send-email: add and use a local copy of Mail::Address

We used to have two versions of the email parsing code. Our
parse_mailboxes (in Git.pm), and Mail::Address which we used if
installed. Unfortunately, both versions have different sets of bugs, and
changing the behavior of git depending on whether Mail::Address is
installed was a bad idea.

A first attempt to solve this was cc90750 (send-email: don't use
Mail::Address, even if available, 2017-08-23), but it turns out our
parse_mailboxes is too buggy for some uses. For example the lack of
nested comments support breaks get_maintainer.pl in the Linux kernel
tree:

  https://public-inbox.org/git/20171116154814.23785-1-alex.bennee@linaro.org/

This patch goes the other way: use Mail::Address anyway, but have a
local copy from CPAN as a fallback, when the system one is not
available.

The duplicated script is small (276 lines of code) and stable in time.
Maintaining the local copy should not be an issue, and will certainly be
less burden than maintaining our own parse_mailboxes.

Another option would be to consider Mail::Address as a hard dependency,
but it's easy enough to save the trouble of extra-dependency to the end
user or packager.

Signed-off-by: Matthieu Moy <git@matthieu-moy.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

2 files changed, 300 insertions, 0 deletions

diff --git a/perl/Git/FromCPAN/Mail/Address.pm b/perl/Git/FromCPAN/Mail/Address.pm
new file mode 100644
index 0000000000..13b2ff7d05
--- /dev/null
+++ b/perl/Git/FromCPAN/Mail/Address.pm
@@ -0,0 +1,276 @@
+# Copyrights 1995-2017 by [Mark Overmeer <perl@overmeer.net>].
+#  For other contributors see ChangeLog.
+# See the manual pages for details on the licensing terms.
+# Pod stripped from pm file by OODoc 2.02.
+package Mail::Address;
+use vars '$VERSION';
+$VERSION = '2.19';
+
+use strict;
+
+use Carp;
+
+# use locale;   removed in version 1.78, because it causes taint problems
+
+sub Version { our $VERSION }
+
+
+
+# given a comment, attempt to extract a person's name
+sub _extract_name
+{   # This function can be called as method as well
+    my $self = @_ && ref $_[0] ? shift : undef;
+
+    local $_ = shift
+        or return '';
+
+    # Using encodings, too hard. See Mail::Message::Field::Full.
+    return '' if m/\=\?.*?\?\=/;
+
+    # trim whitespace
+    s/^\s+//;
+    s/\s+$//;
+    s/\s+/ /;
+
+    # Disregard numeric names (e.g. 123456.1234@compuserve.com)
+    return "" if /^[\d ]+$/;
+
+    s/^\((.*)\)$/$1/; # remove outermost parenthesis
+    s/^"(.*)"$/$1/;   # remove outer quotation marks
+    s/\(.*?\)//g;     # remove minimal embedded comments
+    s/\\//g;          # remove all escapes
+    s/^"(.*)"$/$1/;   # remove internal quotation marks
+    s/^([^\s]+) ?, ?(.*)$/$2 $1/; # reverse "Last, First M." if applicable
+    s/,.*//;
+
+    # Change casing only when the name contains only upper or only
+    # lower cased characters.
+    unless( m/[A-Z]/ && m/[a-z]/ )
+    {   # Set the case of the name to first char upper rest lower
+        s/\b(\w+)/\L\u$1/igo;  # Upcase first letter on name
+        s/\bMc(\w)/Mc\u$1/igo; # Scottish names such as 'McLeod'
+        s/\bo'(\w)/O'\u$1/igo; # Irish names such as 'O'Malley, O'Reilly'
+        s/\b(x*(ix)?v*(iv)?i*)\b/\U$1/igo; # Roman numerals, eg 'Level III Support'
+    }
+
+    # some cleanup
+    s/\[[^\]]*\]//g;
+    s/(^[\s'"]+|[\s'"]+$)//g;
+    s/\s{2,}/ /g;
+
+    $_;
+}
+
+sub _tokenise
+{   local $_ = join ',', @_;
+    my (@words,$snippet,$field);
+
+    s/\A\s+//;
+    s/[\r\n]+/ /g;
+
+    while ($_ ne '')
+    {   $field = '';
+        if(s/^\s*\(/(/ )    # (...)
+        {   my $depth = 0;
+
+     PAREN: while(s/^(\(([^\(\)\\]|\\.)*)//)
+            {   $field .= $1;
+                $depth++;
+                while(s/^(([^\(\)\\]|\\.)*\)\s*)//)
+                {   $field .= $1;
+                    last PAREN unless --$depth;
+	            $field .= $1 if s/^(([^\(\)\\]|\\.)+)//;
+                }
+            }
+
+            carp "Unmatched () '$field' '$_'"
+                if $depth;
+
+            $field =~ s/\s+\Z//;
+            push @words, $field;
+
+            next;
+        }
+
+        if( s/^("(?:[^"\\]+|\\.)*")\s*//       # "..."
+         || s/^(\[(?:[^\]\\]+|\\.)*\])\s*//    # [...]
+         || s/^([^\s()<>\@,;:\\".[\]]+)\s*//
+         || s/^([()<>\@,;:\\".[\]])\s*//
+          )
+        {   push @words, $1;
+            next;
+        }
+
+        croak "Unrecognised line: $_";
+    }
+
+    push @words, ",";
+    \@words;
+}
+
+sub _find_next
+{   my ($idx, $tokens, $len) = @_;
+
+    while($idx < $len)
+    {   my $c = $tokens->[$idx];
+        return $c if $c eq ',' || $c eq ';' || $c eq '<';
+        $idx++;
+    }
+
+    "";
+}
+
+sub _complete
+{   my ($class, $phrase, $address, $comment) = @_;
+
+    @$phrase || @$comment || @$address
+       or return undef;
+
+    my $o = $class->new(join(" ",@$phrase), join("",@$address), join(" ",@$comment));
+    @$phrase = @$address = @$comment = ();
+    $o;
+}
+
+#------------
+
+sub new(@)
+{   my $class = shift;
+    bless [@_], $class;
+}
+
+
+sub parse(@)
+{   my $class = shift;
+    my @line  = grep {defined} @_;
+    my $line  = join '', @line;
+
+    my (@phrase, @comment, @address, @objs);
+    my ($depth, $idx) = (0, 0);
+
+    my $tokens  = _tokenise @line;
+    my $len     = @$tokens;
+    my $next    = _find_next $idx, $tokens, $len;
+
+    local $_;
+    for(my $idx = 0; $idx < $len; $idx++)
+    {   $_ = $tokens->[$idx];
+
+        if(substr($_,0,1) eq '(') { push @comment, $_ }
+        elsif($_ eq '<')    { $depth++ }
+        elsif($_ eq '>')    { $depth-- if $depth }
+        elsif($_ eq ',' || $_ eq ';')
+        {   warn "Unmatched '<>' in $line" if $depth;
+            my $o = $class->_complete(\@phrase, \@address, \@comment);
+            push @objs, $o if defined $o;
+            $depth = 0;
+            $next = _find_next $idx+1, $tokens, $len;
+        }
+        elsif($depth)       { push @address, $_ }
+        elsif($next eq '<') { push @phrase,  $_ }
+        elsif( /^[.\@:;]$/ || !@address || $address[-1] =~ /^[.\@:;]$/ )
+        {   push @address, $_ }
+        else
+        {   warn "Unmatched '<>' in $line" if $depth;
+            my $o = $class->_complete(\@phrase, \@address, \@comment);
+            push @objs, $o if defined $o;
+            $depth = 0;
+            push @address, $_;
+        }
+    }
+    @objs;
+}
+
+#------------
+
+sub phrase  { shift->set_or_get(0, @_) }
+sub address { shift->set_or_get(1, @_) }
+sub comment { shift->set_or_get(2, @_) }
+
+sub set_or_get($)
+{   my ($self, $i) = (shift, shift);
+    @_ or return $self->[$i];
+
+    my $val = $self->[$i];
+    $self->[$i] = shift if @_;
+    $val;
+}
+
+
+my $atext = '[\-\w !#$%&\'*+/=?^`{|}~]';
+sub format
+{   my @addrs;
+
+    foreach (@_)
+    {   my ($phrase, $email, $comment) = @$_;
+        my @addr;
+
+        if(defined $phrase && length $phrase)
+        {   push @addr
+              , $phrase =~ /^(?:\s*$atext\s*)+$/o ? $phrase
+              : $phrase =~ /(?<!\\)"/             ? $phrase
+              :                                    qq("$phrase");
+
+            push @addr, "<$email>"
+                if defined $email && length $email;
+        }
+        elsif(defined $email && length $email)
+        {   push @addr, $email;
+        }
+
+        if(defined $comment && $comment =~ /\S/)
+        {   $comment =~ s/^\s*\(?/(/;
+            $comment =~ s/\)?\s*$/)/;
+        }
+
+        push @addr, $comment
+            if defined $comment && length $comment;
+
+        push @addrs, join(" ", @addr)
+            if @addr;
+    }
+
+    join ", ", @addrs;
+}
+
+#------------
+
+sub name
+{   my $self   = shift;
+    my $phrase = $self->phrase;
+    my $addr   = $self->address;
+
+    $phrase    = $self->comment
+        unless defined $phrase && length $phrase;
+
+    my $name   = $self->_extract_name($phrase);
+
+    # first.last@domain address
+    if($name eq '' && $addr =~ /([^\%\.\@_]+([\._][^\%\.\@_]+)+)[\@\%]/)
+    {   ($name  = $1) =~ s/[\._]+/ /g;
+	$name   = _extract_name $name;
+    }
+
+    if($name eq '' && $addr =~ m#/g=#i)    # X400 style address
+    {   my ($f) = $addr =~ m#g=([^/]*)#i;
+	my ($l) = $addr =~ m#s=([^/]*)#i;
+	$name   = _extract_name "$f $l";
+    }
+
+    length $name ? $name : undef;
+}
+
+
+sub host
+{   my $addr = shift->address || '';
+    my $i    = rindex $addr, '@';
+    $i >= 0 ? substr($addr, $i+1) : undef;
+}
+
+
+sub user
+{   my $addr = shift->address || '';
+    my $i    = rindex $addr, '@';
+    $i >= 0 ? substr($addr,0,$i) : $addr;
+}
+
+1;
diff --git a/perl/Git/Mail/Address.pm b/perl/Git/Mail/Address.pm
new file mode 100755
index 0000000000..2ce3e84670
--- /dev/null
+++ b/perl/Git/Mail/Address.pm
@@ -0,0 +1,24 @@
+package Git::Mail::Address;
+use 5.008;
+use strict;
+use warnings;
+
+=head1 NAME
+
+Git::Mail::Address - Wrapper for the L<Mail::Address> module, in case it's not installed
+
+=head1 DESCRIPTION
+
+This module is only intended to be used for code shipping in the
+C<git.git> repository. Use it for anything else at your peril!
+
+=cut
+
+eval {
+    require Mail::Address;
+    1;
+} or do {
+    require Git::FromCPAN::Mail::Address;
+};
+
+1;