stagefiles: further robustify with auto filenames

as suggested by Raphaël

rather than have fixed stagefile filename strings at all in the scripts,
use `$(basename $0)` to use the name of the script (which is the same for
almost all cases anyway, and the stage files are supposed to be almost
exclusively unique per-script). we can thus simplify things by determining
the filename for most use cases within the functions themselves.

this does change the file used by a couple of scripts, affecting backwards
compatibility of executing live-build upon an existing partially or fully
completed build:
 - binary_grub-pc used "binary_grub"
 - chroot_includes used "includes.chroot"

care had to be taken for the following cases:
 - there are some cases like bootstrap_cache, source_debian and
   bootstrap_debootstrap which are dealing with more than one file, and/or
   otherwise a filename that is not specific to the script itself exactly,
   or should not be based upon its name.
 - some cases like chroot_cache, bootstrap_cache and
   chroot_install-packages need to append something to the end of the name
   depending upon which pass/action mode the script is being executed with.
 - furthermore in the bootstrap_cache case one of the filenames is used
   within the bootstrap_debootstrap and thus needs very careful handling
   to be certain that a change in filename of bootstrap_cache does not
   break bootstrap_debootstrap.

Gbp-Dch: Short

1 files changed, 7 insertions, 4 deletions

diff --git a/scripts/build/chroot_cache b/scripts/build/chroot_cache
index 3c9134472..cf526169e 100755
--- a/scripts/build/chroot_cache
+++ b/scripts/build/chroot_cache
@@ -26,14 +26,18 @@ then
 	exit 0
 fi
 
-STAGE_FILE="chroot_cache"
+_ACTION="${1}"
+shift
 
-case "${1}" in
+# Set non-default stage file name (auto picked up by the functions)
+# Setting to default name with appended action name
+STAGE_FILE="$(Stagefile_name "${_ACTION}")"
+
+case "${_ACTION}" in
 	restore)
 		Echo_message "Restoring chroot stage from cache..."
 
 		# Checking stage file
-		STAGE_FILE="${STAGE_FILE}.restore"
 		Check_stagefile "${STAGE_FILE}"
 
 		if [ -d cache/chroot ]
@@ -58,7 +62,6 @@ case "${1}" in
 		Echo_message "Saving chroot stage to cache..."
 
 		# Checking stage file
-		STAGE_FILE="${STAGE_FILE}.save"
 		Check_stagefile "${STAGE_FILE}"
 
 		# Acquire lock file