pylinks

#!/usr/bin/env bash
#
# pylinks
#   set up symlinks in $2 (default /usr/local) to installed python root $1
#
# notes:
#   - aborts on attempt to clobber any regular files in target
#   - symlinks allowed to exist already in the target, get overwritten
#   - audits at finish to make sure all files represented
#
# scott@smemsh.net
# https://github.com/smemsh/utiladm/
# https://spdx.org/licenses/GPL-2.0
#

set -e
errtrap () { echo "$FUNCNAME: code $1, line: $2, cmd: \"$3\""; exit $1; }
trap 'errtrap $? $LINENO "$BASH_COMMAND"' ERR

if [[ $1 == -t || $1 == --test ]]
then run=echo; shift
else ((EUID == 0))
fi

ln --help |& grep -wPq -- --relative && let ++linkrel || true

pyroot=${1:?}
pyrootdir=${pyroot%/*}
pyrootbase=${pyroot##*/}
[[ $pyroot == $(readlink -f $pyroot) ]]
[[ $pyroot == $pyrootdir/$pyrootbase ]]
test -d $pyroot

pyver=${pyrootbase#*-}
[[ $pyver =~ ^([[:digit:]]+)\.([[:digit:]]+)\.([[:digit:]]+)$ ]]
pymajor=${BASH_REMATCH[1]}
pyminor=${BASH_REMATCH[2]}
pypatch=${BASH_REMATCH[3]}
pymmver=python$pymajor.$pyminor
pylibrel=lib/lib$pymmver.a
[[ $pyver == $pymajor.$pyminor.$pypatch ]]

destroot=${2:-/usr/local}
manreldir=share/man/man1
pcreldir=lib/pkgconfig

for dir in bin $pcreldir $manreldir include; do
	testdir=$destroot/$dir
	if ! test -d $testdir
	then mkdir -p $testdir; fi
	[[ $(readlink -f $testdir) == $testdir ]]
done

for dir in {include,lib}/$pymmver; do
	destpath=$destroot/$dir
	pypath=$pyroot/$dir
	test -d $pypath
	[[ $(readlink -f $pypath) == $pypath ]]
	test -L $destpath || ! test -e $destpath
	$run ln ${linkrel:+-r} -nsf $pypath $destpath
done

for dir in bin lib/pkgconfig; do
	pydir=$pyroot/$dir
	destdir=$destroot/$dir
	test -d $pydir
	for path in $pydir/*; do
		file=${path##*/}
		destfile=$destdir/$file
		test -L $destfile || ! test -e $destfile
		$run ln ${linkrel:+-r} -nsf $path $destdir
	done
done

destmandir=$destroot/$manreldir
for path in $pyroot/$manreldir/*; do
	file=${path##*/}
	destfile=$destmandir/$file
	test -L $destfile || ! test -e $destfile
	$run ln ${linkrel:+-r} -nsf $path $destmandir
done

pylibdest=$destroot/$pylibrel
pylibpath=$pyroot/$pylibrel
test -L $pylibdest || ! test -e $pylibdest
ln ${linkrel:+-r} -nsf $pylibpath $pylibdest

disjuncts=($(comm -1 -3 \
	<(find $destroot/ -follow -mindepth 1 -printf '%P\n' | sort) \
	<(find $pyroot/ -mindepth 1 -printf '%P\n' | sort) \
))
if ((${#disjuncts[@]})); then
	echo "warning: disjunction detected:" >&2
	fmt -1 <<< "${disjuncts[@]}"
fi