#!/usr/bin/perl
#
# Copyright 2002,2005 Greg Kroah-Hartman <greg@kroah.com>
# Copyright 2005 Ryan Anderson <ryan@michonline.com>
#
# GPL v2 (See COPYING)
#
# Ported to support git "mbox" format files by Ryan Anderson <ryan@michonline.com>
#
# Sends a collection of emails to the given email addresses, disturbingly fast.
#
# Supports two formats:
# 1. mbox format files (ignoring most headers and MIME formatting - this is designed for sending patches)
# 2. The original format support by Greg's script:
#    first line of the message is who to CC,
#    and second line is the subject of the message.
#

use 5.008;
use strict;
use warnings;
use Term::ReadLine;
use Getopt::Long;
use Text::ParseWords;
use Data::Dumper;
use Term::ANSIColor;
use File::Temp qw/ tempdir tempfile /;
use File::Spec::Functions qw(catfile);
use Error qw(:try);
use Git;

Getopt::Long::Configure qw/ pass_through /;

package FakeTerm;
sub new {
        my ($class, $reason) = @_;
        return bless \$reason, shift;
}
sub readline {
        my $self = shift;
        die "Cannot use readline on FakeTerm: $$self";
}
package main;


sub usage {
        print <<EOT;
git send-email [options] <file | directory | rev-list options >

  Composing:
    --from                  <str>  * Email From:
    --[no-]to               <str>  * Email To:
    --[no-]cc               <str>  * Email Cc:
    --[no-]bcc              <str>  * Email Bcc:
    --subject               <str>  * Email "Subject:"
    --in-reply-to           <str>  * Email "In-Reply-To:"
    --[no-]annotate                * Review each patch that will be sent in an editor.
    --compose                      * Open an editor for introduction.
    --compose-encoding      <str>  * Encoding to assume for introduction.
    --8bit-encoding         <str>  * Encoding to assume 8bit mails if undeclared

  Sending:
    --envelope-sender       <str>  * Email envelope sender.
    --smtp-server       <str:int>  * Outgoing SMTP server to use. The port
                                     is optional. Default 'localhost'.
    --smtp-server-option    <str>  * Outgoing SMTP server option to use.
    --smtp-server-port      <int>  * Outgoing SMTP server port.
    --smtp-user             <str>  * Username for SMTP-AUTH.
    --smtp-pass             <str>  * Password for SMTP-AUTH; not necessary.
    --smtp-encryption       <str>  * tls or ssl; anything else disables.
    --smtp-ssl                     * Deprecated. Use '--smtp-encryption ssl'.
    --smtp-domain           <str>  * The domain name sent to HELO/EHLO handshake
    --smtp-debug            <0|1>  * Disable, enable Net::SMTP debug.

  Automating:
    --identity              <str>  * Use the sendemail.<id> options.
    --to-cmd                <str>  * Email To: via `<str> \$patch_path`
    --cc-cmd                <str>  * Email Cc: via `<str> \$patch_path`
    --suppress-cc           <str>  * author, self, sob, cc, cccmd, body, bodycc, all.
    --[no-]signed-off-by-cc        * Send to Signed-off-by: addresses. Default on.
    --[no-]suppress-from           * Send to self. Default off.
    --[no-]chain-reply-to          * Chain In-Reply-To: fields. Default off.
    --[no-]thread                  * Use In-Reply-To: field. Default on.

  Administering:
    --confirm               <str>  * Confirm recipients before sending;
                                     auto, cc, compose, always, or never.
    --quiet                        * Output one line of info per email.
    --dry-run                      * Don't actually send the emails.
    --[no-]validate                * Perform patch sanity checks. Default on.
    --[no-]format-patch            * understand any non optional arguments as
                                     `git format-patch` ones.
    --force                        * Send even if safety checks would prevent it.

EOT
        exit(1);
}

# most mail servers generate the Date: header, but not all...
sub format_2822_time {
        my ($time) = @_;
        my @localtm = localtime($time);
        my @gmttm = gmtime($time);
        my $localmin = $localtm[1] + $localtm[2] * 60;
        my $gmtmin = $gmttm[1] + $gmttm[2] * 60;
        if ($localtm[0] != $gmttm[0]) {
                die "local zone differs from GMT by a non-minute interval\n";
        }
        if ((($gmttm[6] + 1) % 7) == $localtm[6]) {
                $localmin += 1440;
        } elsif ((($gmttm[6] - 1) % 7) == $localtm[6]) {
                $localmin -= 1440;
        } elsif ($gmttm[6] != $localtm[6]) {
                die "local time offset greater than or equal to 24 hours\n";
        }
        my $offset = $localmin - $gmtmin;
        my $offhour = $offset / 60;
        my $offmin = abs($offset % 60);
        if (abs($offhour) >= 24) {
                die ("local time offset greater than or equal to 24 hours\n");
        }

        return sprintf("%s, %2d %s %d %02d:%02d:%02d %s%02d%02d",
                       qw(Sun Mon Tue Wed Thu Fri Sat)[$localtm[6]],
                       $localtm[3],
                       qw(Jan Feb Mar Apr May Jun
                          Jul Aug Sep Oct Nov Dec)[$localtm[4]],
                       $localtm[5]+1900,
                       $localtm[2],
                       $localtm[1],
                       $localtm[0],
                       ($offset >= 0) ? '+' : '-',
                       abs($offhour),
                       $offmin,
                       );
}

my $have_email_valid = eval { require Email::Valid; 1 };
my $have_mail_address = eval { require Mail::Address; 1 };
my $smtp;
my $auth;

# Variables we fill in automatically, or via prompting:
my (@to,$no_to,@initial_to,@cc,$no_cc,@initial_cc,@bcclist,$no_bcc,@xh,
        $initial_reply_to,$initial_subject,@files,
        $author,$sender,$smtp_authpass,$annotate,$compose,$time);

my $envelope_sender;

# Example reply to:
#$initial_reply_to = ''; #<20050203173208.GA23964@foobar.com>';

my $repo = eval { Git->repository() };
my @repo = $repo ? ($repo) : ();
my $term = eval {
        $ENV{"GIT_SEND_EMAIL_NOTTY"}
                ? new Term::ReadLine 'git-send-email', \*STDIN, \*STDOUT
                : new Term::ReadLine 'git-send-email';
};
if ($@) {
        $term = new FakeTerm "$@: going non-interactive";
}

# Behavior modification variables
my ($quiet, $dry_run) = (0, 0);
my $format_patch;
my $compose_filename;
my $force = 0;

# Handle interactive edition of files.
my $multiedit;
my $editor;

sub do_edit {
        if (!defined($editor)) {
                $editor = Git::command_oneline('var', 'GIT_EDITOR');
        }
        if (defined($multiedit) && !$multiedit) {
                map {
                        system('sh', '-c', $editor.' "$@"', $editor, $_);
                        if (($? & 127) || ($? >> 8)) {
                                die("the editor exited uncleanly, aborting everything");
                        }
                } @_;
        } else {
                system('sh', '-c', $editor.' "$@"', $editor, @_);
                if (($? & 127) || ($? >> 8)) {
                        die("the editor exited uncleanly, aborting everything");
                }
        }
}

# Variables with corresponding config settings
my ($thread, $chain_reply_to, $suppress_from, $signed_off_by_cc);
my ($to_cmd, $cc_cmd);
my ($smtp_server, $smtp_server_port, @smtp_server_options);
my ($smtp_authuser, $smtp_encryption);
my ($identity, $aliasfiletype, @alias_files, $smtp_domain);
my ($validate, $confirm);
my (@suppress_cc);
my ($auto_8bit_encoding);
my ($compose_encoding);

my ($debug_net_smtp) = 0;               # Net::SMTP, see send_message()

my %config_bool_settings = (
    "thread" => [\$thread, 1],
    "chainreplyto" => [\$chain_reply_to, 0],
    "suppressfrom" => [\$suppress_from, undef],
    "signedoffbycc" => [\$signed_off_by_cc, undef],
    "signedoffcc" => [\$signed_off_by_cc, undef],      # Deprecated
    "validate" => [\$validate, 1],
    "multiedit" => [\$multiedit, undef],
    "annotate" => [\$annotate, undef]
);

my %config_settings = (
    "smtpserver" => \$smtp_server,
    "smtpserverport" => \$smtp_server_port,
    "smtpserveroption" => \@smtp_server_options,
    "smtpuser" => \$smtp_authuser,
    "smtppass" => \$smtp_authpass,
    "smtpdomain" => \$smtp_domain,
    "to" => \@initial_to,
    "tocmd" => \$to_cmd,
    "cc" => \@initial_cc,
    "cccmd" => \$cc_cmd,
    "aliasfiletype" => \$aliasfiletype,
    "bcc" => \@bcclist,
    "suppresscc" => \@suppress_cc,
    "envelopesender" => \$envelope_sender,
    "confirm"   => \$confirm,
    "from" => \$sender,
    "assume8bitencoding" => \$auto_8bit_encoding,
    "composeencoding" => \$compose_encoding,
);

my %config_path_settings = (
    "aliasesfile" => \@alias_files,
);

# Handle Uncouth Termination
sub signal_handler {

        # Make text normal
        print color("reset"), "\n";

        # SMTP password masked
        system "stty echo";

        # tmp files from --compose
        if (defined $compose_filename) {
                if (-e $compose_filename) {
                        print "'$compose_filename' contains an intermediate version of the email you were composing.\n";
                }
                if (-e ($compose_filename . ".final")) {
                        print "'$compose_filename.final' contains the composed email.\n"
                }
        }

        exit;
};

$SIG{TERM} = \&signal_handler;
$SIG{INT}  = \&signal_handler;

# Begin by accumulating all the variables (defined above), that we will end up
# needing, first, from the command line:

my $help;
my $rc = GetOptions("h" => \$help,
                    "sender|from=s" => \$sender,
                    "in-reply-to=s" => \$initial_reply_to,
                    "subject=s" => \$initial_subject,
                    "to=s" => \@initial_to,
                    "to-cmd=s" => \$to_cmd,
                    "no-to" => \$no_to,
                    "cc=s" => \@initial_cc,
                    "no-cc" => \$no_cc,
                    "bcc=s" => \@bcclist,
                    "no-bcc" => \$no_bcc,
                    "chain-reply-to!" => \$chain_reply_to,
                    "smtp-server=s" => \$smtp_server,
                    "smtp-server-option=s" => \@smtp_server_options,
                    "smtp-server-port=s" => \$smtp_server_port,
                    "smtp-user=s" => \$smtp_authuser,
                    "smtp-pass:s" => \$smtp_authpass,
                    "smtp-ssl" => sub { $smtp_encryption = 'ssl' },
                    "smtp-encryption=s" => \$smtp_encryption,
                    "smtp-debug:i" => \$debug_net_smtp,
                    "smtp-domain:s" => \$smtp_domain,
                    "identity=s" => \$identity,
                    "annotate!" => \$annotate,
                    "compose" => \$compose,
                    "quiet" => \$quiet,
                    "cc-cmd=s" => \$cc_cmd,
                    "suppress-from!" => \$suppress_from,
                    "suppress-cc=s" => \@suppress_cc,
                    "signed-off-cc|signed-off-by-cc!" => \$signed_off_by_cc,
                    "confirm=s" => \$confirm,
                    "dry-run" => \$dry_run,
                    "envelope-sender=s" => \$envelope_sender,
                    "thread!" => \$thread,
                    "validate!" => \$validate,
                    "format-patch!" => \$format_patch,
                    "8bit-encoding=s" => \$auto_8bit_encoding,
                    "compose-encoding=s" => \$compose_encoding,
                    "force" => \$force,
         );

usage() if $help;
unless ($rc) {
    usage();
}

die "Cannot run git format-patch from outside a repository\n"
        if $format_patch and not $repo;

# Now, let's fill any that aren't set in with defaults:

sub read_config {
        my ($prefix) = @_;

        foreach my $setting (keys %config_bool_settings) {
                my $target = $config_bool_settings{$setting}->[0];
                $$target = Git::config_bool(@repo, "$prefix.$setting") unless (defined $$target);
        }

        foreach my $setting (keys %config_path_settings) {
                my $target = $config_path_settings{$setting};
                if (ref($target) eq "ARRAY") {
                        unless (@$target) {
                                my @values = Git::config_path(@repo, "$prefix.$setting");
                                @$target = @values if (@values && defined $values[0]);
                        }
                }
                else {
                        $$target = Git::config_path(@repo, "$prefix.$setting") unless (defined $$target);
                }
        }

        foreach my $setting (keys %config_settings) {
                my $target = $config_settings{$setting};
                next if $setting eq "to" and defined $no_to;
                next if $setting eq "cc" and defined $no_cc;
                next if $setting eq "bcc" and defined $no_bcc;
                if (ref($target) eq "ARRAY") {
                        unless (@$target) {
                                my @values = Git::config(@repo, "$prefix.$setting");
                                @$target = @values if (@values && defined $values[0]);
                        }
                }
                else {
                        $$target = Git::config(@repo, "$prefix.$setting") unless (defined $$target);
                }
        }

        if (!defined $smtp_encryption) {
                my $enc = Git::config(@repo, "$prefix.smtpencryption");
                if (defined $enc) {
                        $smtp_encryption = $enc;
                } elsif (Git::config_bool(@repo, "$prefix.smtpssl")) {
                        $smtp_encryption = 'ssl';
                }
        }
}

# read configuration from [sendemail "$identity"], fall back on [sendemail]
$identity = Git::config(@repo, "sendemail.identity") unless (defined $identity);
read_config("sendemail.$identity") if (defined $identity);
read_config("sendemail");

# fall back on builtin bool defaults
foreach my $setting (values %config_bool_settings) {
        ${$setting->[0]} = $setting->[1] unless (defined (${$setting->[0]}));
}

# 'default' encryption is none -- this only prevents a warning
$smtp_encryption = '' unless (defined $smtp_encryption);

# Set CC suppressions
my(%suppress_cc);
if (@suppress_cc) {
        foreach my $entry (@suppress_cc) {
                die "Unknown --suppress-cc field: '$entry'\n"
                        unless $entry =~ /^(?:all|cccmd|cc|author|self|sob|body|bodycc)$/;
                $suppress_cc{$entry} = 1;
        }
}

if ($suppress_cc{'all'}) {
        foreach my $entry (qw (cccmd cc author self sob body bodycc)) {
                $suppress_cc{$entry} = 1;
        }
        delete $suppress_cc{'all'};
}

# If explicit old-style ones are specified, they trump --suppress-cc.
$suppress_cc{'self'} = $suppress_from if defined $suppress_from;
$suppress_cc{'sob'} = !$signed_off_by_cc if defined $signed_off_by_cc;

if ($suppress_cc{'body'}) {
        foreach my $entry (qw (sob bodycc)) {
                $suppress_cc{$entry} = 1;
        }
        delete $suppress_cc{'body'};
}

# Set confirm's default value
my $confirm_unconfigured = !defined $confirm;
if ($confirm_unconfigured) {
        $confirm = scalar %suppress_cc ? 'compose' : 'auto';
};
die "Unknown --confirm setting: '$confirm'\n"
        unless $confirm =~ /^(?:auto|cc|compose|always|never)/;

# Debugging, print out the suppressions.
if (0) {
        print "suppressions:\n";
        foreach my $entry (keys %suppress_cc) {
                printf "  %-5s -> $suppress_cc{$entry}\n", $entry;
        }
}

my ($repoauthor, $repocommitter);
($repoauthor) = Git::ident_person(@repo, 'author');
($repocommitter) = Git::ident_person(@repo, 'committer');

# Verify the user input

foreach my $entry (@initial_to) {
        die "Comma in --to entry: $entry'\n" unless $entry !~ m/,/;
}

foreach my $entry (@initial_cc) {
        die "Comma in --cc entry: $entry'\n" unless $entry !~ m/,/;
}

foreach my $entry (@bcclist) {
        die "Comma in --bcclist entry: $entry'\n" unless $entry !~ m/,/;
}

sub parse_address_line {
        if ($have_mail_address) {
                return map { $_->format } Mail::Address->parse($_[0]);
        } else {
                return split_addrs($_[0]);
        }
}

sub split_addrs {
        return quotewords('\s*,\s*', 1, @_);
}

my %aliases;
my %parse_alias = (
        # multiline formats can be supported in the future
        mutt => sub { my $fh = shift; while (<$fh>) {
                if (/^\s*alias\s+(?:-group\s+\S+\s+)*(\S+)\s+(.*)$/) {
                        my ($alias, $addr) = ($1, $2);
                        $addr =~ s/#.*$//; # mutt allows # comments
                         # commas delimit multiple addresses
                        $aliases{$alias} = [ split_addrs($addr) ];
                }}},
        mailrc => sub { my $fh = shift; while (<$fh>) {
                if (/^alias\s+(\S+)\s+(.*)$/) {
                        # spaces delimit multiple addresses
                        $aliases{$1} = [ quotewords('\s+', 0, $2) ];
                }}},
        pine => sub { my $fh = shift; my $f='\t[^\t]*';
                for (my $x = ''; defined($x); $x = $_) {
                        chomp $x;
                        $x .= $1 while(defined($_ = <$fh>) && /^ +(.*)$/);
                        $x =~ /^(\S+)$f\t\(?([^\t]+?)\)?(:?$f){0,2}$/ or next;
                        $aliases{$1} = [ split_addrs($2) ];
                }},
        elm => sub  { my $fh = shift;
                      while (<$fh>) {
                          if (/^(\S+)\s+=\s+[^=]+=\s(\S+)/) {
                              my ($alias, $addr) = ($1, $2);
                               $aliases{$alias} = [ split_addrs($addr) ];
                          }
                      } },

        gnus => sub { my $fh = shift; while (<$fh>) {
                if (/\(define-mail-alias\s+"(\S+?)"\s+"(\S+?)"\)/) {
                        $aliases{$1} = [ $2 ];
                }}}
);

if (@alias_files and $aliasfiletype and defined $parse_alias{$aliasfiletype}) {
        foreach my $file (@alias_files) {
                open my $fh, '<', $file or die "opening $file: $!\n";
                $parse_alias{$aliasfiletype}->($fh);
                close $fh;
        }
}

($sender) = expand_aliases($sender) if defined $sender;

# is_format_patch_arg($f) returns 0 if $f names a patch, or 1 if
# $f is a revision list specification to be passed to format-patch.
sub is_format_patch_arg {
        return unless $repo;
        my $f = shift;
        try {
                $repo->command('rev-parse', '--verify', '--quiet', $f);
                if (defined($format_patch)) {
                        return $format_patch;
                }
                die(<<EOF);
File '$f' exists but it could also be the range of commits
to produce patches for.  Please disambiguate by...

    * Saying "./$f" if you mean a file; or
    * Giving --format-patch option if you mean a range.
EOF
        } catch Git::Error::Command with {
                # Not a valid revision.  Treat it as a filename.
                return 0;
        }
}

# Now that all the defaults are set, process the rest of the command line
# arguments and collect up the files that need to be processed.
my @rev_list_opts;
while (defined(my $f = shift @ARGV)) {
        if ($f eq "--") {
                push @rev_list_opts, "--", @ARGV;
                @ARGV = ();
        } elsif (-d $f and !is_format_patch_arg($f)) {
                opendir my $dh, $f
                        or die "Failed to opendir $f: $!";

                push @files, grep { -f $_ } map { catfile($f, $_) }
                                sort readdir $dh;
                closedir $dh;
        } elsif ((-f $f or -p $f) and !is_format_patch_arg($f)) {
                push @files, $f;
        } else {
                push @rev_list_opts, $f;
        }
}

if (@rev_list_opts) {
        die "Cannot run git format-patch from outside a repository\n"
                unless $repo;
        push @files, $repo->command('format-patch', '-o', tempdir(CLEANUP => 1), @rev_list_opts);
}

if ($validate) {
        foreach my $f (@files) {
                unless (-p $f) {
                        my $error = validate_patch($f);
                        $error and die "fatal: $f: $error\nwarning: no patches were sent\n";
                }
        }
}

if (@files) {
        unless ($quiet) {
                print $_,"\n" for (@files);
        }
} else {
        print STDERR "\nNo patch files specified!\n\n";
        usage();
}

sub get_patch_subject {
        my $fn = shift;
        open (my $fh, '<', $fn);
        while (my $line = <$fh>) {
                next unless ($line =~ /^Subject: (.*)$/);
                close $fh;
                return "GIT: $1\n";
        }
        close $fh;
        die "No subject line in $fn ?";
}

if ($compose) {
        # Note that this does not need to be secure, but we will make a small
        # effort to have it be unique
        $compose_filename = ($repo ?
                tempfile(".gitsendemail.msg.XXXXXX", DIR => $repo->repo_path()) :
                tempfile(".gitsendemail.msg.XXXXXX", DIR => "."))[1];
        open my $c, ">", $compose_filename
                or die "Failed to open for writing $compose_filename: $!";


        my $tpl_sender = $sender || $repoauthor || $repocommitter || '';
        my $tpl_subject = $initial_subject || '';
        my $tpl_reply_to = $initial_reply_to || '';

        print $c <<EOT;
From $tpl_sender # This line is ignored.
GIT: Lines beginning in "GIT:" will be removed.
GIT: Consider including an overall diffstat or table of contents
GIT: for the patch you are writing.
GIT:
GIT: Clear the body content if you don't wish to send a summary.
From: $tpl_sender
Subject: $tpl_subject
In-Reply-To: $tpl_reply_to

EOT
        for my $f (@files) {
                print $c get_patch_subject($f);
        }
        close $c;

        if ($annotate) {
                do_edit($compose_filename, @files);
        } else {
                do_edit($compose_filename);
        }

        open my $c2, ">", $compose_filename . ".final"
                or die "Failed to open $compose_filename.final : " . $!;

        open $c, "<", $compose_filename
                or die "Failed to open $compose_filename : " . $!;

        my $need_8bit_cte = file_has_nonascii($compose_filename);
        my $in_body = 0;
        my $summary_empty = 1;
        if (!defined $compose_encoding) {
                $compose_encoding = "UTF-8";
        }
        while(<$c>) {
                next if m/^GIT:/;
                if ($in_body) {
                        $summary_empty = 0 unless (/^\n$/);
                } elsif (/^\n$/) {
                        $in_body = 1;
                        if ($need_8bit_cte) {
                                print $c2 "MIME-Version: 1.0\n",
                                         "Content-Type: text/plain; ",
                                           "charset=$compose_encoding\n",
                                         "Content-Transfer-Encoding: 8bit\n";
                        }
                } elsif (/^MIME-Version:/i) {
                        $need_8bit_cte = 0;
                } elsif (/^Subject:\s*(.+)\s*$/i) {
                        $initial_subject = $1;
                        my $subject = $initial_subject;
                        $_ = "Subject: " .
                                quote_subject($subject, $compose_encoding) .
                                "\n";
                } elsif (/^In-Reply-To:\s*(.+)\s*$/i) {
                        $initial_reply_to = $1;
                        next;
                } elsif (/^From:\s*(.+)\s*$/i) {
                        $sender = $1;
                        next;
                } elsif (/^(?:To|Cc|Bcc):/i) {
                        print "To/Cc/Bcc fields are not interpreted yet, they have been ignored\n";
                        next;
                }
                print $c2 $_;
        }
        close $c;
        close $c2;

        if ($summary_empty) {
                print "Summary email is empty, skipping it\n";
                $compose = -1;
        }
} elsif ($annotate) {
        do_edit(@files);
}

sub ask {
        my ($prompt, %arg) = @_;
        my $valid_re = $arg{valid_re};
        my $default = $arg{default};
        my $confirm_only = $arg{confirm_only};
        my $resp;
        my $i = 0;
        return defined $default ? $default : undef
                unless defined $term->IN and defined fileno($term->IN) and
                       defined $term->OUT and defined fileno($term->OUT);
        while ($i++ < 10) {
                $resp = $term->readline($prompt);
                if (!defined $resp) { # EOF
                        print "\n";
                        return defined $default ? $default : undef;
                }
                if ($resp eq '' and defined $default) {
                        return $default;
                }
                if (!defined $valid_re or $resp =~ /$valid_re/) {
                        return $resp;
                }
                if ($confirm_only) {
                        my $yesno = $term->readline("Are you sure you want to use <$resp> [y/N]? ");
                        if (defined $yesno && $yesno =~ /y/i) {
                                return $resp;
                        }
                }
        }
        return;
}

my %broken_encoding;

sub file_declares_8bit_cte {
        my $fn = shift;
        open (my $fh, '<', $fn);
        while (my $line = <$fh>) {
                last if ($line =~ /^$/);
                return 1 if ($line =~ /^Content-Transfer-Encoding: .*8bit.*$/);
        }
        close $fh;
        return 0;
}

foreach my $f (@files) {
        next unless (body_or_subject_has_nonascii($f)
                     && !file_declares_8bit_cte($f));
        $broken_encoding{$f} = 1;
}

if (!defined $auto_8bit_encoding && scalar %broken_encoding) {
        print "The following files are 8bit, but do not declare " .
                "a Content-Transfer-Encoding.\n";
        foreach my $f (sort keys %broken_encoding) {
                print "    $f\n";
        }
        $auto_8bit_encoding = ask("Which 8bit encoding should I declare [UTF-8]? ",
                                  default => "UTF-8");
}

if (!$force) {
        for my $f (@files) {
                if (get_patch_subject($f) =~ /\Q*** SUBJECT HERE ***\E/) {
                        die "Refusing to send because the patch\n\t$f\n"
                                . "has the template subject '*** SUBJECT HERE ***'. "
                                . "Pass --force if you really want to send.\n";
                }
        }
}

if (!defined $sender) {
        $sender = $repoauthor || $repocommitter || '';
}

# $sender could be an already sanitized address
# (e.g. sendemail.from could be manually sanitized by user).
# But it's a no-op to run sanitize_address on an already sanitized address.
$sender = sanitize_address($sender);

my $prompting = 0;
if (!@initial_to && !defined $to_cmd) {
        my $to = ask("Who should the emails be sent to (if any)? ",
                     default => "",
                     valid_re => qr/\@.*\./, confirm_only => 1);
        push @initial_to, parse_address_line($to) if defined $to; # sanitized/validated later
        $prompting++;
}

sub expand_aliases {
        return map { expand_one_alias($_) } @_;
}

my %EXPANDED_ALIASES;
sub expand_one_alias {
        my $alias = shift;
        if ($EXPANDED_ALIASES{$alias}) {
                die "fatal: alias '$alias' expands to itself\n";
        }
        local $EXPANDED_ALIASES{$alias} = 1;
        return $aliases{$alias} ? expand_aliases(@{$aliases{$alias}}) : $alias;
}

@initial_to = expand_aliases(@initial_to);
@initial_to = validate_address_list(sanitize_address_list(@initial_to));
@initial_cc = expand_aliases(@initial_cc);
@initial_cc = validate_address_list(sanitize_address_list(@initial_cc));
@bcclist = expand_aliases(@bcclist);
@bcclist = validate_address_list(sanitize_address_list(@bcclist));

if ($thread && !defined $initial_reply_to && $prompting) {
        $initial_reply_to = ask(
                "Message-ID to be used as In-Reply-To for the first email (if any)? ",
                default => "",
                valid_re => qr/\@.*\./, confirm_only => 1);
}
if (defined $initial_reply_to) {
        $initial_reply_to =~ s/^\s*<?//;
        $initial_reply_to =~ s/>?\s*$//;
        $initial_reply_to = "<$initial_reply_to>" if $initial_reply_to ne '';
}

if (!defined $smtp_server) {
        foreach (qw( /usr/sbin/sendmail /usr/lib/sendmail )) {
                if (-x $_) {
                        $smtp_server = $_;
                        last;
                }
        }
        $smtp_server ||= 'localhost'; # could be 127.0.0.1, too... *shrug*
}

if ($compose && $compose > 0) {
        @files = ($compose_filename . ".final", @files);
}

# Variables we set as part of the loop over files
our ($message_id, %mail, $subject, $reply_to, $references, $message,
        $needs_confirm, $message_num, $ask_default);

sub extract_valid_address {
        my $address = shift;
        my $local_part_regexp = qr/[^<>"\s@]+/;
        my $domain_regexp = qr/[^.<>"\s@]+(?:\.[^.<>"\s@]+)+/;

        # check for a local address:
        return $address if ($address =~ /^($local_part_regexp)$/);

        $address =~ s/^\s*<(.*)>\s*$/$1/;
        if ($have_email_valid) {
                return scalar Email::Valid->address($address);
        }

        # less robust/correct than the monster regexp in Email::Valid,
        # but still does a 99% job, and one less dependency
        return $1 if $address =~ /($local_part_regexp\@$domain_regexp)/;
        return;
}

sub extract_valid_address_or_die {
        my $address = shift;
        $address = extract_valid_address($address);
        die "error: unable to extract a valid address from: $address\n"
                if !$address;
        return $address;
}

sub validate_address {
        my $address = shift;
        while (!extract_valid_address($address)) {
                print STDERR "error: unable to extract a valid address from: $address\n";
                $_ = ask("What to do with this address? ([q]uit|[d]rop|[e]dit): ",
                        valid_re => qr/^(?:quit|q|drop|d|edit|e)/i,
                        default => 'q');
                if (/^d/i) {
                        return undef;
                } elsif (/^q/i) {
                        cleanup_compose_files();
                        exit(0);
                }
                $address = ask("Who should the email be sent to (if any)? ",
                        default => "",
                        valid_re => qr/\@.*\./, confirm_only => 1);
        }
        return $address;
}

sub validate_address_list {
        return (grep { defined $_ }
                map { validate_address($_) } @_);
}

# Usually don't need to change anything below here.

# we make a "fake" message id by taking the current number
# of seconds since the beginning of Unix time and tacking on
# a random number to the end, in case we are called quicker than
# 1 second since the last time we were called.

# We'll setup a template for the message id, using the "from" address:

my ($message_id_stamp, $message_id_serial);
sub make_message_id {
        my $uniq;
        if (!defined $message_id_stamp) {
                $message_id_stamp = sprintf("%s-%s", time, $$);
                $message_id_serial = 0;
        }
        $message_id_serial++;
        $uniq = "$message_id_stamp-$message_id_serial";

        my $du_part;
        for ($sender, $repocommitter, $repoauthor) {
                $du_part = extract_valid_address(sanitize_address($_));
                last if (defined $du_part and $du_part ne '');
        }
        if (not defined $du_part or $du_part eq '') {
                require Sys::Hostname;
                $du_part = 'user@' . Sys::Hostname::hostname();
        }
        my $message_id_template = "<%s-git-send-email-%s>";
        $message_id = sprintf($message_id_template, $uniq, $du_part);
        #print "new message id = $message_id\n"; # Was useful for debugging
}



$time = time - scalar $#files;

sub unquote_rfc2047 {
        local ($_) = @_;
        my $encoding;
        s{=\?([^?]+)\?q\?(.*?)\?=}{
                $encoding = $1;
                my $e = $2;
                $e =~ s/_/ /g;
                $e =~ s/=([0-9A-F]{2})/chr(hex($1))/eg;
                $e;
        }eg;
        return wantarray ? ($_, $encoding) : $_;
}

sub quote_rfc2047 {
        local $_ = shift;
        my $encoding = shift || 'UTF-8';
        s/([^-a-zA-Z0-9!*+\/])/sprintf("=%02X", ord($1))/eg;
        s/(.*)/=\?$encoding\?q\?$1\?=/;
        return $_;
}

sub is_rfc2047_quoted {
        my $s = shift;
        my $token = qr/[^][()<>@,;:"\/?.= \000-\037\177-\377]+/;
        my $encoded_text = qr/[!->@-~]+/;
        length($s) <= 75 &&
        $s =~ m/^(?:"[[:ascii:]]*"|=\?$token\?$token\?$encoded_text\?=)$/o;
}

sub subject_needs_rfc2047_quoting {
        my $s = shift;

        return ($s =~ /[^[:ascii:]]/) || ($s =~ /=\?/);
}

sub quote_subject {
        local $subject = shift;
        my $encoding = shift || 'UTF-8';

        if (subject_needs_rfc2047_quoting($subject)) {
                return quote_rfc2047($subject, $encoding);
        }
        return $subject;
}

# use the simplest quoting being able to handle the recipient
sub sanitize_address {
        my ($recipient) = @_;

        # remove garbage after email address
        $recipient =~ s/(.*>).*$/$1/;

        my ($recipient_name, $recipient_addr) = ($recipient =~ /^(.*?)\s*(<.*)/);

        if (not $recipient_name) {
                return $recipient;
        }

        # if recipient_name is already quoted, do nothing
        if (is_rfc2047_quoted($recipient_name)) {
                return $recipient;
        }

        # rfc2047 is needed if a non-ascii char is included
        if ($recipient_name =~ /[^[:ascii:]]/) {
                $recipient_name =~ s/^"(.*)"$/$1/;
                $recipient_name = quote_rfc2047($recipient_name);
        }

        # double quotes are needed if specials or CTLs are included
        elsif ($recipient_name =~ /[][()<>@,;:\\".\000-\037\177]/) {
                $recipient_name =~ s/(["\\\r])/\\$1/g;
                $recipient_name = qq["$recipient_name"];
        }

        return "$recipient_name $recipient_addr";

}

sub sanitize_address_list {
        return (map { sanitize_address($_) } @_);
}

# Returns the local Fully Qualified Domain Name (FQDN) if available.
#
# Tightly configured MTAa require that a caller sends a real DNS
# domain name that corresponds the IP address in the HELO/EHLO
# handshake. This is used to verify the connection and prevent
# spammers from trying to hide their identity. If the DNS and IP don't
# match, the receiveing MTA may deny the connection.
#
# Here is a deny example of Net::SMTP with the default "localhost.localdomain"
#
# Net::SMTP=GLOB(0x267ec28)>>> EHLO localhost.localdomain
# Net::SMTP=GLOB(0x267ec28)<<< 550 EHLO argument does not match calling host
#
# This maildomain*() code is based on ideas in Perl library Test::Reporter
# /usr/share/perl5/Test/Reporter/Mail/Util.pm ==> sub _maildomain ()

sub valid_fqdn {
        my $domain = shift;
        return defined $domain && !($^O eq 'darwin' && $domain =~ /\.local$/) && $domain =~ /\./;
}

sub maildomain_net {
        my $maildomain;

        if (eval { require Net::Domain; 1 }) {
                my $domain = Net::Domain::domainname();
                $maildomain = $domain if valid_fqdn($domain);
        }

        return $maildomain;
}

sub maildomain_mta {
        my $maildomain;

        if (eval { require Net::SMTP; 1 }) {
                for my $host (qw(mailhost localhost)) {
                        my $smtp = Net::SMTP->new($host);
                        if (defined $smtp) {
                                my $domain = $smtp->domain;
                                $smtp->quit;

                                $maildomain = $domain if valid_fqdn($domain);

                                last if $maildomain;
                        }
                }
        }

        return $maildomain;
}

sub maildomain {
        return maildomain_net() || maildomain_mta() || 'localhost.localdomain';
}

sub smtp_host_string {
        if (defined $smtp_server_port) {
                return "$smtp_server:$smtp_server_port";
        } else {
                return $smtp_server;
        }
}

# Returns 1 if authentication succeeded or was not necessary
# (smtp_user was not specified), and 0 otherwise.

sub smtp_auth_maybe {
        if (!defined $smtp_authuser || $auth) {
                return 1;
        }

        # Workaround AUTH PLAIN/LOGIN interaction defect
        # with Authen::SASL::Cyrus
        eval {
                require Authen::SASL;
                Authen::SASL->import(qw(Perl));
        };

        # TODO: Authentication may fail not because credentials were
        # invalid but due to other reasons, in which we should not
        # reject credentials.
        $auth = Git::credential({
                'protocol' => 'smtp',
                'host' => smtp_host_string(),
                'username' => $smtp_authuser,
                # if there's no password, "git credential fill" will
                # give us one, otherwise it'll just pass this one.
                'password' => $smtp_authpass
        }, sub {
                my $cred = shift;
                return !!$smtp->auth($cred->{'username'}, $cred->{'password'});
        });

        return $auth;
}

# Returns 1 if the message was sent, and 0 otherwise.
# In actuality, the whole program dies when there
# is an error sending a message.

sub send_message {
        my @recipients = unique_email_list(@to);
        @cc = (grep { my $cc = extract_valid_address_or_die($_);
                      not grep { $cc eq $_ || $_ =~ /<\Q${cc}\E>$/ } @recipients
                    }
               @cc);
        my $to = join (",\n\t", @recipients);
        @recipients = unique_email_list(@recipients,@cc,@bcclist);
        @recipients = (map { extract_valid_address_or_die($_) } @recipients);
        my $date = format_2822_time($time++);
        my $gitversion = '@@GIT_VERSION@@';
        if ($gitversion =~ m/..GIT_VERSION../) {
            $gitversion = Git::version();
        }

        my $cc = join(",\n\t", unique_email_list(@cc));
        my $ccline = "";
        if ($cc ne '') {
                $ccline = "\nCc: $cc";
        }
        make_message_id() unless defined($message_id);

        my $header = "From: $sender
To: $to${ccline}
Subject: $subject
Date: $date
Message-Id: $message_id
X-Mailer: git-send-email $gitversion
";
        if ($reply_to) {

                $header .= "In-Reply-To: $reply_to\n";
                $header .= "References: $references\n";
        }
        if (@xh) {
                $header .= join("\n", @xh) . "\n";
        }

        my @sendmail_parameters = ('-i', @recipients);
        my $raw_from = $sender;
        if (defined $envelope_sender && $envelope_sender ne "auto") {
                $raw_from = $envelope_sender;
        }
        $raw_from = extract_valid_address($raw_from);
        unshift (@sendmail_parameters,
                        '-f', $raw_from) if(defined $envelope_sender);

        if ($needs_confirm && !$dry_run) {
                print "\n$header\n";
                if ($needs_confirm eq "inform") {
                        $confirm_unconfigured = 0; # squelch this message for the rest of this run
                        $ask_default = "y"; # assume yes on EOF since user hasn't explicitly asked for confirmation
                        print "    The Cc list above has been expanded by additional\n";
                        print "    addresses found in the patch commit message. By default\n";
                        print "    send-email prompts before sending whenever this occurs.\n";
                        print "    This behavior is controlled by the sendemail.confirm\n";
                        print "    configuration setting.\n";
                        print "\n";
                        print "    For additional information, run 'git send-email --help'.\n";
                        print "    To retain the current behavior, but squelch this message,\n";
                        print "    run 'git config --global sendemail.confirm auto'.\n\n";
                }
                $_ = ask("Send this email? ([y]es|[n]o|[q]uit|[a]ll): ",
                         valid_re => qr/^(?:yes|y|no|n|quit|q|all|a)/i,
                         default => $ask_default);
                die "Send this email reply required" unless defined $_;
                if (/^n/i) {
                        return 0;
                } elsif (/^q/i) {
                        cleanup_compose_files();
                        exit(0);
                } elsif (/^a/i) {
                        $confirm = 'never';
                }
        }

        unshift (@sendmail_parameters, @smtp_server_options);

        if ($dry_run) {
                # We don't want to send the email.
        } elsif ($smtp_server =~ m#^/#) {
                my $pid = open my $sm, '|-';
                defined $pid or die $!;
                if (!$pid) {
                        exec($smtp_server, @sendmail_parameters) or die $!;
                }
                print $sm "$header\n$message";
                close $sm or die $!;
        } else {

                if (!defined $smtp_server) {
                        die "The required SMTP server is not properly defined."
                }

                if ($smtp_encryption eq 'ssl') {
                        $smtp_server_port ||= 465; # ssmtp
                        require Net::SMTP::SSL;
                        $smtp_domain ||= maildomain();
                        $smtp ||= Net::SMTP::SSL->new($smtp_server,
                                                      Hello => $smtp_domain,
                                                      Port => $smtp_server_port);
                }
                else {
                        require Net::SMTP;
                        $smtp_domain ||= maildomain();
                        $smtp ||= Net::SMTP->new(smtp_host_string(),
                                                 Hello => $smtp_domain,
                                                 Debug => $debug_net_smtp);
                        if ($smtp_encryption eq 'tls' && $smtp) {
                                require Net::SMTP::SSL;
                                $smtp->command('STARTTLS');
                                $smtp->response();
                                if ($smtp->code == 220) {
                                        $smtp = Net::SMTP::SSL->start_SSL($smtp)
                                                or die "STARTTLS failed! ".$smtp->message;
                                        $smtp_encryption = '';
                                        # Send EHLO again to receive fresh
                                        # supported commands
                                        $smtp->hello($smtp_domain);
                                } else {
                                        die "Server does not support STARTTLS! ".$smtp->message;
                                }
                        }
                }

                if (!$smtp) {
                        die "Unable to initialize SMTP properly. Check config and use --smtp-debug. ",
                            "VALUES: server=$smtp_server ",
                            "encryption=$smtp_encryption ",
                            "hello=$smtp_domain",
                            defined $smtp_server_port ? " port=$smtp_server_port" : "";
                }

                smtp_auth_maybe or die $smtp->message;

                $smtp->mail( $raw_from ) or die $smtp->message;
                $smtp->to( @recipients ) or die $smtp->message;
                $smtp->data or die $smtp->message;
                $smtp->datasend("$header\n$message") or die $smtp->message;
                $smtp->dataend() or die $smtp->message;
                $smtp->code =~ /250|200/ or die "Failed to send $subject\n".$smtp->message;
        }
        if ($quiet) {
                printf (($dry_run ? "Dry-" : "")."Sent %s\n", $subject);
        } else {
                print (($dry_run ? "Dry-" : "")."OK. Log says:\n");
                if ($smtp_server !~ m#^/#) {
                        print "Server: $smtp_server\n";
                        print "MAIL FROM:<$raw_from>\n";
                        foreach my $entry (@recipients) {
                            print "RCPT TO:<$entry>\n";
                        }
                } else {
                        print "Sendmail: $smtp_server ".join(' ',@sendmail_parameters)."\n";
                }
                print $header, "\n";
                if ($smtp) {
                        print "Result: ", $smtp->code, ' ',
                                ($smtp->message =~ /\n([^\n]+\n)$/s), "\n";
                } else {
                        print "Result: OK\n";
                }
        }

        return 1;
}

$reply_to = $initial_reply_to;
$references = $initial_reply_to || '';
$subject = $initial_subject;
$message_num = 0;

foreach my $t (@files) {
        open my $fh, "<", $t or die "can't open file $t";

        my $author = undef;
        my $sauthor = undef;
        my $author_encoding;
        my $has_content_type;
        my $body_encoding;
        @to = ();
        @cc = ();
        @xh = ();
        my $input_format = undef;
        my @header = ();
        $message = "";
        $message_num++;
        # First unfold multiline header fields
        while(<$fh>) {
                last if /^\s*$/;
                if (/^\s+\S/ and @header) {
                        chomp($header[$#header]);
                        s/^\s+/ /;
                        $header[$#header] .= $_;
            } else {
                        push(@header, $_);
                }
        }
        # Now parse the header
        foreach(@header) {
                if (/^From /) {
                        $input_format = 'mbox';
                        next;
                }
                chomp;
                if (!defined $input_format && /^[-A-Za-z]+:\s/) {
                        $input_format = 'mbox';
                }

                if (defined $input_format && $input_format eq 'mbox') {
                        if (/^Subject:\s+(.*)$/i) {
                                $subject = $1;
                        }
                        elsif (/^From:\s+(.*)$/i) {
                                ($author, $author_encoding) = unquote_rfc2047($1);
                                $sauthor = sanitize_address($author);
                                next if $suppress_cc{'author'};
                                next if $suppress_cc{'self'} and $sauthor eq $sender;
                                printf("(mbox) Adding cc: %s from line '%s'\n",
                                        $1, $_) unless $quiet;
                                push @cc, $1;
                        }
                        elsif (/^To:\s+(.*)$/i) {
                                foreach my $addr (parse_address_line($1)) {
                                        printf("(mbox) Adding to: %s from line '%s'\n",
                                                $addr, $_) unless $quiet;
                                        push @to, $addr;
                                }
                        }
                        elsif (/^Cc:\s+(.*)$/i) {
                                foreach my $addr (parse_address_line($1)) {
                                        my $qaddr = unquote_rfc2047($addr);
                                        my $saddr = sanitize_address($qaddr);
                                        if ($saddr eq $sender) {
                                                next if ($suppress_cc{'self'});
                                        } else {
                                                next if ($suppress_cc{'cc'});
                                        }
                                        printf("(mbox) Adding cc: %s from line '%s'\n",
                                                $addr, $_) unless $quiet;
                                        push @cc, $addr;
                                }
                        }
                        elsif (/^Content-type:/i) {
                                $has_content_type = 1;
                                if (/charset="?([^ "]+)/) {
                                        $body_encoding = $1;
                                }
                                push @xh, $_;
                        }
                        elsif (/^Message-Id: (.*)/i) {
                                $message_id = $1;
                        }
                        elsif (!/^Date:\s/i && /^[-A-Za-z]+:\s+\S/) {
                                push @xh, $_;
                        }

                } else {
                        # In the traditional
                        # "send lots of email" format,
                        # line 1 = cc
                        # line 2 = subject
                        # So let's support that, too.
                        $input_format = 'lots';
                        if (@cc == 0 && !$suppress_cc{'cc'}) {
                                printf("(non-mbox) Adding cc: %s from line '%s'\n",
                                        $_, $_) unless $quiet;
                                push @cc, $_;
                        } elsif (!defined $subject) {
                                $subject = $_;
                        }
                }
        }
        # Now parse the message body
        while(<$fh>) {
                $message .=  $_;
                if (/^(Signed-off-by|Cc): (.*)$/i) {
                        chomp;
                        my ($what, $c) = ($1, $2);
                        chomp $c;
                        my $sc = sanitize_address($c);
                        if ($sc eq $sender) {
                                next if ($suppress_cc{'self'});
                        } else {
                                next if $suppress_cc{'sob'} and $what =~ /Signed-off-by/i;
                                next if $suppress_cc{'bodycc'} and $what =~ /Cc/i;
                        }
                        push @cc, $c;
                        printf("(body) Adding cc: %s from line '%s'\n",
                                $c, $_) unless $quiet;
                }
        }
        close $fh;

        push @to, recipients_cmd("to-cmd", "to", $to_cmd, $t)
                if defined $to_cmd;
        push @cc, recipients_cmd("cc-cmd", "cc", $cc_cmd, $t)
                if defined $cc_cmd && !$suppress_cc{'cccmd'};

        if ($broken_encoding{$t} && !$has_content_type) {
                $has_content_type = 1;
                push @xh, "MIME-Version: 1.0",
                        "Content-Type: text/plain; charset=$auto_8bit_encoding",
                        "Content-Transfer-Encoding: 8bit";
                $body_encoding = $auto_8bit_encoding;
        }

        if ($broken_encoding{$t} && !is_rfc2047_quoted($subject)) {
                $subject = quote_subject($subject, $auto_8bit_encoding);
        }

        if (defined $sauthor and $sauthor ne $sender) {
                $message = "From: $author\n\n$message";
                if (defined $author_encoding) {
                        if ($has_content_type) {
                                if ($body_encoding eq $author_encoding) {
                                        # ok, we already have the right encoding
                                }
                                else {
                                        # uh oh, we should re-encode
                                }
                        }
                        else {
                                $has_content_type = 1;
                                push @xh,
                                  'MIME-Version: 1.0',
                                  "Content-Type: text/plain; charset=$author_encoding",
                                  'Content-Transfer-Encoding: 8bit';
                        }
                }
        }

        $needs_confirm = (
                $confirm eq "always" or
                ($confirm =~ /^(?:auto|cc)$/ && @cc) or
                ($confirm =~ /^(?:auto|compose)$/ && $compose && $message_num == 1));
        $needs_confirm = "inform" if ($needs_confirm && $confirm_unconfigured && @cc);

        @to = validate_address_list(sanitize_address_list(@to));
        @cc = validate_address_list(sanitize_address_list(@cc));

        @to = (@initial_to, @to);
        @cc = (@initial_cc, @cc);

        my $message_was_sent = send_message();

        # set up for the next message
        if ($thread && $message_was_sent &&
                ($chain_reply_to || !defined $reply_to || length($reply_to) == 0 ||
                $message_num == 1)) {
                $reply_to = $message_id;
                if (length $references > 0) {
                        $references .= "\n $message_id";
                } else {
                        $references = "$message_id";
                }
        }
        $message_id = undef;
}

# Execute a command (e.g. $to_cmd) to get a list of email addresses
# and return a results array
sub recipients_cmd {
        my ($prefix, $what, $cmd, $file) = @_;

        my @addresses = ();
        open my $fh, "-|", "$cmd \Q$file\E"
            or die "($prefix) Could not execute '$cmd'";
        while (my $address = <$fh>) {
                $address =~ s/^\s*//g;
                $address =~ s/\s*$//g;
                $address = sanitize_address($address);
                next if ($address eq $sender and $suppress_cc{'self'});
                push @addresses, $address;
                printf("($prefix) Adding %s: %s from: '%s'\n",
                       $what, $address, $cmd) unless $quiet;
                }
        close $fh
            or die "($prefix) failed to close pipe to '$cmd'";
        return @addresses;
}

cleanup_compose_files();

sub cleanup_compose_files {
        unlink($compose_filename, $compose_filename . ".final") if $compose;
}

$smtp->quit if $smtp;

sub unique_email_list {
        my %seen;
        my @emails;

        foreach my $entry (@_) {
                my $clean = extract_valid_address_or_die($entry);
                $seen{$clean} ||= 0;
                next if $seen{$clean}++;
                push @emails, $entry;
        }
        return @emails;
}

sub validate_patch {
        my $fn = shift;
        open(my $fh, '<', $fn)
                or die "unable to open $fn: $!\n";
        while (my $line = <$fh>) {
                if (length($line) > 998) {
                        return "$.: patch contains a line longer than 998 characters";
                }
        }
        return;
}

sub file_has_nonascii {
        my $fn = shift;
        open(my $fh, '<', $fn)
                or die "unable to open $fn: $!\n";
        while (my $line = <$fh>) {
                return 1 if $line =~ /[^[:ascii:]]/;
        }
        return 0;
}

sub body_or_subject_has_nonascii {
        my $fn = shift;
        open(my $fh, '<', $fn)
                or die "unable to open $fn: $!\n";
        while (my $line = <$fh>) {
                last if $line =~ /^$/;
                return 1 if $line =~ /^Subject.*[^[:ascii:]]/;
        }
        while (my $line = <$fh>) {
                return 1 if $line =~ /[^[:ascii:]]/;
        }
        return 0;
}