# Copyright 1999-2014 Gentoo Foundation
# Distributed under the terms of the GNU General Public License v2
# $Header: /var/cvsroot/gentoo-x86/eclass/python-utils-r1.eclass,v 1.56 2014/05/26 16:13:35 mgorny Exp $

# @ECLASS: python-utils-r1
# @MAINTAINER:
# Python team <python@gentoo.org>
# @AUTHOR:
# Author: Michał Górny <mgorny@gentoo.org>
# Based on work of: Krzysztof Pawlik <nelchael@gentoo.org>
# @BLURB: Utility functions for packages with Python parts.
# @DESCRIPTION:
# A utility eclass providing functions to query Python implementations,
# install Python modules and scripts.
#
# This eclass does not set any metadata variables nor export any phase
# functions. It can be inherited safely.
#
# For more information, please see the python-r1 Developer's Guide:
# http://www.gentoo.org/proj/en/Python/python-r1/dev-guide.xml

case "${EAPI:-0}" in
	0|1|2|3|4|5)
		;;
	*)
		die "Unsupported EAPI=${EAPI} (unknown) for ${ECLASS}"
		;;
esac

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

if [[ ! ${_PYTHON_UTILS_R1} ]]; then

inherit eutils multilib toolchain-funcs

# @ECLASS-VARIABLE: _PYTHON_ALL_IMPLS
# @INTERNAL
# @DESCRIPTION:
# All supported Python implementations, most preferred last.
_PYTHON_ALL_IMPLS=(
	jython2_5 jython2_7
	pypy
	python3_2 python3_3 python3_4
	python2_6 python2_7
)

# @FUNCTION: _python_impl_supported
# @USAGE: <impl>
# @INTERNAL
# @DESCRIPTION:
# Check whether the implementation <impl> (PYTHON_COMPAT-form)
# is still supported.
#
# Returns 0 if the implementation is valid and supported. If it is
# unsupported, returns 1 -- and the caller should ignore the entry.
# If it is invalid, dies with an appopriate error messages.
_python_impl_supported() {
	debug-print-function ${FUNCNAME} "${@}"

	[[ ${#} -eq 1 ]] || die "${FUNCNAME}: takes exactly 1 argument (impl)."

	local impl=${1}

	# keep in sync with _PYTHON_ALL_IMPLS!
	# (not using that list because inline patterns shall be faster)
	case "${impl}" in
		python2_[67]|python3_[234]|jython2_[57])
			return 0
			;;
		pypy1_[89]|pypy2_0|python2_5|python3_1)
			return 1
			;;
		pypy)
			if [[ ${EAPI:-0} == [01234] ]]; then
				die "PyPy is supported in EAPI 5 and newer only."
			fi
			;;
		*)
			die "Invalid implementation in PYTHON_COMPAT: ${impl}"
	esac
}

# @ECLASS-VARIABLE: PYTHON
# @DEFAULT_UNSET
# @DESCRIPTION:
# The absolute path to the current Python interpreter.
#
# This variable is set automatically in the following contexts:
#
# python-r1: Set in functions called by python_foreach_impl() or after
# calling python_export_best().
#
# python-single-r1: Set after calling python-single-r1_pkg_setup().
#
# distutils-r1: Set within any of the python sub-phase functions.
#
# Example value:
# @CODE
# /usr/bin/python2.6
# @CODE

# @ECLASS-VARIABLE: EPYTHON
# @DEFAULT_UNSET
# @DESCRIPTION:
# The executable name of the current Python interpreter.
#
# This variable is set automatically in the following contexts:
#
# python-r1: Set in functions called by python_foreach_impl() or after
# calling python_export_best().
#
# python-single-r1: Set after calling python-single-r1_pkg_setup().
#
# distutils-r1: Set within any of the python sub-phase functions.
#
# Example value:
# @CODE
# python2.6
# @CODE

# @ECLASS-VARIABLE: PYTHON_SITEDIR
# @DEFAULT_UNSET
# @DESCRIPTION:
# The path to Python site-packages directory.
#
# Set and exported on request using python_export().
#
# Example value:
# @CODE
# /usr/lib64/python2.6/site-packages
# @CODE

# @ECLASS-VARIABLE: PYTHON_INCLUDEDIR
# @DEFAULT_UNSET
# @DESCRIPTION:
# The path to Python include directory.
#
# Set and exported on request using python_export().
#
# Example value:
# @CODE
# /usr/include/python2.6
# @CODE

# @ECLASS-VARIABLE: PYTHON_LIBPATH
# @DEFAULT_UNSET
# @DESCRIPTION:
# The path to Python library.
#
# Set and exported on request using python_export().
# Valid only for CPython.
#
# Example value:
# @CODE
# /usr/lib64/libpython2.6.so
# @CODE

# @ECLASS-VARIABLE: PYTHON_CFLAGS
# @DEFAULT_UNSET
# @DESCRIPTION:
# Proper C compiler flags for building against Python. Obtained from
# pkg-config or python-config.
#
# Set and exported on request using python_export().
# Valid only for CPython. Requires a proper build-time dependency
# on the Python implementation and on pkg-config.
#
# Example value:
# @CODE
# -I/usr/include/python2.7
# @CODE

# @ECLASS-VARIABLE: PYTHON_LIBS
# @DEFAULT_UNSET
# @DESCRIPTION:
# Proper C compiler flags for linking against Python. Obtained from
# pkg-config or python-config.
#
# Set and exported on request using python_export().
# Valid only for CPython. Requires a proper build-time dependency
# on the Python implementation and on pkg-config.
#
# Example value:
# @CODE
# -lpython2.7
# @CODE

# @ECLASS-VARIABLE: PYTHON_PKG_DEP
# @DEFAULT_UNSET
# @DESCRIPTION:
# The complete dependency on a particular Python package as a string.
#
# Set and exported on request using python_export().
#
# Example value:
# @CODE
# dev-lang/python:2.7[xml]
# @CODE

# @ECLASS-VARIABLE: PYTHON_SCRIPTDIR
# @DEFAULT_UNSET
# @DESCRIPTION:
# The location where Python scripts must be installed for current impl.
#
# Set and exported on request using python_export().
#
# Example value:
# @CODE
# /usr/lib/python-exec/python2.7
# @CODE

# @FUNCTION: python_export
# @USAGE: [<impl>] <variables>...
# @DESCRIPTION:
# Set and export the Python implementation-relevant variables passed
# as parameters.
#
# The optional first parameter may specify the requested Python
# implementation (either as PYTHON_TARGETS value, e.g. python2_7,
# or an EPYTHON one, e.g. python2.7). If no implementation passed,
# the current one will be obtained from ${EPYTHON}.
#
# The variables which can be exported are: PYTHON, EPYTHON,
# PYTHON_SITEDIR. They are described more completely in the eclass
# variable documentation.
python_export() {
	debug-print-function ${FUNCNAME} "${@}"

	local impl var

	case "${1}" in
		python*|jython*)
			impl=${1/_/.}
			shift
			;;
		pypy)
			impl=${1}
			shift
			;;
		*)
			impl=${EPYTHON}
			[[ ${impl} ]] || die "python_export: no impl nor EPYTHON"
			;;
	esac
	debug-print "${FUNCNAME}: implementation: ${impl}"

	for var; do
		case "${var}" in
			EPYTHON)
				export EPYTHON=${impl}
				debug-print "${FUNCNAME}: EPYTHON = ${EPYTHON}"
				;;
			PYTHON)
				export PYTHON=${EPREFIX}/usr/bin/${impl}
				debug-print "${FUNCNAME}: PYTHON = ${PYTHON}"
				;;
			PYTHON_SITEDIR)
				local dir
				case "${impl}" in
					python*|pypy)
						dir=/usr/$(get_libdir)/${impl}
						;;
					jython*)
						dir=/usr/share/${impl/n/n-}/Lib
						;;
				esac

				export PYTHON_SITEDIR=${EPREFIX}${dir}/site-packages
				debug-print "${FUNCNAME}: PYTHON_SITEDIR = ${PYTHON_SITEDIR}"
				;;
			PYTHON_INCLUDEDIR)
				local dir
				case "${impl}" in
					python*)
						dir=/usr/include/${impl}
						;;
					pypy)
						dir=/usr/$(get_libdir)/${impl}/include
						;;
					*)
						die "${impl} lacks header files"
						;;
				esac

				export PYTHON_INCLUDEDIR=${EPREFIX}${dir}
				debug-print "${FUNCNAME}: PYTHON_INCLUDEDIR = ${PYTHON_INCLUDEDIR}"
				;;
			PYTHON_LIBPATH)
				local libname
				case "${impl}" in
					python*)
						libname=lib${impl}
						;;
					*)
						die "${impl} lacks a dynamic library"
						;;
				esac

				local path=${EPREFIX}/usr/$(get_libdir)

				export PYTHON_LIBPATH=${path}/${libname}$(get_libname)
				debug-print "${FUNCNAME}: PYTHON_LIBPATH = ${PYTHON_LIBPATH}"
				;;
			PYTHON_CFLAGS)
				local val

				case "${impl}" in
					python2.5|python2.6)
						# old versions support python-config only
						val=$("${impl}-config" --includes)
						;;
					python*)
						# python-2.7, python-3.2, etc.
						val=$($(tc-getPKG_CONFIG) --cflags ${impl/n/n-})
						;;
					*)
						die "${impl}: obtaining ${var} not supported"
						;;
				esac

				export PYTHON_CFLAGS=${val}
				debug-print "${FUNCNAME}: PYTHON_CFLAGS = ${PYTHON_CFLAGS}"
				;;
			PYTHON_LIBS)
				local val

				case "${impl}" in
					python2.5|python2.6)
						# old versions support python-config only
						val=$("${impl}-config" --libs)
						;;
					python*)
						# python-2.7, python-3.2, etc.
						val=$($(tc-getPKG_CONFIG) --libs ${impl/n/n-})
						;;
					*)
						die "${impl}: obtaining ${var} not supported"
						;;
				esac

				export PYTHON_LIBS=${val}
				debug-print "${FUNCNAME}: PYTHON_LIBS = ${PYTHON_LIBS}"
				;;
			PYTHON_PKG_DEP)
				local d
				case ${impl} in
					python2.6)
						PYTHON_PKG_DEP='>=dev-lang/python-2.6.8-r3:2.6';;
					python2.7)
						PYTHON_PKG_DEP='>=dev-lang/python-2.7.5-r2:2.7';;
					python3.2)
						PYTHON_PKG_DEP='>=dev-lang/python-3.2.5-r2:3.2';;
					python3.3)
						PYTHON_PKG_DEP='>=dev-lang/python-3.3.2-r2:3.3';;
					python*)
						PYTHON_PKG_DEP="dev-lang/python:${impl#python}";;
					pypy)
						PYTHON_PKG_DEP='virtual/pypy:0=';;
					jython2.5)
						PYTHON_PKG_DEP='>=dev-java/jython-2.5.3-r2:2.5';;
					jython2.7)
						PYTHON_PKG_DEP='dev-java/jython:2.7';;
					*)
						die "Invalid implementation: ${impl}"
				esac

				# use-dep
				if [[ ${PYTHON_REQ_USE} ]]; then
					PYTHON_PKG_DEP+=[${PYTHON_REQ_USE}]
				fi

				export PYTHON_PKG_DEP
				debug-print "${FUNCNAME}: PYTHON_PKG_DEP = ${PYTHON_PKG_DEP}"
				;;
			PYTHON_SCRIPTDIR)
				local dir
				export PYTHON_SCRIPTDIR=${EPREFIX}/usr/lib/python-exec/${impl}
				debug-print "${FUNCNAME}: PYTHON_SCRIPTDIR = ${PYTHON_SCRIPTDIR}"
				;;
			*)
				die "python_export: unknown variable ${var}"
		esac
	done
}

# @FUNCTION: python_get_sitedir
# @USAGE: [<impl>]
# @DESCRIPTION:
# Obtain and print the 'site-packages' path for the given
# implementation. If no implementation is provided, ${EPYTHON} will
# be used.
#
# If you just need to have PYTHON_SITEDIR set (and exported), then it is
# better to use python_export() directly instead.
python_get_sitedir() {
	debug-print-function ${FUNCNAME} "${@}"

	python_export "${@}" PYTHON_SITEDIR
	echo "${PYTHON_SITEDIR}"
}

# @FUNCTION: python_get_includedir
# @USAGE: [<impl>]
# @DESCRIPTION:
# Obtain and print the include path for the given implementation. If no
# implementation is provided, ${EPYTHON} will be used.
#
# If you just need to have PYTHON_INCLUDEDIR set (and exported), then it
# is better to use python_export() directly instead.
python_get_includedir() {
	debug-print-function ${FUNCNAME} "${@}"

	python_export "${@}" PYTHON_INCLUDEDIR
	echo "${PYTHON_INCLUDEDIR}"
}

# @FUNCTION: python_get_library_path
# @USAGE: [<impl>]
# @DESCRIPTION:
# Obtain and print the Python library path for the given implementation.
# If no implementation is provided, ${EPYTHON} will be used.
#
# Please note that this function can be used with CPython only. Use
# in another implementation will result in a fatal failure.
python_get_library_path() {
	debug-print-function ${FUNCNAME} "${@}"

	python_export "${@}" PYTHON_LIBPATH
	echo "${PYTHON_LIBPATH}"
}

# @FUNCTION: python_get_CFLAGS
# @USAGE: [<impl>]
# @DESCRIPTION:
# Obtain and print the compiler flags for building against Python,
# for the given implementation. If no implementation is provided,
# ${EPYTHON} will be used.
#
# Please note that this function can be used with CPython only.
# It requires Python and pkg-config installed, and therefore proper
# build-time dependencies need be added to the ebuild.
python_get_CFLAGS() {
	debug-print-function ${FUNCNAME} "${@}"

	python_export "${@}" PYTHON_CFLAGS
	echo "${PYTHON_CFLAGS}"
}

# @FUNCTION: python_get_LIBS
# @USAGE: [<impl>]
# @DESCRIPTION:
# Obtain and print the compiler flags for linking against Python,
# for the given implementation. If no implementation is provided,
# ${EPYTHON} will be used.
#
# Please note that this function can be used with CPython only.
# It requires Python and pkg-config installed, and therefore proper
# build-time dependencies need be added to the ebuild.
python_get_LIBS() {
	debug-print-function ${FUNCNAME} "${@}"

	python_export "${@}" PYTHON_LIBS
	echo "${PYTHON_LIBS}"
}

# @FUNCTION: python_get_scriptdir
# @USAGE: [<impl>]
# @DESCRIPTION:
# Obtain and print the script install path for the given
# implementation. If no implementation is provided, ${EPYTHON} will
# be used.
python_get_scriptdir() {
	debug-print-function ${FUNCNAME} "${@}"

	python_export "${@}" PYTHON_SCRIPTDIR
	echo "${PYTHON_SCRIPTDIR}"
}

# @FUNCTION: _python_ln_rel
# @USAGE: <from> <to>
# @INTERNAL
# @DESCRIPTION:
# Create a relative symlink.
_python_ln_rel() {
	debug-print-function ${FUNCNAME} "${@}"

	local target=${1}
	local symname=${2}

	local tgpath=${target%/*}/
	local sympath=${symname%/*}/
	local rel_target=

	while [[ ${sympath} ]]; do
		local tgseg= symseg=

		while [[ ! ${tgseg} && ${tgpath} ]]; do
			tgseg=${tgpath%%/*}
			tgpath=${tgpath#${tgseg}/}
		done

		while [[ ! ${symseg} && ${sympath} ]]; do
			symseg=${sympath%%/*}
			sympath=${sympath#${symseg}/}
		done

		if [[ ${tgseg} != ${symseg} ]]; then
			rel_target=../${rel_target}${tgseg:+${tgseg}/}
		fi
	done
	rel_target+=${tgpath}${target##*/}

	debug-print "${FUNCNAME}: ${symname} -> ${target}"
	debug-print "${FUNCNAME}: rel_target = ${rel_target}"

	ln -fs "${rel_target}" "${symname}"
}

# @FUNCTION: python_optimize
# @USAGE: [<directory>...]
# @DESCRIPTION:
# Compile and optimize Python modules in specified directories (absolute
# paths). If no directories are provided, the default system paths
# are used (prepended with ${D}).
python_optimize() {
	debug-print-function ${FUNCNAME} "${@}"

	if [[ ${EBUILD_PHASE} == pre* || ${EBUILD_PHASE} == post* ]]; then
		eerror "The new Python eclasses expect the compiled Python files to"
		eerror "be controlled by the Package Manager. For this reason,"
		eerror "the python_optimize function can be used only during src_* phases"
		eerror "(src_install most commonly) and not during pkg_* phases."
		echo
		die "python_optimize is not to be used in pre/post* phases"
	fi

	[[ ${EPYTHON} ]] || die 'No Python implementation set (EPYTHON is null).'

	local PYTHON=${PYTHON}
	[[ ${PYTHON} ]] || python_export PYTHON

	# Note: python2.6 can't handle passing files to compileall...

	# default to sys.path
	if [[ ${#} -eq 0 ]]; then
		local f
		while IFS= read -r -d '' f; do
			# 1) accept only absolute paths
			#    (i.e. skip '', '.' or anything like that)
			# 2) skip paths which do not exist
			#    (python2.6 complains about them verbosely)

			if [[ ${f} == /* && -d ${D}${f} ]]; then
				set -- "${D}${f}" "${@}"
			fi
		done < <("${PYTHON}" -c 'import sys; print("\0".join(sys.path))')

		debug-print "${FUNCNAME}: using sys.path: ${*/%/;}"
	fi

	local d
	for d; do
		# make sure to get a nice path without //
		local instpath=${d#${D}}
		instpath=/${instpath##/}

		case "${EPYTHON}" in
			python*)
				"${PYTHON}" -m compileall -q -f -d "${instpath}" "${d}"
				"${PYTHON}" -OO -m compileall -q -f -d "${instpath}" "${d}"
				;;
			*)
				"${PYTHON}" -m compileall -q -f -d "${instpath}" "${d}"
				;;
		esac
	done
}

# @ECLASS-VARIABLE: python_scriptroot
# @DEFAULT_UNSET
# @DESCRIPTION:
# The current script destination for python_doscript(). The path
# is relative to the installation root (${ED}).
#
# When unset, ${DESTTREE}/bin (/usr/bin by default) will be used.
#
# Can be set indirectly through the python_scriptinto() function.
#
# Example:
# @CODE
# src_install() {
#   local python_scriptroot=${GAMES_BINDIR}
#   python_foreach_impl python_doscript foo
# }
# @CODE

# @FUNCTION: python_scriptinto
# @USAGE: <new-path>
# @DESCRIPTION:
# Set the current scriptroot. The new value will be stored
# in the 'python_scriptroot' environment variable. The new value need
# be relative to the installation root (${ED}).
#
# Alternatively, you can set the variable directly.
python_scriptinto() {
	debug-print-function ${FUNCNAME} "${@}"

	python_scriptroot=${1}
}

# @FUNCTION: python_doexe
# @USAGE: <files>...
# @DESCRIPTION:
# Install the given executables into current python_scriptroot,
# for the current Python implementation (${EPYTHON}).
#
# The executable will be wrapped properly for the Python implementation,
# though no shebang mangling will be performed.
python_doexe() {
	debug-print-function ${FUNCNAME} "${@}"

	local f
	for f; do
		python_newexe "${f}" "${f##*/}"
	done
}

# @FUNCTION: python_newexe
# @USAGE: <path> <new-name>
# @DESCRIPTION:
# Install the given executable into current python_scriptroot,
# for the current Python implementation (${EPYTHON}).
#
# The executable will be wrapped properly for the Python implementation,
# though no shebang mangling will be performed. It will be renamed
# to <new-name>.
python_newexe() {
	debug-print-function ${FUNCNAME} "${@}"

	[[ ${EPYTHON} ]] || die 'No Python implementation set (EPYTHON is null).'
	[[ ${#} -eq 2 ]] || die "Usage: ${FUNCNAME} <path> <new-name>"

	local d=${python_scriptroot:-${DESTTREE}/bin}
	local wrapd=${d}

	local f=${1}
	local barefn=${2}
	local newfn

	if _python_want_python_exec2; then
		local PYTHON_SCRIPTDIR
		python_export PYTHON_SCRIPTDIR
		d=${PYTHON_SCRIPTDIR#${EPREFIX}}
		newfn=${barefn}
	else
		newfn=${barefn}-${EPYTHON}
	fi

	(
		dodir "${wrapd}"
		exeinto "${d}"
		newexe "${f}" "${newfn}" || die
	)

	# install the wrapper
	_python_ln_rel "${ED%/}"$(_python_get_wrapper_path) \
		"${ED%/}/${wrapd}/${barefn}" || die

	# don't use this at home, just call python_doscript() instead
	if [[ ${_PYTHON_REWRITE_SHEBANG} ]]; then
		local _PYTHON_FIX_SHEBANG_QUIET=1
		python_fix_shebang "${ED%/}/${d}/${newfn}"
	fi
}

# @FUNCTION: python_doscript
# @USAGE: <files>...
# @DESCRIPTION:
# Install the given scripts into current python_scriptroot,
# for the current Python implementation (${EPYTHON}).
#
# All specified files must start with a 'python' shebang. The shebang
# will be converted, and the files will be wrapped properly
# for the Python implementation.
#
# Example:
# @CODE
# src_install() {
#   python_foreach_impl python_doscript ${PN}
# }
# @CODE
python_doscript() {
	debug-print-function ${FUNCNAME} "${@}"

	local _PYTHON_REWRITE_SHEBANG=1
	python_doexe "${@}"
}

# @FUNCTION: python_newscript
# @USAGE: <path> <new-name>
# @DESCRIPTION:
# Install the given script into current python_scriptroot
# for the current Python implementation (${EPYTHON}), and name it
# <new-name>.
#
# The file must start with a 'python' shebang. The shebang will be
# converted, and the file will be wrapped properly for the Python
# implementation. It will be renamed to <new-name>.
#
# Example:
# @CODE
# src_install() {
#   python_foreach_impl python_newscript foo.py foo
# }
# @CODE
python_newscript() {
	debug-print-function ${FUNCNAME} "${@}"

	local _PYTHON_REWRITE_SHEBANG=1
	python_newexe "${@}"
}

# @ECLASS-VARIABLE: python_moduleroot
# @DEFAULT_UNSET
# @DESCRIPTION:
# The current module root for python_domodule(). The path can be either
# an absolute system path (it must start with a slash, and ${ED} will be
# prepended to it) or relative to the implementation's site-packages directory
# (then it must start with a non-slash character).
#
# When unset, the modules will be installed in the site-packages root.
#
# Can be set indirectly through the python_moduleinto() function.
#
# Example:
# @CODE
# src_install() {
#   local python_moduleroot=bar
#   # installs ${PYTHON_SITEDIR}/bar/baz.py
#   python_foreach_impl python_domodule baz.py
# }
# @CODE

# @FUNCTION: python_moduleinto
# @USAGE: <new-path>
# @DESCRIPTION:
# Set the current module root. The new value will be stored
# in the 'python_moduleroot' environment variable. The new value need
# be relative to the site-packages root.
#
# Alternatively, you can set the variable directly.
python_moduleinto() {
	debug-print-function ${FUNCNAME} "${@}"

	python_moduleroot=${1}
}

# @FUNCTION: python_domodule
# @USAGE: <files>...
# @DESCRIPTION:
# Install the given modules (or packages) into the current
# python_moduleroot. The list can mention both modules (files)
# and packages (directories). All listed files will be installed
# for all enabled implementations, and compiled afterwards.
#
# Example:
# @CODE
# src_install() {
#   # (${PN} being a directory)
#   python_foreach_impl python_domodule ${PN}
# }
# @CODE
python_domodule() {
	debug-print-function ${FUNCNAME} "${@}"

	[[ ${EPYTHON} ]] || die 'No Python implementation set (EPYTHON is null).'

	local d
	if [[ ${python_moduleroot} == /* ]]; then
		# absolute path
		d=${python_moduleroot}
	else
		# relative to site-packages
		local PYTHON_SITEDIR=${PYTHON_SITEDIR}
		[[ ${PYTHON_SITEDIR} ]] || python_export PYTHON_SITEDIR

		d=${PYTHON_SITEDIR#${EPREFIX}}/${python_moduleroot}
	fi

	local INSDESTTREE

	insinto "${d}"
	doins -r "${@}" || die

	python_optimize "${ED}/${d}"
}

# @FUNCTION: python_doheader
# @USAGE: <files>...
# @DESCRIPTION:
# Install the given headers into the implementation-specific include
# directory. This function is unconditionally recursive, i.e. you can
# pass directories instead of files.
#
# Example:
# @CODE
# src_install() {
#   python_foreach_impl python_doheader foo.h bar.h
# }
# @CODE
python_doheader() {
	debug-print-function ${FUNCNAME} "${@}"

	[[ ${EPYTHON} ]] || die 'No Python implementation set (EPYTHON is null).'

	local d PYTHON_INCLUDEDIR=${PYTHON_INCLUDEDIR}
	[[ ${PYTHON_INCLUDEDIR} ]] || python_export PYTHON_INCLUDEDIR

	d=${PYTHON_INCLUDEDIR#${EPREFIX}}

	local INSDESTTREE

	insinto "${d}"
	doins -r "${@}" || die
}

# @FUNCTION: python_wrapper_setup
# @USAGE: [<path> [<impl>]]
# @DESCRIPTION:
# Create proper 'python' executable and pkg-config wrappers
# (if available) in the directory named by <path>. Set up PATH
# and PKG_CONFIG_PATH appropriately. <path> defaults to ${T}/${EPYTHON}.
#
# The wrappers will be created for implementation named by <impl>,
# or for one named by ${EPYTHON} if no <impl> passed.
#
# If the named directory contains a python symlink already, it will
# be assumed to contain proper wrappers already and only environment
# setup will be done. If wrapper update is requested, the directory
# shall be removed first.
python_wrapper_setup() {
	debug-print-function ${FUNCNAME} "${@}"

	local workdir=${1:-${T}/${EPYTHON}}
	local impl=${2:-${EPYTHON}}

	[[ ${workdir} ]] || die "${FUNCNAME}: no workdir specified."
	[[ ${impl} ]] || die "${FUNCNAME}: no impl nor EPYTHON specified."

	if [[ ! -x ${workdir}/bin/python ]]; then
		mkdir -p "${workdir}"/{bin,pkgconfig} || die

		# Clean up, in case we were supposed to do a cheap update.
		rm -f "${workdir}"/bin/python{,2,3,-config}
		rm -f "${workdir}"/bin/2to3
		rm -f "${workdir}"/pkgconfig/python{,2,3}.pc

		local EPYTHON PYTHON
		python_export "${impl}" EPYTHON PYTHON

		local pyver
		if python_is_python3; then
			pyver=3
		else
			pyver=2
		fi

		# Python interpreter
		ln -s "${PYTHON}" "${workdir}"/bin/python || die
		ln -s python "${workdir}"/bin/python${pyver} || die

		local nonsupp=()

		# CPython-specific
		if [[ ${EPYTHON} == python* ]]; then
			ln -s "${PYTHON}-config" "${workdir}"/bin/python-config || die

			# Python 2.6+.
			if [[ ${EPYTHON} != python2.5 ]]; then
				ln -s "${PYTHON/python/2to3-}" "${workdir}"/bin/2to3 || die
			else
				nonsupp+=( 2to3 )
			fi

			# Python 2.7+.
			if [[ ${EPYTHON} != python2.[56] ]]; then
				ln -s "${EPREFIX}"/usr/$(get_libdir)/pkgconfig/${EPYTHON/n/n-}.pc \
					"${workdir}"/pkgconfig/python.pc || die
			else
				# XXX?
				ln -s /dev/null "${workdir}"/pkgconfig/python.pc || die
			fi
			ln -s python.pc "${workdir}"/pkgconfig/python${pyver}.pc || die
		else
			nonsupp+=( 2to3 python-config )
		fi

		local x
		for x in "${nonsupp[@]}"; do
			cat >"${workdir}"/bin/${x} <<__EOF__
#!/bin/sh
echo "${x} is not supported by ${EPYTHON}" >&2
exit 1
__EOF__
			chmod +x "${workdir}"/bin/${x} || die
		done

		# Now, set the environment.
		# But note that ${workdir} may be shared with something else,
		# and thus already on top of PATH.
		if [[ ${PATH##:*} != ${workdir}/bin ]]; then
			PATH=${workdir}/bin${PATH:+:${PATH}}
		fi
		if [[ ${PKG_CONFIG_PATH##:*} != ${workdir}/pkgconfig ]]; then
			PKG_CONFIG_PATH=${workdir}/pkgconfig${PKG_CONFIG_PATH:+:${PKG_CONFIG_PATH}}
		fi
		export PATH PKG_CONFIG_PATH
	fi
}

# @FUNCTION: python_is_python3
# @USAGE: [<impl>]
# @DESCRIPTION:
# Check whether <impl> (or ${EPYTHON}) is a Python3k variant
# (i.e. uses syntax and stdlib of Python 3.*).
#
# Returns 0 (true) if it is, 1 (false) otherwise.
python_is_python3() {
	local impl=${1:-${EPYTHON}}
	[[ ${impl} ]] || die "python_is_python3: no impl nor EPYTHON"

	[[ ${impl} == python3* ]]
}

# @FUNCTION: python_fix_shebang
# @USAGE: <path>...
# @DESCRIPTION:
# Replace the shebang in Python scripts with the current Python
# implementation (EPYTHON). If a directory is passed, works recursively
# on all Python scripts.
#
# Only files having a 'python*' shebang will be modified. Files with
# other shebang will either be skipped when working recursively
# on a directory or treated as error when specified explicitly.
#
# Shebangs matching explicitly current Python version will be left
# unmodified. Shebangs requesting another Python version will be treated
# as fatal error.
python_fix_shebang() {
	debug-print-function ${FUNCNAME} "${@}"

	[[ ${1} ]] || die "${FUNCNAME}: no paths given"
	[[ ${EPYTHON} ]] || die "${FUNCNAME}: EPYTHON unset (pkg_setup not called?)"

	local path f
	for path; do
		local any_correct any_fixed is_recursive

		[[ -d ${path} ]] && is_recursive=1

		while IFS= read -r -d '' f; do
			local shebang=$(head -n 1 "${f}")
			local error

			case "${shebang} " in
				'#!'*"${EPYTHON} "*)
					debug-print "${FUNCNAME}: in file ${f#${D}}"
					debug-print "${FUNCNAME}: shebang matches EPYTHON: ${shebang}"

					# Nothing to do, move along.
					any_correct=1
					;;
				'#!'*python" "*|'#!'*python[23]" "*)
					debug-print "${FUNCNAME}: in file ${f#${D}}"
					debug-print "${FUNCNAME}: rewriting shebang: ${shebang}"

					# Note: for internal use.
					if [[ ! ${_PYTHON_FIX_SHEBANG_QUIET} ]]; then
						einfo "Fixing shebang in ${f#${D}}."
					fi

					local from
					if [[ "${shebang} " == *'python2 '* ]]; then
						from=python2
						python_is_python3 "${EPYTHON}" && error=1
					elif [[ "${shebang} " == *'python3 '* ]]; then
						from=python3
						python_is_python3 "${EPYTHON}" || error=1
					else
						from=python
					fi

					if [[ ! ${error} ]]; then
						sed -i -e "1s:${from}:${EPYTHON}:" "${f}" || die
						any_fixed=1
					fi
					;;
				'#!'*python[23].[0123456789]" "*|'#!'*pypy" "*|'#!'*jython[23].[0123456789]" "*)
					# Explicit mismatch.
					error=1
					;;
				*)
					# Non-Python shebang. Allowed in recursive mode,
					# disallowed when specifying file explicitly.
					[[ ${is_recursive} ]] || error=1
					;;
			esac

			if [[ ${error} ]]; then
				eerror "The file has incompatible shebang:"
				eerror "  file: ${f#${D}}"
				eerror "  current shebang: ${shebang}"
				eerror "  requested impl: ${EPYTHON}"
				die "${FUNCNAME}: conversion of incompatible shebang requested"
			fi
		done < <(find "${path}" -type f -print0)

		if [[ ! ${any_fixed} ]]; then
			eqawarn "QA warning: ${FUNCNAME}, ${path#${D}} did not match any fixable files."
			if [[ ${any_correct} ]]; then
				eqawarn "All files have ${EPYTHON} shebang already."
			else
				eqawarn "There are no Python files in specified directory."
			fi
		fi
	done
}

# @FUNCTION: _python_want_python_exec2
# @INTERNAL
# @DESCRIPTION:
# Check whether we should be using python-exec:2.
_python_want_python_exec2() {
	debug-print-function ${FUNCNAME} "${@}"

	# EAPI 4 lacks slot operators, so just fix it on python-exec:2.
	[[ ${EAPI} == 4 ]] && return 0

	# Check if we cached the result, or someone put an override.
	if [[ ! ${_PYTHON_WANT_PYTHON_EXEC2+1} ]]; then
		has_version 'dev-lang/python-exec:2'
		_PYTHON_WANT_PYTHON_EXEC2=$(( ! ${?} ))
	fi

	# Non-zero means 'yes', zero means 'no'.
	[[ ${_PYTHON_WANT_PYTHON_EXEC2} != 0 ]]
}

# @FUNCTION: _python_get_wrapper_path
# @INTERNAL
# @DESCRIPTION:
# Output path to proper python-exec slot.
_python_get_wrapper_path() {
	debug-print-function ${FUNCNAME} "${@}"

	if _python_want_python_exec2; then
		echo /usr/lib/python-exec/python-exec2
	else
		echo /usr/bin/python-exec
	fi
}

_PYTHON_UTILS_R1=1
fi