From 96deaae7d86edfbc16e411bdb73bf54ced7fb447 Mon Sep 17 00:00:00 2001 From: Mahmoud Al-Qudsi Date: Sun, 5 Feb 2023 16:17:08 -0600 Subject: [PATCH] completions/apt: Read from the dpkg cache directly MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit I have no idea why `apt-cache --no-generate show` is so slow since it basically dumps the contents of the cache file located at `/var/lib/dpkg/status`. We are technically bypassing any waits on the cache lock file so this may produce incorrect results if the cache is being regenerated in the moment, but that's a small price to pay and the results are likely confined to simply not generating comprehensive results. With this change, we no longer need to truncate results to the first n matches and we no longer only print packages beginning with the commandline argument enabling fish's partial completions logic to offer less-perfect suggestions when no better options are available. Even though we are generating more usable completions, we still trounce the old performance by leaps and bounds: ``` Benchmark #1: fish -c "complete -C\"apt install ac\"" Time (mean ± σ): 2.165 s ± 0.033 s [User: 267.0 ms, System: 1932.2 ms] Range (min … max): 2.136 s … 2.256 s 10 runs Benchmark #2: build/fish -c "complete -C\"apt install ac\"" Time (mean ± σ): 111.1 ms ± 1.8 ms [User: 38.9 ms, System: 72.9 ms] Range (min … max): 108.2 ms … 114.9 ms 26 runs Summary 'build/fish -c "complete -C\"apt install ac\""' ran 19.49 ± 0.44 times faster than 'fish -c "complete -C\"apt install ac\""' ``` --- share/completions/apt.fish | 7 +- .../functions/__fish_print_apt_packages.fish | 71 ++++++++++++------- 2 files changed, 50 insertions(+), 28 deletions(-) diff --git a/share/completions/apt.fish b/share/completions/apt.fish index e05fc4d42..5341205e6 100644 --- a/share/completions/apt.fish +++ b/share/completions/apt.fish @@ -33,9 +33,10 @@ end complete -c apt -f -complete -k -c apt -n "__fish_seen_subcommand_from $pkg_subcmds" -a '(__fish_print_apt_packages | string match -re -- "(?:\\b|_)"(commandline -ct | string escape --style=regex) | head -n 250 | sort)' -complete -c apt -n "__fish_seen_subcommand_from $installed_pkg_subcmds" -a '(__fish_print_apt_packages --installed | string match -re -- "(?:\\b|_)"(commandline -ct | string escape --style=regex) | head -n 250)' -complete -k -c apt -n "__fish_seen_subcommand_from $handle_file_pkg_subcmds" -a '(__fish_complete_suffix .deb)' +# We use -k to keep PWD directories (from the .deb completion) after packages, so we need to sort the packages +complete -k -c apt -n "__fish_seen_subcommand_from $handle_file_pkg_subcmds" -kxa '(__fish_complete_suffix .deb)' +complete -k -c apt -n "__fish_seen_subcommand_from $pkg_subcmds" -kxa '(__fish_print_apt_packages | sort)' +complete -c apt -n "__fish_seen_subcommand_from $installed_pkg_subcmds" -kxa '(__fish_print_apt_packages --installed | sort)' complete -c apt -n "__fish_seen_subcommand_from install" -l no-install-recommends # This advanced flag is the safest way to upgrade packages that otherwise would have been kept back diff --git a/share/functions/__fish_print_apt_packages.fish b/share/functions/__fish_print_apt_packages.fish index c8d578c9e..130bf1b21 100644 --- a/share/functions/__fish_print_apt_packages.fish +++ b/share/functions/__fish_print_apt_packages.fish @@ -7,32 +7,53 @@ function __fish_print_apt_packages return end - type -q -f apt-cache || return 1 + set -l search_term (commandline -ct | string replace -ar '[\'"\\\\]' '' | string lower) + + if ! test -f /var/lib/dpkg/status + return 1 + end + + # Do not not use `apt-cache` as it is sometimes inexplicably slow (by multiple orders of magnitude). if not set -q _flag_installed - # Do not generate the cache as apparently sometimes this is slow. - # http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=547550 - # (It is safe to use `sed -r` here as we are guaranteed to be on a GNU platform - # if apt-cache was found.) - # Uses the UTF-8/ASCII record separator (0x1A) character. - # - # Note: This can include "Description:" fields which we need to include, - # "Description-en_GB" (or another locale code) fields which we need to include - # as well as "Description-md5" fields which we absolutely do *not* want to include - # The regex doesn't allow numbers, so unless someone makes a hash algorithm without a number - # in the name, we're safe. (yes, this should absolutely have a better format). - # - # aptitude has options that control the output formatting, but is orders of magnitude slower - # - # sed could probably do all of the heavy lifting here, but would be even less readable - # - # The `head -n 500` causes us to stop once we have 500 lines. We do it after the `sed` because - # Debian package descriptions can be extremely long and are hard-wrapped: texlive-latex-extra - # has about 2700 lines on Debian 11. - apt-cache --no-generate show '.*'(commandline -ct)'.*' 2>/dev/null | sed -r '/^(Package|Description-?[a-zA-Z_]*):/!d;s/Package: (.*)/\1\t/g;s/Description-?[^:]*: (.*)/\1\x1a\n/g' | head -n 500 | string join "" | string replace --all --regex \x1a+ \n | uniq - return 0 + awk -e ' +BEGIN { + FS=": " +} + +/^Package/ { + pkg=$2 +} + +/^Description(-[a-zA-Z]+)?:/ { + desc=$2 + if (index(pkg, "'$search_term'") > 0) { + print pkg "\t" desc + } + pkg="" # Prevent multiple description translations from being printed +}' < /var/lib/dpkg/status else - set -l packages (dpkg --get-selections | string replace -fr '(\S+)\s+install' "\$1" | string match -e (commandline -ct)) - apt-cache --no-generate show $packages 2>/dev/null | sed -r '/^(Package|Description-?[a-zA-Z_]*):/!d;s/Package: (.*)/\1\t/g;s/Description-?[^:]*: (.*)/\1\x1a\n/g' | head -n 500 | string join "" | string replace --all --regex \x1a+ \n | uniq - return 0 + awk -e ' +BEGIN { + FS=": " +} + +/^Package/ { + pkg=$2 +} + +/^Status/ { + installed=0 + if ($2 ~ /(^|\s)installed/) { + installed=1 + } +} + +/^Description(-[a-zA-Z]+)?:/ { + desc=$2 + if (installed == 1 && index(pkg, "'$search_term'") > 0) { + print pkg "\t" desc + installed=0 # Prevent multiple description translations from being printed + } +}' < /var/lib/dpkg/status end end