git/generate-cmdlist.sh
Ævar Arnfjörð Bjarmason 1cecd06e36 generate-cmdlist.sh: don't parse command-list.txt thrice
Change the "define_categories()" and "define_category_names()" functions
to take the already-parsed output of "category_list()" as an argument,
which brings our number of passes over "command-list.txt" from three
to two.

Then have "category_list()" itself take the output of "command_list()"
as an argument, bringing the number of times we parse the file to one.

Compared to the pre-image this speeds us up quite a bit:

    $ git show HEAD~:generate-cmdlist.sh >generate-cmdlist.sh.old
    $ hyperfine --warmup 10 -L v ,.old 'sh generate-cmdlist.sh{v} command-list.txt'
    Benchmark #1: sh generate-cmdlist.sh command-list.txt
      Time (mean ± σ):      22.9 ms ±   0.3 ms    [User: 15.8 ms, System: 9.6 ms]
      Range (min … max):    22.5 ms …  24.0 ms    125 runs

    Benchmark #2: sh generate-cmdlist.sh.old command-list.txt
      Time (mean ± σ):      30.1 ms ±   0.4 ms    [User: 24.4 ms, System: 17.5 ms]
      Range (min … max):    29.5 ms …  32.3 ms    96 runs

    Summary
      'sh generate-cmdlist.sh command-list.txt' ran
        1.32 ± 0.02 times faster than 'sh generate-cmdlist.sh.old command-list.txt'

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-11-05 12:01:13 -07:00

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#!/bin/sh
die () {
echo "$@" >&2
exit 1
}
command_list () {
while read cmd rest
do
case "$cmd" in
"#"* | '')
# Ignore comments and allow empty lines
continue
;;
*)
case "$exclude_programs" in
*":$cmd:"*)
;;
*)
echo "$cmd $rest"
;;
esac
esac
done <"$1"
}
category_list () {
echo "$1" |
cut -d' ' -f2- |
tr ' ' '\012' |
grep -v '^$' |
LC_ALL=C sort -u
}
define_categories () {
echo
echo "/* Command categories */"
bit=0
echo "$1" |
while read cat
do
echo "#define CAT_$cat (1UL << $bit)"
bit=$(($bit+1))
done
test "$bit" -gt 32 && die "Urgh.. too many categories?"
}
define_category_names () {
echo
echo "/* Category names */"
echo "static const char *category_names[] = {"
bit=0
echo "$1" |
while read cat
do
echo " \"$cat\", /* (1UL << $bit) */"
bit=$(($bit+1))
done
echo " NULL"
echo "};"
}
print_command_list () {
echo "static struct cmdname_help command_list[] = {"
echo "$1" |
while read cmd rest
do
synopsis=
while read line
do
case "$line" in
"$cmd - "*)
synopsis=${line#$cmd - }
break
;;
esac
done <"Documentation/$cmd.txt"
printf '\t{ "%s", N_("%s"), 0' "$cmd" "$synopsis"
printf " | CAT_%s" $rest
echo " },"
done
echo "};"
}
exclude_programs=:
while test "--exclude-program" = "$1"
do
shift
exclude_programs="$exclude_programs$1:"
shift
done
commands="$(command_list "$1")"
categories="$(category_list "$commands")"
echo "/* Automatically generated by generate-cmdlist.sh */
struct cmdname_help {
const char *name;
const char *help;
uint32_t category;
};
"
define_categories "$categories"
echo
define_category_names "$categories"
echo
print_command_list "$commands"