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perf(tar): cache the parse result of GNU tar help #1362

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Merged
merged 5 commits into from
Apr 8, 2025
Merged

perf(tar): cache the parse result of GNU tar help #1362

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4cf6d22
refactor(tar): move variable declarations to the relevant places
akinomyoga Apr 7, 2025
8bd337a
refactor(tar): remove duplicate declarations
akinomyoga Apr 7, 2025
281261a
refactor(tar): initialize the variables in parsers
akinomyoga Apr 7, 2025
b030e07
perf(tar): parse the GNU tar help on initialization
akinomyoga Apr 7, 2025
d8d1d82
refactor(tar): rename functions only used in initialization
akinomyoga Apr 8, 2025
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106 changes: 85 additions & 21 deletions completions/tar
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Original file line number Diff line number Diff line change
Expand Up @@ -59,7 +59,7 @@
_comp_deprecate_var 2.12 \
COMP_TAR_INTERNAL_PATHS BASH_COMPLETION_CMD_TAR_INTERNAL_PATHS

_comp_cmd_gtar__parse_help_opt()
_comp_cmd_gtar__init_parse_help_opt()
{
local opttype arg opt separator optvar
opttype=long
Expand Down Expand Up @@ -98,7 +98,7 @@ _comp_cmd_gtar__parse_help_opt()
eval "$optvar=\"\$$optvar$separator\"\"$opt\""
}

_comp_cmd_gtar__parse_help_line()
_comp_cmd_gtar__init_parse_help_line()
{
local i
local -a tmp
Expand All @@ -107,7 +107,7 @@ _comp_cmd_gtar__parse_help_line()
case "$i" in
# regular options
--* | -*)
_comp_cmd_gtar__parse_help_opt "$i" "$2"
_comp_cmd_gtar__init_parse_help_opt "$i" "$2"
;;

# end once there is single non-option word
Expand All @@ -119,8 +119,21 @@ _comp_cmd_gtar__parse_help_line()
done <<<"$1"
}

_comp_cmd_gtar__parse_help()
# Parse the output of "tar --help" with GNU tar and store the parse results
# in a global variable.
#
# @var[out] _comp_cmd_gtar__saved_opts
# The parse results are stored in this global variable in a form that can
# be evaluated by the builtin "eval".
_comp_cmd_gtar__init_parse_help()
{
local long_arg_none=""
local long_arg_opt=""
local long_arg_req=""
local short_arg_none=""
local short_arg_opt=""
local short_arg_req=""

local str line arg
while IFS= read -r line; do
# Ok, this requires some comment probably. The GNU help output prints
Expand All @@ -141,14 +154,49 @@ _comp_cmd_gtar__parse_help()
[[ ${BASH_REMATCH[1]} ]] && arg=opt || arg=req
fi

_comp_cmd_gtar__parse_help_line "$str" "$arg"
_comp_cmd_gtar__init_parse_help_line "$str" "$arg"
fi
done <<<"$(tar --help)"

long_opts="\
$long_arg_none $long_arg_opt $long_arg_req"
local long_opts="$long_arg_none $long_arg_opt $long_arg_req"

local short_opts="$short_arg_none$short_arg_opt$short_arg_req"

printf -v _comp_cmd_gtar__saved_opts '%s=%q ' \
long_opts "$long_opts" \
short_opts "$short_opts" \
long_arg_none "$long_arg_none" \
long_arg_opt "$long_arg_opt" \
long_arg_req "$long_arg_req" \
short_arg_none "$short_arg_none" \
short_arg_opt "$short_arg_opt" \
short_arg_req "$short_arg_req"

short_opts="$short_arg_none$short_arg_opt$short_arg_req"
# Clean up functions only used in initialization
unset -f _comp_cmd_gtar__init_parse_help
unset -f _comp_cmd_gtar__init_parse_help_line
unset -f _comp_cmd_gtar__init_parse_help_opt
}
_comp_cmd_gtar__init_parse_help

# Load the parse results of "tar --help" for GNU tar into variables.
#
# @var[out] long_opts
# @var[out] short_opts
# @var[out] long_arg_none
# @var[out] long_arg_opt
# @var[out] long_arg_req
# @var[out] short_arg_none
# @var[out] short_arg_opt
# @var[out] short_arg_req
# The parse results are returned in these variables.
#
# @var[in] _comp_cmd_gtar__saved_opts
# The parse results are obtained by evaluating this variable with the
# "eval" builtin.
_comp_cmd_gtar__load_opts()
{
eval -- "$_comp_cmd_gtar__saved_opts"
}

# Hack: parse --warning keywords from tar's error output
Expand All @@ -165,8 +213,15 @@ _comp_cmd_gtar__parse_warnings()
_comp_compgen -- -W '"${warnings[@]}"'
}

# @var[out] old_opt_progress
# @var[out] old_opt_used
# @var[out,array] old_opt_parsed
_comp_cmd_tar__parse_old_opt()
{
old_opt_progress=""
old_opt_used=""
old_opt_parsed=()

local first_word char

# current word is the first word
Expand All @@ -193,6 +248,10 @@ _comp_cmd_tar__parse_old_opt()
}

# Make the analysis of whole command line.
#
# @var[out] old_opt_progress
# @var[out] old_opt_used
# @var[out,array] old_opt_parsed
_comp_cmd_tar__preparse_cmdline()
{
local first_arg=set i modes="ctxurdA"
Expand Down Expand Up @@ -507,11 +566,7 @@ _comp_cmd_tar__detect_ext()

_comp_cmd_tar__gnu()
{
local long_opts short_opts basic_tar="" \
long_arg_none="" long_arg_opt="" long_arg_req="" \
short_arg_none="" short_arg_opt="" short_arg_req="" \
tar_mode tar_mode_arg old_opt_progress="" \
old_opt_used="" old_opt_parsed=()
local basic_tar=""

# Main mode, e.g. "x" or "c" or the long forms "extract" or "create"
local tar_mode=none
Expand All @@ -528,12 +583,15 @@ _comp_cmd_tar__gnu()
fi

local cur prev words cword was_split comp_args

_comp_initialize -s -- "$@" || return

# Fill the {long,short}_{opts,arg*}
_comp_cmd_gtar__parse_help
local long_opts short_opts \
long_arg_none long_arg_opt long_arg_req \
short_arg_none short_arg_opt short_arg_req
_comp_cmd_gtar__load_opts

local old_opt_progress old_opt_used old_opt_parsed
_comp_cmd_tar__preparse_cmdline "${words[@]}"

local ext
Expand Down Expand Up @@ -694,11 +752,7 @@ _comp_cmd_tar__posix_prev_handle()

_comp_cmd_tar__posix()
{
local long_opts short_opts basic_tar=set \
long_arg_none="" long_arg_opt long_arg_req="" \
short_arg_none short_arg_opt short_arg_req \
tar_mode tar_mode_arg old_opt_progress="" \
old_opt_used=set old_opt_parsed=()
local basic_tar=set

# Main mode, e.g. -x or -c (extract/creation)
local tar_mode=none
Expand All @@ -710,15 +764,25 @@ _comp_cmd_tar__posix()
local tar_compression_mode=none

local cur prev words cword was_split comp_args

_comp_initialize -s -- "$@" || return

# Initialize option variables:
# relatively compatible modes are {c,t,x}
# relatively compatible options {b,f,m,v,w}
# Note: long_{opts,arg_{none,opt}} and short_arg_opt are currently unused
local long_opts short_opts \
long_arg_none long_arg_opt long_arg_req \
short_arg_none short_arg_opt short_arg_req
long_arg_none=""
long_arg_opt=""
long_arg_req=""
long_opts=""
short_arg_req="fb"
short_arg_opt=""
short_arg_none="wmv"
short_opts="$short_arg_req$short_arg_none"

local old_opt_progress old_opt_used old_opt_parsed
_comp_cmd_tar__preparse_cmdline "${words[@]}"

local ext
Expand Down