Re: [gentoo-dev] [PATCH python-r1 4/8] Introduce functions to replicate Python scripts.

[Reinis Danne]

On Sat, Oct 27, 2012 at 01:02:47PM +0200, Michał Górny wrote:
> This can be used to create copies of Python scripts for various
> implementation when build system doesn't do that.
> ---
>  gx86/eclass/python-r1.eclass | 126 +++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 126 insertions(+)
>
> diff --git a/gx86/eclass/python-r1.eclass b/gx86/eclass/python-r1.eclass
> index d7cdfa8..6178969 100644
> --- a/gx86/eclass/python-r1.eclass
> +++ b/gx86/eclass/python-r1.eclass
> @@ -412,3 +412,129 @@ python_export_best() {
>  	debug-print "${FUNCNAME}: Best implementation is: ${impl}"
>  	python_export "${impl}" "${@}"
>  }
> +
> +# @FUNCTION: _python_rewrite_shebang
> +# @INTERNAL
> +# @USAGE: [<EPYTHON>] <path>...
> +# @DESCRIPTION:
> +# Replaces 'python' executable in the shebang with the executable name
> +# of the specified interpreter. If no EPYTHON value (implementation) is
> +# used, the current ${EPYTHON} will be used.
> +#
> +# All specified files must start with a 'python' shebang. A file not
> +# having a matching shebang will be refused. The exact shebang style
> +# will be preserved in order not to break anything.
> +#
> +# Example conversions:
> +# @CODE
> +# From: #!/usr/bin/python -R
> +# To: #!/usr/bin/python2.7 -R
> +#
> +# From: #!/usr/bin/env FOO=bar python
> +# To: #!/usr/bin/env FOO=bar python2.7
> +# @CODE
> +_python_rewrite_shebang() {
> +	debug-print-function ${FUNCNAME} "${@}"
> +
> +	local impl
> +	case "${1}" in
> +		python*|jython*|pypy-c*)
> +			impl=${1}
> +			shift
> +			;;
> +		*)
> +			impl=${EPYTHON}
> +			[[ ${impl} ]] || die "${FUNCNAME}: no impl nor EPYTHON"
> +			;;
> +	esac
> +	debug-print "${FUNCNAME}: implementation: ${impl}"
> +
> +	local f
> +	for f; do
> +		local shebang=$(head -n 1 "${f}")
> +		debug-print "${FUNCNAME}: path = ${f}"
> +		debug-print "${FUNCNAME}: shebang = ${shebang}"
> +
> +		if [[ ${shebang} != *python* ]]; then
> +			eerror "A file does not seem to have a supported shebang:"
> +			eerror "  file: ${f}"
> +			eerror "  shebang: ${shebang}"
> +			die "${FUNCNAME}: ${f} does not seem to have a valid shebang"
> +		fi
> +
> +		sed -i -e "s:python:${impl}:" "${f}" || die
> +	done
> +}

Better would be also to check if the shebang already has
specific python version and in such a case probably an error
message would be appropriate, so ebuild should explicitly change
it to bare "python" if replication for versions is desired.


Reinis

> +
> +# @FUNCTION: _python_ln_rel
> +# @USAGE: <from> <to>
> +# @DESCRIPTION:
> +# Create a relative symlink.
> +_python_ln_rel() {
> +	debug-print-function ${FUNCNAME} "${@}"
> +
> +	local from=${1}
> +	local to=${2}
> +
> +	local frpath=${from%/*}/
> +	local topath=${to%/*}/
> +	local rel_path=
> +
> +	# remove double slashes
> +	frpath=${frpath/\/\///}
> +	topath=${topath/\/\///}
> +
> +	while [[ ${topath} ]]; do
> +		local frseg=${frpath%%/*}
> +		local toseg=${topath%%/*}
> +
> +		if [[ ${frseg} != ${toseg} ]]; then
> +			rel_path=../${rel_path}${frseg:+${frseg}/}
> +		fi
> +
> +		frpath=${frpath#${frseg}/}
> +		topath=${topath#${toseg}/}
> +	done
> +	rel_path+=${frpath}${1##*/}
> +
> +	debug-print "${FUNCNAME}: ${from} -> ${to}"
> +	debug-print "${FUNCNAME}: rel_path = ${rel_path}"
> +
> +	ln -fs "${rel_path}" "${to}"
> +}
> +
> +# @FUNCTION: python_replicate_scripts
> +# @USAGE: <path>...
> +# @DESCRIPTION:
> +# Copy the given script to variants for all enabled Python
> +# implementations, then replace it with a symlink to the wrapper.
> +#
> +# All specified files must start with a 'python' shebang. A file not
> +# having a matching shebang will be refused.
> +python_replicate_scripts() {
> +	debug-print-function ${FUNCNAME} "${@}"
> +
> +	local suffixes=()
> +
> +	_add_suffix() {
> +		suffixes+=( "${EPYTHON}" )
> +	}
> +	python_foreach_impl _add_suffix
> +	debug-print "${FUNCNAME}: suffixes = ( ${suffixes[@]} )"
> +
> +	local f suffix
> +	for suffix in "${suffixes[@]}"; do
> +		for f; do
> +			local newf=${f}-${suffix}
> +
> +			debug-print "${FUNCNAME}: ${f} -> ${newf}"
> +			cp "${f}" "${newf}" || die
> +		done
> +
> +		_python_rewrite_shebang "${suffix}" "${@/%/-${suffix}}"
> +	done
> +
> +	for f; do
> +		_python_ln_rel "${ED}"/usr/bin/python-exec "${f}" || die
> +	done
> +}
> --
> 1.7.12.4
>
>