#!/usr/bin/perl -w
# This script was originally based on the script of the same name from
# the KDE SDK (by dfaure@kde.org)
#
# This version is
#   Copyright (C) 2007, 2008 Adam D. Barratt
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

=head1 NAME

licensecheck - simple license checker for source files

=head1 SYNOPSIS

B<licensecheck> B<--help|--version>

B<licensecheck> [B<--verbose>] [B<--copyright>] [B<-l|--lines=N>] 
[B<-i|--ignore=regex>] [B<-c|--check=regex>] [B<-r|--recursive>]
I<list of files and directories to check>

=head1 DESCRIPTION

B<licensecheck> attempts to determine the license that applies to each file
passed to it, by searching the start of the file for text belonging to
various licenses.

If any of the arguments passed are directories, B<licensecheck> will add
the files contained within to the list of files to process.

=head1 OPTIONS

=over 4

=item B<--verbose> B<--no-verbose>

Specify whether to output the text being processed from each file before
the corresponding license information.

Default is to be quiet.

=item B<-l=N> B<--lines=N>

Specify the number of lines of each file's header which should be parsed 
for license information. (Default is 60).

=item B<-i=regex> B<--ignore=regex>

When processing the list of files and directories, the regular 
expression specified by this option will be used to indicate those which 
should not be considered (e.g. backup files, VCS metadata). 

=item B<-r> B<--recursive>

Specify that the contents of directories should be added 
recursively.

=item B<-c=regex> B<--check=regex>

Specify a pattern against which filenames will be matched in order to 
decide which files to check the license of.

The default includes common source files.

=item B<--copyright>

Also display copyright text found within the file

=back

=head1 CONFIGURATION VARIABLES

The two configuration files F</etc/devscripts.conf> and
F<~/.devscripts> are sourced by a shell in that order to set
configuration variables.  Command line options can be used to override
configuration file settings.  Environment variable settings are
ignored for this purpose.  The currently recognised variables are:

=over 4

=item B<LICENSECHECK_VERBOSE>

If this is set to I<yes>, then it is the same as the --verbose command
line parameter being used. The default is I<no>.

=item B<LICENSECHECK_PARSELINES>

If this is set to a positive number then the specified number of lines
at the start of each file will be read whilst attempting to determine
the license(s) in use.  This is equivalent to the --lines command line
option.

=back

=head1 LICENSE

This code is copyright by Adam D. Barratt <adam@adam-barratt.org.uk>, 
all rights reserved; based on a script of the same name from the KDE 
SDK, which is copyright by <dfaure@kde.org>.
This program comes with ABSOLUTELY NO WARRANTY.
You are free to redistribute this code under the terms of the GNU 
General Public License, version 2 or later.

=head1 AUTHOR

Adam D. Barratt <adam@adam-barratt.org.uk>

=cut

use strict;
use warnings;
use Getopt::Long;
use File::Basename;

sub fatal($);
sub parse_copyright($);
sub parselicense($);

my $progname = basename($0);

# From dpkg-source
my $default_ignore_regex = '
# Ignore general backup files
(?:^|/).*~$|
# Ignore emacs recovery files
(?:^|/)\.#.*$|
# Ignore vi swap files
(?:^|/)\..*\.swp$|
# Ignore baz-style junk files or directories
(?:^|/),,.*(?:$|/.*$)|
# File-names that should be ignored (never directories)
(?:^|/)(?:DEADJOE|\.cvsignore|\.arch-inventory|\.bzrignore|\.gitignore)$|
# File or directory names that should be ignored
(?:^|/)(?:CVS|RCS|\.deps|\{arch\}|\.arch-ids|\.svn|\.hg|_darcs|\.git|
\.shelf|_MTN|\.bzr(?:\.backup|tags)?)(?:$|/.*$)
';

# Take out comments and newlines
$default_ignore_regex =~ s/^#.*$//mg;
$default_ignore_regex =~ s/\n//sg;

my $default_check_regex = '\.(c(c|pp|xx)?|h(h|pp|xx)?|p(l|m)|sh|php|py|rb|java|el)$';

my $modified_conf_msg;

my ($opt_verbose, $opt_lines, $opt_noconf, $opt_ignore_regex, $opt_check_regex);
my $opt_recursive = 0;
my $opt_copyright = 0;
my ($opt_help, $opt_version);
my $def_lines = 60;

# Read configuration files and then command line
# This is boilerplate

if (@ARGV and $ARGV[0] =~ /^--no-?conf$/) {
    $modified_conf_msg = "  (no configuration files read)";
    shift;
} else {
    my @config_files = ('/etc/devscripts.conf', '~/.devscripts');
    my %config_vars = (
		       'LICENSECHECK_VERBOSE' => 'no',
		       'LICENSECHECK_PARSELINES' => $def_lines,
		      );
    my %config_default = %config_vars;

    my $shell_cmd;
    # Set defaults
    foreach my $var (keys %config_vars) {
	$shell_cmd .= qq[$var="$config_vars{$var}";\n];
    }
    $shell_cmd .= 'for file in ' . join(" ", @config_files) . "; do\n";
    $shell_cmd .= '[ -f $file ] && . $file; done;' . "\n";
    # Read back values
    foreach my $var (keys %config_vars) { $shell_cmd .= "echo \$$var;\n" }
    my $shell_out = `/bin/bash -c '$shell_cmd'`;
    @config_vars{keys %config_vars} = split /\n/, $shell_out, -1;

    # Check validity
    $config_vars{'LICENSECHECK_VERBOSE'} =~ /^(yes|no)$/
	or $config_vars{'LICENSECHECK_VERBOSE'} = 'no';
    $config_vars{'LICENSECHECK_PARSELINES'} =~ /^[1-9][0-9]*$/
	or $config_vars{'LICENSECHECK_PARSELINES'} = $def_lines;

    foreach my $var (sort keys %config_vars) {
	if ($config_vars{$var} ne $config_default{$var}) {
	    $modified_conf_msg .= "  $var=$config_vars{$var}\n";
	}
    }
    $modified_conf_msg ||= "  (none)\n";
    chomp $modified_conf_msg;

    $opt_verbose = $config_vars{'LICENSECHECK_VERBOSE'} eq 'yes' ? 1 : 0;
    $opt_lines = $config_vars{'LICENSECHECK_PARSELINES'};
}

GetOptions("help|h" => \$opt_help,
	   "version|v" => \$opt_version,
	   "verbose!" => \$opt_verbose,
	   "lines|l=i" => \$opt_lines,
	   "ignore|i=s" => \$opt_ignore_regex,
	   "recursive|r" => \$opt_recursive,
	   "check|c=s" => \$opt_check_regex,
	   "copyright" => \$opt_copyright,
	   "noconf" => \$opt_noconf,
	   "no-conf" => \$opt_noconf,
	   )
    or die "Usage: $progname [options] filelist\nRun $progname --help for more details\n";

$opt_lines =~ /^[1-9][0-9]*$/ or $opt_lines = $def_lines;
$opt_ignore_regex = $default_ignore_regex if !$opt_ignore_regex;
$opt_check_regex = $default_check_regex if !$opt_check_regex;

if ($opt_noconf) {
    fatal "--no-conf is only acceptable as the first command-line option!";
}
if ($opt_help) { help(); exit 0; }
if ($opt_version) { version(); exit 0; }

die "Usage: $progname [options] filelist\nRun $progname --help for more details\n" unless @ARGV;

$opt_lines = $def_lines if not defined $opt_lines;

my @files = ();
my @find_args = ();
my $files_count = @ARGV;

push @find_args, qw(-maxdepth 1) unless $opt_recursive;
push @find_args, qw(-follow -type f -print);

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

    if (-d $file) {
	open FIND, '-|', 'find', $file, @find_args
	    or die "$progname: couldn't exec find: $!\n";

	while (<FIND>) {
	    chomp;
	    next unless m%$opt_check_regex%;
	    push @files, $_ unless m%$opt_ignore_regex%;
	}
	close FIND;
    } else {
	next unless ($files_count == 1) or $file =~ m%$opt_check_regex%;
	push @files, $file unless $file =~ m%$opt_ignore_regex%;
    }
}

while (@files) {
    my $file = shift @files;
    my $content = '';
    my $copyright_match;
    my $copyright = '';
    my $license = '';
    my %copyrights;

    open (F, "<$file") or die "Unable to access $file\n";
    while (<F>) {
        last if ($. > $opt_lines);
        $content .= $_;
	$copyright_match = parse_copyright($_);
	if ($copyright_match) {
	    $copyrights{lc("$copyright_match")} = "$copyright_match";
	}
    }
    close(F);

    $copyright = join(" / ", values %copyrights);

    print qq(----- $file header -----\n$content----- end header -----\n\n)
	if $opt_verbose;

    $content =~ tr/\t\r\n/ /;
    $content =~ tr% A-Za-z.,@;0-9\(\)/-%%cd;
    $content =~ s#//##g;
    $content =~ tr/ //s;

    $license = parselicense($content);
    print "$file: ";
    print "*No copyright* " unless $copyright;
    print $license . "\n";
    print "  [Copyright: " . $copyright . "]\n"
      if $copyright and $opt_copyright;
    print "\n" if $opt_copyright;
}

sub parse_copyright($) {
    my $copyright = '';
    my $match;

    my $copyright_indicator_regex = '
	(?:copyright	# The full word
	|copr\.		# Legally-valid abbreviation
	|\x{00a9}	# Unicode character COPYRIGHT SIGN
	|\xc2\xa9	# Unicode copyright sign encoded in iso8859
	|\(c\)		# Legally-null representation of sign
	)';
    my $copyright_disindicator_regex = '
	\b(?:info(?:rmation)?	# Discussing copyright information
	|notice			# Discussing the notice
	|and|or                 # Part of a sentence
	)\b';

    if (m%$copyright_indicator_regex(?::\s*|\s+)(\S.*)$%ix) {
	$match = $1;

	# Ignore lines matching "see foo for copyright information" etc.
	if ($match !~ m%^\s*$copyright_disindicator_regex%ix) {
	    # De-cruft
	    $match =~ s/([,.])?\s*$//;
	    $match =~ s/$copyright_indicator_regex//igx;
	    $match =~ s/^\s+//;
	    $match =~ s/\s{2,}/ /g;
	    $match =~ s/\\@/@/g;
	    $copyright = $match;
	}
    }

    return $copyright;
}

sub help {
   print <<"EOF";
Usage: $progname [options] filename [filename ...]
Valid options are:
   --help, -h             Display this message
   --version, -v          Display version and copyright info
   --verbose              Display the header of each file before its
                            license information
   --lines, -l            Specify how many lines of the file header
                            should be parsed for license information
                            (Default: $def_lines)
   --check, -c            Specify a pattern indicating which files should
                             be checked
                             (Default: '$default_check_regex')
   --recursive, -r        Add the contents of directories recursively
   --copyright            Also display the file's copyright
   --ignore, -i		  Specify that files / directories matching the
                            regular expression should be ignored when
                            checking files
                            (Default: '$default_ignore_regex')

Default settings modified by devscripts configuration files:
$modified_conf_msg
EOF
}

sub version {
    print <<"EOF";
This is $progname, from the Debian devscripts package, version 2.10.35lenny7
Copyright (C) 2007, 2008 by Adam D. Barratt <adam\@adam-barratt.org.uk>; based
on a script of the same name from the KDE SDK by <dfaure\@kde.org>.

This program comes with ABSOLUTELY NO WARRANTY.
You are free to redistribute this code under the terms of the
GNU General Public License, version 2, or (at your option) any 
later version.
EOF
}

sub parselicense($) {
    my ($licensetext) = @_;

    my $gplver = "";
    my $extrainfo = "";
    my $license = "";

    if ($licensetext =~ /version ([^ ]+) (?:\(?only\)?.? )?(?:of the GNU General Public License )?as published by the Free Software Foundation/i or
	$licensetext =~ /GNU General Public License as published by the Free Software Foundation; version ([^ ]+) /i) {

	$gplver = " (v$1)";
    } elsif ($licensetext =~ /either version ([^ ]+) of the License, or \(at your option\) any later version/) {
	$gplver = " (v$1 or later)";
    }

    if ($licensetext =~ /(?:675 Mass Ave|59 Temple Place|51 Franklin Steet|02139|02111-1307)/i) {
	$extrainfo = " (with incorrect FSF address)$extrainfo";
    }

    if ($licensetext =~ /permission (?:is (also granted|given))? to link (the code of )?this program with (any edition of )?(Qt|the Qt library)/i) {
	$extrainfo = " (with Qt exception)$extrainfo"
    }

    if ($licensetext =~ /(All changes made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in this file will be lost|DO NOT (EDIT|delete this file)|Gs made in 