extern/nixos-installer
1
0
Fork 1
mirror of https://github.com/NiklasGollenstede/nixos-installer.git synced 2025-08-08 23:21:28 +02:00
Code Issues Packages Projects Releases Wiki Activity

better CLI argument handling, some small fixes

Browse Source
This commit is contained in:
Niklas Gollenstede
2022-08-31 08:38:33 +02:00
parent 7ab9215b0a
commit 1d93a8acc0
12 changed files with 121 additions and 54 deletions
Download Patch File Download Diff File Expand all files Collapse all files

34
lib/setup-scripts/utils.sh
View File

@ -19,6 +19,40 @@ function generic-arg-parse { # ...
shift ; done
}
## Shows the help text for a program and exits, if »--help« was passed as argument and parsed, or does nothing otherwise.
# Expects to be called between parsing and verifying the arguments.
# Uses »allowedArgs« for the list of the named arguments (the values are the descriptions).
# »name« should be the program name/path (usually »$0«), »args« the form/names of any positional arguments expected (e.g. »SOURCE... DEST«) and is included in the "Usage" description,
# »description« the introductory text shown before the "Usage", and »suffix« any text printed after the argument list.
function generic-arg-help { # 1: name, 2?: args, 3?: description, 4?: suffix
if [[ ! ${args[help]:-} ]] ; then : ${allowedArgs[help]:=1} ; return 0 ; fi
[[ ! ${3:-} ]] || echo "$3"
printf 'Usage:\n %s [ARG[=value]]... [--] %s\n\nWhere »ARG« may be any of:\n' "$1" "${2:-}"
local name ; while IFS= read -r name ; do
printf ' %s\n %s\n' "$name" "${allowedArgs[$name]}"
done < <( printf '%s\n' "${!allowedArgs[@]}" | LC_ALL=C sort )
printf ' %s\n %s\n' "--help" "Do nothing but print this message and exit with success."
[[ ! ${4:-} ]] || echo "$4"
exit 0
}
## Performs a basic verification of the named arguments passed by the user and parsed by »generic-arg-parse« against the names in »allowedArgs«.
# Entries in »allowedArgs« should have the form »[--name]="description"« for boolean flags, and »[--name=VAL]="description"« for string arguments.
# »description« is used by »generic-arg-help«. Boolean flags may only have the values »1« (as set by »generic-ags-parse« for flags without value) or be empty.
# »VAL« is purely nominal. Any argument passed that is not in »allowedArgs« raises an error.
function generic-arg-verify { # 1: exitCode
local exitCode=${1:-1}
local names=' '"${!allowedArgs[@]}"
for name in "${!args[@]}" ; do
if [[ ${allowedArgs[--$name]:-} ]] ; then
if [[ ${args[$name]} == '' || ${args[$name]} == 1 ]] ; then continue ; fi
echo "Argument »--$name« should be a boolean, but its value is: ${args[$name]}" ; return $exitCode
fi
if [[ $names == *' --'"$name"'='* || $names == *' --'"$name"'[='* ]] ; then continue ; fi
echo "Unexpected argument »--$name«.${allowedArgs[help]:+ Call with »--help« for a list of valid arguments.}" ; return $exitCode
done
}
## Prepends a command to a trap. Especially useful fo define »finally« commands via »prepend_trap '<command>' EXIT«.
# NOTE: When calling this in a sub-shell whose parents already has traps installed, make sure to do »trap - trapName« first. On a new shell, this should be a no-op, but without it, the parent shell's traps will be added to the sub-shell as well (due to strange behavior of »trap -p« (in bash ~5.1.8)).
function prepend_trap { # 1: command, ...: trapNames