templates: add filter to reverse list
The filter supports only lists because for lists, it’s straightforward to
implement. Reversing text doesn’t seem very useful and is hard to implement.
Reversing the bytes would break multi-bytes encodings. Reversing the code
points would break characters consisting of multiple code points. Reversing
graphemes is non-trivial without using a library not included in the standard
library.
#!/bin/sh
#
# wait up to TIMEOUT seconds until a WAIT_ON_FILE is created.
#
# In addition, this script can create CREATE_FILE once it is ready to wait.
if [ $# -lt 2 ] || [ $# -gt 3 ]; then
echo $#
echo "USAGE: $0 TIMEOUT WAIT_ON_FILE [CREATE_FILE]"
fi
timer="$1"
# Scale the timeout to match the sleep steps below, i.e. 1/0.02.
timer=$(( 50 * $timer ))
# If the test timeout have been extended, also scale the timer relative
# to the normal timing.
if [ "$HGTEST_TIMEOUT_DEFAULT" -lt "$HGTEST_TIMEOUT" ]; then
timer=$(( ( $timer * $HGTEST_TIMEOUT) / $HGTEST_TIMEOUT_DEFAULT ))
fi
wait_on="$2"
create=""
if [ $# -eq 3 ]; then
create="$3"
fi
if [ -n "$create" ]; then
touch "$create"
create=""
fi
while [ "$timer" -gt 0 ] && !([ -e "$wait_on" ] || [ -L "$wait_on" ]) ; do
timer=$(( $timer - 1))
sleep 0.02
done
if [ "$timer" -le 0 ]; then
echo "file not created after $1 seconds: $wait_on" >&2
exit 1
fi