[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 | 124 +++++++++++++++++++++++++++++++++
 1 file changed, 124 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..ceb362d89ba
--- /dev/null
+++ b/eclass/go-module-vendor.eclass
@@ -0,0 +1,124 @@
+# 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 ${S} and unpacks any modules
+# mentioned in EGO_VENDOR to ${S}/vendor.
+#
+# Please note that this eclass currently handles only tarballs
+# (.tar.gz), but support for more formats may be added in the future.
+#
+# Since Go programs are statically linked, it is important that your ebuild's
+# LICENSE= setting includes the licenses of all statically linked
+# dependencies. So please make sure it is accurate.
+#
+# @EXAMPLE:
+#
+# @CODE
+# inherit go-module-vendor
+#
+# EGO_VENDOR=(
+#	"github.com/xenolf/lego 6cac0ea7d8b28c889f709ec7fa92e92b82f490dd"
+# "golang.org/x/crypto 453249f01cfeb54c3d549ddb75ff152ca243f9d8 github.com/golang/crypto"
+# )
+#
+# SRC_URI="https://github.com/example/${PN}/archive/v${PV}.tar.gz -> ${P}.tar.gz
+# $(go-module-vendor_get_vendor_uri)"
+# @CODE
+
+inherit go-module
+
+case ${EAPI:-0} in
+	7) ;;
+	*) die "${ECLASS} API in EAPI ${EAPI} not yet established."
+esac
+
+if [[ -z ${_GO_MODULE_VENDOR} ]]; then
+
+_GO_MODULE_VENDOR=1
+
+EXPORT_FUNCTIONS src_unpack
+
+# @ECLASS-VARIABLE: EGO_VENDOR
+# @REQUIRED
+# @DESCRIPTION:
+# This variable contains a list of vendored packages.
+# The items of this array are strings that contain the
+# import path and the git commit hash for a vendored package.
+# If the import path does not start with github.com, the third argument
+# can be used to point to a github repository.
+
+# @FUNCTION: go-module-vendor_get_vendor_uri
+# @DESCRIPTION:
+# Convert the information in EGO_VENDOR to a format suitable for
+# SRC_URI.
+# A call to this function should be added to SRC_URI in your ebuild.
+go-module-vendor_get_vendor_uri() {
+	local hash import line repo
+	for line in "${EGO_VENDOR[@]}"; do
+		read -r import hash repo _ <<< "${line}"
+		if [[ -n ${repo} ]]; then
+			echo "https://${repo}/archive/${hash}.tar.gz -> ${repo//\//-}-${hash}.tar.gz"
+		else
+			echo "https://${import}/archive/${hash}.tar.gz -> ${import//\//-}-${hash}.tar.gz"
+		fi
+	done
+}
+
+# @FUNCTION: go-module-vendor_src_unpack
+# @DESCRIPTION:
+# Extract all archives in ${a} which are not nentioned in ${EGO_VENDOR}
+# to their usual locations then extract all archives mentioned in
+# ${EGO_VENDOR} to ${S}/vendor.
+go-module-vendor_src_unpack() {
+	local f hash import line repo tarball vendor_uri
+	if [[ -z "${EGO_VENDOR}" ]]; then
+		die "EGO_VENDOR is not defined"
+	fi
+
+	vendor_uri="$(go-module-vendor_get_vendor_uri)"
+	for f in $A; do
+		[[ $vendor_uri == *"$f"* ]] && continue
+		unpack $f
+	done
+
+	if [[ -d "${S}/vendor" ]]; then
+		eerror "Upstream for ${P}.ebuild vendors dependencies."
+		die "This ebuild should inherit go-module.eclass"
+	fi
+
+	mkdir -p "${S}/vendor" || die
+	for line in "${EGO_VENDOR[@]}"; do
+		read -r import hash repo _ <<< "${line}"
+		if [[ -n ${repo} ]]; then
+			tarball=${repo//\//-}-${hash}.tar.gz
+		else
+			tarball=${import//\//-}-${hash}.tar.gz
+		fi
+		einfo "Vendoring ${import} ${tarball}"
+		rm -fr "${S}/vendor/${import}" || die
+		mkdir -p "${S}/vendor/${import}" || die
+		tar -C "${S}/vendor/${import}" -x --strip-components 1\
+			-f "${DISTDIR}/${tarball}" || die
+	done
+}
+
+fi
-- 
2.21.0