installer: remove unused functions, pointless case, recursive calls and faulty breaks

I suspect the recursive calls were to work around the error caused by break
being called in a case statement which itself is within a while loop - the break
causes the while loop to terminate, bringing the installer to a grinding halt... whoops.

Now, menu_main() is called only from the main process loop, which we don't exit accidentally.

I've removed an entire case statement from do_install_quick() as this function either
performs an installation, or it doesn't - the case statement is pointless.

Due to the removal of whitespace, add ?w=1 in github.com when reviewing.

packages/tools/installer/scripts/installer

@@ -103,6 +103,7 @@ create_device_list() {
 
   if [ "$DEVICES" = "" ]; then
     msg_no_device
+    return 1
   fi
 
   for i in $DEVICES; do
@@ -111,6 +112,7 @@ create_device_list() {
     DEVICE_NAME=$(echo $DEVICE_MODEL ${DEVICE_SIZE} | sed 's/ /_/g')
     DEVICE_LIST="$DEVICE_LIST $i $DEVICE_NAME"
   done
+  return 0
 }
 
 do_install_quick() {
@@ -119,15 +121,14 @@ do_install_quick() {
   MSG_MENU="\nUse the up/down arrows to select the device you wish to install to.\n\nPlease select a device:"
   MSG_CANCEL="Back"
 
-  create_device_list
+  create_device_list || return
 
   whiptail --backtitle "$BACKTITLE" --cancel-button "$MSG_CANCEL" \
     $DIALOG_OPTIONS --title "$MSG_TITLE" --menu "$MSG_MENU" 20 50 5 \
     $DEVICE_LIST 2> $TMPDIR/device_for_install
+  [ $? -ne 0 ] && return
 
   # now we must do everything
-  case $? in
-    0)
   INSTALL_DEVICE=$(cat "$TMPDIR/device_for_install")
   INSTALL_DEVICE_FULL=$(echo $DEVICE_LIST | sed "s|.*$INSTALL_DEVICE \([^ ]*\).*|$INSTALL_DEVICE \1|")
 
@@ -151,18 +152,14 @@ do_install_quick() {
   DIALOG_OPTIONS="--defaultno"
   whiptail --backtitle "$BACKTITLE" --title "$MSG_TITLE" \
     $DIALOG_OPTIONS --yesno "$MSG_DETAIL" 0 0
-      if [ $? -ne 0 ]; then
+  [ $? -ne 0 ] && return
-        menu_main
-      fi
 
   MSG_TITLE="Confirmation before installing"
   MSG_DETAIL="\nThis is last chance to abort the installation!\n\nIf you continue the target disk will be wiped out:\n\n$INSTALL_DEVICE_FULL\n\n\n"
   DIALOG_OPTIONS="--defaultno"
   whiptail --backtitle "$BACKTITLE" --title "$MSG_TITLE" \
     $DIALOG_OPTIONS --yesno "$MSG_DETAIL" 0 0
-      if [ $? -ne 0 ]; then
+  [ $? -ne 0 ] && return
-        menu_main
-      fi
 
   # start the progress bar (whiptail --gauge)
   {
@@ -257,6 +254,7 @@ LABEL linux
  KERNEL /KERNEL
  APPEND boot=UUID=$UUID_SYSTEM disk=UUID=$UUID_STORAGE $SYSLINUX_PARAMETERS quiet
 EOF
+
     cat << EOF > $TMPDIR/part1/EFI/BOOT/grub.cfg
 set timeout="0"
 set default="LibreELEC"
@@ -266,6 +264,7 @@ menuentry "LibreELEC" {
 	linux /KERNEL boot=UUID=$UUID_SYSTEM disk=UUID=$UUID_STORAGE quiet
 }
 EOF
+
     # uefi boot / hybrid mode
     cp /usr/share/syslinux/bootx64.efi $TMPDIR/part1/EFI/BOOT
     cp /usr/share/syslinux/ldlinux.e64 $TMPDIR/part1/EFI/BOOT
@@ -305,16 +304,6 @@ EOF
   MSG_TITLE="@DISTRONAME@ Install Complete"
   MSG_DETAIL="You may now remove the install media and reboot.\n"
   whiptail --backtitle "$BACKTITLE" --title "$MSG_TITLE" --msgbox "$MSG_DETAIL" 7 52
-
-      menu_main
-      ;;
-    1)
-      menu_main
-      ;;
-    255)
-      do_poweroff
-      ;;
-  esac
 }
 
 msg_no_device() {
@@ -323,18 +312,6 @@ msg_no_device() {
   MSG_INFOBOX=" No devices were found. "
 
   whiptail --backtitle "$BACKTITLE" --title "$MSG_TITLE" --msgbox "$MSG_INFOBOX" 9 73
-
-  menu_main
-}
-
-msg_target_space() {
-  # show an error dialog for missing space
-  MSG_TITLE="TARGET SPACE"
-  MSG_INFOBOX="Not enough target space!\nInstallation aborted.\n"
-
-  whiptail --backtitle "$BACKTITLE" --title "$MSG_TITLE" --msgbox "$MSG_INFOBOX" 9 73
-
-  menu_main
 }
 
 msg_progress_install() {
@@ -348,15 +325,6 @@ msg_progress_install() {
   echo XXX
 }
 
-msg_install_ready() {
-  # show a dialog that we have installed
-  MSG_TITLE="INFORMATION"
-
-  whiptail --backtitle "$BACKTITLE" --title "$MSG_TITLE" --msgbox " $1" 7 73
-
-  menu_main
-}
-
 prompt_gpt() {
   GPT="0"
   UEFI="0"
@@ -403,16 +371,16 @@ out during the installation. \
   whiptail --backtitle "$BACKTITLE" --cancel-button "$MSG_CANCEL" \
     --title "$MSG_TITLE" --menu "$MSG_MENU" 18 73 3 \
       1 "Install @DISTRONAME@" \
-      2 "Installation log" \
+      2 "View installation log" \
       3 "Reboot" 2> $TMPDIR/mainmenu
 
   case $? in
     0)
       ITEM_MAINMENU=$(cat "$TMPDIR/mainmenu")
       case $ITEM_MAINMENU in
-        1) do_install_quick; break;;
+        1) do_install_quick;;
-        2) logfile_show; break;;
+        2) logfile_show;;
-        3) do_reboot;
+        3) do_reboot;;
       esac
       ;;
     1)
@@ -426,8 +394,6 @@ out during the installation. \
 
 logfile_show() {
   whiptail --textbox "$LOGFILE" 20 73 --scrolltext --backtitle "$BACKTITLE"
-  clear
-  menu_main
 }
 
 do_reboot() {