fish-shell/share/functions/__fish_print_apt_packages.fish
Fabian Boehm 81cd035950 print_apt_packages: Go back to apt-cache for non-installed packages
Unfortunately, /var/lib/dpkg/status on recent-ish Debian versions at
least only contains the *installed* packages, rendering this solution
broken.

What we do instead is:

1. Remove a useless newline from each package, so our limit would now
let more full package data sets through
2. Increase the limit by 5x

This yields a completion that runs in ~800ms instead of ~700ms on a
raspberry pi, but gives ~10x the candidates, compared to the old
apt-cache version.

This partially reverts 96deaae7d8
2023-08-22 22:17:22 +02:00

65 lines
2.4 KiB
Fish

function __fish_print_apt_packages
argparse --name=__fish_print_packages i/installed -- $argv
or return
switch (commandline -ct)
case '-**'
return
end
set -l search_term (commandline -ct | string replace -ar '[\'"\\\\]' '' | string lower)
if ! test -f /var/lib/dpkg/status
return 1
end
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/g' | head -n 2500 | string join "" | string replace --all --regex \x1a+ \n | uniq
return 0
else
# Do not not use `apt-cache` as it is sometimes inexplicably slow (by multiple orders of magnitude).
awk '
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