scripts/sphinx-pre-install - linux/kernel/git/gregkh/driver-core - Git at Google

 #!/usr/bin/perl
 # SPDX-License-Identifier: GPL-2.0-or-later
 use strict;

 # Copyright (c) 2017-2020 Mauro Carvalho Chehab <mchehab@kernel.org>
 #

 my $prefix = "./";
 $prefix = "$ENV{'srctree'}/" if ($ENV{'srctree'});

 my $conf = $prefix . "Documentation/conf.py";
 my $requirement_file = $prefix . "Documentation/sphinx/requirements.txt";
 my $virtenv_prefix = "sphinx_";

 #
 # Static vars
 #

 my %missing;
 my $system_release;
 my $need = 0;
 my $optional = 0;
 my $need_symlink = 0;
 my $need_sphinx = 0;
 my $need_venv = 0;
 my $need_virtualenv = 0;
 my $rec_sphinx_upgrade = 0;
 my $install = "";
 my $virtenv_dir = "";
 my $python_cmd = "";
 my $min_version;
 my $cur_version;
 my $rec_version = "1.7.9";	# PDF won't build here
 my $min_pdf_version = "2.4.4";	# Min version where pdf builds

 #
 # Command line arguments
 #

 my $pdf = 1;
 my $virtualenv = 1;
 my $version_check = 0;

 #
 # List of required texlive packages on Fedora and OpenSuse
 #

 my %texlive = (
 	'amsfonts.sty'       => 'texlive-amsfonts',
 	'amsmath.sty'        => 'texlive-amsmath',
 	'amssymb.sty'        => 'texlive-amsfonts',
 	'amsthm.sty'         => 'texlive-amscls',
 	'anyfontsize.sty'    => 'texlive-anyfontsize',
 	'atbegshi.sty'       => 'texlive-oberdiek',
 	'bm.sty'             => 'texlive-tools',
 	'capt-of.sty'        => 'texlive-capt-of',
 	'cmap.sty'           => 'texlive-cmap',
 	'ecrm1000.tfm'       => 'texlive-ec',
 	'eqparbox.sty'       => 'texlive-eqparbox',
 	'eu1enc.def'         => 'texlive-euenc',
 	'fancybox.sty'       => 'texlive-fancybox',
 	'fancyvrb.sty'       => 'texlive-fancyvrb',
 	'float.sty'          => 'texlive-float',
 	'fncychap.sty'       => 'texlive-fncychap',
 	'footnote.sty'       => 'texlive-mdwtools',
 	'framed.sty'         => 'texlive-framed',
 	'luatex85.sty'       => 'texlive-luatex85',
 	'multirow.sty'       => 'texlive-multirow',
 	'needspace.sty'      => 'texlive-needspace',
 	'palatino.sty'       => 'texlive-psnfss',
 	'parskip.sty'        => 'texlive-parskip',
 	'polyglossia.sty'    => 'texlive-polyglossia',
 	'tabulary.sty'       => 'texlive-tabulary',
 	'threeparttable.sty' => 'texlive-threeparttable',
 	'titlesec.sty'       => 'texlive-titlesec',
 	'ucs.sty'            => 'texlive-ucs',
 	'upquote.sty'        => 'texlive-upquote',
 	'wrapfig.sty'        => 'texlive-wrapfig',
 );

 #
 # Subroutines that checks if a feature exists
 #

 sub check_missing(%)
 {
 	my %map = %{$_[0]};

 	foreach my $prog (sort keys %missing) {
 		my $is_optional = $missing{$prog};

 		# At least on some LTS distros like CentOS 7, texlive doesn't
 		# provide all packages we need. When such distros are
 		# detected, we have to disable PDF output.
 		#
 		# So, we need to ignore the packages that distros would
 		# need for LaTeX to work
 		if ($is_optional == 2 && !$pdf) {
 			$optional--;
 			next;
 		}

 		if ($is_optional) {
 			print "Warning: better to also install \"$prog\".\n";
 		} else {
 			print "ERROR: please install \"$prog\", otherwise, build won't work.\n";
 		}
 		if (defined($map{$prog})) {
 			$install .= " " . $map{$prog};
 		} else {
 			$install .= " " . $prog;
 		}
 	}

 	$install =~ s/^\s//;
 }

 sub add_package($$)
 {
 	my $package = shift;
 	my $is_optional = shift;

 	$missing{$package} = $is_optional;
 	if ($is_optional) {
 		$optional++;
 	} else {
 		$need++;
 	}
 }

 sub check_missing_file($$$)
 {
 	my $files = shift;
 	my $package = shift;
 	my $is_optional = shift;

 	for (@$files) {
 		return if(-e $_);
 	}

 	add_package($package, $is_optional);
 }

 sub findprog($)
 {
 	foreach(split(/:/, $ENV{PATH})) {
 		return "$_/$_[0]" if(-x "$_/$_[0]");
 	}
 }

 sub find_python_no_venv()
 {
 	my $prog = shift;

 	my $cur_dir = qx(pwd);
 	$cur_dir =~ s/\s+$//;

 	foreach my $dir (split(/:/, $ENV{PATH})) {
 		next if ($dir =~ m,($cur_dir)/sphinx,);
 		return "$dir/python3" if(-x "$dir/python3");
 	}
 	foreach my $dir (split(/:/, $ENV{PATH})) {
 		next if ($dir =~ m,($cur_dir)/sphinx,);
 		return "$dir/python" if(-x "$dir/python");
 	}
 	return "python";
 }

 sub check_program($$)
 {
 	my $prog = shift;
 	my $is_optional = shift;

 	return $prog if findprog($prog);

 	add_package($prog, $is_optional);
 }

 sub check_perl_module($$)
 {
 	my $prog = shift;
 	my $is_optional = shift;

 	my $err = system("perl -M$prog -e 1 2>/dev/null /dev/null");
 	return if ($err == 0);

 	add_package($prog, $is_optional);
 }

 sub check_python_module($$)
 {
 	my $prog = shift;
 	my $is_optional = shift;

 	return if (!$python_cmd);

 	my $err = system("$python_cmd -c 'import $prog' 2>/dev/null /dev/null");
 	return if ($err == 0);

 	add_package($prog, $is_optional);
 }

 sub check_rpm_missing($$)
 {
 	my @pkgs = @{$_[0]};
 	my $is_optional = $_[1];

 	foreach my $prog(@pkgs) {
 		my $err = system("rpm -q '$prog' 2>/dev/null >/dev/null");
 		add_package($prog, $is_optional) if ($err);
 	}
 }

 sub check_pacman_missing($$)
 {
 	my @pkgs = @{$_[0]};
 	my $is_optional = $_[1];

 	foreach my $prog(@pkgs) {
 		my $err = system("pacman -Q '$prog' 2>/dev/null >/dev/null");
 		add_package($prog, $is_optional) if ($err);
 	}
 }

 sub check_missing_tex($)
 {
 	my $is_optional = shift;
 	my $kpsewhich = findprog("kpsewhich");

 	foreach my $prog(keys %texlive) {
 		my $package = $texlive{$prog};
 		if (!$kpsewhich) {
 			add_package($package, $is_optional);
 			next;
 		}
 		my $file = qx($kpsewhich $prog);
 		add_package($package, $is_optional) if ($file =~ /^\s*$/);
 	}
 }

 sub get_sphinx_fname()
 {
 	my $fname = "sphinx-build";
 	return $fname if findprog($fname);

 	$fname = "sphinx-build-3";
 	if (findprog($fname)) {
 		$need_symlink = 1;
 		return $fname;
 	}

 	return "";
 }

 sub get_sphinx_version($)
 {
 	my $cmd = shift;
 	my $ver;

 	open IN, "$cmd --version 2>&1 |";
 	while (<IN>) {
 		if (m/^\s*sphinx-build\s+([\d\.]+)(\+\/[\da-f]+)?$/) {
 			$ver=$1;
 			last;
 		}
 		# Sphinx 1.2.x uses a different format
 		if (m/^\s*Sphinx.*\s+([\d\.]+)$/) {
 			$ver=$1;
 			last;
 		}
 	}
 	close IN;
 	return $ver;
 }

 sub check_sphinx()
 {
 	my $default_version;

 	open IN, $conf or die "Can't open $conf";
 	while (<IN>) {
 		if (m/^\s*needs_sphinx\s*=\s*[\'\"]([\d\.]+)[\'\"]/) {
 			$min_version=$1;
 			last;
 		}
 	}
 	close IN;

 	die "Can't get needs_sphinx version from $conf" if (!$min_version);

 	open IN, $requirement_file or die "Can't open $requirement_file";
 	while (<IN>) {
 		if (m/^\s*Sphinx\s*==\s*([\d\.]+)$/) {
 			$default_version=$1;
 			last;
 		}
 	}
 	close IN;

 	die "Can't get default sphinx version from $requirement_file" if (!$default_version);

 	$virtenv_dir = $virtenv_prefix . $default_version;

 	my $sphinx = get_sphinx_fname();
 	if ($sphinx eq "") {
 		$need_sphinx = 1;
 		return;
 	}

 	$cur_version = get_sphinx_version($sphinx);
 	die ("$sphinx returned an error") if (!$cur_version);

 	die "$sphinx didn't return its version" if (!$cur_version);

 	if ($cur_version lt $min_version) {
 		printf "ERROR: Sphinx version is %s. It should be >= %s (recommended >= %s)\n",
 		       $cur_version, $min_version, $default_version;
 		$need_sphinx = 1;
 		return;
 	}

 	if ($cur_version lt $rec_version) {
 		$rec_sphinx_upgrade = 1;
 		return;
 	}
 	if ($cur_version lt $min_pdf_version) {
 		$rec_sphinx_upgrade = 1;
 		return;
 	}

 	# On version check mode, just assume Sphinx has all mandatory deps
 	exit (0) if ($version_check);
 }

 #
 # Ancillary subroutines
 #

 sub catcheck($)
 {
   my $res = "";
   $res = qx(cat $_[0]) if (-r $_[0]);
   return $res;
 }

 sub which($)
 {
 	my $file = shift;
 	my @path = split ":", $ENV{PATH};

 	foreach my $dir(@path) {
 		my $name = $dir.'/'.$file;
 		return $name if (-x $name );
 	}
 	return undef;
 }

 #
 # Subroutines that check distro-specific hints
 #

 sub give_debian_hints()
 {
 	my %map = (
 		"python-sphinx"		=> "python3-sphinx",
 		"sphinx_rtd_theme"	=> "python3-sphinx-rtd-theme",
 		"ensurepip"		=> "python3-venv",
 		"virtualenv"		=> "virtualenv",
 		"dot"			=> "graphviz",
 		"convert"		=> "imagemagick",
 		"Pod::Usage"		=> "perl-modules",
 		"xelatex"		=> "texlive-xetex",
 		"rsvg-convert"		=> "librsvg2-bin",
 	);

 	if ($pdf) {
 		check_missing_file(["/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf"],
 				   "fonts-dejavu", 2);

 		check_missing_file(["/usr/share/fonts/noto-cjk/NotoSansCJK-Regular.ttc",
 				    "/usr/share/fonts/opentype/noto/NotoSansCJK-Regular.ttc",
 				    "/usr/share/fonts/opentype/noto/NotoSerifCJK-Regular.ttc"],
 				   "fonts-noto-cjk", 2);
 	}

 	check_program("dvipng", 2) if ($pdf);
 	check_missing(\%map);

 	return if (!$need && !$optional);
 	printf("You should run:\n\n\tsudo apt-get install $install\n");
 }

 sub give_redhat_hints()
 {
 	my %map = (
 		"python-sphinx"		=> "python3-sphinx",
 		"sphinx_rtd_theme"	=> "python3-sphinx_rtd_theme",
 		"virtualenv"		=> "python3-virtualenv",
 		"dot"			=> "graphviz",
 		"convert"		=> "ImageMagick",
 		"Pod::Usage"		=> "perl-Pod-Usage",
 		"xelatex"		=> "texlive-xetex-bin",
 		"rsvg-convert"		=> "librsvg2-tools",
 	);

 	my @fedora26_opt_pkgs = (
 		"graphviz-gd",		# Fedora 26: needed for PDF support
 	);

 	my @fedora_tex_pkgs = (
 		"texlive-collection-fontsrecommended",
 		"texlive-collection-latex",
 		"texlive-xecjk",
 		"dejavu-sans-fonts",
 		"dejavu-serif-fonts",
 		"dejavu-sans-mono-fonts",
 	);

 	#
 	# Checks valid for RHEL/CentOS version 7.x.
 	#
 	my $old = 0;
 	my $rel;
 	$rel = $1 if ($system_release =~ /release\s+(\d+)/);

 	if (!($system_release =~ /Fedora/)) {
 		$map{"virtualenv"} = "python-virtualenv";

 		if ($rel && $rel < 8) {
 			$old = 1;
 			$pdf = 0;

 			printf("Note: texlive packages on RHEL/CENTOS <= 7 are incomplete. Can't support PDF output\n");
 			printf("If you want to build PDF, please read:\n");
 			printf("\thttps://www.systutorials.com/241660/how-to-install-tex-live-on-centos-7-linux/\n");
 		}
 	} else {
 		if ($rel && $rel < 26) {
 			$old = 1;
 		}
 	}
 	if (!$rel) {
 		printf("Couldn't identify release number\n");
 		$old = 1;
 		$pdf = 0;
 	}

 	if ($pdf) {
 		check_missing_file(["/usr/share/fonts/google-noto-cjk/NotoSansCJK-Regular.ttc"],
 				   "google-noto-sans-cjk-ttc-fonts", 2);
 	}

 	check_rpm_missing(\@fedora26_opt_pkgs, 2) if ($pdf && !$old);
 	check_rpm_missing(\@fedora_tex_pkgs, 2) if ($pdf);
 	check_missing_tex(2) if ($pdf);
 	check_missing(\%map);

 	return if (!$need && !$optional);

 	if (!$old) {
 		# dnf, for Fedora 18+
 		printf("You should run:\n\n\tsudo dnf install -y $install\n");
 	} else {
 		# yum, for RHEL (and clones) or Fedora version < 18
 		printf("You should run:\n\n\tsudo yum install -y $install\n");
 	}
 }

 sub give_opensuse_hints()
 {
 	my %map = (
 		"python-sphinx"		=> "python3-sphinx",
 		"sphinx_rtd_theme"	=> "python3-sphinx_rtd_theme",
 		"virtualenv"		=> "python3-virtualenv",
 		"dot"			=> "graphviz",
 		"convert"		=> "ImageMagick",
 		"Pod::Usage"		=> "perl-Pod-Usage",
 		"xelatex"		=> "texlive-xetex-bin",
 	);

 	# On Tumbleweed, this package is also named rsvg-convert
 	$map{"rsvg-convert"} = "rsvg-view" if (!($system_release =~ /Tumbleweed/));

 	my @suse_tex_pkgs = (
 		"texlive-babel-english",
 		"texlive-caption",
 		"texlive-colortbl",
 		"texlive-courier",
 		"texlive-dvips",
 		"texlive-helvetic",
 		"texlive-makeindex",
 		"texlive-metafont",
 		"texlive-metapost",
 		"texlive-palatino",
 		"texlive-preview",
 		"texlive-times",
 		"texlive-zapfchan",
 		"texlive-zapfding",
 	);

 	$map{"latexmk"} = "texlive-latexmk-bin";

 	# FIXME: add support for installing CJK fonts
 	#
 	# I tried hard, but was unable to find a way to install
 	# "Noto Sans CJK SC" on openSUSE

 	check_rpm_missing(\@suse_tex_pkgs, 2) if ($pdf);
 	check_missing_tex(2) if ($pdf);
 	check_missing(\%map);

 	return if (!$need && !$optional);
 	printf("You should run:\n\n\tsudo zypper install --no-recommends $install\n");
 }

 sub give_mageia_hints()
 {
 	my %map = (
 		"python-sphinx"		=> "python3-sphinx",
 		"sphinx_rtd_theme"	=> "python3-sphinx_rtd_theme",
 		"virtualenv"		=> "python3-virtualenv",
 		"dot"			=> "graphviz",
 		"convert"		=> "ImageMagick",
 		"Pod::Usage"		=> "perl-Pod-Usage",
 		"xelatex"		=> "texlive",
 		"rsvg-convert"		=> "librsvg2",
 	);

 	my @tex_pkgs = (
 		"texlive-fontsextra",
 	);

 	$map{"latexmk"} = "texlive-collection-basic";

 	my $packager_cmd;
 	my $noto_sans;
 	if ($system_release =~ /OpenMandriva/) {
 		$packager_cmd = "dnf install";
 		$noto_sans = "noto-sans-cjk-fonts";
 		@tex_pkgs = ( "texlive-collection-fontsextra" );
 	} else {
 		$packager_cmd = "urpmi";
 		$noto_sans = "google-noto-sans-cjk-ttc-fonts";
 	}


 	if ($pdf) {
 		check_missing_file(["/usr/share/fonts/google-noto-cjk/NotoSansCJK-Regular.ttc",
 				    "/usr/share/fonts/TTF/NotoSans-Regular.ttf"],
 				   $noto_sans, 2);
 	}

 	check_rpm_missing(\@tex_pkgs, 2) if ($pdf);
 	check_missing(\%map);

 	return if (!$need && !$optional);
 	printf("You should run:\n\n\tsudo $packager_cmd $install\n");
 }

 sub give_arch_linux_hints()
 {
 	my %map = (
 		"sphinx_rtd_theme"	=> "python-sphinx_rtd_theme",
 		"virtualenv"		=> "python-virtualenv",
 		"dot"			=> "graphviz",
 		"convert"		=> "imagemagick",
 		"xelatex"		=> "texlive-bin",
 		"latexmk"		=> "texlive-core",
 		"rsvg-convert"		=> "extra/librsvg",
 	);

 	my @archlinux_tex_pkgs = (
 		"texlive-core",
 		"texlive-latexextra",
 		"ttf-dejavu",
 	);
 	check_pacman_missing(\@archlinux_tex_pkgs, 2) if ($pdf);

 	if ($pdf) {
 		check_missing_file(["/usr/share/fonts/noto-cjk/NotoSansCJK-Regular.ttc"],
 				   "noto-fonts-cjk", 2);
 	}

 	check_missing(\%map);

 	return if (!$need && !$optional);
 	printf("You should run:\n\n\tsudo pacman -S $install\n");
 }

 sub give_gentoo_hints()
 {
 	my %map = (
 		"sphinx_rtd_theme"	=> "dev-python/sphinx_rtd_theme",
 		"virtualenv"		=> "dev-python/virtualenv",
 		"dot"			=> "media-gfx/graphviz",
 		"convert"		=> "media-gfx/imagemagick",
 		"xelatex"		=> "dev-texlive/texlive-xetex media-fonts/dejavu",
 		"rsvg-convert"		=> "gnome-base/librsvg",
 	);

 	check_missing_file(["/usr/share/fonts/dejavu/DejaVuSans.ttf"],
 			   "media-fonts/dejavu", 2) if ($pdf);

 	if ($pdf) {
 		check_missing_file(["/usr/share/fonts/noto-cjk/NotoSansCJKsc-Regular.otf",
 				    "/usr/share/fonts/noto-cjk/NotoSerifCJK-Regular.ttc"],
 				   "media-fonts/noto-cjk", 2);
 	}

 	check_missing(\%map);

 	return if (!$need && !$optional);

 	printf("You should run:\n\n");

 	my $imagemagick = "media-gfx/imagemagick svg png";
 	my $cairo = "media-gfx/graphviz cairo pdf";
 	my $portage_imagemagick = "/etc/portage/package.use/imagemagick";
 	my $portage_cairo = "/etc/portage/package.use/graphviz";

 	if (qx(grep imagemagick $portage_imagemagick 2>/dev/null) eq "") {
 		printf("\tsudo su -c 'echo \"$imagemagick\" > $portage_imagemagick'\n")
 	}
 	if (qx(grep graphviz $portage_cairo 2>/dev/null) eq  "") {
 		printf("\tsudo su -c 'echo \"$cairo\" > $portage_cairo'\n");
 	}

 	printf("\tsudo emerge --ask $install\n");

 }

 sub check_distros()
 {
 	# Distro-specific hints
 	if ($system_release =~ /Red Hat Enterprise Linux/) {
 		give_redhat_hints;
 		return;
 	}
 	if ($system_release =~ /CentOS/) {
 		give_redhat_hints;
 		return;
 	}
 	if ($system_release =~ /Scientific Linux/) {
 		give_redhat_hints;
 		return;
 	}
 	if ($system_release =~ /Oracle Linux Server/) {
 		give_redhat_hints;
 		return;
 	}
 	if ($system_release =~ /Fedora/) {
 		give_redhat_hints;
 		return;
 	}
 	if ($system_release =~ /Ubuntu/) {
 		give_debian_hints;
 		return;
 	}
 	if ($system_release =~ /Debian/) {
 		give_debian_hints;
 		return;
 	}
 	if ($system_release =~ /openSUSE/) {
 		give_opensuse_hints;
 		return;
 	}
 	if ($system_release =~ /Mageia/) {
 		give_mageia_hints;
 		return;
 	}
 	if ($system_release =~ /OpenMandriva/) {
 		give_mageia_hints;
 		return;
 	}
 	if ($system_release =~ /Arch Linux/) {
 		give_arch_linux_hints;
 		return;
 	}
 	if ($system_release =~ /Gentoo/) {
 		give_gentoo_hints;
 		return;
 	}

 	#
 	# Fall-back to generic hint code for other distros
 	# That's far from ideal, specially for LaTeX dependencies.
 	#
 	my %map = (
 		"sphinx-build" => "sphinx"
 	);
 	check_missing_tex(2) if ($pdf);
 	check_missing(\%map);
 	print "I don't know distro $system_release.\n";
 	print "So, I can't provide you a hint with the install procedure.\n";
 	print "There are likely missing dependencies.\n";
 }

 #
 # Common dependencies
 #

 sub deactivate_help()
 {
 	printf "\nIf you want to exit the virtualenv, you can use:\n";
 	printf "\tdeactivate\n";
 }

 sub check_needs()
 {
 	# Check if Sphinx is already accessible from current environment
 	check_sphinx();

 	if ($system_release) {
 		print "Detected OS: $system_release.\n";
 	} else {
 		print "Unknown OS\n";
 	}
 	printf "Sphinx version: %s\n\n", $cur_version if ($cur_version);

 	# Check python command line, trying first python3
 	$python_cmd = findprog("python3");
 	$python_cmd = check_program("python", 0) if (!$python_cmd);

 	# Check the type of virtual env, depending on Python version
 	if ($python_cmd) {
 		if ($virtualenv) {
 			my $tmp = qx($python_cmd --version 2>&1);
 			if ($tmp =~ m/(\d+\.)(\d+\.)/) {
 				if ($1 >= 3 && $2 >= 3) {
 					$need_venv = 1;		# python 3.3 or upper
 				} else {
 					$need_virtualenv = 1;
 				}
 				if ($1 < 3) {
 					# Complain if it finds python2 (or worse)
 					printf "Warning: python$1 support is deprecated. Use it with caution!\n";
 				}
 			} else {
 				die "Warning: couldn't identify $python_cmd version!";
 			}
 		} else {
 			add_package("python-sphinx", 0);
 		}
 	}

 	# Set virtualenv command line, if python < 3.3
 	my $virtualenv_cmd;
 	if ($need_virtualenv) {
 		$virtualenv_cmd = findprog("virtualenv-3");
 		$virtualenv_cmd = findprog("virtualenv-3.5") if (!$virtualenv_cmd);
 		if (!$virtualenv_cmd) {
 			check_program("virtualenv", 0);
 			$virtualenv_cmd = "virtualenv";
 		}
 	}

 	# Check for needed programs/tools
 	check_perl_module("Pod::Usage", 0);
 	check_program("make", 0);
 	check_program("gcc", 0);
 	check_python_module("sphinx_rtd_theme", 1) if (!$virtualenv);
 	check_program("dot", 1);
 	check_program("convert", 1);

 	# Extra PDF files - should use 2 for is_optional
 	check_program("xelatex", 2) if ($pdf);
 	check_program("rsvg-convert", 2) if ($pdf);
 	check_program("latexmk", 2) if ($pdf);

 	if ($need_sphinx || $rec_sphinx_upgrade) {
 		check_python_module("ensurepip", 0) if ($need_venv);
 	}

 	# Do distro-specific checks and output distro-install commands
 	check_distros();

 	if (!$python_cmd) {
 		if ($need == 1) {
 			die "Can't build as $need mandatory dependency is missing";
 		} elsif ($need) {
 			die "Can't build as $need mandatory dependencies are missing";
 		}
 	}

 	# Check if sphinx-build is called sphinx-build-3
 	if ($need_symlink) {
 		printf "\tsudo ln -sf %s /usr/bin/sphinx-build\n\n",
 		       which("sphinx-build-3");
 	}

 	# NOTE: if the system has a too old Sphinx version installed,
 	# it will recommend installing a newer version using virtualenv

 	if ($need_sphinx || $rec_sphinx_upgrade) {
 		my $min_activate = "$ENV{'PWD'}/${virtenv_prefix}${min_version}/bin/activate";
 		my @activates = glob "$ENV{'PWD'}/${virtenv_prefix}*/bin/activate";

 		if ($cur_version lt $rec_version) {
 			print "Warning: It is recommended at least Sphinx version $rec_version.\n";
 			print "         If you want pdf, you need at least $min_pdf_version.\n";
 		}
 		if ($cur_version lt $min_pdf_version) {
 			print "Note: It is recommended at least Sphinx version $min_pdf_version if you need PDF support.\n";
 		}
 		@activates = sort {$b cmp $a} @activates;
 		my ($activate, $ver);
 		foreach my $f (@activates) {
 			next if ($f lt $min_activate);

 			my $sphinx_cmd = $f;
 			$sphinx_cmd =~ s/activate/sphinx-build/;
 			next if (! -f $sphinx_cmd);

 			$ver = get_sphinx_version($sphinx_cmd);
 			if ($need_sphinx && ($ver ge $min_version)) {
 				$activate = $f;
 				last;
 			} elsif ($ver gt $cur_version) {
 				$activate = $f;
 				last;
 			}
 		}
 		if ($activate ne "") {
 			if ($need_sphinx) {
 				printf "\nNeed to activate Sphinx (version $ver) on virtualenv with:\n";
 				printf "\t. $activate\n";
 				deactivate_help();
 				exit (1);
 			} else {
 				printf "\nYou may also use a newer Sphinx (version $ver) with:\n";
 				printf "\tdeactivate && . $activate\n";
 			}
 		} else {
 			my $rec_activate = "$virtenv_dir/bin/activate";

 			print "To upgrade Sphinx, use:\n\n" if ($rec_sphinx_upgrade);

 			$python_cmd = find_python_no_venv();

 			if ($need_venv) {
 				printf "\t$python_cmd -m venv $virtenv_dir\n";
 			} else {
 				printf "\t$virtualenv_cmd $virtenv_dir\n";
 			}
 			printf "\t. $rec_activate\n";
 			printf "\tpip install -r $requirement_file\n";
 			deactivate_help();

 			$need++ if (!$rec_sphinx_upgrade);
 		}
 	}
 	printf "\n";

 	print "All optional dependencies are met.\n" if (!$optional);

 	if ($need == 1) {
 		die "Can't build as $need mandatory dependency is missing";
 	} elsif ($need) {
 		die "Can't build as $need mandatory dependencies are missing";
 	}

 	print "Needed package dependencies are met.\n";
 }

 #
 # Main
 #

 while (@ARGV) {
 	my $arg = shift(@ARGV);

 	if ($arg eq "--no-virtualenv") {
 		$virtualenv = 0;
 	} elsif ($arg eq "--no-pdf"){
 		$pdf = 0;
 	} elsif ($arg eq "--version-check"){
 		$version_check = 1;
 	} else {
 		print "Usage:\n\t$0 <--no-virtualenv> <--no-pdf> <--version-check>\n\n";
 		print "Where:\n";
 		print "\t--no-virtualenv\t- Recommend installing Sphinx instead of using a virtualenv\n";
 		print "\t--version-check\t- if version is compatible, don't check for missing dependencies\n";
 		print "\t--no-pdf\t- don't check for dependencies required to build PDF docs\n\n";
 		exit -1;
 	}
 }

 #
 # Determine the system type. There's no standard unique way that would
 # work with all distros with a minimal package install. So, several
 # methods are used here.
 #
 # By default, it will use lsb_release function. If not available, it will
 # fail back to reading the known different places where the distro name
 # is stored
 #

 $system_release = qx(lsb_release -d) if which("lsb_release");
 $system_release =~ s/Description:\s*// if ($system_release);
 $system_release = catcheck("/etc/system-release") if !$system_release;
 $system_release = catcheck("/etc/redhat-release") if !$system_release;
 $system_release = catcheck("/etc/lsb-release") if !$system_release;
 $system_release = catcheck("/etc/gentoo-release") if !$system_release;

 # This seems more common than LSB these days
 if (!$system_release) {
 	my %os_var;
 	if (open IN, "cat /etc/os-release|") {
 		while (<IN>) {
 			if (m/^([\w\d\_]+)=\"?([^\"]*)\"?\n/) {
 				$os_var{$1}=$2;
 			}
 		}
 		$system_release = $os_var{"NAME"};
 		if (defined($os_var{"VERSION_ID"})) {
 			$system_release .= " " . $os_var{"VERSION_ID"} if (defined($os_var{"VERSION_ID"}));
 		} else {
 			$system_release .= " " . $os_var{"VERSION"};
 		}
 	}
 }
 $system_release = catcheck("/etc/issue") if !$system_release;
 $system_release =~ s/\s+$//;

 check_needs;
	#!/usr/bin/perl
	# SPDX-License-Identifier: GPL-2.0-or-later
	use strict;

	# Copyright (c) 2017-2020 Mauro Carvalho Chehab <mchehab@kernel.org>
	#

	my $prefix = "./";
	$prefix = "$ENV{'srctree'}/" if ($ENV{'srctree'});

	my $conf = $prefix . "Documentation/conf.py";
	my $requirement_file = $prefix . "Documentation/sphinx/requirements.txt";
	my $virtenv_prefix = "sphinx_";

	#
	# Static vars
	#

	my %missing;
	my $system_release;
	my $need = 0;
	my $optional = 0;
	my $need_symlink = 0;
	my $need_sphinx = 0;
	my $need_venv = 0;
	my $need_virtualenv = 0;
	my $rec_sphinx_upgrade = 0;
	my $install = "";
	my $virtenv_dir = "";
	my $python_cmd = "";
	my $min_version;
	my $cur_version;
	my $rec_version = "1.7.9"; # PDF won't build here
	my $min_pdf_version = "2.4.4"; # Min version where pdf builds

	#
	# Command line arguments
	#

	my $pdf = 1;
	my $virtualenv = 1;
	my $version_check = 0;

	#
	# List of required texlive packages on Fedora and OpenSuse
	#

	my %texlive = (
	'amsfonts.sty' => 'texlive-amsfonts',
	'amsmath.sty' => 'texlive-amsmath',
	'amssymb.sty' => 'texlive-amsfonts',
	'amsthm.sty' => 'texlive-amscls',
	'anyfontsize.sty' => 'texlive-anyfontsize',
	'atbegshi.sty' => 'texlive-oberdiek',
	'bm.sty' => 'texlive-tools',
	'capt-of.sty' => 'texlive-capt-of',
	'cmap.sty' => 'texlive-cmap',
	'ecrm1000.tfm' => 'texlive-ec',
	'eqparbox.sty' => 'texlive-eqparbox',
	'eu1enc.def' => 'texlive-euenc',
	'fancybox.sty' => 'texlive-fancybox',
	'fancyvrb.sty' => 'texlive-fancyvrb',
	'float.sty' => 'texlive-float',
	'fncychap.sty' => 'texlive-fncychap',
	'footnote.sty' => 'texlive-mdwtools',
	'framed.sty' => 'texlive-framed',
	'luatex85.sty' => 'texlive-luatex85',
	'multirow.sty' => 'texlive-multirow',
	'needspace.sty' => 'texlive-needspace',
	'palatino.sty' => 'texlive-psnfss',
	'parskip.sty' => 'texlive-parskip',
	'polyglossia.sty' => 'texlive-polyglossia',
	'tabulary.sty' => 'texlive-tabulary',
	'threeparttable.sty' => 'texlive-threeparttable',
	'titlesec.sty' => 'texlive-titlesec',
	'ucs.sty' => 'texlive-ucs',
	'upquote.sty' => 'texlive-upquote',
	'wrapfig.sty' => 'texlive-wrapfig',
	);

	#
	# Subroutines that checks if a feature exists
	#

	sub check_missing(%)
	{
	my %map = %{$_[0]};

	foreach my $prog (sort keys %missing) {
	my $is_optional = $missing{$prog};

	# At least on some LTS distros like CentOS 7, texlive doesn't
	# provide all packages we need. When such distros are
	# detected, we have to disable PDF output.
	#
	# So, we need to ignore the packages that distros would
	# need for LaTeX to work
	if ($is_optional == 2 && !$pdf) {
	$optional--;
	next;
	}

	if ($is_optional) {
	print "Warning: better to also install \"$prog\".\n";
	} else {
	print "ERROR: please install \"$prog\", otherwise, build won't work.\n";
	}
	if (defined($map{$prog})) {
	$install .= " " . $map{$prog};
	} else {
	$install .= " " . $prog;
	}
	}

	$install =~ s/^\s//;
	}

	sub add_package($$)
	{
	my $package = shift;
	my $is_optional = shift;

	$missing{$package} = $is_optional;
	if ($is_optional) {
	$optional++;
	} else {
	$need++;
	}
	}

	sub check_missing_file($$$)
	{
	my $files = shift;
	my $package = shift;
	my $is_optional = shift;

	for (@$files) {
	return if(-e $_);
	}

	add_package($package, $is_optional);
	}

	sub findprog($)
	{
	foreach(split(/:/, $ENV{PATH})) {
	return "$_/$_[0]" if(-x "$_/$_[0]");
	}
	}

	sub find_python_no_venv()
	{
	my $prog = shift;

	my $cur_dir = qx(pwd);
	$cur_dir =~ s/\s+$//;

	foreach my $dir (split(/:/, $ENV{PATH})) {
	next if ($dir =~ m,($cur_dir)/sphinx,);
	return "$dir/python3" if(-x "$dir/python3");
	}
	foreach my $dir (split(/:/, $ENV{PATH})) {
	next if ($dir =~ m,($cur_dir)/sphinx,);
	return "$dir/python" if(-x "$dir/python");
	}
	return "python";
	}

	sub check_program($$)
	{
	my $prog = shift;
	my $is_optional = shift;

	return $prog if findprog($prog);

	add_package($prog, $is_optional);
	}

	sub check_perl_module($$)
	{
	my $prog = shift;
	my $is_optional = shift;

	my $err = system("perl -M$prog -e 1 2>/dev/null /dev/null");
	return if ($err == 0);

	add_package($prog, $is_optional);
	}

	sub check_python_module($$)
	{
	my $prog = shift;
	my $is_optional = shift;

	return if (!$python_cmd);

	my $err = system("$python_cmd -c 'import $prog' 2>/dev/null /dev/null");
	return if ($err == 0);

	add_package($prog, $is_optional);
	}

	sub check_rpm_missing($$)
	{
	my @pkgs = @{$_[0]};
	my $is_optional = $_[1];

	foreach my $prog(@pkgs) {
	my $err = system("rpm -q '$prog' 2>/dev/null >/dev/null");
	add_package($prog, $is_optional) if ($err);
	}
	}

	sub check_pacman_missing($$)
	{
	my @pkgs = @{$_[0]};
	my $is_optional = $_[1];

	foreach my $prog(@pkgs) {
	my $err = system("pacman -Q '$prog' 2>/dev/null >/dev/null");
	add_package($prog, $is_optional) if ($err);
	}
	}

	sub check_missing_tex($)
	{
	my $is_optional = shift;
	my $kpsewhich = findprog("kpsewhich");

	foreach my $prog(keys %texlive) {
	my $package = $texlive{$prog};
	if (!$kpsewhich) {
	add_package($package, $is_optional);
	next;
	}
	my $file = qx($kpsewhich $prog);
	add_package($package, $is_optional) if ($file =~ /^\s*$/);
	}
	}

	sub get_sphinx_fname()
	{
	my $fname = "sphinx-build";
	return $fname if findprog($fname);

	$fname = "sphinx-build-3";
	if (findprog($fname)) {
	$need_symlink = 1;
	return $fname;
	}

	return "";
	}

	sub get_sphinx_version($)
	{
	my $cmd = shift;
	my $ver;

	open IN, "$cmd --version 2>&1 \|";
	while (<IN>) {
	if (m/^\s*sphinx-build\s+([\d\.]+)(\+\/[\da-f]+)?$/) {
	$ver=$1;
	last;
	}
	# Sphinx 1.2.x uses a different format
	if (m/^\sSphinx.\s+([\d\.]+)$/) {
	$ver=$1;
	last;
	}
	}
	close IN;
	return $ver;
	}

	sub check_sphinx()
	{
	my $default_version;

	open IN, $conf or die "Can't open $conf";
	while (<IN>) {
	if (m/^\sneeds_sphinx\s=\s*[\'\"]([\d\.]+)[\'\"]/) {
	$min_version=$1;
	last;
	}
	}
	close IN;

	die "Can't get needs_sphinx version from $conf" if (!$min_version);

	open IN, $requirement_file or die "Can't open $requirement_file";
	while (<IN>) {
	if (m/^\sSphinx\s==\s*([\d\.]+)$/) {
	$default_version=$1;
	last;
	}
	}
	close IN;

	die "Can't get default sphinx version from $requirement_file" if (!$default_version);

	$virtenv_dir = $virtenv_prefix . $default_version;

	my $sphinx = get_sphinx_fname();
	if ($sphinx eq "") {
	$need_sphinx = 1;
	return;
	}

	$cur_version = get_sphinx_version($sphinx);
	die ("$sphinx returned an error") if (!$cur_version);

	die "$sphinx didn't return its version" if (!$cur_version);

	if ($cur_version lt $min_version) {
	printf "ERROR: Sphinx version is %s. It should be >= %s (recommended >= %s)\n",
	$cur_version, $min_version, $default_version;
	$need_sphinx = 1;
	return;
	}

	if ($cur_version lt $rec_version) {
	$rec_sphinx_upgrade = 1;
	return;
	}
	if ($cur_version lt $min_pdf_version) {
	$rec_sphinx_upgrade = 1;
	return;
	}

	# On version check mode, just assume Sphinx has all mandatory deps
	exit (0) if ($version_check);
	}

	#
	# Ancillary subroutines
	#

	sub catcheck($)
	{
	my $res = "";
	$res = qx(cat $_[0]) if (-r $_[0]);
	return $res;
	}

	sub which($)
	{
	my $file = shift;
	my @path = split ":", $ENV{PATH};

	foreach my $dir(@path) {
	my $name = $dir.'/'.$file;
	return $name if (-x $name );
	}
	return undef;
	}

	#
	# Subroutines that check distro-specific hints
	#

	sub give_debian_hints()
	{
	my %map = (
	"python-sphinx" => "python3-sphinx",
	"sphinx_rtd_theme" => "python3-sphinx-rtd-theme",
	"ensurepip" => "python3-venv",
	"virtualenv" => "virtualenv",
	"dot" => "graphviz",
	"convert" => "imagemagick",
	"Pod::Usage" => "perl-modules",
	"xelatex" => "texlive-xetex",
	"rsvg-convert" => "librsvg2-bin",
	);

	if ($pdf) {
	check_missing_file(["/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf"],
	"fonts-dejavu", 2);

	check_missing_file(["/usr/share/fonts/noto-cjk/NotoSansCJK-Regular.ttc",
	"/usr/share/fonts/opentype/noto/NotoSansCJK-Regular.ttc",
	"/usr/share/fonts/opentype/noto/NotoSerifCJK-Regular.ttc"],
	"fonts-noto-cjk", 2);
	}

	check_program("dvipng", 2) if ($pdf);
	check_missing(\%map);

	return if (!$need && !$optional);
	printf("You should run:\n\n\tsudo apt-get install $install\n");
	}

	sub give_redhat_hints()
	{
	my %map = (
	"python-sphinx" => "python3-sphinx",
	"sphinx_rtd_theme" => "python3-sphinx_rtd_theme",
	"virtualenv" => "python3-virtualenv",
	"dot" => "graphviz",
	"convert" => "ImageMagick",
	"Pod::Usage" => "perl-Pod-Usage",
	"xelatex" => "texlive-xetex-bin",
	"rsvg-convert" => "librsvg2-tools",
	);

	my @fedora26_opt_pkgs = (
	"graphviz-gd", # Fedora 26: needed for PDF support
	);

	my @fedora_tex_pkgs = (
	"texlive-collection-fontsrecommended",
	"texlive-collection-latex",
	"texlive-xecjk",
	"dejavu-sans-fonts",
	"dejavu-serif-fonts",
	"dejavu-sans-mono-fonts",
	);

	#
	# Checks valid for RHEL/CentOS version 7.x.
	#
	my $old = 0;
	my $rel;
	$rel = $1 if ($system_release =~ /release\s+(\d+)/);

	if (!($system_release =~ /Fedora/)) {
	$map{"virtualenv"} = "python-virtualenv";

	if ($rel && $rel < 8) {
	$old = 1;
	$pdf = 0;

	printf("Note: texlive packages on RHEL/CENTOS <= 7 are incomplete. Can't support PDF output\n");
	printf("If you want to build PDF, please read:\n");
	printf("\thttps://www.systutorials.com/241660/how-to-install-tex-live-on-centos-7-linux/\n");
	}
	} else {
	if ($rel && $rel < 26) {
	$old = 1;
	}
	}
	if (!$rel) {
	printf("Couldn't identify release number\n");
	$old = 1;
	$pdf = 0;
	}

	if ($pdf) {
	check_missing_file(["/usr/share/fonts/google-noto-cjk/NotoSansCJK-Regular.ttc"],
	"google-noto-sans-cjk-ttc-fonts", 2);
	}

	check_rpm_missing(\@fedora26_opt_pkgs, 2) if ($pdf && !$old);
	check_rpm_missing(\@fedora_tex_pkgs, 2) if ($pdf);
	check_missing_tex(2) if ($pdf);
	check_missing(\%map);

	return if (!$need && !$optional);

	if (!$old) {
	# dnf, for Fedora 18+
	printf("You should run:\n\n\tsudo dnf install -y $install\n");
	} else {
	# yum, for RHEL (and clones) or Fedora version < 18
	printf("You should run:\n\n\tsudo yum install -y $install\n");
	}
	}

	sub give_opensuse_hints()
	{
	my %map = (
	"python-sphinx" => "python3-sphinx",
	"sphinx_rtd_theme" => "python3-sphinx_rtd_theme",
	"virtualenv" => "python3-virtualenv",
	"dot" => "graphviz",
	"convert" => "ImageMagick",
	"Pod::Usage" => "perl-Pod-Usage",
	"xelatex" => "texlive-xetex-bin",
	);

	# On Tumbleweed, this package is also named rsvg-convert
	$map{"rsvg-convert"} = "rsvg-view" if (!($system_release =~ /Tumbleweed/));

	my @suse_tex_pkgs = (
	"texlive-babel-english",
	"texlive-caption",
	"texlive-colortbl",
	"texlive-courier",
	"texlive-dvips",
	"texlive-helvetic",
	"texlive-makeindex",
	"texlive-metafont",
	"texlive-metapost",
	"texlive-palatino",
	"texlive-preview",
	"texlive-times",
	"texlive-zapfchan",
	"texlive-zapfding",
	);

	$map{"latexmk"} = "texlive-latexmk-bin";

	# FIXME: add support for installing CJK fonts
	#
	# I tried hard, but was unable to find a way to install
	# "Noto Sans CJK SC" on openSUSE

	check_rpm_missing(\@suse_tex_pkgs, 2) if ($pdf);
	check_missing_tex(2) if ($pdf);
	check_missing(\%map);

	return if (!$need && !$optional);
	printf("You should run:\n\n\tsudo zypper install --no-recommends $install\n");
	}

	sub give_mageia_hints()
	{
	my %map = (
	"python-sphinx" => "python3-sphinx",
	"sphinx_rtd_theme" => "python3-sphinx_rtd_theme",
	"virtualenv" => "python3-virtualenv",
	"dot" => "graphviz",
	"convert" => "ImageMagick",
	"Pod::Usage" => "perl-Pod-Usage",
	"xelatex" => "texlive",
	"rsvg-convert" => "librsvg2",
	);

	my @tex_pkgs = (
	"texlive-fontsextra",
	);

	$map{"latexmk"} = "texlive-collection-basic";

	my $packager_cmd;
	my $noto_sans;
	if ($system_release =~ /OpenMandriva/) {
	$packager_cmd = "dnf install";
	$noto_sans = "noto-sans-cjk-fonts";
	@tex_pkgs = ( "texlive-collection-fontsextra" );
	} else {
	$packager_cmd = "urpmi";
	$noto_sans = "google-noto-sans-cjk-ttc-fonts";
	}


	if ($pdf) {
	check_missing_file(["/usr/share/fonts/google-noto-cjk/NotoSansCJK-Regular.ttc",
	"/usr/share/fonts/TTF/NotoSans-Regular.ttf"],
	$noto_sans, 2);
	}

	check_rpm_missing(\@tex_pkgs, 2) if ($pdf);
	check_missing(\%map);

	return if (!$need && !$optional);
	printf("You should run:\n\n\tsudo $packager_cmd $install\n");
	}

	sub give_arch_linux_hints()
	{
	my %map = (
	"sphinx_rtd_theme" => "python-sphinx_rtd_theme",
	"virtualenv" => "python-virtualenv",
	"dot" => "graphviz",
	"convert" => "imagemagick",
	"xelatex" => "texlive-bin",
	"latexmk" => "texlive-core",
	"rsvg-convert" => "extra/librsvg",
	);

	my @archlinux_tex_pkgs = (
	"texlive-core",
	"texlive-latexextra",
	"ttf-dejavu",
	);
	check_pacman_missing(\@archlinux_tex_pkgs, 2) if ($pdf);

	if ($pdf) {
	check_missing_file(["/usr/share/fonts/noto-cjk/NotoSansCJK-Regular.ttc"],
	"noto-fonts-cjk", 2);
	}

	check_missing(\%map);

	return if (!$need && !$optional);
	printf("You should run:\n\n\tsudo pacman -S $install\n");
	}

	sub give_gentoo_hints()
	{
	my %map = (
	"sphinx_rtd_theme" => "dev-python/sphinx_rtd_theme",
	"virtualenv" => "dev-python/virtualenv",
	"dot" => "media-gfx/graphviz",
	"convert" => "media-gfx/imagemagick",
	"xelatex" => "dev-texlive/texlive-xetex media-fonts/dejavu",
	"rsvg-convert" => "gnome-base/librsvg",
	);

	check_missing_file(["/usr/share/fonts/dejavu/DejaVuSans.ttf"],
	"media-fonts/dejavu", 2) if ($pdf);

	if ($pdf) {
	check_missing_file(["/usr/share/fonts/noto-cjk/NotoSansCJKsc-Regular.otf",
	"/usr/share/fonts/noto-cjk/NotoSerifCJK-Regular.ttc"],
	"media-fonts/noto-cjk", 2);
	}

	check_missing(\%map);

	return if (!$need && !$optional);

	printf("You should run:\n\n");

	my $imagemagick = "media-gfx/imagemagick svg png";
	my $cairo = "media-gfx/graphviz cairo pdf";
	my $portage_imagemagick = "/etc/portage/package.use/imagemagick";
	my $portage_cairo = "/etc/portage/package.use/graphviz";

	if (qx(grep imagemagick $portage_imagemagick 2>/dev/null) eq "") {
	printf("\tsudo su -c 'echo \"$imagemagick\" > $portage_imagemagick'\n")
	}
	if (qx(grep graphviz $portage_cairo 2>/dev/null) eq "") {
	printf("\tsudo su -c 'echo \"$cairo\" > $portage_cairo'\n");
	}

	printf("\tsudo emerge --ask $install\n");

	}

	sub check_distros()
	{
	# Distro-specific hints
	if ($system_release =~ /Red Hat Enterprise Linux/) {
	give_redhat_hints;
	return;
	}
	if ($system_release =~ /CentOS/) {
	give_redhat_hints;
	return;
	}
	if ($system_release =~ /Scientific Linux/) {
	give_redhat_hints;
	return;
	}
	if ($system_release =~ /Oracle Linux Server/) {
	give_redhat_hints;
	return;
	}
	if ($system_release =~ /Fedora/) {
	give_redhat_hints;
	return;
	}
	if ($system_release =~ /Ubuntu/) {
	give_debian_hints;
	return;
	}
	if ($system_release =~ /Debian/) {
	give_debian_hints;
	return;
	}
	if ($system_release =~ /openSUSE/) {
	give_opensuse_hints;
	return;
	}
	if ($system_release =~ /Mageia/) {
	give_mageia_hints;
	return;
	}
	if ($system_release =~ /OpenMandriva/) {
	give_mageia_hints;
	return;
	}
	if ($system_release =~ /Arch Linux/) {
	give_arch_linux_hints;
	return;
	}
	if ($system_release =~ /Gentoo/) {
	give_gentoo_hints;
	return;
	}

	#
	# Fall-back to generic hint code for other distros
	# That's far from ideal, specially for LaTeX dependencies.
	#
	my %map = (
	"sphinx-build" => "sphinx"
	);
	check_missing_tex(2) if ($pdf);
	check_missing(\%map);
	print "I don't know distro $system_release.\n";
	print "So, I can't provide you a hint with the install procedure.\n";
	print "There are likely missing dependencies.\n";
	}

	#
	# Common dependencies
	#

	sub deactivate_help()
	{
	printf "\nIf you want to exit the virtualenv, you can use:\n";
	printf "\tdeactivate\n";
	}

	sub check_needs()
	{
	# Check if Sphinx is already accessible from current environment
	check_sphinx();

	if ($system_release) {
	print "Detected OS: $system_release.\n";
	} else {
	print "Unknown OS\n";
	}
	printf "Sphinx version: %s\n\n", $cur_version if ($cur_version);

	# Check python command line, trying first python3
	$python_cmd = findprog("python3");
	$python_cmd = check_program("python", 0) if (!$python_cmd);

	# Check the type of virtual env, depending on Python version
	if ($python_cmd) {
	if ($virtualenv) {
	my $tmp = qx($python_cmd --version 2>&1);
	if ($tmp =~ m/(\d+\.)(\d+\.)/) {
	if ($1 >= 3 && $2 >= 3) {
	$need_venv = 1; # python 3.3 or upper
	} else {
	$need_virtualenv = 1;
	}
	if ($1 < 3) {
	# Complain if it finds python2 (or worse)
	printf "Warning: python$1 support is deprecated. Use it with caution!\n";
	}
	} else {
	die "Warning: couldn't identify $python_cmd version!";
	}
	} else {
	add_package("python-sphinx", 0);
	}
	}

	# Set virtualenv command line, if python < 3.3
	my $virtualenv_cmd;
	if ($need_virtualenv) {
	$virtualenv_cmd = findprog("virtualenv-3");
	$virtualenv_cmd = findprog("virtualenv-3.5") if (!$virtualenv_cmd);
	if (!$virtualenv_cmd) {
	check_program("virtualenv", 0);
	$virtualenv_cmd = "virtualenv";
	}
	}

	# Check for needed programs/tools
	check_perl_module("Pod::Usage", 0);
	check_program("make", 0);
	check_program("gcc", 0);
	check_python_module("sphinx_rtd_theme", 1) if (!$virtualenv);
	check_program("dot", 1);
	check_program("convert", 1);

	# Extra PDF files - should use 2 for is_optional
	check_program("xelatex", 2) if ($pdf);
	check_program("rsvg-convert", 2) if ($pdf);
	check_program("latexmk", 2) if ($pdf);

	if ($need_sphinx \|\| $rec_sphinx_upgrade) {
	check_python_module("ensurepip", 0) if ($need_venv);
	}

	# Do distro-specific checks and output distro-install commands
	check_distros();

	if (!$python_cmd) {
	if ($need == 1) {
	die "Can't build as $need mandatory dependency is missing";
	} elsif ($need) {
	die "Can't build as $need mandatory dependencies are missing";
	}
	}

	# Check if sphinx-build is called sphinx-build-3
	if ($need_symlink) {
	printf "\tsudo ln -sf %s /usr/bin/sphinx-build\n\n",
	which("sphinx-build-3");
	}

	# NOTE: if the system has a too old Sphinx version installed,
	# it will recommend installing a newer version using virtualenv

	if ($need_sphinx \|\| $rec_sphinx_upgrade) {
	my $min_activate = "$ENV{'PWD'}/${virtenv_prefix}${min_version}/bin/activate";
	my @activates = glob "$ENV{'PWD'}/${virtenv_prefix}*/bin/activate";

	if ($cur_version lt $rec_version) {
	print "Warning: It is recommended at least Sphinx version $rec_version.\n";
	print " If you want pdf, you need at least $min_pdf_version.\n";
	}
	if ($cur_version lt $min_pdf_version) {
	print "Note: It is recommended at least Sphinx version $min_pdf_version if you need PDF support.\n";
	}
	@activates = sort {$b cmp $a} @activates;
	my ($activate, $ver);
	foreach my $f (@activates) {
	next if ($f lt $min_activate);

	my $sphinx_cmd = $f;
	$sphinx_cmd =~ s/activate/sphinx-build/;
	next if (! -f $sphinx_cmd);

	$ver = get_sphinx_version($sphinx_cmd);
	if ($need_sphinx && ($ver ge $min_version)) {
	$activate = $f;
	last;
	} elsif ($ver gt $cur_version) {
	$activate = $f;
	last;
	}
	}
	if ($activate ne "") {
	if ($need_sphinx) {
	printf "\nNeed to activate Sphinx (version $ver) on virtualenv with:\n";
	printf "\t. $activate\n";
	deactivate_help();
	exit (1);
	} else {
	printf "\nYou may also use a newer Sphinx (version $ver) with:\n";
	printf "\tdeactivate && . $activate\n";
	}
	} else {
	my $rec_activate = "$virtenv_dir/bin/activate";

	print "To upgrade Sphinx, use:\n\n" if ($rec_sphinx_upgrade);

	$python_cmd = find_python_no_venv();

	if ($need_venv) {
	printf "\t$python_cmd -m venv $virtenv_dir\n";
	} else {
	printf "\t$virtualenv_cmd $virtenv_dir\n";
	}
	printf "\t. $rec_activate\n";
	printf "\tpip install -r $requirement_file\n";
	deactivate_help();

	$need++ if (!$rec_sphinx_upgrade);
	}
	}
	printf "\n";

	print "All optional dependencies are met.\n" if (!$optional);

	if ($need == 1) {
	die "Can't build as $need mandatory dependency is missing";
	} elsif ($need) {
	die "Can't build as $need mandatory dependencies are missing";
	}

	print "Needed package dependencies are met.\n";
	}

	#
	# Main
	#

	while (@ARGV) {
	my $arg = shift(@ARGV);

	if ($arg eq "--no-virtualenv") {
	$virtualenv = 0;
	} elsif ($arg eq "--no-pdf"){
	$pdf = 0;
	} elsif ($arg eq "--version-check"){
	$version_check = 1;
	} else {
	print "Usage:\n\t$0 <--no-virtualenv> <--no-pdf> <--version-check>\n\n";
	print "Where:\n";
	print "\t--no-virtualenv\t- Recommend installing Sphinx instead of using a virtualenv\n";
	print "\t--version-check\t- if version is compatible, don't check for missing dependencies\n";
	print "\t--no-pdf\t- don't check for dependencies required to build PDF docs\n\n";
	exit -1;
	}
	}

	#
	# Determine the system type. There's no standard unique way that would
	# work with all distros with a minimal package install. So, several
	# methods are used here.
	#
	# By default, it will use lsb_release function. If not available, it will
	# fail back to reading the known different places where the distro name
	# is stored
	#

	$system_release = qx(lsb_release -d) if which("lsb_release");
	$system_release =~ s/Description:\s*// if ($system_release);
	$system_release = catcheck("/etc/system-release") if !$system_release;
	$system_release = catcheck("/etc/redhat-release") if !$system_release;
	$system_release = catcheck("/etc/lsb-release") if !$system_release;
	$system_release = catcheck("/etc/gentoo-release") if !$system_release;

	# This seems more common than LSB these days
	if (!$system_release) {
	my %os_var;
	if (open IN, "cat /etc/os-release\|") {
	while (<IN>) {
	if (m/^([\w\d\_]+)=\"?([^\"]*)\"?\n/) {
	$os_var{$1}=$2;
	}
	}
	$system_release = $os_var{"NAME"};
	if (defined($os_var{"VERSION_ID"})) {
	$system_release .= " " . $os_var{"VERSION_ID"} if (defined($os_var{"VERSION_ID"}));
	} else {
	$system_release .= " " . $os_var{"VERSION"};
	}
	}
	}
	$system_release = catcheck("/etc/issue") if !$system_release;
	$system_release =~ s/\s+$//;

	check_needs;