#!/usr/bin/bash
errors_terminate=$2

# Usage of %_python_bytecompile_extra is not allowed anymore
# See: https://fedoraproject.org/wiki/Changes/No_more_automagic_Python_bytecompilation_phase_3
# Therefore $1 ($default_python) is not needed and is invoked with "" by default.
# $default_python stays in the arguments for backward compatibility and $extra for the following check:
extra=$3
if [ 0$extra -eq 1 ]; then
    echo -e "%_python_bytecompile_extra is discontinued, use %py_byte_compile instead.\nSee: https://fedoraproject.org/wiki/Changes/No_more_automagic_Python_bytecompilation_phase_3" >/dev/stderr
    exit 1
fi

# If using normal root, avoid changing anything.
if [ -z "$RPM_BUILD_ROOT" -o "$RPM_BUILD_ROOT" = "/" ]; then
	exit 0
fi

# Figure out how deep we need to descend.  We could pick an insanely high
# number and hope it's enough, but somewhere, somebody's sure to run into it.
depth=`(find "$RPM_BUILD_ROOT" -type f -name "*.py" -print0 ; echo /) | \
       xargs -0 -n 1 dirname | sed 's,[^/],,g' | sort -u | tail -n 1 | wc -c`
if [ -z "$depth" -o "$depth" -le "1" ]; then
	exit 0
fi

# This function now implements Python byte-compilation in three different ways:
# Python >= 3.4 and < 3.9 uses a new module compileall2 - https://github.com/fedora-python/compileall2
# Python < 3.4 (inc. Python 2) uses compileall module from stdlib with some hacks
# When we drop support for Python 2, we'd be able to use all compileall2 features like:
# - -s and -p options to manipulate with a path baked into pyc files instead of $real_libdir
# - -o 0 -o 1 to produce multiple files in one run - each with a different optimization level - instead of $options
# - removed useless $depth - both compileall and compileall2 are limited by sys.getrecursionlimit()
# These changes will make this script much simpler
# In Python >= 3.9, compileall2 was merged back to standard library (compileall) so we can use it directly again.
function python_bytecompile()
{
    local options=$1
    local python_binary=$2
    local exclude=$3
    local python_libdir=$4
    local depth=$5 # Not used for Python >= 3.4
    local real_libdir=$6 # Not used for Python >= 3.4

	python_version=$($python_binary -c "import sys; sys.stdout.write('{0.major}{0.minor}'.format(sys.version_info))")

	#
	# Python 3.9 and higher
	#
	if [ "$python_version" -ge 39 ]; then

		[ ! -z $exclude ] && exclude="-x '$exclude'"
		# -q disables verbose output
		# -f forces the process to overwrite existing compiled files
		# -x excludes paths defined by regex
		# -e excludes symbolic links pointing outside the build root
		# -x and -e together implements the same functionality as the Filter class below
		# -s strips $RPM_BUILD_ROOT from the path
		# -p prepends the leading slash to the path to make it absolute
		$python_binary -B $options -m compileall -q -f $exclude -s $RPM_BUILD_ROOT -p / -e $RPM_BUILD_ROOT --invalidation-mode=timestamp $python_libdir

	#
	# Python 3.4 and higher
	#
	elif [ "$python_version" -ge 34 ]; then

		[ ! -z $exclude ] && exclude="-x '$exclude'"
		# /usr/lib/rpm/redhat/ contains compileall2 Python module
		# -q disables verbose output
		# -f forces the process to overwrite existing compiled files
		# -x excludes paths defined by regex
		# -e excludes symbolic links pointing outside the build root
		# -x and -e together implements the same functionality as the Filter class below
		# -s strips $RPM_BUILD_ROOT from the path
		# -p prepends the leading slash to the path to make it absolute
		PYTHONPATH=/usr/lib/rpm/redhat/ $python_binary -B $options -m compileall2 -q -f $exclude -s $RPM_BUILD_ROOT -p / -e $RPM_BUILD_ROOT $python_libdir
	else
#
# Python 3.3 and lower (incl. Python 2)
#

cat << EOF | $python_binary $options
import compileall, sys, os, re

python_libdir = "$python_libdir"
depth = $depth
real_libdir = "$real_libdir"
build_root = "$RPM_BUILD_ROOT"
exclude = r"$exclude"

class Filter:
    def search(self, path):
        ret = not os.path.realpath(path).startswith(build_root)
        if exclude:
            ret = ret or re.search(exclude, path)
        return ret

sys.exit(not compileall.compile_dir(python_libdir, depth, real_libdir, force=1, rx=Filter(), quiet=1))
EOF

fi
}

# .pyc/.pyo files embed a "magic" value, identifying the ABI version of Python
# bytecode that they are for.
#
# The files below RPM_BUILD_ROOT could be targeting multiple versions of
# python (e.g. a single build that emits several subpackages e.g. a
# python26-foo subpackage, a python31-foo subpackage etc)
#
# Support this by assuming that below each /usr/lib/python$VERSION/, all
# .pyc/.pyo files are to be compiled for /usr/bin/python$VERSION.
#
# For example, below /usr/lib/python2.6/, we're targeting /usr/bin/python2.6
# and below /usr/lib/python3.1/, we're targeting /usr/bin/python3.1

# Disable Python hash seed randomization
# This should help with byte-compilation reproducibility: https://bugzilla.redhat.com/show_bug.cgi?id=1686078
export PYTHONHASHSEED=0

shopt -s nullglob
for python_libdir in `find "$RPM_BUILD_ROOT" -type d|grep -E "/(usr|app)/lib(64)?/python[0-9]\.[0-9]+$"`;
do
	python_binary=$(basename $python_libdir)
	real_libdir=${python_libdir/$RPM_BUILD_ROOT/}
	echo "Bytecompiling .py files below $python_libdir using $python_binary"

	# Generate normal (.pyc) byte-compiled files.
	python_bytecompile "" "$python_binary" "" "$python_libdir" "$depth" "$real_libdir"
	if [ $? -ne 0 -a 0$errors_terminate -ne 0 ]; then
		# One or more of the files had a syntax error
		exit 1
	fi

	# Generate optimized (.pyo) byte-compiled files.
	python_bytecompile "-O" "$python_binary" "" "$python_libdir" "$depth" "$real_libdir"
	if [ $? -ne 0 -a 0$errors_terminate -ne 0 ]; then
		# One or more of the files had a syntax error
		exit 1
	fi
done
