gitweb: A bit of code cleanup in git_blame()

Among others, here are the highlights:

 * move variable declaration closer to the place it is set and used,
   if possible,

 * uniquify and simplify coding style a bit, which includes removing
   unnecessary '()'.

 * check type only if $hash was defined, as otherwise from the way
   git_get_hash_by_path() is called (and works), we know that it is
   a blob,

 * use modern calling convention for git-blame,

 * remove unused variable,

 * don't use implicit variables ($_),

 * add some comments

Signed-off-by: Jakub Narebski <jnareb@gmail.com>
Acked-by: Luben Tuikov <ltuikov@yahoo.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/gitweb/gitweb.perl b/gitweb/gitweb.perl
index e01e1afe95bc49b0ab264bcdd8ee91af5deee23a..ccbf5d47452d9ea14e44d20a1586097741a2451e 100755 (executable)
--- a/gitweb/gitweb.perl
+++ b/gitweb/gitweb.perl
@@ -4575,28 +4575,33 @@ sub git_tag {
 }
 
 sub git_blame {
-       my $fd;
-       my $ftype;
-
+       # permissions
        gitweb_check_feature('blame')
-           or die_error(403, "Blame view not allowed");
+               or die_error(403, "Blame view not allowed");
 
+       # error checking
        die_error(400, "No file name given") unless $file_name;
        $hash_base ||= git_get_head_hash($project);
-       die_error(404, "Couldn't find base commit") unless ($hash_base);
+       die_error(404, "Couldn't find base commit") unless $hash_base;
        my %co = parse_commit($hash_base)
                or die_error(404, "Commit not found");
+       my $ftype = "blob";
        if (!defined $hash) {
                $hash = git_get_hash_by_path($hash_base, $file_name, "blob")
                        or die_error(404, "Error looking up file");
+       } else {
+               $ftype = git_get_type($hash);
+               if ($ftype !~ "blob") {
+                       die_error(400, "Object is not a blob");
+               }
        }
-       $ftype = git_get_type($hash);
-       if ($ftype !~ "blob") {
-               die_error(400, "Object is not a blob");
-       }
-       open ($fd, "-|", git_cmd(), "blame", '-p', '--',
-             $file_name, $hash_base)
+
+       # run git-blame --porcelain
+       open my $fd, "-|", git_cmd(), "blame", '-p',
+               $hash_base, '--', $file_name
                or die_error(500, "Open git-blame failed");
+
+       # page header
        git_header_html();
        my $formats_nav =
                $cgi->a({-href => href(action=>"blob", -replay=>1)},
@@ -4610,40 +4615,44 @@ sub git_blame {
        git_print_page_nav('','', $hash_base,$co{'tree'},$hash_base, $formats_nav);
        git_print_header_div('commit', esc_html($co{'title'}), $hash_base);
        git_print_page_path($file_name, $ftype, $hash_base);
-       my @rev_color = (qw(light2 dark2));
+
+       # page body
+       my @rev_color = qw(light2 dark2);
        my $num_colors = scalar(@rev_color);
        my $current_color = 0;
-       my $last_rev;
+       my %metainfo = ();
+
        print <<HTML;
 <div class="page_body">
 <table class="blame">
 <tr><th>Commit</th><th>Line</th><th>Data</th></tr>
 HTML
-       my %metainfo = ();
-       while (1) {
-               $_ = <$fd>;
-               last unless defined $_;
+ LINE:
+       while (my $line = <$fd>) {
+               chomp $line;
+               # the header: <SHA-1> <src lineno> <dst lineno> [<lines in group>]
+               # no <lines in group> for subsequent lines in group of lines
                my ($full_rev, $orig_lineno, $lineno, $group_size) =
-                   /^([0-9a-f]{40}) (\d+) (\d+)(?: (\d+))?$/;
+                  ($line =~ /^([0-9a-f]{40}) (\d+) (\d+)(?: (\d+))?$/);
                if (!exists $metainfo{$full_rev}) {
                        $metainfo{$full_rev} = {};
                }
                my $meta = $metainfo{$full_rev};
-               while (<$fd>) {
-                       last if (s/^\t//);
-                       if (/^(\S+) (.*)$/) {
+               my $data;
+               while ($data = <$fd>) {
+                       chomp $data;
+                       last if ($data =~ s/^\t//); # contents of line
+                       if ($data =~ /^(\S+) (.*)$/) {
                                $meta->{$1} = $2;
                        }
                }
-               my $data = $_;
-               chomp $data;
-               my $rev = substr($full_rev, 0, 8);
+               my $short_rev = substr($full_rev, 0, 8);
                my $author = $meta->{'author'};
-               my %date = parse_date($meta->{'author-time'},
-                                     $meta->{'author-tz'});
+               my %date =
+                       parse_date($meta->{'author-time'}, $meta->{'author-tz'});
                my $date = $date{'iso-tz'};
                if ($group_size) {
-                       $current_color = ++$current_color % $num_colors;
+                       $current_color = ($current_color + 1) % $num_colors;
                }
                print "<tr id=\"l$lineno\" class=\"$rev_color[$current_color]\">\n";
                if ($group_size) {
@@ -4654,7 +4663,7 @@ HTML
                        print $cgi->a({-href => href(action=>"commit",
                                                     hash=>$full_rev,
                                                     file_name=>$file_name)},
-                                     esc_html($rev));
+                                     esc_html($short_rev));
                        print "</td>\n";
                }
                open (my $dd, "-|", git_cmd(), "rev-parse", "$full_rev^")
@@ -4677,6 +4686,8 @@ HTML
        print "</div>";
        close $fd
                or print "Reading blob failed\n";
+
+       # page footer
        git_footer_html();
 }