eclass/nuget.eclass: add new nuget eclass

common functions and variables for handling .NET NuGets

Bug: https://bugs.gentoo.org/900597
Bug: https://github.com/gentoo/gentoo/pull/32109
Signed-off-by: Maciej Barć <xgqt@gentoo.org>

eclass/nuget.eclass

@@ -0,0 +1,197 @@
+# Copyright 1999-2023 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+# @ECLASS: nuget.eclass
+# @MAINTAINER:
+# Gentoo Dotnet project <dotnet@gentoo.org>
+# @AUTHOR:
+# Anna Figueiredo Gomes <navi@vlhl.dev>
+# Maciej Barć <xgqt@gentoo.org>
+# @SUPPORTED_EAPIS: 8
+# @BLURB: common functions and variables for handling .NET NuGets
+# @DESCRIPTION:
+# This eclass is designed to provide support for .NET NuGet's ".nupkg" files.
+# It is used to handle NuGets installation and usage.
+# "dotnet-pkg" and "dotnet-pkg-utils" inherit this eclass.
+#
+# This eclass does not export any phase functions, for that see
+# the "dotnet-pkg" eclass.
+
+case ${EAPI} in
+	8) ;;
+	*) die "${ECLASS}: EAPI ${EAPI:-0} not supported" ;;
+esac
+
+if [[ -z ${_NUGET_ECLASS} ]] ; then
+_NUGET_ECLASS=1
+
+# @ECLASS_VARIABLE: NUGET_SYSTEM_NUGETS
+# @DESCRIPTION:
+# Location of the system NuGet packages directory.
+readonly NUGET_SYSTEM_NUGETS=/opt/dotnet-nugets
+
+# @ECLASS_VARIABLE: NUGET_APIS
+# @PRE_INHERIT
+# @DESCRIPTION:
+# NuGet API URLs to use for precompiled NuGet package ".nupkg" downloads.
+# Set this variable pre-inherit.
+#
+# Defaults to an array of one item:
+# "https://api.nuget.org/v3-flatcontainer"
+#
+# Example:
+# @CODE
+# NUGET_APIS+=( "https://api.nuget.org/v3-flatcontainer" )
+# inherit nuget
+# SRC_URI="https://example.com/example.tar.xz"
+# SRC_URI+=" ${NUGET_URIS} "
+# @CODE
+if [[ -z "${NUGET_APIS}" ]] ; then
+	NUGET_APIS=( "https://api.nuget.org/v3-flatcontainer" )
+fi
+
+# @ECLASS_VARIABLE: NUGET_PACKAGES
+# @DEFAULT_UNSET
+# @PRE_INHERIT
+# @DESCRIPTION:
+# Path from where NuGets will be restored from.
+# This is a special variable that modifies the behavior of "dotnet".
+#
+# Defaults to ${T}/nugets for use with "NUGETS" but may be set to a custom
+# location to, for example, restore NuGets extracted from a prepared archive.
+# Do not set this variable in conjunction with non-empty "NUGETS".
+if [[ -n "${NUGETS}" || -z "${NUGET_PACKAGES}" ]] ; then
+	NUGET_PACKAGES="${T}"/nugets
+fi
+export NUGET_PACKAGES
+
+# @ECLASS_VARIABLE: NUGETS
+# @DEFAULT_UNSET
+# @PRE_INHERIT
+# @DESCRIPTION:
+# String containing all NuGet packages that need to be downloaded.
+#
+# Used by "_nuget_uris".
+#
+# Example:
+# @CODE
+# NUGETS="
+#	ImGui.NET@1.87.2
+#	Config.Net@4.19.0
+# "
+#
+# inherit dotnet-pkg
+#
+# ...
+#
+# SRC_URI+=" ${NUGET_URIS} "
+# @CODE
+
+# @ECLASS_VARIABLE: NUGET_URIS
+# @OUTPUT_VARIABLE
+# @DESCRIPTION:
+# List of URIs to put in SRC_URI created from NUGETS variable.
+
+# @FUNCTION: _nuget_set_nuget_uris
+# @USAGE: <nugets>
+# @DESCRIPTION:
+# Generates the URIs to put in SRC_URI to help fetch dependencies.
+# Constructs a list of NuGets from its arguments.
+# The value is set as "NUGET_URIS".
+_nuget_set_nuget_uris() {
+	local nugets="${1}"
+
+	NUGET_URIS=""
+
+	local nuget
+	local name version
+	local nuget_api url
+	for nuget in ${nugets} ; do
+		name="${nuget%@*}"
+		version="${nuget##*@}"
+
+		for nuget_api in "${NUGET_APIS[@]}" ; do
+			case ${nuget_api%/} in
+				*/v2 )
+					url="${nuget_api}/package/${name}/${version}
+							-> ${name}.${version}.nupkg"
+					;;
+				* )
+					url="${nuget_api}/${name}/${version}/${name}.${version}.nupkg"
+					;;
+			esac
+
+			NUGET_URIS+="${url} "
+		done
+	done
+}
+
+_nuget_set_nuget_uris "${NUGETS}"
+
+# @FUNCTION: nuget_link
+# @USAGE: <nuget-path>
+# @DESCRIPTION:
+# Link a specified NuGet package at "nuget-path" to the "NUGET_PACKAGES"
+# directory.
+#
+# Example:
+# @CODE
+# nuget_link "${DISTDIR}"/pkg.0.nupkg
+# @CODE
+#
+# This function is used inside "dotnet-pkg_src_unpack"
+# from the "dotnet-pkg" eclass.
+nuget_link() {
+	[[ -z "${1}" ]] && die "${FUNCNAME[0]}: no nuget path given"
+
+	mkdir -p "${NUGET_PACKAGES}" || die
+
+	local nuget_name="${1##*/}"
+
+	if [[ -f "${NUGET_PACKAGES}/${nuget_name}" ]] ; then
+		eqawarn "QA Notice: \"${nuget_name}\" already exists, not linking it"
+	else
+		ln -s "${1}" "${NUGET_PACKAGES}/${nuget_name}" || die
+	fi
+}
+
+# @FUNCTION: nuget_link-system-nugets
+# @DESCRIPTION:
+# Link all system NuGet packages to the "NUGET_PACKAGES" directory.
+#
+# Example:
+# @CODE
+# src_unpack() {
+#     nuget_link-system-nugets
+#     default
+# }
+# @CODE
+#
+# This function is used inside "dotnet-pkg_src_unpack"
+# from the "dotnet-pkg" eclass.
+nuget_link-system-nugets() {
+	local runtime_nuget
+	for runtime_nuget in "${EPREFIX}${NUGET_SYSTEM_NUGETS}"/*.nupkg ; do
+		if [[ -f "${runtime_nuget}" ]] ; then
+			nuget_link "${runtime_nuget}"
+		fi
+	done
+}
+
+# @FUNCTION: nuget_donuget
+# @USAGE: <nuget-path> ...
+# @DESCRIPTION:
+# Install NuGet package(s) at "nuget-path" to the system nugets directory.
+#
+# Example:
+# @CODE
+# src_install() {
+#     nuget_donuget my-pkg.nupkg
+# }
+# @CODE
+nuget_donuget() {
+	insinto "${NUGET_SYSTEM_NUGETS}"
+	doins "${@}"
+}
+
+fi