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Feat: Efficient waiting with long-running sleep

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Replace short foreground sleep in a loop with a long background sleep
in a loop that we wait, which should be much more efficient.
This commit is contained in:
Narvin Singh 2020-12-29 15:56:54 -05:00
parent ea4806df9d
commit 96442be9b3
1 changed files with 21 additions and 8 deletions
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29
xrsbd
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@ -5,18 +5,16 @@
main() { main() {
# Customizable configuration constants # Customizable configuration constants
local -r DEFAULT_MOD_LIST='cpu mem bl vol-amixer bat dt' local -r DEFAULT_MOD_LIST='cpu mem bl vol-amixer bat dt'
local -r DEFAULT_RES=.25
local -r DEFAULT_PRE=' ' local -r DEFAULT_PRE=' '
local -r DEFAULT_SEP_L='| ' local -r DEFAULT_SEP_L='| '
local -r DEFAULT_SEP_R=' ' local -r DEFAULT_SEP_R=' '
local -r DEFAULT_SUF=' ' local -r DEFAULT_SUF=' '
local -r mod_list="${1-${DEFAULT_MOD_LIST}}" local -r mod_list="${1-${DEFAULT_MOD_LIST}}"
local -r res="${2:-${DEFAULT_RES}}" local -r pre="${2-${DEFAULT_PRE}}"
local -r pre="${3-${DEFAULT_PRE}}" local -r sep_l="${3-${DEFAULT_SEP_L}}"
local -r sep_l="${4-${DEFAULT_SEP_L}}" local -r sep_r="${4-${DEFAULT_SEP_R}}"
local -r sep_r="${5-${DEFAULT_SEP_R}}" local -r suf="${5-${DEFAULT_SUF}}"
local -r suf="${6-${DEFAULT_SUF}}"
local -r MOD_DIR="$(dirname "$0")"/module local -r MOD_DIR="$(dirname "$0")"/module
local -r ACTION_DIR=/tmp/xrsb-action local -r ACTION_DIR=/tmp/xrsb-action
@ -84,12 +82,27 @@ main() {
if [[ -v is_changed ]]; then draw_status; fi if [[ -v is_changed ]]; then draw_status; fi
} }
# Wait for signals # Begin trapping signals
mkdir -p "${ACTION_DIR}" mkdir -p "${ACTION_DIR}"
trap process_signal SIGUSR1 trap process_signal SIGUSR1
# Wait for signals efficiently. In a loop begin a long-running sleep command
# in the background, then wait on it. If we trap a signal before the wait
# is over and sleep is still running, trap will call process_signal, then
# code execution will resume at the line after the wait statement. So on
# that line we kill the (probably) still running sleep command so they
# don't pile up, and loop to sleep and wait for the next signal. If we
# don't trap a signal during the long running sleep, then the wait ends,
# we try to kill the sleep command that has already exited, so it doesn't
# matter, and loop to sleep and wait again. Note that we don't make the
# sleep too long because if the daemon is killed, the sleep will become
# an orphaned process until the sleep period elapses.
local -i sleep_pid
while :; do while :; do
sleep "${res}" sleep 30m &
sleep_pid="$!"
wait "${sleep_pid}"
kill "${sleep_pid}" 2>/dev/null
done done
} }