# Copyright 1999-2014 Gentoo Foundation
# Distributed under the terms of the GNU General Public License v2
# $Header: /var/cvsroot/gentoo-x86/eclass/python-single-r1.eclass,v 1.29 2014/11/07 18:11:58 axs Exp $

# @ECLASS: python-single-r1
# @MAINTAINER:
# Python team <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 the PYTHON_SINGLE_TARGET when the inheriting ebuild
# can be supported by more than one Python implementation. 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 ${ECLASS}"
		;;
	4|5)
		# EAPI=4 is required for USE default deps on USE_EXPAND flags
		;;
	*)
		die "Unsupported EAPI=${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.'
elif [[ ${_PYTHON_ANY_R1} ]]; then
	die 'python-single-r1.eclass can not be used with python-any-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.
#
# This should be set before calling `inherit'.
#
# 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-lang/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

# @ECLASS-VARIABLE: PYTHON_REQUIRED_USE
# @DESCRIPTION:
# This is an eclass-generated required-use expression which ensures the following
# when more than one python implementation is possible:
# 1. Exactly one PYTHON_SINGLE_TARGET value has been enabled.
# 2. The selected PYTHON_SINGLE_TARGET value is enabled in PYTHON_TARGETS.
#
# This expression should be utilized in an ebuild by including it in
# REQUIRED_USE, optionally behind a use flag.
#
# Example use:
# @CODE
# REQUIRED_USE="python? ( ${PYTHON_REQUIRED_USE} )"
# @CODE
#
# Example value:
# @CODE
# python_single_target_python2_6? ( python_targets_python2_6 )
# python_single_target_python2_7? ( python_targets_python2_7 )
# ^^ ( python_single_target_python2_6 python_single_target_python2_7 )
# @CODE

_python_single_set_globals() {
	local impls=()
	local unimpls=()

	PYTHON_DEPS=
	local i PYTHON_PKG_DEP
	for i in "${_PYTHON_ALL_IMPLS[@]}"; do
		has "${i}" "${PYTHON_COMPAT[@]}" \
			&& impls+=( "${i}" ) \
			|| unimpls+=( "${i}" )
	done

	if [[ ${#impls[@]} -eq 0 ]]; then
		die "No supported implementation in PYTHON_COMPAT."
	fi

	local flags_mt=( "${impls[@]/#/python_targets_}" )
	local flags=( "${impls[@]/#/python_single_target_}" )
	local unflags=( "${unimpls[@]/#/-python_single_target_}" )

	local optflags=${flags_mt[@]/%/(-)?},${unflags[@]/%/(-)}

	IUSE="${flags_mt[*]}"

	if [[ ${#impls[@]} -eq 1 ]]; then
		# There is only one supported implementation; set IUSE and other
		# variables without PYTHON_SINGLE_TARGET.
		PYTHON_REQUIRED_USE="${flags_mt[*]}"
		python_export "${impls[0]}" PYTHON_PKG_DEP
		PYTHON_DEPS="${PYTHON_PKG_DEP} "
		# Force on the python_single_target_* flag for this impl, so
		# that any dependencies that inherit python-single-r1 and
		# happen to have multiple implementations will still need
		# to bound by the implementation used by this package.
		optflags+=,${flags[0]/%/(+)}
	else
		# Multiple supported implementations; honor PYTHON_SINGLE_TARGET.
		IUSE+=" ${flags[*]}"
		PYTHON_REQUIRED_USE="^^ ( ${flags[*]} )"
		# Ensure deps honor the same python_single_target_* flag as is set
		# on this package.
		optflags+=,${flags[@]/%/(+)?}

		for i in "${impls[@]}"; do
			# The chosen targets need to be in PYTHON_TARGETS as well.
			# This is in order to enforce correct dependencies on packages
			# supporting multiple implementations.
			PYTHON_REQUIRED_USE+=" python_single_target_${i}? ( python_targets_${i} )"

			python_export "${i}" PYTHON_PKG_DEP
			PYTHON_DEPS+="python_single_target_${i}? ( ${PYTHON_PKG_DEP} ) "
		done
	fi
	PYTHON_USEDEP=${optflags// /,}

	# 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
	# 3) use whichever python-exec slot installed in EAPI 5. For EAPI 4,
	# just fix :2 since := deps are not supported.
	if [[ ${_PYTHON_WANT_PYTHON_EXEC2} == 0 ]]; then
		PYTHON_DEPS+="dev-lang/python-exec:0[${PYTHON_USEDEP}]"
	elif [[ ${EAPI} != 4 ]]; then
		PYTHON_DEPS+="dev-lang/python-exec:=[${PYTHON_USEDEP}]"
	else
		PYTHON_DEPS+="dev-lang/python-exec:2[${PYTHON_USEDEP}]"
	fi
}
_python_single_set_globals

# @FUNCTION: python_setup
# @DESCRIPTION:
# Determine what the selected Python implementation is and set
# the Python build environment up for it.
python_setup() {
	debug-print-function ${FUNCNAME} "${@}"

	unset EPYTHON

	local impl impls=()
	for impl in "${PYTHON_COMPAT[@]}"; do
		_python_impl_supported "${impl}" || continue
		impls+=( "${impl}" )
	done

	if [[ ${#impls[@]} -eq 1 ]]; then
		if use "python_targets_${impls[0]}"; then
			# Only one supported implementation, enable it explicitly
			python_export "${impls[0]}" EPYTHON PYTHON
			python_wrapper_setup
		fi
	else
		for impl in "${impls[@]}"; do
			if use "python_single_target_${impl}"; then
				if [[ ${EPYTHON} ]]; then
					eerror "Your PYTHON_SINGLE_TARGET setting lists more than a single Python"
					eerror "implementation. Please set it to just one value. If you need"
					eerror "to override the value for a single package, please use package.env"
					eerror "or an equivalent solution (man 5 portage)."
					echo
					die "More than one implementation in PYTHON_SINGLE_TARGET."
				fi

				if ! use "python_targets_${impl}"; then
					eerror "The implementation chosen as PYTHON_SINGLE_TARGET must be added"
					eerror "to PYTHON_TARGETS as well. This is in order to ensure that"
					eerror "dependencies are satisfied correctly. We're sorry"
					eerror "for the inconvenience."
					echo
					die "Build target (${impl}) not in PYTHON_TARGETS."
				fi

				python_export "${impl}" EPYTHON PYTHON
				python_wrapper_setup
			fi
		done
	fi

	if [[ ! ${EPYTHON} ]]; then
		eerror "No Python implementation selected for the build. Please set"
		if [[ ${#impls[@]} -eq 1 ]]; then
			eerror "the PYTHON_TARGETS variable in your make.conf to include one"
		else
			eerror "the PYTHON_SINGLE_TARGET variable in your make.conf to one"
		fi
		eerror "of the following values:"
		eerror
		eerror "${impls[@]}"
		echo
		die "No supported Python implementation in PYTHON_SINGLE_TARGET/PYTHON_TARGETS."
	fi
}

# @FUNCTION: python-single-r1_pkg_setup
# @DESCRIPTION:
# Runs python_setup.
python-single-r1_pkg_setup() {
	debug-print-function ${FUNCNAME} "${@}"

	python_setup
}

_PYTHON_SINGLE_R1=1
fi