eclass/python-single-r1.eclass

# Copyright 1999-2012 Gentoo Foundation
# Distributed under the terms of the GNU General Public License v2
# $Header: /var/cvsroot/gentoo-x86/eclass/python-single-r1.eclass,v 1.6 2012/11/30 22:57:26 mgorny Exp $

# @ECLASS: python-single-r1
# @MAINTAINER:
# Michał Górny <mgorny@gentoo.org>
# Python herd <python@gentoo.org>
# @AUTHOR:
# Author: Michał Górny <mgorny@gentoo.org>
# Based on work of: Krzysztof Pawlik <nelchael@gentoo.org>
# @BLURB: An eclass for Python packages not installed for multiple implementations.
# @DESCRIPTION:
# An extension of the python-r1 eclass suite for packages which
# don't support being installed for multiple Python implementations.
# This mostly includes tools embedding Python.
#
# This eclass extends the IUSE and REQUIRED_USE set by python-r1
# to request correct PYTHON_SINGLE_TARGET. It also replaces
# PYTHON_USEDEP and PYTHON_DEPS with a more suitable form.
#
# Please note that packages support multiple Python implementations
# (using python-r1 eclass) can not depend on packages not supporting
# them (using this eclass).
#
# Please note that python-single-r1 will always inherit python-utils-r1
# as well. Thus, all the functions defined there can be used
# in the packages using python-single-r1, and there is no need ever
# to inherit both.
#
# For more information, please see the python-r1 Developer's Guide:
# http://www.gentoo.org/proj/en/Python/python-r1/dev-guide.xml

case "${EAPI:-0}" in
	0|1|2|3)
		die "Unsupported EAPI=${EAPI:-0} (too old) for ${ECLASS}"
		;;
	4|5)
		# EAPI=4 needed by python-r1
		;;
	*)
		die "Unsupported EAPI=${EAPI} (unknown) for ${ECLASS}"
		;;
esac

if [[ ! ${_PYTHON_SINGLE_R1} ]]; then

if [[ ${_PYTHON_R1} ]]; then
	die 'python-single-r1.eclass can not be used with python-r1.eclass.'
fi

inherit python-utils-r1

fi

EXPORT_FUNCTIONS pkg_setup

if [[ ! ${_PYTHON_SINGLE_R1} ]]; then

# @ECLASS-VARIABLE: PYTHON_COMPAT
# @REQUIRED
# @DESCRIPTION:
# This variable contains a list of Python implementations the package
# supports. It must be set before the `inherit' call. It has to be
# an array.
#
# Example:
# @CODE
# PYTHON_COMPAT=( python{2_5,2_6,2_7} )
# @CODE
if ! declare -p PYTHON_COMPAT &>/dev/null; then
	die 'PYTHON_COMPAT not declared.'
fi

# @ECLASS-VARIABLE: PYTHON_REQ_USE
# @DEFAULT_UNSET
# @DESCRIPTION:
# The list of USEflags required to be enabled on the chosen Python
# implementations, formed as a USE-dependency string. It should be valid
# for all implementations in PYTHON_COMPAT, so it may be necessary to
# use USE defaults.
#
# Example:
# @CODE
# PYTHON_REQ_USE="gdbm,ncurses(-)?"
# @CODE
#
# It will cause the Python dependencies to look like:
# @CODE
# python_single_target_pythonX_Y? ( dev-lang/python:X.Y[gdbm,ncurses(-)?] )
# @CODE

# @ECLASS-VARIABLE: PYTHON_DEPS
# @DESCRIPTION:
# This is an eclass-generated Python dependency string for all
# implementations listed in PYTHON_COMPAT.
#
# The dependency string is conditional on PYTHON_SINGLE_TARGET.
#
# Example use:
# @CODE
# RDEPEND="${PYTHON_DEPS}
#	dev-foo/mydep"
# DEPEND="${RDEPEND}"
# @CODE
#
# Example value:
# @CODE
# dev-python/python-exec
# python_single_target_python2_6? ( dev-lang/python:2.6[gdbm] )
# python_single_target_python2_7? ( dev-lang/python:2.7[gdbm] )
# @CODE

# @ECLASS-VARIABLE: PYTHON_USEDEP
# @DESCRIPTION:
# This is an eclass-generated USE-dependency string which can be used to
# depend on another Python package being built for the same Python
# implementations.
#
# The generate USE-flag list is compatible with packages using python-r1,
# python-single-r1 and python-distutils-ng eclasses. It must not be used
# on packages using python.eclass.
#
# Example use:
# @CODE
# RDEPEND="dev-python/foo[${PYTHON_USEDEP}]"
# @CODE
#
# Example value:
# @CODE
# python_targets_python2_7?,python_single_target_python2_7(+)?
# @CODE

_python_single_set_globals() {
	local flags_mt=( "${PYTHON_COMPAT[@]/#/python_targets_}" )
	local flags=( "${PYTHON_COMPAT[@]/#/python_single_target_}" )
	local optflags=${flags_mt[@]/%/?}
	optflags+=,${flags[@]/%/(+)?}

	IUSE="${flags_mt[*]} ${flags[*]}"
	REQUIRED_USE="|| ( ${flags_mt[*]} ) ^^ ( ${flags[*]} )"
	PYTHON_USEDEP=${optflags// /,}

	local usestr
	[[ ${PYTHON_REQ_USE} ]] && usestr="[${PYTHON_REQ_USE}]"

	# 1) well, python-exec would suffice as an RDEP
	# but no point in making this overcomplex, BDEP doesn't hurt anyone
	# 2) python-exec should be built with all targets forced anyway
	# but if new targets were added, we may need to force a rebuild
	PYTHON_DEPS="dev-python/python-exec[${PYTHON_USEDEP}]"
	local i
	for i in "${PYTHON_COMPAT[@]}"; do
		# The chosen targets need to be in PYTHON_TARGETS as well.
		# This is in order to enforce correct dependencies on packages
		# supporting multiple implementations.
		REQUIRED_USE+=" python_single_target_${i}? ( python_targets_${i} )"

		local d
		case ${i} in
			python*)
				d='dev-lang/python';;
			jython*)
				d='dev-java/jython';;
			pypy*)
				d='dev-python/pypy';;
			*)
				die "Invalid implementation: ${i}"
		esac

		local v=${i##*[a-z]}
		PYTHON_DEPS+=" python_single_target_${i}? ( ${d}:${v/_/.}${usestr} )"
	done
}
_python_single_set_globals

# @FUNCTION: python-single-r1_pkg_setup
# @DESCRIPTION:
# Determine what the selected Python implementation is and set EPYTHON
# and PYTHON accordingly.
python-single-r1_pkg_setup() {
	debug-print-function ${FUNCNAME} "${@}"

	local impl
	for impl in "${_PYTHON_ALL_IMPLS[@]}"; do
		if has "${impl}" "${PYTHON_COMPAT[@]}" \
			&& use "python_single_target_${impl}"
		then
			python_export "${impl}" EPYTHON PYTHON
			break
		fi
	done
}

_PYTHON_SINGLE_R1=1
fi