feat(util): parallelize srcinfo generation

Heavily improve the runtime of huge split packages, by creating an own
parallelized high level implementation of the makepkg low level building
blocks for srcinfo generation.

This reduces the runtine to generate the srcinfo file for thunderbird
from 24 seconds down to 1 second.

src/commitpkg.in

@@ -5,9 +5,12 @@
 _DEVTOOLS_LIBRARY_DIR=${_DEVTOOLS_LIBRARY_DIR:-@pkgdatadir@}
 # shellcheck source=src/lib/common.sh
 source "${_DEVTOOLS_LIBRARY_DIR}"/lib/common.sh
+# shellcheck source=src/lib/util/srcinfo.sh
+source "${_DEVTOOLS_LIBRARY_DIR}"/lib/util/srcinfo.sh
 
 source /usr/share/makepkg/util/util.sh
-source /usr/share/makepkg/srcinfo.sh
+
+set -eo pipefail
 
 
 check_pkgbuild_validity() {
@@ -185,10 +188,9 @@ done
 check_pkgbuild_validity
 
 # auto generate .SRCINFO
-stat_busy 'Generating .SRCINFO'
-write_srcinfo_content > .SRCINFO
+# shellcheck disable=SC2119
+write_srcinfo_file
 git add --force .SRCINFO
-stat_done
 
 if [[ -n $(git status --porcelain --untracked-files=no) ]]; then
 	stat_busy 'Staging files'

src/lib/build/build.sh

@@ -14,6 +14,8 @@ source "${_DEVTOOLS_LIBRARY_DIR}"/lib/db/update.sh
 source "${_DEVTOOLS_LIBRARY_DIR}"/lib/release.sh
 # shellcheck source=src/lib/util/git.sh
 source "${_DEVTOOLS_LIBRARY_DIR}"/lib/util/git.sh
+# shellcheck source=src/lib/util/srcinfo.sh
+source "${_DEVTOOLS_LIBRARY_DIR}"/lib/util/srcinfo.sh
 # shellcheck source=src/lib/util/pacman.sh
 source "${_DEVTOOLS_LIBRARY_DIR}"/lib/util/pacman.sh
 # shellcheck source=src/lib/valid-repos.sh
@@ -26,8 +28,7 @@ source "${_DEVTOOLS_LIBRARY_DIR}"/lib/valid-inspect.sh
 source /usr/share/makepkg/util/config.sh
 source /usr/share/makepkg/util/message.sh
 
-set -e
-set -o pipefail
+set -eo pipefail
 
 
 pkgctl_build_usage() {

src/lib/util/srcinfo.sh

@@ -0,0 +1,69 @@
+#!/hint/bash
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+[[ -z ${DEVTOOLS_INCLUDE_UTIL_SRCINFO_SH:-} ]] || return 0
+DEVTOOLS_INCLUDE_UTIL_SRCINFO_SH=1
+
+_DEVTOOLS_LIBRARY_DIR=${_DEVTOOLS_LIBRARY_DIR:-@pkgdatadir@}
+# shellcheck source=src/lib/common.sh
+source "${_DEVTOOLS_LIBRARY_DIR}"/lib/common.sh
+
+source /usr/share/makepkg/util/util.sh
+source /usr/share/makepkg/srcinfo.sh
+
+set -eo pipefail
+
+
+print_srcinfo() {
+	local pkgpath=${1:-.}
+	local outdir pkg pid
+	local pids=()
+
+	# source the PKGBUILD
+	# shellcheck source=contrib/makepkg/PKGBUILD.proto
+	. "${pkgpath}"/PKGBUILD
+
+	# run without parallelization for single packages
+	if (( ${#pkgname[@]} == 1 )); then
+		write_srcinfo_content
+		return 0
+	fi
+
+	[[ -z ${WORKDIR:-} ]] && setup_workdir
+	outdir=$(mktemp --directory --tmpdir="${WORKDIR}" pkgctl-srcinfo.XXXXXXXXXX)
+
+	# fork workload for each split pkgname
+	for pkg in "${pkgname[@]}"; do
+		(
+			# deactivate errexit to avoid makepkg abort on grep_function
+			set +e
+			srcinfo_write_package "$pkg" > "${outdir}/${pkg}"
+		)&
+		pids+=($!)
+	done
+
+	# join workload
+	for pid in "${pids[@]}"; do
+		if ! wait "${pid}"; then
+			return 1
+		fi
+	done
+
+	# collect output
+	srcinfo_write_global
+	for pkg in "${pkgname[@]}"; do
+		srcinfo_separate_section
+		cat "${outdir}/${pkg}"
+	done
+}
+
+write_srcinfo_file() {
+	local pkgpath=${1:-.}
+	stat_busy 'Generating .SRCINFO'
+	if ! print_srcinfo "${pkgpath}" > "${pkgpath}"/.SRCINFO; then
+		error 'Failed to write .SRCINFO file'
+		return 1
+	fi
+	stat_done
+}