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functions.sh
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functions.sh
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# Copyright 1999-2024 Gentoo Authors
# Distributed under the terms of the GNU General Public License v2
# shellcheck shell=sh disable=2153,2209,3013,3043
# This file contains a series of function declarations followed by some
# initialisation code. Functions intended for internal use shall be prefixed
# with an <underscore> and shall not be considered as being a part of the public
# API. With the exception of those declared by the local builtin, all variables
# intended for internal use shall be prefixed with "genfun_" to indicate so,
# and to reduce the probability of name space conflicts.
# The functions shall be compatible with the POSIX-1.2018 Shell and Utilities
# (XCU), except where otherwise noted and with the exception that the use of
# the local utility is permitted, despite the results of its invocation being
# formally unspecified. Should any of the errexit, pipefail or nounset options
# be enabled in the shell, the behaviour of gentoo-functions as a whole shall
# be unspecified.
# The following variables affect initialisation and/or function behaviour.
# BASH : whether bash-specific features may be employed
# BASH_VERSINFO : whether bash-specific features may be employed
# BASHPID : may be used by _update_columns() and _update_pid()
# COLUMNS : may be used by _update_columns() to get the column count
# EPOCHREALTIME : potentially used by _update_time() to get the time
# GENFUN_MODULES : which of the optional function collections must be sourced
# IFS : warn() operands are joined by its first character
# INVOCATION_ID : used by from_unit()
# KSH_VERSION : used to detect ksh93, which is currently unsupported
# PORTAGE_BIN_PATH : used by from_portage()
# POSIXLY_CORRECT : if unset/empty, quote_args() may emit dollar-single-quotes
# RC_OPENRC_PID : used by from_runscript()
# SENTINEL : can define a value separating two distinct argument lists
# SYSTEMD_EXEC_PID : used by from_unit()
# TERM : used to detect dumb terminals
# YASH_VERSION : for detecting yash before checking for incompatible options
#------------------------------------------------------------------------------#
#
# Prints a diagnostic message prefixed with the basename of the running script.
#
warn()
{
printf '%s: %s\n' "${0##*/}" "$*" >&2
}
case $- in *e*)
# https://lists.gnu.org/archive/html/help-bash/2020-04/msg00049.html
warn "gentoo-functions does not support the errexit option; unexpected behaviour may ensue"
esac
case $- in *u*)
# https://lists.gnu.org/archive/html/help-bash/2020-04/msg00049.html
warn "gentoo-functions does not support the nounset option; unexpected behaviour may ensue"
esac
case ${KSH_VERSION} in 'Version AJM 93'*)
# The ksh93 shell has a typeset builtin but no local builtin.
warn "gentoo-functions does not currently support ksh93"
return 1
esac
if [ "${YASH_VERSION}" ] && set +o | grep -qxF 'set -o posixlycorrect'; then
# The yash shell disables the local builtin in its POSIXly-correct mode.
warn "gentoo-functions does not support yash in posixlycorrect mode"
return 1
fi
#
# Considers the first parameter as a reference to a variable by name and
# assigns the second parameter as its value. If the first parameter is found
# not to be a legal identifier, no assignment shall occur and the return value
# shall be greater than 0.
#
assign()
{
if [ "$#" -ne 2 ]; then
warn "assign: wrong number of arguments (got $#, expected 2)"
false
elif ! is_identifier "$1"; then
_warn_for_args assign "$@"
false
else
eval "$1=\$2"
fi
}
#
# A safe wrapper for the cd builtin. To run cd "$dir" is problematic because:
#
# - it may consider its operand as an option
# - it will search CDPATH for an operand not beginning with ./, ../ or /
# - it will switch to OLDPWD if the operand is -
# - cdable_vars causes bash to treat the operand as a potential variable name
#
chdir()
{
if [ "$#" -eq 1 ]; then
case $1 in
'')
_warn_for_args chdir "$1"
return 1
;;
-)
set -- ./-
esac
fi
if [ "${BASH}" ]; then
# shellcheck disable=3044
shopt -u cdable_vars
fi
# shellcheck disable=1007,2164
CDPATH= cd -- "$@"
}
#
# Considers the first parameter as a string comprising zero or more
# whitespace-separated words then determines whether all of the remaining
# parameters can be found within the resulting list in their capacity as
# discrete words. If they cannot be, or if fewer than two parameters were given,
# the return value shall be 1. Of the words to be searched for, any which are
# empty or which contain whitespace characters shall be deemed unfindable.
#
contains_all()
{
local arg haystack
[ "$#" -gt 1 ] || return
haystack=" $1 "
shift
for arg; do
case ${arg} in
''|*[[:space:]]*)
return 1
esac
case ${haystack} in
*" ${arg} "*)
;;
*)
return 1
esac
done
}
#
# Considers the first parameter as a string comprising zero or more
# whitespace-separated words then determines whether any of the remaining
# parameters can be found within the resulting list in their capacity as
# discrete words. If none can be, or if no parameters were given, the return
# value shall be greater than 0. Of the words to be searched for, any which are
# empty or which contain whitespace characters shall be disregarded.
#
contains_any()
{
local arg haystack
[ "$#" -gt 0 ] || return
haystack=" $1 "
shift
for arg; do
case ${arg} in
''|*[[:space:]]*)
continue
esac
case ${haystack} in
*" ${arg} "*)
return 0
esac
done
false
}
#
# Considers the first parameter as a reference to a variable by name and
# attempts to retrieve its presently assigned value. If only one parameter is
# specified, the retrieved value shall be printed to the standard output. If a
# second parameter is also specified, it shall be be taken as the name of a
# variable to which the retrieved value shall be assigned. If any parameter is
# found not to be a legal identifier, or if the variable referenced by the
# first parameter is unset, the return value shall be greater than 0.
#
deref()
{
if [ "$#" -eq 0 ] || [ "$#" -gt 2 ]; then
warn "deref: wrong number of arguments (got $#, expected between 1 and 2)"
elif ! trueof_all is_identifier -- "$@"; then
_warn_for_args deref "$@"
false
elif ! eval "test \"\${$1+set}\""; then
false
elif [ "$#" -eq 1 ]; then
eval "printf '%s\\n' \"\$$1\""
else
eval "$2=\$$1"
fi
}
#
# Determines whether the current shell is a subprocess of portage.
#
from_portage()
{
test "${PORTAGE_BIN_PATH}"
}
#
# Determines whether the current shell is executing an OpenRC runscript, or is
# a subprocess of one.
#
from_runscript()
{
has_openrc && test "${RC_OPENRC_PID}"
}
#
# Determines whether the current shell is a subprocess of a systemd unit that
# handles a service, socket, mount point or swap device, per systemd.exec(5).
#
from_unit()
{
has_systemd && test "${SYSTEMD_EXEC_PID}" && test "${INVOCATION_ID}"
}
#
# Determines whether OpenRC appears to be operational as a service manager in
# the context of the present root filesystem namespace.
#
has_openrc()
{
test -d /run/openrc
}
#
# Determines whether systemd appears to be operational as a service manager in
# the context of the present root filesystem namespace.
#
has_systemd()
{
test -d /run/systemd
}
#
# Prints a horizontal rule. If specified, the first parameter shall be taken as
# a string whose first character is to be repeated in the course of composing
# the rule. Otherwise, or if specified as the empty string, it shall default to
# the <hyphen-minus>. If specified, the second parameter shall define the length
# of the rule in characters. Otherwise, it shall default to the width of the
# terminal if such can be determined, or 80 if it cannot be.
#
hr()
{
local c hr i length
if [ "$#" -ge 2 ] && is_int "$2"; then
length=$2
elif _update_tty_level <&1; [ "${genfun_tty}" -eq 2 ]; then
length=${genfun_cols}
else
length=80
fi
c=${1--}
c=${c%"${c#?}"}
i=0
while [ "$(( i += 16 ))" -le "${length}" ]; do
hr=${hr}${c}${c}${c}${c}${c}${c}${c}${c}${c}${c}${c}${c}${c}${c}${c}${c}
done
i=${#hr}
while [ "$(( i += 1 ))" -le "${length}" ]; do
hr=${hr}${c}
done
printf '%s\n' "${hr}"
}
#
# Determines whether the first parameter is a valid identifier (variable name).
#
is_identifier()
{
case $1 in
''|_|[0123456789]*|*[!_0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz]*)
false
esac
}
#
# Determines whether the first parameter is a valid integer. A leading
# <hyphen-minus> shall be permitted. Thereafter, leading zeroes shall not be
# permitted because the string might later be considered to be octal in an
# arithmetic context, causing the shell to exit if the number be invalid.
#
is_int()
{
set -- "${1#-}"
case $1 in
''|*[!0123456789]*)
false
;;
0)
true
;;
*)
test "$1" = "${1#0}"
esac
}
#
# Determines whether the first parameter matches any of the parameters that
# follow it.
#
is_anyof()
{
local arg needle
if [ "$#" -eq 0 ]; then
warn "is_anyof: too few arguments (got $#, expected at least 1)"
else
needle=$1
shift
for arg; do
if [ "${arg}" = "${needle}" ]; then
return
fi
done
fi
false
}
#
# Considers one or more pathnames and prints the one having the newest
# modification time. If at least one parameter is provided, all parameters
# shall be considered as pathnames to be compared to one another. Otherwise,
# the pathnames to be compared shall be read from the standard input as
# null-terminated records. In the case that two or more pathnames are
# candidates, whichever was first specified shall take precedence over the
# other. If no pathnames are given, or those specified do not exist, the return
# value shall be greater than 0.
#
# Pathnames containing <newline> characters shall be handled correctly if
# conveyed as positional parameters. Otherwise, the behaviour for such
# pathnames is unspecified. Users of the function are duly expected to refrain
# from conveying such pathnames for consumption from the standard input; for
# example, by specifying a predicate of ! -path $'*\n*' to the find utility.
# This constraint is expected to be eliminated by a future amendment to the
# function, once support for read -d becomes sufficiently widespread.
#
# The test utility is required to support the -nt primary, per POSIX-1.2024.
# However, measures are in place to to achieve compatibility with shells that
# implement the primary without yet fully adhering to the specification.
#
newest()
{
local path newest
newest=
if [ "$#" -gt 0 ]; then
for path; do
# The tests within curly braces address a conformance
# issue whereby [ existent -nt nonexistent ] is
# incorrectly false. As of August 2024, busybox ash,
# dash, FreeBSD sh and NetBSD sh are known to be
# non-conforming in this respect.
if { [ ! "${newest}" ] && [ -e "${path}" ]; } || [ "${path}" -nt "${newest}" ]; then
newest=${path}
fi
done
test "${newest}" && printf '%s\n' "${newest}"
else
# Support for read -d '' is not yet sufficiently widespread.
tr '\0' '\n' |
{
while IFS= read -r path; do
if { [ ! "${newest}" ] && [ -e "${path}" ]; } || [ "${path}" -nt "${newest}" ]; then
newest=${path}
fi
done
test "${newest}" && printf '%s\n' "${newest}"
}
fi
}
#
# Tries to determine the number of available processors. Falls back to trying to
# determine the number of online processors in a way that is somewhat portable.
#
get_nprocs()
{
if nproc 2>/dev/null; then
# The nproc(1) utility is provided by GNU coreutils. It has the
# advantage of acknowledging the effect of sched_setaffinity(2).
true
elif getconf _NPROCESSORS_ONLN 2>/dev/null; then
# This constant is standard as of POSIX-1.2024 and was already
# supported by glibc, musl-utils, macOS, FreeBSD, NetBSD and
# OpenBSD.
true
else
warn "get_nprocs: failed to determine the number of processors"
false
fi
}
#
# Considers one or more pathnames and prints the one having the oldest
# modification time. If at least one parameter is provided, all parameters
# shall be considered as pathnames to be compared to one another. Otherwise,
# the pathnames to be compared shall be read from the standard input as
# null-terminated records. In the case that two or more pathnames are
# candidates, whichever was first specified shall take precedence over the
# other. If no pathnames are given, or those specified do not exist, the return
# value shall be greater than 0.
#
# Pathnames containing <newline> characters shall be handled correctly if
# conveyed as positional parameters. Otherwise, the behaviour for such
# pathnames is unspecified. Users of the function are duly expected to refrain
# from conveying such pathnames for consumption from the standard input; for
# example, by specifying a predicate of ! -path $'*\n*' to the find utility.
# This constraint is expected to be eliminated by a future amendment to the
# function, once support for read -d becomes sufficiently widespread.
#
# The test utility is required to support the -ot primary, per POSIX-1.2024.
#
oldest()
{
local path oldest
oldest=
if [ "$#" -gt 0 ]; then
for path; do
# The specification has [ nonexistent -ot existent ] as
# being true. Such is a nuisance in this case but the
# preceding tests suffice as a workaround.
if [ ! -e "${path}" ]; then
continue
elif [ ! "${oldest}" ] || [ "${path}" -ot "${oldest}" ]; then
oldest=${path}
fi
done
test "${oldest}" && printf '%s\n' "${oldest}"
else
# Support for read -d '' is not yet sufficiently widespread.
tr '\0' '\n' |
{
while IFS= read -r path; do
if [ ! -e "${path}" ]; then
continue
elif [ ! "${oldest}" ] || [ "${path}" -ot "${oldest}" ]; then
oldest=${path}
fi
done
test "${oldest}" && printf '%s\n' "${oldest}"
}
fi
}
#
# Executes a simple command in parallel. At least two parameters are expected.
# The first parameter shall be taken as the maximum number of jobs to run
# concurrently. If specified as less than or equal to 0, the number shall be
# determined by calling the get_nprocs function. The second parameter shall be
# taken as a command name. The remaining parameters shall be conveyed to the
# specified command, one at a time. Should at least one command fail, the
# return value shall be greater than 0.
#
parallel_run()
{
local arg cmd i statedir w workers
if [ "$#" -lt 3 ]; then
warn "parallel_run: too few arguments (got $#, expected at least 3)"
return 1
elif ! is_int "$1"; then
_warn_for_args parallel_run "$1"
return 1
elif [ "$1" -le 0 ] && ! workers=$(get_nprocs); then
return 1
elif ! statedir=${TMPDIR:-/tmp}/parallel_run.$$.$(srandom); then
return 1
fi
workers=${workers:-$1} cmd=$2
shift 2
w=0
i=0
(
while [ "$(( w += 1 ))" -le "${workers}" ]; do
i=$w
while [ "$i" -le "$#" ]; do
eval "arg=\$${i}"
if ! "${cmd}" "${arg}"; then
mkdir -p -- "${statedir}"
fi
i=$(( i + workers ))
done &
done
wait
)
! rmdir -- "${statedir}" 2>/dev/null
}
#
# Prints the positional parameters in a format that may be reused as shell
# input. For each considered, it shall be determined whether its value contains
# any bytes that are either outside the scope of the US-ASCII character set or
# which are considered as non-printable. If no such bytes are found, the value
# shall have each instance of <apostrophe> be replaced by <apostrophe>
# <backslash> <apostrophe> <apostrophe> before being enclosed by a pair of
# <apostrophe> characters. However, as a special case, a value consisting of a
# single <apostrophe> shall be replaced by <backslash> <apostrophe>.
#
# If any such bytes are found, the value shall instead be requoted in a manner
# that conforms with section 2.2.4 of the Shell Command Language, wherein the
# the use of dollar-single-quotes sequences is described. Such sequences are
# standard as of POSIX-1.2024. However, as of August 2024, many implementations
# lack support for this feature. So as to mitigate this state of affairs, the
# use of dollar-single-quotes may be suppressed by setting POSIXLY_CORRECT as a
# non-empty string.
#
quote_args()
{
# Call into a bash-optimised implementation where appropriate.
# shellcheck disable=3028
if [ ! "${POSIXLY_CORRECT}" ] && [ "${BASH_VERSINFO-0}" -ge 5 ]; then
_quote_args_bash "$@"
return
fi
LC_ALL=C awk -v q=\' -f - -- "$@" <<-'EOF'
function init_table() {
# Iterate over ranges \001-\037 and \177-\377.
for (i = 1; i <= 255; i += (i == 31 ? 96 : 1)) {
char = sprintf("%c", i)
seq_by[char] = sprintf("%03o", i)
}
seq_by["\007"] = "a"
seq_by["\010"] = "b"
seq_by["\011"] = "t"
seq_by["\012"] = "n"
seq_by["\013"] = "v"
seq_by["\014"] = "f"
seq_by["\015"] = "r"
seq_by["\033"] = "e"
seq_by["\047"] = "'"
seq_by["\134"] = "\\"
}
BEGIN {
issue = length(ENVIRON["POSIXLY_CORRECT"]) ? 7 : 8;
argc = ARGC
ARGC = 1
for (arg_idx = 1; arg_idx < argc; arg_idx++) {
arg = ARGV[arg_idx]
if (arg == q) {
word = "\\" q
} else if (issue < 8 || arg !~ /[\001-\037\177-\377]/) {
gsub(q, q "\\" q q, arg)
word = q arg q
} else {
# Use $'' quoting per POSIX-1.2024.
if (! ("\001" in seq_by)) {
init_table()
}
word = "$'"
for (i = 1; i <= length(arg); i++) {
char = substr(arg, i, 1)
if (char in seq_by) {
word = word "\\" seq_by[char]
} else {
word = word char
}
}
word = word q
}
line = line word
if (arg_idx < argc - 1) {
line = line " "
}
}
print line
}
EOF
}
#
# Generates a random number between 0 and 2147483647 (2^31-1) with the
# assistance of the kernel CSPRNG. Upon success, the number shall be printed to
# the standard output along with a trailing <newline>. Otherwise, the return
# value shall be greater than 0.
#
srandom()
{
# shellcheck disable=3028
_has_srandom()
{
# The SRANDOM variable was introduced by bash 5.1. Check for at
# least 5.0, letting the alternate branch confirm its efficacy.
if [ "${BASH_VERSINFO-0}" -lt 5 ]; then
false
else
for _ in 1 2 3; do
test "${SRANDOM}" != "${SRANDOM}" && break
done
fi
}
if _has_srandom; then
srandom()
{
printf '%d\n' "$(( SRANDOM >> 1 ))"
}
elif [ -c /dev/urandom ]; then
# Employ a method which entails searching for 8 consecutive hex
# digits, where the first is between 0 and 7.
genfun_int32_pat='[0-7][[:xdigit:]][[:xdigit:]][[:xdigit:]][[:xdigit:]][[:xdigit:]][[:xdigit:]][[:xdigit:]]'
unset -v genfun_entropy
srandom()
{
local hex i slice
# If the shell has forked, or if it cannot be determined
# whether it has done so, populate the pool with 64
# bytes worth of fresh entropy.
if ! _update_pid; then
_collect_entropy
elif ! eval "test \"\${genfun_pool_${genfun_pid}+set}\""; then
_collect_entropy &&
eval "genfun_pool_${genfun_pid}=1"
fi || return
for i in 1 2 3; do
# shellcheck disable=2295
slice=${genfun_entropy%${genfun_int32_pat}*}
if [ "${#slice}" -ne "${#genfun_entropy}" ]; then
hex=${genfun_entropy#"$slice"}
genfun_entropy=${genfun_entropy%"$hex"}
while [ "${#hex}" -gt 8 ]; do
hex=${hex%?}
done
break
elif [ "$i" -lt 3 ]; then
# The pool does not contain a suitable
# sequence. Refill it then try again.
_collect_entropy
else
false
fi
done &&
printf '%d\n' "0x${hex}"
}
else
warn "srandom: /dev/urandom doesn't exist as a character device"
return 1
fi
unset -f _has_srandom
srandom
}
#
# Trims leading and trailing whitespace from one or more lines. If at least one
# parameter is provided, each positional parameter shall be considered as a line
# to be processed. Otherwise, the lines to be processed shall be read from the
# standard input. The trimmed lines shall be printed to the standard output.
#
trim()
{
local arg
if [ "$#" -gt 0 ] && [ "${BASH}" ]; then
for arg; do
eval '[[ ${arg} =~ ^[[:space:]]+ ]] && arg=${arg:${#BASH_REMATCH}}'
eval '[[ ${arg} =~ [[:space:]]+$ ]] && arg=${arg:0:${#arg} - ${#BASH_REMATCH}}'
printf '%s\n' "${arg}"
done
else
if [ "$#" -gt 0 ]; then
printf '%s\n' "$@"
else
cat
fi | sed -e 's/^[[:space:]]\{1,\}//' -e 's/[[:space:]]\{1,\}$//'
fi
}
#
# Considers the parameters up to - but not including - a sentinel value as the
# words comprising a simple command then determines whether said command
# succeeds for all of the remaining parameters, passing them one at a time. If
# the SENTINEL variable is set, it shall be taken as the value of the sentinel.
# Otherwise, the value of the sentinel shall be defined as <hyphen-dash>
# <hyphen-dash>. If the composed command is empty, the sentinel value is not
# encountered or there are no parameters following the sentinel, the return
# value shall be greater than 0.
#
trueof_all()
{
local arg arg_idx i j
arg_idx=0
i=0
j=0
for arg; do
if [ "$(( arg_idx += 1 ))" -eq 1 ]; then
set --
fi
if [ "$i" -gt 1 ]; then
"$@" "${arg}" || return
j=${arg_idx}
elif [ "${arg}" = "${SENTINEL-"--"}" ]; then
i=${arg_idx}
else
set -- "$@" "${arg}"
fi
done
test "$i" -gt 1 && test "$j" -gt "$i"
}
#
# Considers the parameters up to - but not including - a sentinel value as the
# words comprising a simple command then determines whether said command
# succeeds for at least one of the remaining parameters, passing them one at a
# time. If the SENTINEL variable is set, it shall be taken as the value of the
# sentinel. Otherwise, the value of the sentinel shall be defined as
# <hyphen-dash> <hyphen-dash>. If the composed command is empty, the sentinel
# value is not encountered or there are no parameters following the sentinel,
# the return value shall be greater than 0.
#
trueof_any()
{
local arg arg_idx i
arg_idx=0
i=0
for arg; do
if [ "$(( arg_idx += 1 ))" -eq 1 ]; then
set --
fi
if [ "$i" -gt 1 ]; then
"$@" "${arg}" && return
elif [ "${arg}" = "${SENTINEL-"--"}" ]; then
i=${arg_idx}
else
set -- "$@" "${arg}"
fi
done
false
}
#
# Considers the first parameter as a command name before trying to locate it as
# a regular file. If not specified as an absolute pathname, a PATH search shall
# be performed in accordance with the Environment Variables section of the Base
# Definitions. If a file is found, its path shall be printed. Otherwise, the
# return value shall be 1. If the -x option is specified then the file must
# also be executable by the present user in order to be matched. This function
# serves as an alternative to type -P in bash. It is useful for determining the
# existence and location of an external utility without potentially matching
# against aliases, builtins and functions (as command -v can).
#
whenceforth()
(
local bin executable opt path prefix
executable=
while getopts :x opt; do
case ${opt} in
x)
executable=1
;;
'?')
_warn_for_args whenceforth "-${OPTARG}"
return 1
esac
done
shift "$(( OPTIND - 1 ))"
case $1 in
/*)
# Absolute command paths must be directly checked.
test -f "$1" && test ${executable:+-x} "$1" && bin=$1
;;
*)
# Relative command paths must be searched for in PATH.
# https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html#tag_08_03
case ${PATH} in
''|:)
# Work around a bug in OpenBSD sh and
# its ports. Where IFS has a value of
# ":", splitting a word having the same
# value produces no words at all. Handle
# it by repeating the field terminator.
path=::
;;
*:)
path=${PATH}:
;;
*)
path=${PATH}
esac
IFS=:
set -f
for prefix in ${path}; do
case ${prefix} in
*/)
bin=${prefix}$1
;;
*)
bin=${prefix:-.}/$1
esac
test -f "${bin}" && test ${executable:+-x} "${bin}" && break
done
esac \
&& printf '%s\n' "${bin}"
)
#------------------------------------------------------------------------------#
#
# Collects 64 bytes worth of entropy from /dev/urandom and assigns it to the
# genfun_entropy variable in the form of 128 hex digits.
#
_collect_entropy() {
genfun_entropy=$(LC_ALL=C od -vAn -N64 -tx1 /dev/urandom | tr -d '[:space:]')
test "${#genfun_entropy}" -eq 128
}
#
# Determines whether the terminal is a dumb one.
#
_has_dumb_terminal()
{
! case ${TERM} in *dumb*) false ;; esac
}
#
# Potentially called by quote_args(), duly acting as a bash-optimised variant.
# It leverages the ${paramater@Q} form of expansion, which is supported as of
# bash 4.4. However, it is simpler just to test for 5.0 or greater in sh.
#
# shellcheck disable=3028
if [ "${BASH_VERSINFO-0}" -ge 5 ]; then
eval '
_quote_args_bash() {
local IFS=" " args i
(( $# > 0 )) || return 0
args=("${@@Q}")
for i in "${!args[@]}"; do
if [[ ${args[i]} == \$* ]]; then
args[i]=${args[i]//\\E/\\e}
fi
done
printf "%s\\n" "${args[*]}"
}
'
fi
#
# Considers the first parameter as a number of centiseconds and determines
# whether fewer have elapsed since the last occasion on which the function was
# called, or whether the last genfun_time update resulted in integer overflow.
#
_should_throttle()
{
_update_time || return
# shellcheck disable=2317
_should_throttle()
{
_update_time || return
if [ "$(( (genfun_time < 0 && genfun_last_time >= 0) || genfun_time - genfun_last_time > $1 ))" -eq 1 ]
then
genfun_last_time=${genfun_time}
false
fi
}
genfun_last_time=${genfun_time}
false
}
#
# Determines whether the terminal on STDIN is able to report its dimensions.
# Upon success, the number of columns shall be stored in genfun_cols.
#
_update_columns()
{
# shellcheck disable=3044
if [ "${BASH}" ] && shopt -q checkwinsize; then
genfun_bin_true=$(whenceforth -x true)
fi
_update_columns()
{
# Two optimisations are applied. Firstly, the rate at which
# updates can be performed is throttled to intervals of half a
# second. Secondly, if running on bash then the COLUMNS variable
# may be gauged, albeit only in situations where doing so can be
# expected to work reliably; it is an unreliable method where
# operating from a subshell. Note that executing true(1) is
# faster than executing stty(1) within a comsub.
# shellcheck disable=3028
if _should_throttle 50; then
test "${genfun_cols}"
return
elif [ "${genfun_bin_true}" ] && [ "$$" = "${BASHPID}" ]; then
"${genfun_bin_true}"
set -- 0 "${COLUMNS}"
else
# This use of stty(1) is portable as of POSIX-1.2024.
genfun_ifs=${IFS}
IFS=' '
# shellcheck disable=2046
set -- $(stty size 2>/dev/null)
IFS=${genfun_ifs}
fi
[ "$#" -eq 2 ] && is_int "$2" && [ "$2" -gt 0 ] && genfun_cols=$2
}
_update_columns
}
#
# Determines the PID of the current shell process. Upon success, the PID shall
# be assigned to genfun_pid. Otherwise, the return value shall be greater than
# 0. The obtained PID value will differ from the value of $$ under certain
# circumstances, such as where a shell forks itself to create a subshell.
#
_update_pid()
{
if [ "${BASH}" ]; then
_update_pid()
{
# shellcheck disable=3028
genfun_pid=${BASHPID}
}
elif [ -d /proc/self/task ]; then
# This method relies on the proc_pid_task(5) interface of Linux.
_update_pid()
{
local dir tid
tid=
for dir in /proc/self/task/*/; do
if [ "${tid}" ] || [ ! -e "${dir}" ]; then
return 1
else
dir=${dir%/}
tid=${dir##*/}
fi
done
genfun_pid=${tid}
}
else
_update_pid()
{
false
}
fi
_update_pid
}
#
# Determines either the number of centiseconds elapsed since the unix epoch or
# the number of centiseconds that the operating system has been online,
# depending on the capabilities of the shell and/or platform. Upon success, the
# obtained value shall be assigned to genfun_time. Otherwise, the return value
# shall be greater than 0.
#
_update_time()
{
# shellcheck disable=3028
if [ "${EPOCHREALTIME}" != "${EPOCHREALTIME}" ]; then
# shellcheck disable=2034,3045
_update_time()
{
# Setting LC_NUMERIC as C ensures a radix character of
# U+2E, duly affecting both EPOCHREALTIME and printf.
local LC_ALL LC_NUMERIC=C cs s timeval
timeval=${EPOCHREALTIME}
s=${timeval%.*}
printf -v cs '%.2f' ".${timeval#*.}"
if [ "${cs}" = "1.00" ]; then
cs=100
else
cs=${cs#0.} cs=${cs#0}
fi
genfun_time=$(( s * 100 + cs ))
}
elif [ -f /proc/uptime ] && [ ! "${YASH_VERSION}" ]; then
# Yash is blacklisted because it dies upon integer overflow.
_update_time()
{
local cs s
IFS='. ' read -r s cs _ < /proc/uptime \
&& genfun_time=$(( s * 100 + ${cs#0} ))
}
else
_update_time()