[gentoo-dev] [PATCH 2/2] go-module-vendor.eclass: new eclass for go modules that do not vendor

[William Hubbs <williamh@gentoo.org>]

This eclass adds a src_unpack function that supports the EGO_VENDOR
variable for vendoring modules.
---
 eclass/go-module-vendor.eclass | 133 +++++++++++++++++++++++++++++++++
 1 file changed, 133 insertions(+)
 create mode 100644 eclass/go-module-vendor.eclass

diff --git a/eclass/go-module-vendor.eclass b/eclass/go-module-vendor.eclass
new file mode 100644
index 00000000000..af9007df411
--- /dev/null
+++ b/eclass/go-module-vendor.eclass
@@ -0,0 +1,133 @@
+# Copyright 2019 gentoo authors
+# Distributed under the terms of the GNU General Public License v2
+
+# @ECLASS: go-module-vendor.eclass
+# @MAINTAINER:
+# William Hubbs <williamh@gentoo.org>
+# @SUPPORTED_EAPIS: 7
+# @BLURB: Eclass for building software written in the go
+# programming language that uses go modules and does not vendor.
+# @DESCRIPTION:
+# This eclass provides a src_unpack function which supports vendoring
+# dependencies for software written in the go programming language that
+# uses go modules.
+#
+# You will know the software you are packaging uses modules because
+# it will have files named go.sum and go.mod in its top-level source
+# directory. If it does not have these files, use the golang-* eclasses.
+#
+# If there is also a directory named vendor in the top level source directory
+# of your package, use the golang-module eclass instead of this one.
+#
+# This eclass provides a src_unpack function which unpacks the 
+# first tarball mentioned in SRC_URI to the usual location and unpacks
+# any modules mentioned in EGO_VENDOR to ${S}/vendor.
+#
+# Please note that this eclass currently handles only tarballs
+# (.tar.gz), but support for more formats may be added in the future.
+#
+# Since Go programs are statically linked, it is important that your ebuild's
+# LICENSE= setting includes the licenses of all statically linked
+# dependencies. So please make sure it is accurate.
+#
+# @EXAMPLE:
+#
+# @CODE
+# EGO_VENDOR=(
+#	"github.com/xenolf/lego 6cac0ea7d8b28c889f709ec7fa92e92b82f490dd"
+# "golang.org/x/crypto 453249f01cfeb54c3d549ddb75ff152ca243f9d8 github.com/golang/crypto"
+# )
+#
+# inherit go-module-vendor
+#
+# SRC_URI="https://github.com/example/${PN}/archive/v${PV}.tar.gz -> ${P}.tar.gz
+# ${EGO_VENDOR_URI}"
+# @CODE
+#
+# The above example will extract the tarball to ${S} and
+# extract the contents of EGO_VENDOR to ${S}/vendor.
+
+inherit go-module
+
+case ${EAPI:-0} in
+	7) ;;
+	*) die "${ECLASS} API in EAPI ${EAPI} not yet established."
+esac
+
+if [[ -z ${_GO_MODULE_VENDOR} ]]; then
+
+_GO_MODULE_VENDOR=1
+
+EXPORT_FUNCTIONS src_unpack
+
+# @ECLASS-VARIABLE: EGO_VENDOR
+# @DESCRIPTION:
+# This variable contains a list of vendored packages.
+# The items of this array are strings that contain the
+# import path and the git commit hash for a vendored package.
+# If the import path does not start with github.com, the third argument
+# can be used to point to a github repository.
+
+declare -arg EGO_VENDOR
+
+_go-module-vendor_set_vendor_uri() {
+	EGO_VENDOR_URI=
+	local lib
+	for lib in "${EGO_VENDOR[@]}"; do
+		lib=(${lib})
+		if [[ -n ${lib[2]} ]]; then
+			EGO_VENDOR_URI+=" https://${lib[2]}/archive/${lib[1]}.tar.gz -> ${lib[2]//\//-}-${lib[1]}.tar.gz"
+		else
+			EGO_VENDOR_URI+=" https://${lib[0]}/archive/${lib[1]}.tar.gz -> ${lib[0]//\//-}-${lib[1]}.tar.gz"
+		fi
+	done
+	readonly EGO_VENDOR_URI
+}
+
+_go-module-vendor_set_vendor_uri
+unset -f _go-module-vendor_set_vendor_uri
+
+_go-module-vendor_dovendor() {
+	local VENDOR_PATH=$1 VENDORPN=$2 TARBALL=$3
+	rm -fr "${VENDOR_PATH}/${VENDORPN}" || die
+	mkdir -p "${VENDOR_PATH}/${VENDORPN}" || die
+	tar -C "${VENDOR_PATH}/${VENDORPN}" -x --strip-components 1\
+		-f "${DISTDIR}/${TARBALL}" || die
+}
+
+# @FUNCTION: go-module-vendor_src_unpack
+# @DESCRIPTION:
+# Extract the first archive from ${A} to ${S}, then extract
+# any sources mentioned in ${EGO_VENDOR} to ${S}/vendor.
+go-module-vendor_src_unpack() {
+	local lib vendor_path x
+	set -- ${A}
+	x="$1"
+	mkdir -p "${S}" || die
+	tar -C "${S}/" -x --strip-components 1 \
+		-f "${DISTDIR}/${x}" || die
+
+	if [[ -d "${S}/vendor" ]]; then
+		eerror "Upstream for ${P}.ebuild vendors dependencies."
+		die "This ebuild should inherit go-module.eclass"
+	fi
+
+	if [[ -n "${EGO_VENDOR}" ]]; then
+		vendor_path="${S}/vendor"
+		mkdir -p "${vendor_path}" || die
+		for lib in "${EGO_VENDOR[@]}"; do
+			lib=(${lib})
+			if [[ -n ${lib[2]} ]]; then
+				einfo "Vendoring ${lib[0]} ${lib[2]//\//-}-${lib[1]}.tar.gz"
+				_go-module_dovendor "${vendor_path}" ${lib[0]} \
+					${lib[2]//\//-}-${lib[1]}.tar.gz
+			else
+				einfo "Vendoring ${lib[0]} ${lib[0]//\//-}-${lib[1]}.tar.gz"
+				_go-module_dovendor "${vendor_path}" ${lib[0]} \
+				${lib[0]//\//-}-${lib[1]}.tar.gz
+			fi
+		done
+	fi
+}
+
+fi
-- 
2.21.0