#!/usr/bin/perl -w
#
# Library functions for debhelper programs, perl version.
#
# Joey Hess, GPL copyright 1997-2000.

package Debian::Debhelper::Dh_Lib;
use strict;

use Exporter;
use vars qw(@ISA @EXPORT %dh);
@ISA=qw(Exporter);
@EXPORT=qw(&init &doit &complex_doit &verbose_print &error &warning &tmpdir
	    &pkgfile &pkgext &isnative &autoscript &filearray &GetPackages
	    &basename &xargs %dh &compat);

my $max_compat=3;

sub init {
	# If DH_OPTIONS is set, prepend it @ARGV.
	if (defined($ENV{DH_OPTIONS})) {
		unshift @ARGV,split(/\s+/,$ENV{DH_OPTIONS});
	}

	# Check to see if an argument on the command line starts with a dash.
	# if so, we need to pass this off to the resource intensive 
	# Getopt::Long, which I'd prefer to avoid loading at all if possible.
	my $parseopt=undef;
	my $arg;
	foreach $arg (@ARGV) {
		if ($arg=~m/^-/) {
			$parseopt=1;
			last;
		}       
	}
	if ($parseopt) {
		eval "use Debian::Debhelper::Dh_Getopt";
		error($!) if $@;
		%dh=Debian::Debhelper::Dh_Getopt::parseopts();
	}

	# Check to see if DH_VERBOSE environment variable was set, if so,
	# make sure verbose is on.
	if (defined $ENV{DH_VERBOSE} && $ENV{DH_VERBOSE} ne "") {
		$dh{VERBOSE}=1;
	}

	# Check to see if DH_NO_ACT environment variable was set, if so, 
	# make sure no act mode is on.
	if (defined $ENV{DH_NO_ACT} && $ENV{DH_NO_ACT} ne "") {
		$dh{NO_ACT}=1;
	}

	# Get the name of the main binary package (first one listed in
	# debian/control).
	my @allpackages=GetPackages();
	$dh{MAINPACKAGE}=$allpackages[0];

	# Check if packages to build have been specified, if not, fall back to
	# the default, doing them all.
	if (! defined $dh{DOPACKAGES} || ! @{$dh{DOPACKAGES}}) {
		if ($dh{DOINDEP} || $dh{DOARCH} || $dh{DOSAME}) {
			error("You asked that all arch in(dep) packages be built, but there are none of that type.");
		}
		push @{$dh{DOPACKAGES}},@allpackages;
	}

	# Check to see if -P was specified. If so, we can only act on a single
	# package.
	if ($dh{TMPDIR} && $#{$dh{DOPACKAGES}} > 0) {
		error("-P was specified, but multiple packages would be acted on (".join(",",@{$dh{DOPACKAGES}}).").");
	}

	# Figure out which package is the first one we were instructed to build.
	# This package gets special treatement: files and directories specified on
	# the command line may affect it.
	$dh{FIRSTPACKAGE}=${$dh{DOPACKAGES}}[0];
}

# Pass it an array containing the arguments of a shell command like would
# be run by exec(). It turns that into a line like you might enter at the
# shell, escaping metacharacters and quoting qrguments that contain spaces.
sub escape_shell {
	my @args=@_;
	my $line="";
	my @ret;
	foreach my $word (@args) {
		if ($word=~/\s/) {
			# Escape only a few things since it will be quoted.
			# Note we use double quotes because you cannot
			# escape ' in qingle quotes, while " can be escaped
			# in double.
			# This does make -V"foo bar" turn into "-Vfoo bar",
			# but that will be parsed identically by the shell
			# anyway..
			$word=~s/([\n`\$"\\])/\$1/g;
			push @ret, "\"$word\"";
		}
		else {
			# This list is from _Unix in a Nutshell_. (except '#')
			$word=~s/([\s!"\$()*+#;<>?@\[\]\\`|~])/\\$1/g;
			push @ret,$word;
		}
	}
	return join(' ', @ret);
}

# Run a command, and display the command to stdout if verbose mode is on.
# All commands that modifiy files in $TMP should be ran via this 
# function.
#
# Note that this cannot handle complex commands, especially anything
# involving redirection. Use complex_doit instead.
sub doit {
	verbose_print(escape_shell(@_));

	if (! $dh{NO_ACT}) {
		system(@_) == 0 || error("command returned error code");
	}
}

# Run a command and display the command to stdout if verbose mode is on.
# Use doit() if you can, instead of this function, because this function
# forks a shell. However, this function can handle more complicated stuff
# like redirection.
sub complex_doit {
	verbose_print(join(" ",@_));
	
	if (! $dh{NO_ACT}) {
		# The join makes system get a scalar so it forks off a shell.
		system(join(" ",@_)) == 0
			|| error("command returned error code");
	}			
}

# Run a command that may have a huge number of arguments, like xargs does.
# Pass in a reference to an array containing the arguments, and then other
# parameters that are the command and any parameters that should be passed to
# it each time.
sub xargs {
	my $args=shift;

        # The kernel can accept command lines up to 20k worth of characters.
	my $command_max=20000; # LINUX SPECIFIC!!
			# I could use POSIX::ARG_MAX, but that would be slow.

	# Figure out length of static portion of command.
	my $static_length=0;
	foreach (@_) {
		$static_length+=length($_)+1;
	}
	
	my @collect=();
	my $length=$static_length;
	foreach (@$args) {
		if (length($_) + 1 + $static_length > $command_max) {
			error("This command is greater than the maximum command size allowed by the kernel, and cannot be split up further. What on earth are you doing? \"@_ $_\"");
		}
		$length+=length($_) + 1;
		if ($length < $command_max) {
			push @collect, $_;
		}
		else {
			doit(@_,@collect) if $#collect > -1;
			@collect=($_);
			$length=$static_length + length($_) + 1;
		}
	}
	doit(@_,@collect) if $#collect > -1;
}

# Print something if the verbose flag is on.
sub verbose_print {
	my $message=shift;
	
	if ($dh{VERBOSE}) {
		print "\t$message\n";
	}
}

# Output an error message and exit.
sub error {
	my $message=shift;

	warning($message);
	exit 1;
}

# Output a warning.
sub warning {
	my $message=shift;
	
	print STDERR basename($0).": $message\n";
}

# Returns the basename of the argument passed to it.
sub basename {
	my $fn=shift;
	
	$fn=~s:^.*/(.*?)$:$1:;
	return $fn;
}

# Returns the directory name of the argument passed to it.
sub dirname {
	my $fn=shift;
	
	$fn=~s:^(.*)/.*?$:$1:;
	return $fn;
}

# Pass in a number, will return true iff the current compatability level
# is less than or equal to that number.
sub compat {
	my $num=shift;
	
	my $c=1;
	if (defined $ENV{DH_COMPAT}) {
		$c=$ENV{DH_COMPAT};
	}

	if ($c > $max_compat) {
		error("Sorry, but $max_compat is the highest compatability level of debhelper currently supported.");
	}

	return ($c <= $num);
}

# Pass it a name of a binary package, it returns the name of the tmp dir to
# use, for that package.
sub tmpdir {
	my $package=shift;

	if ($dh{TMPDIR}) {
		return $dh{TMPDIR};
	}
	elsif (compat(1) && $package eq $dh{MAINPACKAGE}) {
		# This is for back-compatability with the debian/tmp tradition.
		return "debian/tmp";
	}
	else {
		return "debian/$package";
	}
}

# Pass this the name of a binary package, and the name of the file wanted
# for the package, and it will return the actual existing filename to use.
#
# It tries several filenames:
#   * debian/package.filename.buildarch
#   * debian/package.filename
#   * debian/file (if the package is the main package)
sub pkgfile {
	my $package=shift;
	my $filename=shift;

	if (-f "debian/$package.$filename.".buildarch()) {
		return "debian/$package.$filename.".buildarch();
	}
	elsif (-f "debian/$package.$filename") {
		return "debian/$package.$filename";
	}
	elsif ($package eq $dh{MAINPACKAGE} && -f "debian/$filename") {
		return "debian/$filename";
	}
	else {
		return "";
	}
}

# Pass it a name of a binary package, it returns the name to prefix to files
# in debian for this package.
sub pkgext {
	my $package=shift;

	if (compat(1) and $package eq $dh{MAINPACKAGE}) {
		return "";
	}
	return "$package.";
}

# Returns 1 if the package is a native debian package, null otherwise.
# As a side effect, sets $dh{VERSION} to the version of this package.
{
	# Caches return code so it only needs to run dpkg-parsechangelog once.
	my %isnative_cache;
	
	sub isnative {
		my $package=shift;

		return $isnative_cache{$package} if defined $isnative_cache{$package};
		
		# Make sure we look at the correct changelog.
		my $isnative_changelog=pkgfile($package,"changelog");
		if (! $isnative_changelog) {
			$isnative_changelog="debian/changelog";
		}
		# Get the package version.
		my $version=`dpkg-parsechangelog -l$isnative_changelog`;
		($dh{VERSION})=$version=~m/Version:\s*(.*)/m;
		# Did the changelog parse fail?
		if (! defined $dh{VERSION}) {
			error("changelog parse failure");
		}

		# Is this a native Debian package?
		if ($dh{VERSION}=~m/.*-/) {
			return $isnative_cache{$package}=0;
		}
		else {
			return $isnative_cache{$package}=1;
		}
	}
}

# Automatically add a shell script snippet to a debian script.
# Only works if the script has #DEBHELPER# in it.
#
# Parameters:
# 1: package
# 2: script to add to
# 3: filename of snippet
# 4: sed to run on the snippet. Ie, s/#PACKAGE#/$PACKAGE/
sub autoscript {
	my $package=shift;
	my $script=shift;
	my $filename=shift;
	my $sed=shift || "";

	# This is the file we will append to.
	my $outfile="debian/".pkgext($package)."$script.debhelper";

	# Figure out what shell script snippet to use.
	my $infile;
	if (defined($ENV{DH_AUTOSCRIPTDIR}) && 
	    -e "$ENV{DH_AUTOSCRIPTDIR}/$filename") {
		$infile="$ENV{DH_AUTOSCRIPTDIR}/$filename";
	}
	else {
		if (-e "/usr/share/debhelper/autoscripts/$filename") {
			$infile="/usr/share/debhelper/autoscripts/$filename";
		}
		else {
			error("/usr/share/debhelper/autoscripts/$filename does not exist");
		}
	}

	complex_doit("echo \"# Automatically added by ".basename($0)."\">> $outfile");
	complex_doit("sed \"$sed\" $infile >> $outfile");
	complex_doit("echo '# End automatically added section' >> $outfile");
}

# Reads in the specified file, one word at a time, and returns an array of
# the result. If a value is passed in as the second parameter, then glob
# expansion is done in the directory specified by the parameter ("." is
# frequently a good choice).
sub filearray {
	my $file=shift;
	my $globdir=shift;

	my @ret;
	open (DH_FARRAY_IN, $file) || error("cannot read $file: $1");
	while (<DH_FARRAY_IN>) {
		# Only do glob expansion in v3 mode.
		#
		# The tricky bit is that the glob expansion is done
		# as if we were in the specified directory, so the
		# filenames that come out are relative to it.
		if (defined $globdir && ! compat(2)) {
			for (map { glob "$globdir/$_" } split) {
				s#^$globdir/##;
				push @ret, $_;
			}
		}
		else {
			push @ret, split;
		}
	}
	close DH_FARRAY_IN;
	
	return @ret;
}

# Returns the build architecture. (Memoized)
{
	my $arch;
	
	sub buildarch {
  		return $arch if defined $arch;

		$arch=`dpkg --print-architecture` || error($!);
		chomp $arch;
		return $arch;
	}
}

# Returns a list of packages in the control file.
# Must pass "arch" or "indep" or "same" to specify arch-dependant or
# -independant or same arch packages. If nothing is specified, returns all
# packages.
sub GetPackages {
	my $type=shift;
	
	$type="" if ! defined $type;
	
	# Look up the build arch if we need to.
	my $buildarch='';
	if ($type eq 'same') {
		$buildarch=buildarch();
	}

	my $package="";
	my $arch="";
	my @list=();
	open (CONTROL, 'debian/control') ||
		error("cannot read debian/control: $!\n");
	while (<CONTROL>) {
		chomp;
		s/\s+$//;
		if (/^Package:\s*(.*)/) {
			$package=$1;
		}
		if (/^Architecture:\s*(.*)/) {
			$arch=$1;
		}
		if (!$_ or eof) { # end of stanza.
			if ($package &&
			    (($type eq 'indep' && $arch eq 'all') ||
			     ($type eq 'arch' && $arch ne 'all') ||
			     ($type eq 'same' && ($arch eq 'any' || $arch =~ /\b$buildarch\b/)) ||
			     ! $type)) {
				push @list, $package;
				$package="";
				$arch="";
			}
		}
	}
	close CONTROL;

	return @list;
}

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