libmakepkg: automatically add library dependencies

Add linked libraries to a packages dependency list. This is the partner
to automatically generated library provides, and thus depends take the
same format. To help with bootstrapping, library dependencies are only
added if the relevant provide exists.

Signed-off-by: Allan McRae <allan@archlinux.org>

scripts/libmakepkg/autodep/library_depends.sh.in

@@ -0,0 +1,75 @@
+#!/bin/bash
+#
+#   library_depends.sh - Automatically add library requirements to depends
+#
+#   Copyright (c) 2021 Pacman Development Team <pacman-dev@lists.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/>.
+#
+
+[[ -n "$LIBMAKEPKG_AUTODEP_LIBRARY_DEPENDS_SH" ]] && return
+LIBMAKEPKG_AUTODEP_LIBRARY_DEPENDS_SH=1
+
+LIBRARY=${LIBRARY:-'@libmakepkgdir@'}
+
+autodep_functions+=('library_depends')
+
+library_depends() {
+	if check_option "autodeps" "y"; then
+		local dep filename libdeps libdir libpath prefix sofile
+		declare -a libdeps
+
+		while IFS= read -rd '' filename; do
+			for sofile in $(LC_ALL=C readelf -d $filename 2>/dev/null | sed -nr 's/.*Shared library: \[(.*)\].*/\1/p'); do
+				# get the full path of the library
+				libpath=$(ldd $filename | sed -nr "s/.$sofile => (.*) \(.*\)/\1/p")
+
+				# if ldd can not find the library, it is likely part of the package and not in filesystem
+				if [[ -z $libpath ]]; then
+					continue
+				fi
+
+				# skip if the library is part of the package
+				if [[ -e "$pkgdir/$libpath" ]]; then
+					continue
+				fi
+
+				# find the prefix for the dependency
+				libpath=${libpath#/}
+				libpath=${libpath%/*}
+
+				unset prefix
+				for libdir in ${LIB_DIRS[@]}; do
+					if [[ ${libdir/*:} == ${libpath} ]]; then
+						prefix=${libdir/:*}
+					fi
+				done
+
+				if [[ -z ${prefix} ]]; then
+					continue
+				fi
+
+				# only add library dependency if it exists - this helps bootstraping dependencies
+				if [[ $(run_pacman -T "$prefix:$sofile") ]]; then
+					continue
+				fi
+
+				libdeps+=("$prefix:$sofile")
+			done
+
+		done < <(find "$pkgdir" -type f -perm -u+x -print0)
+
+		depends+=($(printf '%s\n' "${libdeps[@]}" | LC_ALL=C sort -u))
+	fi
+}

scripts/libmakepkg/autodep/meson.build

@@ -1,8 +1,8 @@
 libmakepkg_module = 'tidy'
 
 sources = [
+  'library_depends.sh.in',
   'library_provides.sh.in',
-
 ]
 
 foreach src : sources