90 lines
3.5 KiB
Bash
90 lines
3.5 KiB
Bash
#!/usr/bin/env bash
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# ------------------------------------------------------------------------------
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# Copyright (c) 2013-2026 Geoffray Levasseur <fatalerrors@geoffray-levasseur.org>
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# Protected by the BSD3 license. Please read bellow for details.
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#
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# * Redistribution and use in source and binary forms,
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# * with or without modification, are permitted provided
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# * that the following conditions are met:
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# *
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# * Redistributions of source code must retain the above
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# * copyright notice, this list of conditions and the
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# * following disclaimer.
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# *
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# * Redistributions in binary form must reproduce the above
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# * copyright notice, this list of conditions and the following
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# * disclaimer in the documentation and/or other materials
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# * provided with the distribution.
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# *
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# * Neither the name of the copyright holder nor the names
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# * of any other contributors may be used to endorse or
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# * promote products derived from this software without
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# * specific prior written permission.
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# *
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# * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
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# * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
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# * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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# * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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# * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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# * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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# * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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# * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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# * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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# * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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# * OF SUCH DAMAGE.
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# ------------------------------------------------------------------------------
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# Private helpers of profile.d/fun.sh, loaded by the module itself.
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# Convert a number of milliseconds into a seconds string usable by sleep
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# (1500 -> 1.500), in pure bash (no awk fork per call).
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# Usage: _fun_ms_to_s <ms>
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_fun_ms_to_s()
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{
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printf '%d.%03d' $(( $1 / 1000 )) $(( $1 % 1000 ))
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}
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export -f _fun_ms_to_s
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# Fail with a message unless a terminal is available: the demos wait for a key
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# read from /dev/tty to stop.
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# Usage: _fun_need_tty <command-name>
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_fun_need_tty()
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{
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if ! { : </dev/tty; } 2>/dev/null; then
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disp E "$1: a terminal is required (it runs until a key is pressed)."
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return 1
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fi
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}
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export -f _fun_need_tty
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# Wait for a key press, then stop the background job $1 and its children.
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# The job runs as "( ... ) &"; with job control (interactive shell) it is the
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# leader of its own process group, which is signalled as a whole. Without job
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# control that group does not exist, so its direct children (the pipeline) are
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# killed first, then the subshell. SIGINT is trapped meanwhile so that Ctrl-C
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# stops the job like a key press instead of aborting the caller and leaving it
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# running. The wait is a polling loop of short timed reads: a blocking read is
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# restarted by bash after a trapped signal and would never notice the Ctrl-C.
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# Usage: _fun_stop_on_key <pid>
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_fun_stop_on_key()
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{
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local pid=$1 old_int interrupted=0
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old_int=$(trap -p INT)
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trap 'interrupted=1' INT
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while (( ! interrupted )); do
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IFS= read -r -n 1 -s -t 0.3 _ </dev/tty && break
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# Status above 128 is just the timeout; anything else (such as end of
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# input on the terminal) ends the wait.
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(( $? > 128 )) || break
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done
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kill -- -"$pid" 2>/dev/null || {
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pkill -P "$pid" 2>/dev/null
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kill "$pid" 2>/dev/null
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}
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wait "$pid" 2>/dev/null
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trap - INT
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_trap_restore "$old_int"
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return 0
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}
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export -f _fun_stop_on_key
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