tools/toolbox: Add run convenience script

Wrapping the gnome-shell call with `dbus-run-session` is *mostly*
enough for testing, but not quite.

When running without gnome-session, the wayland display is not
propagated to the D-Bus daemon, so any app that is D-Bus activated
still opens in the host session.

This can be worked around by using a specific wayland-display name
and exporting it to the `dbus-run-session` environment up-front.

At this point the invocation is finicky enough to justify another
convenience script. This also gives us a place to expose some
useful features for testing, like forcing a right-to-left layout
or simulating the greeter.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2935>

tools/toolbox/run-gnome-shell.sh

@@ -0,0 +1,161 @@
+#!/bin/bash
+# vi: sw=2 ts=4
+
+set -e
+
+DEFAULT_TOOLBOX=gnome-shell-devel
+CONFIG_FILE=${XDG_CONFIG_HOME:-$HOME/.config}/gnome-shell-toolbox-tools.conf
+
+usage() {
+  cat <<-EOF
+	Usage: $(basename $0) [OPTION…]
+
+	Run gnome-shell from a toolbox
+
+	Options:
+	  -t, --toolbox=TOOLBOX   Use TOOLBOX instead of the default "$DEFAULT_TOOLBOX"
+
+	  --classic               Run in Classic mode
+	  --greeter               Run (simulated) login screen
+
+	  -2, --multi-monitor     Run with two monitors
+	  -0, --headless          Run headless
+
+	  --rtl                   Force right-to-left layout
+	  --locale=LOCALE         Use specified LOCALE
+
+	  --debug                 Run in gdb
+	  -v, --verbose           Enable debug logging
+
+	  --unsafe-mode           Do no restrict D-Bus APIs
+	  --force-animations      Force animations to be enabled
+
+	  --version               Print version
+	  -h, --help              Display this help
+
+	EOF
+}
+
+die() {
+  echo "$@" >&2
+  exit 1
+}
+
+find_locale() {
+  locale -a | sed -e "/^$1/!d" -e '/\.utf8$/I!d' | head -n 1
+}
+
+should_run_nested() {
+  [[ "$XDG_SESSION_TYPE" != "tty" ]] && [[ ! "$HEADLESS" ]]
+}
+
+# load defaults
+. $CONFIG_FILE
+TOOLBOX=$DEFAULT_TOOLBOX
+
+SHELL_ENV=(XDG_CURRENT_DESKTOP=GNOME)
+SHELL_ARGS=()
+
+TEMP=$(getopt \
+ --name $(basename $0) \
+ --options '20t:vh' \
+ --longoptions 'toolbox:' \
+ --longoptions 'classic' \
+ --longoptions 'greeter' \
+ --longoptions 'multi-monitor' \
+ --longoptions 'headless' \
+ --longoptions 'rtl' \
+ --longoptions 'locale:' \
+ --longoptions 'debug' \
+ --longoptions 'verbose' \
+ --longoptions 'unsafe-mode' \
+ --longoptions 'force-animations' \
+ --longoptions 'version' \
+ --longoptions 'help' \
+ -- "$@") || die "Run $(basename $0) --help to see available options"
+
+eval set -- "$TEMP"
+unset TEMP
+
+while true; do
+  case $1 in
+    -t|--toolbox)
+      TOOLBOX=$2
+      shift 2
+    ;;
+
+    --classic)
+      SHELL_ENV+=(XDG_CURRENT_DESKTOP=GNOME-Classic:GNOME)
+      SHELL_ARGS+=(--mode=classic)
+      shift
+    ;;
+
+    --greeter)
+      SHELL_ENV+=(GDM_GREETER_TEST=1)
+      SHELL_ARGS+=(--mode=gdm)
+      shift
+    ;;
+
+    -2|--multi-monitor)
+      SHELL_ENV+=(MUTTER_DEBUG_NUM_DUMMY_MONITORS=2)
+      shift
+    ;;
+
+    -0|--headless)
+      HEADLESS=1
+      SHELL_ARGS+=(--headless)
+      shift
+    ;;
+
+    --rtl)
+      SHELL_ENV+=(CLUTTER_TEXT_DIRECTION=rtl)
+      shift
+    ;;
+
+    --locale)
+      SHELL_ENV+=(LANG=$(find_locale $2))
+      shift 2
+    ;;
+
+    --debug)
+      GDB="gdb --args"
+      shift
+    ;;
+
+    -v|--verbose)
+      SHELL_ENV+=(
+        G_MESSAGES_DEBUG="GNOME Shell"
+        SHELL_DEBUG=backtrace-warnings
+      )
+      shift
+    ;;
+
+    --unsafe-mode|--force-animations|--version)
+      SHELL_ARGS+=($1)
+      shift
+    ;;
+
+    -h|--help)
+      usage
+      exit 0
+    ;;
+
+    --)
+      shift
+      break
+    ;;
+  esac
+done
+
+if should_run_nested; then
+  SHELL_ARGS+=( --nested )
+else
+  SHELL_ARGS+=( --wayland )
+fi
+
+display=toolbox-wayland-$RANDOM
+SHELL_ENV+=(WAYLAND_DISPLAY=$display)
+SHELL_ARGS+=(--wayland-display=$display)
+
+toolbox --container $TOOLBOX run \
+  env "${SHELL_ENV[@]}" dbus-run-session $GDB gnome-shell "${SHELL_ARGS[@]}"