+	>=dev-util/gtk-update-icon-cache-3
+"
+# librsvg for svg icons (PDEPEND to avoid circular dep), bug #547710
+PDEPEND="
+	gnome-base/librsvg
+	>=x11-themes/adwaita-icon-theme-3.14
+"
+BDEPEND="
+	dev-libs/gobject-introspection-common
+	introspection? (
+		${PYTHON_DEPS}
+		$(python_gen_any_dep '
+			dev-python/pygobject:3[${PYTHON_USEDEP}]
+		')
+	)
+	dev-python/docutils
+	dev-libs/glib
+	>=dev-util/gdbus-codegen-2.48
+	dev-util/glib-utils
+	>=sys-devel/gettext-0.19.7
+	virtual/pkgconfig
+	vulkan? ( media-libs/shaderc )
+	wayland? (
+		dev-util/wayland-scanner
+	)
+	test? (
+		dev-libs/glib:2
+		media-fonts/cantarell
+		wayland? ( dev-libs/weston[headless] )
+	)
+"
+
+PATCHES=(
+	# Gentoo-specific patch to add a "poison" macro support, allowing other ebuilds
+	# with USE="-wayland -X" to trick gtk into claiming that it wasn't built with
+	# such support.
+	# https://bugs.gentoo.org/624960
+	"${FILESDIR}"/0001-gdk-add-a-poison-macro-to-hide-GDK_WINDOWING_.patch
+)
+
+python_check_deps() {
+	python_has_version "dev-python/pygobject:3[${PYTHON_USEDEP}]" || return
+}
+
+pkg_setup() {
+	use introspection && python-any-r1_pkg_setup
+}
+
+src_prepare() {
+	default
+	xdg_environment_reset
+
+	# Nothing should use gtk4-update-icon-cache and an unversioned one is shipped by dev-util/gtk-update-icon-cache
+	sed -i \
+		-e '/gtk4-update-icon-cache/d' \
+		docs/reference/gtk/meson.build \
+		tools/meson.build \
+		|| die
+
+	# The border-image-excess-size.ui test is known to fail on big-endian platforms
+	# See https://gitlab.gnome.org/GNOME/gtk/-/issues/5904
+	if [[ $(tc-endian) == big ]]; then
+		sed -i \
+			-e "/border-image-excess-size.ui/d" \
+			-e "/^xfails =/a 'border-image-excess-size.ui'," \
+			testsuite/reftests/meson.build || die
+	fi
+}
+
+src_configure() {
+	local emesonargs=(
+		# GDK backends
+		$(meson_use X x11-backend)
+		$(meson_use wayland wayland-backend)
+		$(meson_use broadway broadway-backend)
+		-Dwin32-backend=false
+		$(meson_use aqua macos-backend)
+
+		# Media backends
+		$(meson_feature ffmpeg media-ffmpeg)
+		$(meson_feature gstreamer media-gstreamer)
+
+		# Print backends
+		-Dprint-cpdb=disabled
+		$(meson_feature cups print-cups)
+
+		# Optional dependencies
+		$(meson_feature vulkan)
+		$(meson_feature cloudproviders)
+		$(meson_feature sysprof)
+		-Dtracker=disabled  # tracker3 is not packaged in Gentoo yet
+		$(meson_feature colord)
+		# Expected to fail with GCC < 11
+		# See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71993
+		$(meson_feature cpu_flags_x86_f16c f16c)
+
+		# Introspection
+		$(meson_feature introspection)
+
+		# Documentation
+		-Ddocumentation=false # we ship pregenerated API docs from tarball
+		-Dscreenshots=false
+		-Dman-pages=true
+
+		# Demos, examples, and tests
+		-Ddemo-profile=default
+		$(meson_use examples build-demos)
+		$(meson_use test build-testsuite)
+		$(meson_use examples build-examples)
+		-Dbuild-tests=false
+	)
+	meson_src_configure
+}
+
+src_test() {
+	"${BROOT}${GLIB_COMPILE_SCHEMAS}" --allow-any-name "${S}/gtk" || die
+
+	if use X; then
+		einfo "Running tests under X"
+		GSETTINGS_SCHEMA_DIR="${S}/gtk" virtx meson_src_test --setup=x11 --timeout-multiplier=130
+	fi
+
+	if use wayland; then
+		einfo "Running tests under Weston"
+
+		export XDG_RUNTIME_DIR="$(mktemp -p $(pwd) -d xdg-runtime-XXXXXX)"
+
+		weston --backend=headless-backend.so --socket=wayland-5 --idle-time=0 &
+		compositor=$!
+		export WAYLAND_DISPLAY=wayland-5
+
+		GSETTINGS_SCHEMA_DIR="${S}/gtk" meson_src_test --setup=wayland --timeout-multiplier=130
+
+		exit_code=$?
+		kill ${compositor}
+	fi
+}
+
+src_install() {
+	meson_src_install
+
+	insinto /usr/share/gtk-doc/html
+	# This will install API docs specific to X11 and wayland regardless of USE flags, but this is intentional
+	doins -r "${S}"/docs/reference/{gtk/gtk4,gsk/gsk4,gdk/gdk4{,-wayland,-x11}}
+}
+
+pkg_preinst() {
+	xdg_pkg_preinst
+	gnome2_schemas_savelist
+}
+
+pkg_postinst() {
+	xdg_pkg_postinst
+	gnome2_schemas_update
+
+	if ! has_version "app-text/evince"; then
+		elog "Please install app-text/evince for print preview functionality."
+		elog "Alternatively, check \"gtk-print-preview-command\" documentation and"
+		elog "add it to your settings.ini file."
+	fi
+
+	if use examples ; then
+		optfeature "syntax highlighting in gtk4-demo" app-text/highlight
+	fi
+}
+
+pkg_postrm() {
+	xdg_pkg_postrm
+	gnome2_schemas_update
+}
diff --git a/gui-libs/gtk/gtk-4.14.3.ebuild b/gui-libs/gtk/gtk-4.14.3-r1.ebuild
index 7f0c8930ab74..00d8f5bbcaa1 100644
--- a/gui-libs/gtk/gtk-4.14.3.ebuild
+++ b/gui-libs/gtk/gtk-4.14.3-r1.ebuild
@@ -108,6 +108,14 @@ BDEPEND="
 	)
 "
 
+PATCHES=(
+	# Gentoo-specific patch to add a "poison" macro support, allowing other ebuilds
+	# with USE="-wayland -X" to trick gtk into claiming that it wasn't built with
+	# such support.
+	# https://bugs.gentoo.org/624960
+	"${FILESDIR}"/0001-gdk-add-a-poison-macro-to-hide-GDK_WINDOWING_.patch
+)
+
 python_check_deps() {
 	python_has_version "dev-python/pygobject:3[${PYTHON_USEDEP}]" || return
 }
diff --git a/gui-libs/gtk/gtk-4.14.4.ebuild b/gui-libs/gtk/gtk-4.14.4-r1.ebuild
index 7f0c8930ab74..00d8f5bbcaa1 100644
--- a/gui-libs/gtk/gtk-4.14.4.ebuild
+++ b/gui-libs/gtk/gtk-4.14.4-r1.ebuild
@@ -108,6 +108,14 @@ BDEPEND="
 	)
 "
 
+PATCHES=(
+	# Gentoo-specific patch to add a "poison" macro support, allowing other ebuilds
+	# with USE="-wayland -X" to trick gtk into claiming that it wasn't built with
+	# such support.
+	# https://bugs.gentoo.org/624960
+	"${FILESDIR}"/0001-gdk-add-a-poison-macro-to-hide-GDK_WINDOWING_.patch
+)
+
 python_check_deps() {
 	python_has_version "dev-python/pygobject:3[${PYTHON_USEDEP}]" || return
 }