# Copyright 1999-2025 Gentoo Authors
# Distributed under the terms of the GNU General Public License v2

# @ECLASS: ninja-utils.eclass
# @MAINTAINER:
# base-system@gentoo.org
# @AUTHOR:
# Michał Górny <mgorny@gentoo.org>
# Mike Gilbert <floppym@gentoo.org>
# @SUPPORTED_EAPIS: 7 8
# @BLURB: common bits to run app-alternatives/ninja builder
# @DESCRIPTION:
# This eclass provides a single function -- eninja -- that can be used
# to run the ninja builder alike emake. It does not define any
# dependencies, you need to depend on app-alternatives/ninja yourself. Since
# ninja is rarely used stand-alone, most of the time this eclass will
# be used indirectly by the eclasses for other build systems (CMake,
# Meson).

case ${EAPI} in
	7|8) ;;
	*) die "${ECLASS}: EAPI ${EAPI:-0} not supported" ;;
esac

if [[ -z ${_NINJA_UTILS_ECLASS} ]]; then
_NINJA_UTILS_ECLASS=1

# @ECLASS_VARIABLE: NINJA
# @PRE_INHERIT
# @DESCRIPTION:
# Specify a compatible ninja implementation to be used by eninja().
# Accepts the following values:
#
# - ninja -- use the "ninja" symlink per app-alternatives/ninja
#
# - ninja-reference -- use "ninja-reference" for dev-build/ninja
#
# - samu -- use "samu" for dev-build/samurai
#
# The default is set to "ninja".
: "${NINJA:=ninja}"

# @ECLASS_VARIABLE: NINJA_DEPEND
# @OUTPUT_VARIABLE
# @DESCRIPTION:
# Contains a set of build-time dependencies based on the NINJA setting.

# @ECLASS_VARIABLE: NINJAOPTS
# @DEFAULT_UNSET
# @DESCRIPTION:
# The default set of options to pass to Ninja. Similar to MAKEOPTS,
# supposed to be set in make.conf. If unset, eninja() will convert
# MAKEOPTS instead.

# @ECLASS_VARIABLE: NINJA_VERBOSE
# @USER_VARIABLE
# @DESCRIPTION:
# Set to OFF to disable verbose messages during compilation
: "${NINJA_VERBOSE:=ON}"

inherit multiprocessing

case ${NINJA} in
	ninja)
		NINJA_DEPEND="app-alternatives/ninja"
		;;
	ninja-reference)
		NINJA_DEPEND="dev-build/ninja"
		;;
	samu)
		NINJA_DEPEND="dev-build/samurai"
		;;
esac

# @FUNCTION: _ninja_uses_jobserver
# @DESCRIPTION:
# Return true if current ${NINJA} has jobserver support and we have one
# running (via MAKEFLAGS).
_ninja_uses_jobserver() {
	# ninja supports jobserver via FIFO only
	[[ ${MAKEFLAGS} == *--jobserver-auth=fifo:* ]] || return 1

	case ${NINJA} in
		# if using "ninja", make sure its a symlink to real ninja
		# samu: https://github.com/michaelforney/samurai/issues/71
		ninja)
			if ! has_version -b "app-alternatives/ninja[reference]"; then
				einfo "ninja != ninja-reference, no jobserver support"
				return 1
			fi
			;&
		# plus, it must be at least 1.13.0
		ninja-reference)
			if ! has_version -b ">=dev-build/ninja-1.13"; then
				einfo "ninja >= 1.13 required for jobserver support"
				return 1
			fi
			;;
		*)
			einfo "NINJA=${NINJA}, no jobserver support"
			return 1
			;;
	esac

	einfo "ninja will use the jobserver"
	return 0
}

# @FUNCTION: get_NINJAOPTS
# @DESCRIPTION:
# Get the value of NINJAOPTS, inferring them from MAKEOPTS if unset.
get_NINJAOPTS() {
	if [[ -z ${NINJAOPTS+set} ]]; then
		NINJAOPTS="-l$(get_makeopts_loadavg 0)"
		if ! _ninja_uses_jobserver; then
			# ninja only uses jobserver if -j is not passed
			NINJAOPTS+=" -j$(get_makeopts_jobs 999)"
		fi
	elif _ninja_uses_jobserver && [[ ${NINJAOPTS} == *-j* ]]; then
		ewarn "Jobserver detected, but NINJAOPTS specifies -j option."
		ewarn "To enable ninja jobserver support, remove -j from NINJAOPTS."
	fi
	echo "${NINJAOPTS}"
}

# @FUNCTION: eninja
# @USAGE: [<args>...]
# @DESCRIPTION:
# Call Ninja, passing the NINJAOPTS (or converted MAKEOPTS), followed
# by the supplied arguments.  This function dies if ninja fails.  It
# also supports being called via 'nonfatal'.
eninja() {
	case "${NINJA}" in
		ninja|ninja-reference|samu)
			;;
		*)
			ewarn "Unknown value '${NINJA}' for \${NINJA}"
			;;
	esac

	local v
	case "${NINJA_VERBOSE}" in
		OFF) ;;
		*) v="-v"
	esac
	set -- "${NINJA}" ${v} $(get_NINJAOPTS) "$@"
	echo "$@" >&2
	"$@" || die -n "${*} failed"
}

fi