[gentoo-dev] [PATCH 1/5] zig-toolchain.eclass: new eclass

[Eric Joldasov <bratishkaerik@landless-city.net>]

Signed-off-by: Eric Joldasov <bratishkaerik@landless-city.net>
---
 eclass/zig-toolchain.eclass | 375 ++++++++++++++++++++++++++++++++++++
 1 file changed, 375 insertions(+)
 create mode 100644 eclass/zig-toolchain.eclass

diff --git a/eclass/zig-toolchain.eclass b/eclass/zig-toolchain.eclass
new file mode 100644
index 000000000000..42a3f8ec3706
--- /dev/null
+++ b/eclass/zig-toolchain.eclass
@@ -0,0 +1,375 @@
+# Copyright 2024 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+# @ECLASS: zig-toolchain.eclass
+# @MAINTAINER:
+# Eric Joldasov <bratishkaerik@landless-city.net>
+# @AUTHOR:
+# Eric Joldasov <bratishkaerik@landless-city.net>
+# @SUPPORTED_EAPIS: 8
+# @BLURB: Prepare Zig toolchain and set environment variables
+# @DESCRIPTION:
+# Prepare Zig toolchain and set environment variables.
+# Supports Zig 0.13+.
+# Does not set any default function, ebuilds must call them manually.
+# Generally, only "zig-toolchain_populate_env_vars" is needed.
+#
+# Intended to be used by ebuilds that call "zig build-exe/lib/obj"
+# or "zig test" directly and by "dev-lang/zig".
+# For ebuilds with ZBS (Zig Build System), it's usually better
+# to inherit zig-build instead, as it has default phases-functions.
+
+if [[ ! ${_ZIG_TOOLCHAIN_ECLASS} ]]; then
+_ZIG_TOOLCHAIN_ECLASS=1
+
+case ${EAPI} in
+	8) ;;
+	*) die "${ECLASS}: EAPI ${EAPI:-0} not supported" ;;
+esac
+
+inherit edo flag-o-matic
+
+# @ECLASS_VARIABLE: ZIG_SLOT
+# @PRE_INHERIT
+# @REQUIRED
+# @DESCRIPTION:
+# Zig slot that will be used in "ezig" function.  Also, if
+# ZIG_OPTIONAL is empty, adds dev-lang/zig and dev-lang/zig-bin
+# dependency to BDEPEND.  Must be >= "0.13".
+#
+# Example:
+# @CODE
+# 0.13
+# @CODE
+#
+# When a new Zig release occurs, it is advisable for maintainers to
+# check whether their ebuild supports that new version.  If yes, they
+# they should bump ZIG_SLOT to the latest version; if not supported,
+# they need to patch any issues with new version and again bump
+# ZIG_SLOT.  This helps to reduce dependencies on outdated Zig
+# versions.
+#
+# This policy of "1 exclusive Zig slot" will work until it
+# stabilizes enough (probably near 1.0), then it will be re-evaluated
+# and most likely changed to more common in other eclasses ZIG_MIN/
+# ZIG_MAX form.
+
+# @ECLASS_VARIABLE: ZIG_OPTIONAL
+# @PRE_INHERIT
+# @DEFAULT_UNSET
+# @DESCRIPTION:
+# If set to a non-empty value, all logic in zig-toolchain and
+# zig-build eclasses will be considered optional.  No dependencies
+# will be added and no phase functions will be exported.
+#
+# For zig-toolchain.eclass users:
+# You have to add Zig dependency in your BDEPEND manually and call
+# at least "zig-toolchain_populate_env_vars" before using "ezig".
+#
+# For zig-build.eclass users: see documentation in zig-build.eclass
+# instead.
+if [[ ! ${ZIG_OPTIONAL} ]]; then
+	BDEPEND="|| (
+		dev-lang/zig:${ZIG_SLOT}
+		dev-lang/zig-bin:${ZIG_SLOT}
+	)"
+fi
+
+# @ECLASS_VARIABLE: ZIG_TARGET
+# @DESCRIPTION:
+# Zig target triple to use.  Has the following format:
+# arch-os[.os_version_range]-abi[.abi_version]
+# Can be passed as:
+# * "-target " option in "zig test" or "zig build-exe/lib/obj",
+# * "-Dtarget=" option in "zig build"
+#   (if project uses "std.Build.standardTargetOptions").
+#
+# Can be overriden by user.  If not overriden, then set by
+# "zig-toolchain_populate_env_vars".
+#
+# Example:
+# @CODE
+# # Autodetected by Zig:
+# native
+# # Machine running Linux x86_64 system, with glibc:
+# x86_64-linux-gnu
+# # Similar to above, but versions are passed explicitly:
+# x86_64-linux.6.1.12...6.6.16-gnu.2.38
+# # Machine running Linux PPC64 little-endian system, with musl
+# powerpc64le-linux-musl
+# @CODE
+#
+
+# @ECLASS_VARIABLE: ZIG_CPU
+# @DESCRIPTION:
+# Zig target CPU and features to use.  Has the following format:
+# family_name(\+enable_feature|\-disable_feature)*
+# Can be passed as:
+# * "-mcpu " option in "zig test" or "zig build-exe/lib/obj",
+# * "-Dcpu=" option in "zig build"
+#   (if project uses "std.Build.standardTargetOptions").
+#
+# Can be overriden by user.  If not overriden, then set by
+# "zig-toolchain_populate_env_vars".
+#
+# Example:
+# @CODE
+# # Autodetected by Zig:
+# native
+# # AMD Zen 2 processor
+# znver2
+# # x86_64 processor, X87 support enabled, SSE2 support disabled
+# x86_64+x87-sse2
+# @CODE
+
+# @ECLASS_VARIABLE: ZIG_EXE
+# @DESCRIPTION:
+# Absolute path to the used Zig executable.
+#
+# Please note that when passing one flag several times with different
+# values:
+# * (only "zig build") in "-Dbar=false -Dbar" form:
+#   errors due to conflict of flags,
+# * (only "zig build") in "-Dbar=false -Dbar=true" form:
+#   "bar" becomes a list, which is likely not what you want,
+# * in "-fbar -fno-bar" form:
+#   latest value overwrites values before.
+# Example above shows only boolean option, but it is same with other
+# types of options (enums, "std.zig.BuildId", "std.SemanticVersion",
+# integers, strings, etc.).
+#
+# Can be overriden by user.  If not overriden, then set by
+# "zig-toolchain_populate_env_vars".
+
+# @ECLASS_VARIABLE: ZIG_VER
+# @OUTPUT_VARIABLE
+# @DESCRIPTION:
+# Zig version found during "zig-toolchain_find_installation",
+# as reported in dev-lang/zig-${PV} PV part.
+#
+# Example:
+# @CODE
+# 0.13.0
+# @CODE
+
+# @FUNCTION: zig-toolchain_get_target
+# @USAGE: <C-style target triple>
+# @DESCRIPTION:
+# Translates C-style target triple (like CHOST or CBUILD)
+# to Zig-style target triple.  Some information (like ARM features)
+# is handled by "zig-toolchain_get_cpu".  Mostly used during
+# cross-compiling if user does not set ZIG_TARGET variable.
+#
+# See ZIG_TARGET description for more information.
+zig-toolchain_get_target() {
+	if [[ ${#} -ne 1 ]]; then
+		die "${FUNCNAME[0]}: expected 1 arguments, got ${#}"
+	fi
+	local c_target=${1}
+	local c_target_prefix=${c_target%%-*}
+	local c_target_suffix=${c_target##*-}
+
+	local arch os abi
+
+	case ${c_target_prefix} in
+		i?86)	arch=x86;;
+		arm64)	arch=aarch64;;
+		arm*)	arch=arm;;
+		*)		arch=${c_target_prefix};;
+	esac
+
+	case ${c_target} in
+		*linux*)	os=linux;;
+		*apple*)	os=macos;;
+	esac
+
+	case ${c_target_suffix} in
+		solaris*)	os=solaris abi=none;;
+		darwin*)	abi=none;;
+		*)			abi=${c_target_suffix};;
+	esac
+
+	if [[ ${arch} == arm && ${abi} == gnu ]]; then
+		die "${FUNCNAME[0]}: Zig does not support old ARM ABI"
+	fi
+
+	echo ${arch}-${os}-${abi}
+}
+
+
+
+# @FUNCTION: zig-toolchain_get_cpu
+# @USAGE: <C-style target triple>
+# @DESCRIPTION:
+# Translates C-style target triple (like CHOST or CBUILD)
+# to Zig-style target CPU and features.  Mostly used to get generic
+# target CPU during cross-compiling if user does not set ZIG_CPU
+# variable.
+#
+# See ZIG_CPU description for more information.
+zig-toolchain_get_cpu() {
+	if [[ ${#} -ne 1 ]]; then
+		die "${FUNCNAME[0]}: expected 1 arguments, got ${#}"
+	fi
+	local c_target=${1}
+	local c_target_prefix=${c_target%%-*}
+
+	local base_cpu features=""
+
+	case ${c_target_prefix} in
+		i?86)					base_cpu=${c_target_prefix};;
+		loongarch64)			base_cpu=generic_la64;;
+		powerpc | powerpcle)	base_cpu=ppc;;
+		powerpc64)				base_cpu=ppc64;;
+		powerpc64le)			base_cpu=ppc64le;;
+		riscv32)				base_cpu=generic_rv32;;
+		riscv64)				base_cpu=generic_rv64;;
+		*)						base_cpu=generic;;
+	esac
+
+	case ${c_target_prefix} in
+		armv5tel)	features+="+v5te";;
+		armv*)		features+="+${c_target_prefix##armv}";;
+	esac
+
+	case ${c_target_prefix} in
+		arm64)	;;
+		arm*)
+			local is_softfloat=$(CTARGET=${c_target} tc-tuple-is-softfloat)
+			case ${is_softfloat} in
+				only | yes) features+="+soft_float";;
+				softfp | no) features+="-soft_float";;
+				*) die "${FUNCNAME[0]}: tc-tuple-is-softfloat returned unexpected value"
+			esac
+		;;
+	esac
+
+	echo ${base_cpu}${features}
+}
+
+# @FUNCTION: zig-toolchain_find_installation
+# @DESCRIPTION:
+# Detects suitable Zig installation and sets ZIG_VER and ZIG_EXE
+# variables.
+#
+# See ZIG_EXE and ZIG_VER descriptions for more information.
+zig-toolchain_find_installation() {
+	# Adapted from https://github.com/gentoo/gentoo/pull/28986
+	# Many thanks to Florian Schmaus (Flowdalic)!
+
+	[[ -n ${ZIG_SLOT} ]] || die "${FUNCNAME[0]}: ZIG_SLOT must be set"
+	if ver_test "${ZIG_SLOT}" -lt "0.13"; then
+		die "${ECLASS}: ZIG_SLOT must be >= 0.13, found ${ZIG_SLOT}"
+	fi
+
+	einfo "Searching Zig ${ZIG_SLOT}..."
+
+	local zig_supported_versions=(
+		"9999"
+		"0.13.1"
+		"0.13.0"
+	)
+
+	local base_path="${BROOT}/usr/bin"
+
+	local selected_path selected_ver
+	for selected_ver in "${zig_supported_versions[@]}"; do
+		# Check if candidate satisfies ZIG_SLOT condition.
+		local candidate_slot
+		candidate_slot=$(ver_cut 1-2 ${selected_ver})
+		if ver_test "${candidate_slot}" -ne ${ZIG_SLOT}; then
+			continue
+		fi
+
+		local candidate_path
+		# Prefer "dev-lang/zig" over "dev-lang/zig-bin"
+		candidate_path="${base_path}/zig-${selected_ver}"
+		if [[ -x "${candidate_path}" ]]; then
+			selected_path="${candidate_path}"
+			break;
+		fi
+
+		candidate_path="${base_path}/zig-bin-${selected_ver}"
+		if [[ -x "${candidate_path}" ]]; then
+			selected_path="${candidate_path}"
+			break;
+		fi
+	done
+
+	if [[ -z "${selected_path}" ]]; then
+		die "Could not find (suitable) Zig at \"${base_path}\""
+	fi
+
+	export ZIG_EXE="${selected_path}"
+	export ZIG_VER="${selected_ver}"
+	# Sanity check, comment from upstream:
+	# > Check libc++ linkage to make sure Zig was built correctly,
+	# > but only for "env" and "version" to avoid affecting the
+	# > startup time for build-critical commands
+	# > (check takes about ~10 μs)
+	"${ZIG_EXE}" version > /dev/null \
+		|| die "Sanity check failed for \"${ZIG_EXE}\""
+}
+
+# @FUNCTION: zig-toolchain_populate_env_vars
+# @DESCRIPTION:
+# Populates ZIG_TARGET, ZIG_CPU, ZIG_EXE and ZIG_VER environment
+# variables with detected values, or, if user set them already,
+# leaves as-is.
+zig-toolchain_populate_env_vars() {
+	# Should be first because it sets ZIG_VER which might be used
+	# in the future when setting ZIG_TARGET and ZIG_CPU variables
+	# for incompatible versions.
+	if [[ -z "${ZIG_EXE}" ]]; then
+		zig-toolchain_find_installation
+	fi
+
+	if [[ -z ${ZIG_TARGET} ]]; then
+		if tc-is-cross-compiler; then
+			export ZIG_TARGET=$(zig-toolchain_get_target ${CHOST})
+		else
+			export ZIG_TARGET=native
+		fi
+	fi
+
+	if [[ -z ${ZIG_CPU} ]]; then
+		if tc-is-cross-compiler; then
+			export ZIG_CPU=$(zig-toolchain_get_cpu ${CHOST})
+		else
+			export ZIG_CPU=native
+		fi
+	fi
+
+	einfo "ZIG_EXE:    \"${ZIG_EXE}\""
+	einfo "ZIG_VER:     ${ZIG_VER}"
+	einfo "ZIG_TARGET:  ${ZIG_TARGET}"
+	einfo "ZIG_CPU:     ${ZIG_CPU}"
+}
+
+# @FUNCTION: ezig
+# @USAGE: [<args>...]
+# @DESCRIPTION:
+# Runs ZIG_EXE with supplied arguments.  Dies if ZIG_EXE is not set or
+# if command exits with error.  Respects `nonfatal`.
+#
+# Always disables progress tree.  By default enables ANSI escape codes
+# (colours, etc.), user can set NO_COLOR environment variable to
+# disable them.
+ezig() {
+	# Sync description above and comments below with upstream's
+	# "std.io.tty.detectConfig".
+	debug-print-function "${FUNCNAME[0]}" "${@}"
+
+	if [[ -z "${ZIG_EXE}" ]] ; then
+		die "${FUNCNAME[0]}: ZIG_EXE is not set. Was 'zig-toolchain_populate_env_vars' called before using ezig?"
+	fi
+
+	# Progress tree is helpful indicator in TTY, but unfortunately
+	# they make Portage logs harder to read in plaintext. We pass
+	# "TERM=dumb" here to have clean logs, and CLICOLOR_FORCE to
+	# preserve colors.
+	# User's NO_COLOR takes precendence over this.
+	TERM=dumb CLICOLOR_FORCE=1 "${ZIG_EXE}" "${@}" \
+		|| die -n "Failed to run command: ${ZIG_EXE} ${@}"
+}
+fi
-- 
2.47.0