paccache: add new contrib script

paccache is a robust and flexible package cache cleaner with a variety
of options. Much credit goes to DJ Mills and Pat Brisbin for ideas
behind this script.

Signed-off-by: Dave Reisner <dreisner@archlinux.org>
[Dan: add .gitignore entry]
Signed-off-by: Dan McGee <dan@archlinux.org>

1 files changed, 291 insertions, 0 deletions

diff --git a/contrib/paccache.in b/contrib/paccache.in
new file mode 100755
index 00000000..0bd0cf79
--- /dev/null
+++ b/contrib/paccache.in
@@ -0,0 +1,291 @@
+#!/bin/bash
+#
+# pacache - flexible pacman cache cleaning
+#
+# Copyright (C) 2011 Dave Reisner <dreisner@archlinux.org>
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+
+shopt -s extglob
+
+declare -a candidates=() cmdopts=() whitelist=() blacklist=()
+declare -i delete=0 dryrun=0 filecount=0 keep=3 move=0 totalsaved=0
+declare    cachedir=@localstatedir@/cache/pacman/pkg delim=$'\n' movedir= scanarch=
+
+msg() {
+	local mesg=$1; shift
+	printf "==> $mesg\n" "$@"
+} >&2
+
+error() {
+	local mesg=$1; shift
+	printf "==> ERROR: $mesg\n" "$@"
+} >&2
+
+die() {
+	error "$@"
+	exit 1
+}
+
+# reads a list of files on stdin and prints out deletion candidates
+pkgfilter() {
+	# there's whitelist and blacklist parameters passed to this
+	# script after the block of awk.
+
+	awk -v keep="$1" -v scanarch="$2" '
+	function parse_filename(filename,     parts, count, i, pkgname, arch) {
+
+		count = split(filename, parts, "-")
+
+		i = 1
+		pkgname = parts[i++]
+		while (i <= count - 3) {
+			pkgname = pkgname "-" parts[i++]
+		}
+
+		arch = substr(parts[count], 1, index(parts[count], ".") - 1)
+
+		# filter on whitelist or blacklist
+		if (wlen && !whitelist[pkgname]) return
+		if (blen && blacklist[pkgname]) return
+
+		if ("" == packages[pkgname,arch]) {
+			packages[pkgname,arch] = filename
+		} else {
+			packages[pkgname,arch] = packages[pkgname,arch] SUBSEP filename
+		}
+	}
+
+	BEGIN {
+		# create whitelist
+		wlen = ARGV[1]; delete ARGV[1]
+		for (i = 2; i < 2 + wlen; i++) {
+			whitelist[ARGV[i]] = 1
+			delete ARGV[i]
+		}
+
+		# create blacklist
+		blen = ARGV[i]; delete ARGV[i]
+		while (i++ < ARGC) {
+			blacklist[ARGV[i]] = 1
+			delete ARGV[i]
+		}
+
+		# read package filenames
+		while (getline < "/dev/stdin") {
+			parse_filename($0)
+		}
+	}
+
+	END {
+		for (pkglist in packages) {
+			# idx[1,2] = idx[pkgname,arch]
+			split(pkglist, idx, SUBSEP)
+
+			# enforce architecture match if specified
+			if (!scanarch || scanarch == idx[2]) {
+				count = split(packages[idx[1], idx[2]], pkgs, SUBSEP)
+				if (count > keep) {
+					for(i = 1; i <= count - keep; i++) {
+						print pkgs[i]
+					}
+				}
+			}
+		}
+	}' "${@:3}"
+}
+
+size_to_human() {
+	awk -v size="$1" '
+	BEGIN {
+		suffix[1] = "KiB"
+		suffix[2] = "MiB"
+		suffix[3] = "GiB"
+		suffix[4] = "TiB"
+		count = 1
+
+		while (size > 1024) {
+			size /= 1024
+			count++
+		}
+
+		sizestr = sprintf("%.2f", size)
+		sub(/.?0+$/, "", sizestr)
+		printf("%s %s", sizestr, suffix[count])
+	}'
+}
+
+runcmd() {
+	if (( needsroot )); then
+		msg "Privilege escalation required"
+		if sudo -v &>/dev/null && sudo -l &>/dev/null; then
+			sudo "$@"
+		else
+			printf '%s ' 'root'
+			su -c "$(printf '%q ' "$@")"
+		fi
+	else
+		"$@"
+	fi
+}
+
+summarize() {
+	local -i filecount=$#
+	local seenarch= seen= arch= name=
+	local -r pkg_re='(.+)-[^-]+-[0-9]+-([^.]+)\.pkg.*'
+
+	if (( delete )); then
+		printf -v output 'finished: %d packages removed' "$filecount"
+	elif (( move )); then
+		printf -v output "finished: %d packages moved to \`%s'" "$filecount" "$movedir"
+	elif (( dryrun )); then
+		if (( verbose )); then
+			msg "Candidate packages:"
+			while read -r pkg; do
+				if (( verbose >= 3 )); then
+					[[ $pkg =~ $pkg_re ]] && name=${BASH_REMATCH[1]} arch=${BASH_REMATCH[2]}
+					if [[ -z $seen || $seenarch != $arch || $seen != $name ]]; then
+						printf '%s (%s):\n' "$name" "$arch"
+					fi
+					printf '  %s\n' "$pkg"
+				elif (( verbose >= 2 )); then
+					printf "$PWD/%s$delim" "$pkg"
+				else
+					printf "%s$delim" "$pkg"
+				fi
+			done < <(printf '%s\n' "$@" | sort -V)
+			printf '\n' >&2
+		fi
+
+		printf -v output 'finished dry run: %d candidates' "$filecount"
+	fi
+
+  msg "$output (diskspace saved: %s)" "$(size_to_human "$totalsaved")"
+}
+
+usage() {
+	cat <<EOF
+usage: ${0##*/} <operation> [options] [targets...]
+
+${0##*/} is a flexible pacman cache cleaning utility, which has numerous
+options to help control how much, and what, is deleted from any directory
+containing pacman package tarballs.
+
+  Operations:
+    -d               perform a dry run, only finding candidate packages.
+    -m  <movedir>    move candidate packages to 'movedir'.
+    -r               remove candidate packages.
+
+  Options:
+    -a  <arch>       scan for 'arch' (default: all architectures).
+    -c  <cachedir>   scan 'cachedir' for packages (default: @localstatedir@/cache/pacman/pkg).
+    -f               apply force to mv(1) and rm(1) operations.
+    -h               display this help message.
+    -i  <pkgs>       ignore 'pkgs', which is a comma separated. Alternatively,
+                     specify '-' to read package names from stdin, newline delimited.
+    -k  <num>        keep 'num' of each package in 'cachedir' (default: 3).
+    -u               target uninstalled packages.
+    -v               increase verbosity. specify up to 3 times.
+    -z               use null delimiters for candidate names (only with -v and -vv)
+
+EOF
+}
+
+if (( ! UID )); then
+	error "Bad dog, no biscuit. You will be prompted for privilege escalation."
+	exit 42
+fi
+
+while getopts ':a:c:dfhi:k:m:rsuvz' opt; do
+	case $opt in
+		a) scanarch=$OPTARG ;;
+		c) cachedir=$OPTARG ;;
+		d) dryrun=1 ;;
+		f) cmdopts=(-f) ;;
+		h) usage
+			exit 0 ;;
+		i) if [[ $OPTARG = '-' ]]; then
+				 [[ ! -t 0 ]] && IFS=$'\n' read -r -d '' -a ign
+			 else
+				 IFS=',' read -r -a ign <<< "$OPTARG"
+			 fi
+			 blacklist+=("${ign[@]}")
+			unset i ign ;;
+		k) keep=$OPTARG
+			if [[ $keep != $OPTARG ]] || (( keep < 0 )); then
+				die 'argument to option -k must be a non-negative integer'
+			fi ;;
+		m) move=1 movedir=$OPTARG ;;
+		r) delete=1 ;;
+		u) IFS=$'\n' read -r -d '' -a ign < <(pacman -Qq)
+			 blacklist+=("${ign[@]}")
+			 unset ign ;;
+		v) (( ++verbose )) ;;
+		z) delim='\0' ;;
+		:) die "option '--%s' requires an argument" "$OPTARG" ;;
+		?) die "invalid option -- '%s'" "$OPTARG" ;;
+	esac
+done
+shift $(( OPTIND - 1 ))
+
+# remaining args are a whitelist
+whitelist=("$@")
+
+# sanity checks
+case $(( dryrun+delete+move )) in
+	0) die "no operation specified (use -h for help)" ;;
+	[^1]) die "only one operation may be used at a time" ;;
+esac
+
+[[ -d $cachedir ]] ||
+	die "cachedir \`%s' does not exist or is not a directory" "$cachedir"
+
+[[ $movedir && ! -d $movedir ]] &&
+	die "move-to directory \`%s' does not exist or is not a directory" "$movedir"
+
+if (( move || delete )); then
+	# make it an absolute path since we're about to chdir
+	[[ ${movedir:0:1} != '/' ]] && movedir=$PWD/$movedir
+	[[ ! -w $cachedir || ( $movedir && ! -w $movedir ) ]] && needsroot=1
+fi
+
+# unlikely that this will fail, but better make sure
+cd "$cachedir" || die "failed to chdir to \`%s'" "$cachedir"
+
+# note that these results are returned in an arbitrary order from awk, but
+# they'll be resorted (in summarize) iff we have a verbosity level set.
+IFS=$'\n' read -r -d '' -a candidates < \
+	<(printf '%s\n' *.pkg.tar?(.+([^.])) | sort -V |
+		pkgfilter "$keep" "$scanarch" \
+			"${#whitelist[*]}" "${whitelist[@]}" \
+			"${#blacklist[*]}" "${blacklist[@]}")
+
+if (( ! ${#candidates[*]} )); then
+	msg 'no candidate packages found for pruning'
+	exit 1
+fi
+
+# do this before we destroy anything
+totalsaved=$(@SIZECMD@ "${candidates[@]}" | awk '{ sum = $1 } END { print sum }')
+
+# crush. kill. destroy.
+(( verbose )) && cmdopts+=(-v)
+if (( delete )); then
+	runcmd rm "${cmdopts[@]}" "${candidates[@]}"
+elif (( move )); then
+	runcmd mv "${cmdopts[@]}" "${candidates[@]}" "$movedir"
+fi
+
+summarize "${candidates[@]}"