path: root/src/modules/rust.eselect

# -*-eselect-*-  vim: ft=eselect
# Copyright 2015 Gentoo Foundation
# Distributed under the terms of the GNU GPL version 2 or later

DESCRIPTION="Manage the Rust compiler versions"
MAINTAINER="jauhien@gentoo.org"
VERSION="0.3"

inherit package-manager path-manipulation

# find a list of installed rust compilers
# each compiler provider should install
# a config file named provider-$pkgname-$pkgver
# in "${EROOT}"/etc/env.d/rust directory
# this function prints list of $pkgname-$pkgver values
find_targets() {
	local f
	local -a providers
	for f in "${EROOT}"/etc/env.d/rust/provider-*; do
		[[ -f ${f} ]] || continue
		providers=("${providers[@]}" "${f##*/provider-}")
	done
	echo "${providers[@]}"
}

#get rustc postfix
get_postfix() {
	local target=$1
	echo "${target}" | cut -d- -f2-
}

#get current target
get_current_target() {
	local i targets=( $(find_targets) )
	for (( i = 0; i < ${#targets[@]}; i++ )); do
		[[ rustc-$(get_postfix ${targets[i]}) = \
			$(basename "$(canonicalise "${EROOT}/usr/bin/rustc")") ]] \
		&& echo $i && return 0
	done
	echo "NOT_SET"
}

#get lists of symlinks
get_symlinks() {
	local target=$1
	if [ "${target}" == "NOT_SET" ]; then
		echo /usr/bin/rustdoc
		return
	fi
	if is_number "${target}"; then
		local targets=( $(find_targets) )
		target=${targets[target]}
	fi

	local symlinks=()
	local i
	for i in `cat "${EROOT}/etc/env.d/rust/provider-${target}"`; do
		symlinks+=($i)
	done

	if [ ${#symlinks[@]} -eq 0 ]; then
		echo /usr/bin/rustdoc
	else
		echo "${symlinks[@]}"
	fi
}

# remove symlink if exists
remove_symlink() {
	local symlink=$1

	if [[ -L ${symlink} ]]; then
		# existing symlink
		rm ${symlink} || die -q "Couldn't remove existing symlink ${symlink}"
	elif [[ -e ${symlink} ]]; then
		# we have something strange
		die -q "${symlink} exists but is not a symlink"
	fi
}

# set symlink if source exists
set_symlink() {
	local source=$1
	local dest=$2

	if [[ -e ${source} ]]; then
		mkdir -p "$(dirname ${dest})" || die -q "directory creation failed for $(dirname ${dest})"
		ln -s "${source}" "${dest}" || die -q "${dest} symlink setting failed"
	else
		false
	fi
}

# unset the rust version
unset_version() {
	local target=$(get_current_target)
	local symlinks=( $(get_symlinks ${target}) )
	for i in "${symlinks[@]}"; do
		remove_symlink "${EROOT}${i}"
	done
	remove_symlink "${EROOT}/usr/bin/rustc"
}

# set the rust version
# each compiler provider should install
# files named rustc-$postfix and rustdoc-$postfix
# in ${EROOT}/usr/bin directory
# $postfix is defined as the part of $pkgname-$pkgver after the first -
# for dev-lang/rust-bin-9999 ebuild it would be bin-9999
set_version() {
	local target=$1

	if is_number "${target}"; then
		local targets=( $(find_targets) )
		target=${targets[target-1]}
	fi

	target_postfix=$(get_postfix ${target})

	[[ -z ${target_postfix} || ! -x "${EROOT}/usr/bin/rustc-${target_postfix}" ]] \
		&& die -q "Target \"$1\" doesn't appear to be valid!"

	unset_version

	set_symlink "${EROOT}/usr/bin/rustc-${target_postfix}" "${EROOT}/usr/bin/rustc" \
		|| die -q "rustc symlink setting failed"

	local symlinks=( $(get_symlinks ${target}) )
	for i in "${symlinks[@]}"; do
		set_symlink "${EROOT}${i}-${target_postfix}" "${EROOT}${i}" \
			|| die -q "${i} symlink setting failed"
	done
}

### list action ###

describe_list() {
	echo "List available Rust versions"
}

do_list() {
	local i
	local targets=( $(find_targets) )
	local target=$(get_current_target)

	if is_number "${target}"; then
		targets[target]=$(highlight_marker "${targets[target]}")
	fi

	write_list_start "Available Rust versions:"
	write_numbered_list -m "(none found)" "${targets[@]}"
}

### set action ###

describe_set() {
	echo "Set active Rust version"
}

describe_set_parameters() {
    echo "<target>"
}

describe_set_options() {
    echo "target : Target number (from 'list' action)"
}

do_set() {
    [[ -z $1 ]] && die -q "You didn't tell me what to set the version to"
    [[ $# -gt 1 ]] && die -q "Too many parameters"

	set_version "$1" || die -q "Couldn't set new active version"
}

### update action ###

describe_update() {
	echo "Switch to the most recent Rust compiler"
}

describe_update_options() {
	echo "--if-unset    : Do not override existing implementation"
}

do_update() {
	local if_unset="0"
	while [[ $# > 0 ]]; do
		case "$1" in
			--if-unset)
				if_unset="1"
				;;
			*)
				die -q "Unrecognized argument '$1'"
				;;
		esac
		shift
	done

	if [[ "${if_unset}" == "1" && -f "${EROOT}"/usr/bin/rustc ]]; then
		return
	fi

	local targets=( $(find_targets) )
	do_set ${#targets[@]}
}

### unset action ###

describe_unset() {
	echo "Unset active Rust version"
}

describe_unset_options() {
	echo "--if-invalid    : Unset only if symlink is invalid (e.g. package was uninstalled)"
}

do_unset() {
	local if_invalid="0"
	while [[ $# > 0 ]]; do
		case "$1" in
			--if-invalid)
				if_invalid="1"
				;;
			*)
				die -q "Unrecognized argument '$1'"
				;;
		esac
		shift
	done

	if [[ "${if_invalid}" == "1" && -e "${EROOT}"/usr/bin/rustc ]]; then
		return
	fi

	unset_version || die -q "Couldn't unset active version"
}