nixpkgs/pkgs/build-support/setup-hooks/make-wrapper.sh
talyz c67f885fe4
makeWrapper: Don't readd existing values in prefix/suffix
When prefixing or suffixing list variables, check that the value or
values aren't already part of the list. If this is the case when
suffixing, the list won't be touched at all. When prefixing, however,
the last matching instance of the value will be moved to the beginning
of the list. Any remaining duplicates of the value will be left as-is.

Co-authored-by: Vincenzo Mantova <xworld21@users.sf.net>
2022-02-02 19:46:58 +01:00

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# Assert that FILE exists and is executable
#
# assertExecutable FILE
assertExecutable() {
local file="$1"
[[ -f "$file" && -x "$file" ]] || \
die "Cannot wrap '$file' because it is not an executable file"
}
# construct an executable file that wraps the actual executable
# makeWrapper EXECUTABLE OUT_PATH ARGS
# ARGS:
# --argv0 NAME : set name of executed process to NAME
# (otherwise its called …-wrapped)
# --set VAR VAL : add VAR with value VAL to the executables
# environment
# --set-default VAR VAL : like --set, but only adds VAR if not already set in
# the environment
# --unset VAR : remove VAR from the environment
# --run COMMAND : run command before the executable
# --add-flags FLAGS : add FLAGS to invocation of executable
# --prefix ENV SEP VAL : suffix/prefix ENV with VAL, separated by SEP
# --suffix
# --prefix-each ENV SEP VALS : like --prefix, but VALS is a list
# --suffix-each ENV SEP VALS : like --suffix, but VALS is a list
# --prefix-contents ENV SEP FILES : like --suffix-each, but contents of FILES
# are read first and used as VALS
# --suffix-contents
makeWrapper() {
local original="$1"
local wrapper="$2"
local params varName value command separator n fileNames
local argv0 flagsBefore flags
assertExecutable "$original"
# Write wrapper code which adds `value` to the beginning or end of
# the list variable named by `varName`, depending on the `mode`
# specified.
#
# A value which is already part of the list will not be added
# again. If this is the case and the `suffix` mode is used, the
# list won't be touched at all. The `prefix` mode will however
# move the last matching instance of the value to the beginning
# of the list. Any remaining duplicates of the value will be left
# as-is.
addValue() {
local mode="$1" # `prefix` or `suffix` to add to the beginning or end respectively
local varName="$2" # name of list variable to add to
local separator="$3" # character used to separate elements of list
local value="$4" # one value, or multiple values separated by `separator`, to add to list
if test -n "$value"; then
local old_ifs=$IFS
IFS=$separator
if [[ "$mode" == '--prefix'* ]]; then
# Keep the order of the components as written when
# prefixing; normally, they would be added in the
# reverse order.
local tmp=
for v in $value; do
tmp=$v${tmp:+$separator}$tmp
done
value="$tmp"
fi
for v in $value; do
{
echo "$varName=\${$varName:+${separator@Q}\$$varName${separator@Q}}" # add separators on both ends unless empty
if [[ "$mode" == '--prefix'* ]]; then # -- in prefix mode --
echo "$varName=\${$varName/${separator@Q}${v@Q}${separator@Q}/${separator@Q}}" # remove the first instance of the value (if any)
echo "$varName=${v@Q}\$$varName" # prepend the value
elif [[ "$mode" == '--suffix'* ]]; then # -- in suffix mode --
echo "if [[ \$$varName != *${separator@Q}${v@Q}${separator@Q}* ]]; then" # if the value isn't already in the list
echo " $varName=\$$varName${v@Q}" # append the value
echo "fi"
else
echo "unknown mode $mode!" 1>&2
exit 1
fi
echo "$varName=\${$varName#${separator@Q}}" # remove leading separator
echo "$varName=\${$varName%${separator@Q}}" # remove trailing separator
echo "export $varName"
} >> "$wrapper"
done
IFS=$old_ifs
fi
}
mkdir -p "$(dirname "$wrapper")"
echo "#! @shell@ -e" > "$wrapper"
params=("$@")
for ((n = 2; n < ${#params[*]}; n += 1)); do
p="${params[$n]}"
if [[ "$p" == "--set" ]]; then
varName="${params[$((n + 1))]}"
value="${params[$((n + 2))]}"
n=$((n + 2))
echo "export $varName=${value@Q}" >> "$wrapper"
elif [[ "$p" == "--set-default" ]]; then
varName="${params[$((n + 1))]}"
value="${params[$((n + 2))]}"
n=$((n + 2))
echo "export $varName=\${$varName-${value@Q}}" >> "$wrapper"
elif [[ "$p" == "--unset" ]]; then
varName="${params[$((n + 1))]}"
n=$((n + 1))
echo "unset $varName" >> "$wrapper"
elif [[ "$p" == "--run" ]]; then
command="${params[$((n + 1))]}"
n=$((n + 1))
echo "$command" >> "$wrapper"
elif [[ ("$p" == "--suffix") || ("$p" == "--prefix") ]]; then
varName="${params[$((n + 1))]}"
separator="${params[$((n + 2))]}"
value="${params[$((n + 3))]}"
n=$((n + 3))
addValue "$p" "$varName" "$separator" "$value"
elif [[ ("$p" == "--suffix-each") || ("$p" == "--prefix-each") ]]; then
varName="${params[$((n + 1))]}"
separator="${params[$((n + 2))]}"
values="${params[$((n + 3))]}"
n=$((n + 3))
for value in $values; do
addValue "$p" "$varName" "$separator" "$value"
done
elif [[ ("$p" == "--suffix-contents") || ("$p" == "--prefix-contents") ]]; then
varName="${params[$((n + 1))]}"
separator="${params[$((n + 2))]}"
fileNames="${params[$((n + 3))]}"
n=$((n + 3))
for fileName in $fileNames; do
contents="$(cat "$fileName")"
addValue "$p" "$varName" "$separator" "$contents"
done
elif [[ "$p" == "--add-flags" ]]; then
flags="${params[$((n + 1))]}"
n=$((n + 1))
flagsBefore="$flagsBefore $flags"
elif [[ "$p" == "--argv0" ]]; then
argv0="${params[$((n + 1))]}"
n=$((n + 1))
else
die "makeWrapper doesn't understand the arg $p"
fi
done
echo exec ${argv0:+-a \"$argv0\"} \""$original"\" \
"$flagsBefore" '"$@"' >> "$wrapper"
chmod +x "$wrapper"
}
addSuffix() {
suffix="$1"
shift
for name in "$@"; do
echo "$name$suffix"
done
}
filterExisting() {
for fn in "$@"; do
if test -e "$fn"; then
echo "$fn"
fi
done
}
# Syntax: wrapProgram <PROGRAM> <MAKE-WRAPPER FLAGS...>
wrapProgram() {
local prog="$1"
local hidden
assertExecutable "$prog"
hidden="$(dirname "$prog")/.$(basename "$prog")"-wrapped
while [ -e "$hidden" ]; do
hidden="${hidden}_"
done
mv "$prog" "$hidden"
# Silence warning about unexpanded $0:
# shellcheck disable=SC2016
makeWrapper "$hidden" "$prog" --argv0 '$0' "${@:2}"
}