Merge branch 'xz/send-email-batch-size'

"git send-email" learned to overcome some SMTP server limitation
that does not allow many pieces of e-mails to be sent over a single
session.

* xz/send-email-batch-size:
  send-email: --batch-size to work around some SMTP server limit

git-send-email.perl

@@ -82,6 +82,10 @@ git send-email --dump-aliases
                                      This setting forces to use one of the listed mechanisms.
     --smtp-debug            <0|1>  * Disable, enable Net::SMTP debug.
 
+    --batch-size            <int>  * send max <int> message per connection.
+    --relogin-delay         <int>  * delay <int> seconds between two successive login.
+                                     This option can only be used with --batch-size
+
   Automating:
     --identity              <str>  * Use the sendemail.<id> options.
     --to-cmd                <str>  * Email To: via `<str> \$patch_path`
@@ -154,6 +158,7 @@ my $have_email_valid = eval { require Email::Valid; 1 };
 my $have_mail_address = eval { require Mail::Address; 1 };
 my $smtp;
 my $auth;
+my $num_sent = 0;
 
 # Regexes for RFC 2047 productions.
 my $re_token = qr/[^][()<>@,;:\\"\/?.= \000-\037\177-\377]+/;
@@ -217,6 +222,7 @@ my ($cover_cc, $cover_to);
 my ($to_cmd, $cc_cmd);
 my ($smtp_server, $smtp_server_port, @smtp_server_options);
 my ($smtp_authuser, $smtp_encryption, $smtp_ssl_cert_path);
+my ($batch_size, $relogin_delay);
 my ($identity, $aliasfiletype, @alias_files, $smtp_domain, $smtp_auth);
 my ($validate, $confirm);
 my (@suppress_cc);
@@ -248,6 +254,8 @@ my %config_settings = (
     "smtppass" => \$smtp_authpass,
     "smtpdomain" => \$smtp_domain,
     "smtpauth" => \$smtp_auth,
+    "smtpbatchsize" => \$batch_size,
+    "smtprelogindelay" => \$relogin_delay,
     "to" => \@initial_to,
     "tocmd" => \$to_cmd,
     "cc" => \@initial_cc,
@@ -359,6 +367,8 @@ $rc = GetOptions(
 		    "force" => \$force,
 		    "xmailer!" => \$use_xmailer,
 		    "no-xmailer" => sub {$use_xmailer = 0},
+		    "batch-size=i" => \$batch_size,
+		    "relogin-delay=i" => \$relogin_delay,
 	 );
 
 usage() if $help;
@@ -1681,6 +1691,14 @@ foreach my $t (@files) {
 		}
 	}
 	$message_id = undef;
+	$num_sent++;
+	if (defined $batch_size && $num_sent == $batch_size) {
+		$num_sent = 0;
+		$smtp->quit if defined $smtp;
+		undef $smtp;
+		undef $auth;
+		sleep($relogin_delay) if defined $relogin_delay;
+	}
 }
 
 # Execute a command (e.g. $to_cmd) to get a list of email addresses