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#!/bin/sh
progname=$(basename "${0}")
# @FUNCTION: err
# @USAGE: [-x] <message> ...
# @DESCRIPTION:
# Print given messages to stderr line by line and exit with status 1.
#
# If "-x" is specified, suppress the program prefix (`program: `)
# from the output. Otherwise, the first line is prefixed with "program: ".
#
# This function is intended for fatal errors; it always exits the script.
# @EXAMPLE:
# err "Invalid usage" "Try '${progname} -h' for help."
err() {
if [ "${1}" != "-x" ]; then
printf "%s: " "${progname}"
else
shift
fi
for line in "${@}"; do
echo "${line}" >&2
done
exit 1
}
# @FUNCTION: invalid_use
# USAGE: [-h]
# @DESCRIPTION:
# Output a usage error message. If `-h` is not specified output:
# "<program>: Invalid usage "
# "Try 'program -h' for help."
# else output only:
# "Try 'program -h' for help."
invalid_use() {
[ "${1}" = "-h" ] && err -x "Try '${progname} -h' for help."
err "Invalid usage" "Try '${progname} -h' for help."
}
# @FUNCTION: check_program
# USAGE: <command> [error-msg]
# @DESCRIPTION:
# Check if command exists on the system.
# If not, print an error message to stderr and exit with status 1.
# The default error message is "`command` must be installed"
# but can optionally be overwritten.
#
# @EXAMPLE:
# Check if pulseaudio is installed.
#
# check_program "pactl" "pulseaudio must be installed"
check_program() {
command -v "${1}" > /dev/null 2>&1 && return 0
[ -n "${2}" ] && err "${2}"
err "${1} must be installed"
}
# @FUNCTION: get_random_filename
# @USAGE: get_random_filename [parentdir] <extension>
# @DESCRIPTION:
# Write a random file path to stdout, under parentdir, (if provided else under /tmp) with the extension.
#
# @EXAMPLE:
# Get a filepath in the `/var` directory with the extension `.png`
#
# get_random_filename .png /var
get_random_filename() {
[ "${#}" -eq 2 ] && parentdir="${2}" || parentdir="/tmp"
extension="${1}"
echo "${parentdir}/$(date '+%b%d::%H%M%S')${extension}"
}
# @FUNCTION: run
# @USAGE: [--reload-status] [--reload-compositor] [--success-notify <msg>] [--failure-notify <msg>] <command> [success-msg] [failure-msg]
# @DESCRIPTION:
# Safely execute a simple shell command, print optional success/failure messages,
# and optionally reload the status bar or restart the compositor.
#
# Success messages are printed to stdout; failure messages are printed to stderr.
# Optional desktop notifications can be sent using --success-notify and --failure-notify.
# Command output is not suppressed.
#
# Options:
# --reload-status Reload the status bar (via `slreload`).
# --reload-compositor Restart the compositor (kills and restarts `picom`).
# --success-notify <msg> Send a desktop notification on success.
# --failure-notify <msg> Send a desktop notification on failure.
#
# Restrictions:
# - Does NOT use `eval`; only simple commands and arguments are supported.
# - Shell operators like `&&`, `||`, `|`, `>`, `>>`, etc. will NOT work.
# - This design prevents unintended execution and makes the function safe in scripts.
#
# Return value:
# Exits with 0 if the command succeeds, 1 otherwise.
#
# @EXAMPLES:
# # Run xwallpaper and print the image path on success
# run "xwallpaper --zoom ${image}" "${image}"
#
# # Restart compositor and show a success message
# run --reload-compositor "xwallpaper --zoom ${image}" "Wallpaper updated" "Wallpaper failed"
#
# # With notification hooks
# run --success-notify "Wallpaper set" \
# --failure-notify "Wallpaper failed" \
# "xwallpaper --zoom ${image}" "Wallpaper updated" "Wallpaper failed"
run() {
no_exit=0
reload_status=0
reload_compositor=0
[ "${1}" = "--no-exit" ] && no_exit=1 && shift
[ "${1}" = "--reload-status" ] && reload_status=1 && shift
[ "${1}" = "--reload-compositor" ] && reload_compositor=1 && shift
trap '
[ "${reload_status}" -eq 1 ] && status_handle reload
[ "${reload_compositor}" -eq 1 ] && compositor_handle start
' EXIT
[ "${reload_compositor}" -eq 1 ] && compositor_handle stop
eval "${@}"
[ "${no_exit}" -eq 1 ] || exit "${?}"
}
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