Refactor: Lifted code outside of main function
It seemed like overkill to enclose the entire script in a function just so readonly variables would work correctly.
This commit is contained in:
Narvin Singh
parent
7a2f2bbf08
commit
bf2f67a28d
253
xrsbd
253
xrsbd
@ -1,153 +1,140 @@
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#!/bin/bash
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# Global readonly variables can't be shadowed by local variables so wrap
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# our code in a function so we can declare all variables local
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main() {
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local -r USAGE="
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USAGE: xrsbd [<mod_list>='cpu mem bl vol-amixer bat dt']
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[<pre>=' '] [<sep_l>='| '] [<sep_r>=' '] [<suf>=' ']
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USAGE="
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USAGE: xrsbd [<mod_list>='cpu mem bl vol-amixer bat dt']
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[<pre>=' '] [<sep_l>='| '] [<sep_r>=' '] [<suf>=' ']
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mod_list
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A comma or space separated list of modules that define both
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the order and the content of the status bar.
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mod_list
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A comma or space separated list of modules that define both
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the order and the content of the status bar.
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pre The prefix prepended to the beginning of the status bar.
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pre The prefix prepended to the beginning of the status bar.
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sep_l The left separator between status bar sections.
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sep_l The left separator between status bar sections.
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sep_r The right separator between status bar sections.
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sep_r The right separator between status bar sections.
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suf The suffix appended to the end of the status bar.
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suf The suffix appended to the end of the status bar.
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EXAMPLES:
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EXAMPLES:
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Any of these will display this help message.
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Any of these will display this help message.
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xrsbd -h
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xrsbd -help
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xrsbd --help
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xrsbd -h
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xrsbd -help
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xrsbd --help
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Run the daemon in the background to create a status bar with the
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default sections, prefix, separators, and suffix.
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Run the daemon in the background to create a status bar with the
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default sections, prefix, separators, and suffix.
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xrsbd &
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xrsbd &
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Run the daemon in the background to create a status with only the
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volume and date/time sections, with the entire status between square
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brackets, and each section surrounded by angle brackets. Note that
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the first left separator and the last right separator are stripped
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from the output, so if you want them, simply include them in the
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prefix and suffix as shown here.
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Run the daemon in the background to create a status with only the
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volume and date/time sections, with the entire status between square
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brackets, and each section surrounded by angle brackets. Note that
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the first left separator and the last right separator are stripped
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from the output, so if you want them, simply include them in the
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prefix and suffix as shown here.
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xrsbd 'vol-amixer dt' '[<' '<' '>' '>]' &"
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# Customizable configuration constants
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local -r DEFAULT_MOD_LIST='cpu mem bl vol-amixer bat dt'
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local -r DEFAULT_PRE=' '
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local -r DEFAULT_SEP_L='| '
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local -r DEFAULT_SEP_R=' '
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local -r DEFAULT_SUF=' '
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xrsbd 'vol-amixer dt' '[<' '<' '>' '>]' &
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"
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# Customizable configuration constants
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DEFAULT_MOD_LIST='cpu mem bl vol-amixer bat dt'
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DEFAULT_PRE=' '
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DEFAULT_SEP_L='| '
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DEFAULT_SEP_R=' '
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DEFAULT_SUF=' '
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local -r mod_list="${1-${DEFAULT_MOD_LIST}}"
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local -r pre="${2-${DEFAULT_PRE}}"
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local -r sep_l="${3-${DEFAULT_SEP_L}}"
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local -r sep_r="${4-${DEFAULT_SEP_R}}"
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local -r suf="${5-${DEFAULT_SUF}}"
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mod_list="${1-${DEFAULT_MOD_LIST}}"
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pre="${2-${DEFAULT_PRE}}"
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sep_l="${3-${DEFAULT_SEP_L}}"
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sep_r="${4-${DEFAULT_SEP_R}}"
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suf="${5-${DEFAULT_SUF}}"
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local -r MOD_DIR="$(dirname "$0")"/module
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local -r ACTION_DIR=/tmp/xrsb-action
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local -i ACTION_DIR_LEN=${#ACTION_DIR}
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MOD_DIR="$(dirname "$0")"/module
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ACTION_DIR=/tmp/xrsb-action
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ACTION_DIR_LEN=${#ACTION_DIR}
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# Cache module values so we can reuse them without recomputing them
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local -A stat_cache
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# Since stat_cache is hash ordered, maintain the display order (as defined
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# by mod_list) of the keys so we can loop over the cache in display order
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# when generating the full status
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local -a stat_cache_ordered_mods mods
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local mod mod_file
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# Map the module file name to the module function
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mod_to_fn() {
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printf 'mod_%s' "${1//-/_}"
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}
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# Check if the user needs help
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if [[ "${mod_list}" =~ ^(-h|-(-)?help)$ ]]; then
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printf '%s\n' "${USAGE}" 1>&2
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exit 0
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fi
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# For each module in the list, if the module file exists then source it, add
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# its name to the ordered array, and call its function and cache the value
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IFS=', ' read -r -a mods <<< "${mod_list}"
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for mod in "${mods[@]}"; do
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mod_file="${MOD_DIR}/${mod}"
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if [[ -r "${mod_file}" ]]; then
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# shellcheck source=/dev/null
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source "${mod_file}"
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stat_cache_ordered_mods+=("${mod}")
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stat_cache["${mod}"]="$(eval "$(mod_to_fn "${mod}")")"
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fi
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done
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# Construct and display the status by looping over the cached values in order
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draw_status() {
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local mod stat
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for mod in "${stat_cache_ordered_mods[@]}"; do
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printf -v stat '%b%b%b%b' \
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"${stat}" "${sep_l}" "${stat_cache[${mod}]}" "${sep_r}"
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done
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# Trim the leading left separator and trailing right separator, and
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# display the status
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local -ri offset=${#sep_l}
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local -ri len=$((${#stat} - offset - ${#sep_r}))
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xsetroot -name "${pre}${stat:${offset}:${len}}${suf}"
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}
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# Draw the initial status
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draw_status
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# For each file in the action directory, remove the file, and if a module for
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# the action is cached, call the module function and update the cache. If
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# any cache entries were updated, redraw the status.
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process_signal () {
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local -a action_paths
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local action_path mod is_changed
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readarray -d '' action_paths< \
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<(find "${ACTION_DIR}" -maxdepth 1 -type f -exec rm -f {} + -print0)
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for action_path in "${action_paths[@]}"; do
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mod="${action_path:$((ACTION_DIR_LEN + 1))}"
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if [[ -v stat_cache[${mod}] ]]; then
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stat_cache["${mod}"]="$(eval "$(mod_to_fn "${mod}")")"
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is_changed=1
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fi
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done
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if [[ -v is_changed ]]; then draw_status; fi
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}
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# Begin trapping signals
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mkdir -p "${ACTION_DIR}"
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trap process_signal SIGUSR1
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# Wait for signals efficiently. In a loop begin a long-running sleep command
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# in the background, then wait on it. If we trap a signal before the wait
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# is over and sleep is still running, trap will call process_signal, then
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# code execution will resume at the line after the wait statement. So on
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# that line we kill the (probably) still running sleep command so they
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# don't pile up, and loop to sleep and wait for the next signal. If we
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# don't trap a signal during the long running sleep, then the wait ends,
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# we try to kill the sleep command that has already exited, so it doesn't
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# matter, and loop to sleep and wait again. Note that we don't make the
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# sleep too long because if the daemon is killed, the sleep will become
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# an orphaned process until the sleep period elapses.
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local -i sleep_pid
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while :; do
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sleep 30m &
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sleep_pid="$!"
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wait "${sleep_pid}"
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kill "${sleep_pid}" 2>/dev/null
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done
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# Map the module file name to the module function
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mod_to_fn() {
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printf 'mod_%s' "${1//-/_}"
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}
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main "$@"
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# Check if the user needs help
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if [[ "${mod_list}" =~ ^(-h|-(-)?help)$ ]]; then
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printf '%s' "${USAGE}" 1>&2
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exit 0
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fi
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# For each module in the list, if the module file exists then source it,
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# add its name to the ordered array, and call its function and cache the value
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declare -A stat_cache
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IFS=', ' read -r -a mods <<< "${mod_list}"
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for mod in "${mods[@]}"; do
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mod_file="${MOD_DIR}/${mod}"
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if [[ -r "${mod_file}" ]]; then
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# shellcheck source=/dev/null
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source "${mod_file}"
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stat_cache_ordered_mods+=("${mod}")
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stat_cache["${mod}"]="$(eval "$(mod_to_fn "${mod}")")"
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fi
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done
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# Construct and display the status by looping over the cached values in order
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draw_status() {
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local mod stat
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for mod in "${stat_cache_ordered_mods[@]}"; do
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printf -v stat '%b%b%b%b' \
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"${stat}" "${sep_l}" "${stat_cache[${mod}]}" "${sep_r}"
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done
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# Trim the leading left separator and trailing right separator, and display
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# the status
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local -ri offset=${#sep_l}
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local -ri len=$((${#stat} - offset - ${#sep_r}))
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xsetroot -name "${pre}${stat:${offset}:${len}}${suf}"
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}
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# Draw the initial status
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draw_status
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# For each file in the action directory, remove the file, and if a module
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# for the action is cached, call the module function and update the cache. If
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# any cache entries were updated, redraw the status.
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process_signal () {
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local -a action_paths
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local action_path mod is_changed
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readarray -d '' action_paths< \
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<(find "${ACTION_DIR}" -maxdepth 1 -type f -exec rm -f {} + -print0)
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for action_path in "${action_paths[@]}"; do
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mod="${action_path:$((ACTION_DIR_LEN + 1))}"
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if [[ -v stat_cache[${mod}] ]]; then
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stat_cache["${mod}"]="$(eval "$(mod_to_fn "${mod}")")"
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is_changed=1
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fi
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done
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if [[ -v is_changed ]]; then draw_status; fi
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}
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# Begin trapping signals
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mkdir -p "${ACTION_DIR}"
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trap process_signal SIGUSR1
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# Wait for signals efficiently. In a loop begin a long-running sleep command
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# in the background, then wait on it. If we trap a signal before the wait is
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# over and sleep is still running, trap will call process_signal, then code
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# execution will resume at the line after the wait statement. So on that line
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# we kill the (probably) still running sleep command so they don't pile up,
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# and loop to sleep and wait for the next signal. If we don't trap a signal
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# during the long running sleep, then the wait ends, we try to kill the
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# sleep command that has already exited, so it doesn't matter, and loop to
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# sleep and wait again. Note that we don't make the sleep too long because
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# if the daemon is killed, the sleep will become an orphaned process until
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# the sleep period elapses.
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while :; do
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sleep 30m &
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sleep_pid="$!"
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wait "${sleep_pid}"
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kill "${sleep_pid}" 2>/dev/null
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done
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