Description: Add configure option to bypass boot menu if possible
 If other operating systems are installed, then automatically unhide the
 menu.  Otherwise, if GRUB_HIDDEN_TIMEOUT is 0, then use keystatus if
 available to check whether Shift is pressed.  If it is, show the menu,
 otherwise boot immediately.  If keystatus is not available, then fall back
 to a short delay interruptible with Escape.
 .
 This may or may not remain Ubuntu-specific, although it's not obviously
 wanted upstream.  It implements a requirement of
 https://wiki.ubuntu.com/DesktopExperienceTeam/KarmicBootExperienceDesignSpec#Bootloader.
Author: Colin Watson <cjwatson@ubuntu.com>
Forwarded: no
Last-Update: 2013-11-12

Index: b/configure.ac
===================================================================
--- a/configure.ac
+++ b/configure.ac
@@ -1087,6 +1087,17 @@
 fi
 AC_SUBST([QUIET_BOOT])
 
+AC_ARG_ENABLE([quick-boot],
+              [AS_HELP_STRING([--enable-quick-boot],
+                              [bypass boot menu if possible (default=no)])],
+              [], [enable_quick_boot=no])
+if test x"$enable_quick_boot" = xyes ; then
+  QUICK_BOOT=1
+else
+  QUICK_BOOT=0
+fi
+AC_SUBST([QUICK_BOOT])
+
 LIBS=""
 
 AC_SUBST([FONT_SOURCE])
Index: b/util/grub.d/00_header.in
===================================================================
--- a/util/grub.d/00_header.in
+++ b/util/grub.d/00_header.in
@@ -23,6 +23,7 @@
 exec_prefix="@exec_prefix@"
 datarootdir="@datarootdir@"
 grub_lang=`echo $LANG | cut -d . -f 1`
+quick_boot="@QUICK_BOOT@"
 
 export TEXTDOMAIN=@PACKAGE@
 export TEXTDOMAINDIR="@localedir@"
@@ -272,7 +273,7 @@
 
 make_timeout ()
 {
-    if [ "x${1}" != "x" ] ; then
+    if [ "$quick_boot" = 0 ] && [ "x${1}" != "x" ] ; then
 	if [ "x${GRUB_HIDDEN_TIMEOUT_QUIET}" = "xtrue" ] ; then
 	    verbose=
 	else
Index: b/util/grub.d/30_os-prober.in
===================================================================
--- a/util/grub.d/30_os-prober.in
+++ b/util/grub.d/30_os-prober.in
@@ -20,18 +20,78 @@
 prefix="@prefix@"
 exec_prefix="@exec_prefix@"
 datarootdir="@datarootdir@"
+quick_boot="@QUICK_BOOT@"
 
 export TEXTDOMAIN=@PACKAGE@
 export TEXTDOMAINDIR="@localedir@"
 
 . "@datadir@/@PACKAGE@/grub-mkconfig_lib"
 
+found_other_os=
+
+make_timeout () {
+  if [ "x${found_other_os}" = "x" ] ; then
+    if [ "x${1}" != "x" ] ; then
+      if [ "x${GRUB_HIDDEN_TIMEOUT_QUIET}" = "xtrue" ] ; then
+	verbose=
+      else
+	verbose=" --verbose"
+      fi
+
+      if [ "x${1}" = "x0" ] ; then
+	cat <<EOF
+if [ "x\${timeout}" != "x-1" ]; then
+  if keystatus; then
+    if keystatus --shift; then
+      set timeout=-1
+    else
+      set timeout=0
+    fi
+  else
+    if sleep$verbose --interruptible 3 ; then
+      set timeout=0
+    fi
+  fi
+fi
+EOF
+      else
+	cat << EOF
+if [ "x\${timeout}" != "x-1" ]; then
+  if sleep$verbose --interruptible ${GRUB_HIDDEN_TIMEOUT} ; then
+    set timeout=0
+  fi
+fi
+EOF
+      fi
+    fi
+  fi
+}
+
+adjust_timeout () {
+  if [ "$quick_boot" = 0 ]; then
+    return
+  fi
+  if [ "x$GRUB_BUTTON_CMOS_ADDRESS" != "x" ]; then
+    cat <<EOF
+if cmostest $GRUB_BUTTON_CMOS_ADDRESS ; then
+EOF
+    make_timeout "${GRUB_HIDDEN_TIMEOUT_BUTTON}" "${GRUB_TIMEOUT_BUTTON}"
+    echo else
+    make_timeout "${GRUB_HIDDEN_TIMEOUT}" "${GRUB_TIMEOUT}"
+    echo fi
+  else
+    make_timeout "${GRUB_HIDDEN_TIMEOUT}" "${GRUB_TIMEOUT}"
+  fi
+}
+
 if [ "x${GRUB_DISABLE_OS_PROBER}" = "xtrue" ]; then
+  adjust_timeout
   exit 0
 fi
 
 if [ -z "`which os-prober 2> /dev/null`" -o -z "`which linux-boot-prober 2> /dev/null`" ] ; then
   # missing os-prober and/or linux-boot-prober
+  adjust_timeout
   exit 0
 fi
 
@@ -43,10 +103,12 @@
 OSPROBED="`os-prober | tr ' ' '^' | paste -s -d ' '`"
 if [ -z "${OSPROBED}" ] ; then
   # empty os-prober output, nothing doing
+  adjust_timeout
   exit 0
 fi
 
 osx_entry() {
+    found_other_os=1
     if [ x$2 = x32 ]; then
         # TRANSLATORS: it refers to kernel architecture (32-bit)
 	bitstr="$(gettext "(32-bit)")"
@@ -146,6 +208,7 @@
 	  ;;
       esac
 
+      found_other_os=1
 	  onstr="$(gettext_printf "(on %s)" "${DEVICE}")"
       cat << EOF
 menuentry '$(echo "${LONGNAME} $onstr" | grub_quote)' --class windows --class os \$menuentry_id_option 'osprober-chain-$(grub_get_device_id "${DEVICE}")' {
@@ -169,6 +232,7 @@
 EOF
     ;;
     efi)
+      found_other_os=1
       EFIPATH=${DEVICE#*@}
       DEVICE=${DEVICE%@*}
       cat << EOF
@@ -211,6 +275,7 @@
 	  [ "${prepare_boot_cache}" ] || continue
 	fi
 
+	found_other_os=1
 	onstr="$(gettext_printf "(on %s)" "${DEVICE}")"
 	recovery_params="$(echo "${LPARAMS}" | grep 'single\|recovery')" || true
 	counter=1
@@ -277,6 +342,7 @@
       osx_entry xnu_kernel64 64
     ;;
     hurd)
+      found_other_os=1
       onstr="$(gettext_printf "(on %s)" "${DEVICE}")"
       cat << EOF
 menuentry '$(echo "${LONGNAME} $onstr" | grub_quote)' --class hurd --class gnu --class os \$menuentry_id_option 'osprober-gnuhurd-/boot/gnumach.gz-false-$(grub_get_device_id "${DEVICE}")' {
@@ -309,3 +375,5 @@
     ;;
   esac
 done
+
+adjust_timeout