rebar3.eclass: add new eclass

Add a new eclass for dev-util/rebar:3, based on the work of Anna
Vyalkova in ::guru (thanks!).

The Erlang/OTP ecosystem is moving to Rebar3. Upstreams start to drop
support for Rebar2, or at least consider it.

Signed-off-by: Florian Schmaus <flow@gentoo.org>

1 files changed, 194 insertions, 0 deletions

diff --git a/eclass/rebar3.eclass b/eclass/rebar3.eclass
new file mode 100644
index 000000000000..f6383b9c8cdd
--- /dev/null
+++ b/eclass/rebar3.eclass
@@ -0,0 +1,194 @@
+# Copyright 1999-2024 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+# @ECLASS: rebar3.eclass
+# @MAINTAINER:
+# Florian Schmaus <flow@gentoo.org>
+# @AUTHOR:
+# Amadeusz Żołnowski <aidecoe@gentoo.org>
+# Anna (cybertailor) Vyalkova <cyber+gentoo@sysrq.in>
+# @SUPPORTED_EAPIS: 8
+# @PROVIDES: rebar-utils
+# @BLURB: Build Erlang/OTP projects using dev-util/rebar:3.
+# @DESCRIPTION:
+# An eclass providing functions to build Erlang/OTP projects using
+# dev-util/rebar:3.
+#
+# rebar is a tool which tries to resolve dependencies itself which is by
+# cloning remote git repositories. Dependent projects are usually expected to
+# be in sub-directory 'deps' rather than looking at system Erlang lib
+# directory. Projects relying on rebar usually don't have 'install' make
+# targets. The eclass workarounds some of these problems. It handles
+# installation in a generic way for Erlang/OTP structured projects.
+
+case ${EAPI} in
+	8) ;;
+	*) die "${ECLASS}: EAPI ${EAPI:-0} not supported" ;;
+esac
+
+if [[ -z ${_REBAR3_ECLASS} ]]; then
+_REBAR3_ECLASS=1
+
+inherit edo rebar-utils
+
+RDEPEND="dev-lang/erlang:="
+DEPEND="${RDEPEND}"
+BDEPEND="
+	dev-util/rebar:3
+	>=sys-apps/gawk-4.1
+"
+
+# @ECLASS_VARIABLE: REBAR_PROFILE
+# @DESCRIPTION:
+# Rebar profile to use. Defaults to
+# 'default'.
+: "${REBAR_PROFILE:=default}"
+
+# @FUNCTION: _rebar_find_dep
+# @INTERNAL
+# @USAGE: <project_name>
+# @RETURN: 0 success, 1 dependency not found, 2 multiple versions found
+# @DESCRIPTION:
+# Find a Erlang package/project by name in Erlang lib directory. Project
+# directory is usually suffixed with version. It is matched to '<project_name>'
+# or '<project_name>-*'.
+_rebar_find_dep() {
+	local pn="${1}"
+	local p
+	local result
+
+	pushd "${EPREFIX}$(get_erl_libs)" >/dev/null || return 1
+	for p in ${pn} ${pn}-*; do
+		if [[ -d ${p} ]]; then
+			# Ensure there's at most one matching.
+			[[ ${result} ]] && return 2
+			result="${p}"
+		fi
+	done
+	popd >/dev/null || die
+
+	[[ ${result} ]] || return 1
+	echo "${result}"
+}
+
+# @FUNCTION: erebar3
+# @USAGE: <targets>
+# @DESCRIPTION:
+# Run rebar with verbose flag. Die on failure.
+erebar3() {
+	debug-print-function ${FUNCNAME} "${@}"
+
+	(( $# > 0 )) || die "${FUNCNAME}: at least one target is required"
+
+	case ${1} in
+		eunit|ct)
+			local -x ERL_LIBS="." ;;
+		*)
+			local -x ERL_LIBS="${EPREFIX}$(get_erl_libs)" ;;
+	esac
+
+	local -x HEX_OFFLINE=true
+	edo rebar3 "$@"
+}
+
+# @FUNCTION: rebar3_src_prepare
+# @DESCRIPTION:
+# Prevent rebar3 from fetching and compiling dependencies. Set version in
+# project description file if it's not set.
+#
+# Existence of rebar.config is optional, but file description file must exist
+# at 'src/${PN}.app.src'.
+rebar3_src_prepare() {
+	debug-print-function ${FUNCNAME} "${@}"
+
+	default
+	rebar_set_vsn
+
+	if [[ -f rebar.lock ]]; then
+		rm rebar.lock || die
+	fi
+
+	if [[ -f rebar.config ]]; then
+		rebar_disable_coverage
+		rebar_remove_deps
+	fi
+}
+
+# @FUNCTION: rebar3_src_configure
+# @DESCRIPTION:
+# Configure with ERL_LIBS set.
+rebar3_src_configure() {
+	debug-print-function ${FUNCNAME} "${@}"
+
+	local -x ERL_LIBS="${EPREFIX}$(get_erl_libs)"
+	default
+}
+
+# @FUNCTION: rebar3_src_compile
+# @DESCRIPTION:
+# Compile project with rebar3.
+rebar3_src_compile() {
+	debug-print-function ${FUNCNAME} "${@}"
+
+	erebar3 as "${REBAR_PROFILE}" release --all
+}
+
+# @FUNCTION: rebar3_src_test
+# @DESCRIPTION:
+# Run unit tests.
+rebar3_src_test() {
+	debug-print-function ${FUNCNAME} "${@}"
+
+	erebar3 eunit -v
+}
+
+# @FUNCTION: rebar3_install_lib
+# @USAGE: <dir>
+# @DESCRIPTION:
+# Install BEAM files, include headers and native libraries.
+#
+# Function expects that project conforms to Erlang/OTP structure.
+rebar3_install_lib() {
+	debug-print-function ${FUNCNAME} "${@}"
+
+	local dest="$(get_erl_libs)/${P}"
+	insinto "${dest}"
+
+	pushd "${1?}" >/dev/null || die
+	for dir in ebin include priv; do
+		if [[ -d ${dir} && ! -L ${dir} ]]; then
+			doins -r "${dir}"
+		fi
+	done
+	popd >/dev/null || die
+}
+
+# @FUNCTION: rebar3_src_install
+# @DESCRIPTION:
+# Install built release or library.
+#
+# Function expects that project conforms to Erlang/OTP structure.
+rebar3_src_install() {
+	debug-print-function ${FUNCNAME} "${@}"
+
+	pushd "_build/${REBAR_PROFILE}" >/dev/null || die
+	if [[ -d rel/${PN} ]]; then
+		if ! declare -f rebar3_install_release >/dev/null; then
+			die "${FUNCNAME}: a custom function named 'rebar3_install_release' is required to install a release"
+		fi
+		pushd rel/${PN} >/dev/null || die
+		rebar3_install_release || die
+		popd >/dev/null || die
+	elif [[ -d lib/${PN} ]]; then
+		rebar3_install_lib lib/${PN}
+	else
+		die "No releases or libraries to install"
+	fi
+	popd >/dev/null || die
+
+	einstalldocs
+}
+
+fi
+
+EXPORT_FUNCTIONS src_prepare src_compile src_test src_install