gitweb: refactor If-Modified-Since handling

The current gitweb only generates Last-Modified and handles
If-Modified-Since headers for the git_feed action.  This patch breaks
the Last-Modified and If-Modified-Since handling code out from
git_feed into a new function exit_if_unmodified_since.  This makes the
code easy to reuse for other actions.

Only gitweb actions which can easily calculate a modification time
should use exit_if_unmodified_since, as the goal is to balance local
processing time vs. upload bandwidth.

Signed-off-by: W Trevor King <redacted>
Acked-by: Jakub Narebski <redacted>
Signed-off-by: Junio C Hamano <redacted>

diff --git a/gitweb.perl b/gitweb.perl
index 2d03fd76a27b8b7489f219d3672d3faa445be382e337a5bec91d050454831803..349a7d22f4a9ec4bd421111ae501f7f351dc632160d4ea03bbc51db2afe28452 100755 (executable)
--- a/gitweb.perl
+++ b/gitweb.perl
@@ -7004,6 +7004,28 @@ sub snapshot_name {
        return wantarray ? ($name, $name) : $name;
 }
 
        return wantarray ? ($name, $name) : $name;
 }
 

+sub exit_if_unmodified_since {
+       my ($latest_epoch) = @_;
+       our $cgi;
+
+       my $if_modified = $cgi->http('IF_MODIFIED_SINCE');
+       if (defined $if_modified) {
+               my $since;
+               if (eval { require HTTP::Date; 1; }) {
+                       $since = HTTP::Date::str2time($if_modified);
+               } elsif (eval { require Time::ParseDate; 1; }) {
+                       $since = Time::ParseDate::parsedate($if_modified, GMT => 1);
+               }
+               if (defined $since && $latest_epoch <= $since) {
+                       my %latest_date = parse_date($latest_epoch);
+                       print $cgi->header(
+                               -last_modified => $latest_date{'rfc2822'},
+                               -status => '304 Not Modified');
+                       goto DONE_GITWEB;
+               }
+       }
+}
+

 sub git_snapshot {
        my $format = $input_params{'snapshot_format'};
        if (!@snapshot_fmts) {
 sub git_snapshot {
        my $format = $input_params{'snapshot_format'};
        if (!@snapshot_fmts) {


@@ -7821,35 +7843,14 @@ sub git_feed {
        if (defined($commitlist[0])) {
                %latest_commit = %{$commitlist[0]};
                my $latest_epoch = $latest_commit{'committer_epoch'};
        if (defined($commitlist[0])) {
                %latest_commit = %{$commitlist[0]};
                my $latest_epoch = $latest_commit{'committer_epoch'};

-               %latest_date   = parse_date($latest_epoch, $latest_commit{'comitter_tz'});
-               my $if_modified = $cgi->http('IF_MODIFIED_SINCE');
-               if (defined $if_modified) {
-                       my $since;
-                       if (eval { require HTTP::Date; 1; }) {
-                               $since = HTTP::Date::str2time($if_modified);
-                       } elsif (eval { require Time::ParseDate; 1; }) {
-                               $since = Time::ParseDate::parsedate($if_modified, GMT => 1);
-                       }
-                       if (defined $since && $latest_epoch <= $since) {
-                               print $cgi->header(
-                                       -type => $content_type,
-                                       -charset => 'utf-8',
-                                       -last_modified => $latest_date{'rfc2822'},
-                                       -status => '304 Not Modified');
-                               return;
-                       }
-               }
-               print $cgi->header(
-                       -type => $content_type,
-                       -charset => 'utf-8',
-                       -last_modified => $latest_date{'rfc2822'},
-                       -status => '200 OK');
-       } else {
-               print $cgi->header(
-                       -type => $content_type,
-                       -charset => 'utf-8',
-                       -status => '200 OK');
+               exit_if_unmodified_since($latest_epoch);
+               %latest_date = parse_date($latest_epoch, $latest_commit{'comitter_tz'});

        }
        }

+       print $cgi->header(
+               -type => $content_type,
+               -charset => 'utf-8',
+               %latest_date ? (-last_modified => $latest_date{'rfc2822'}) : (),
+               -status => '200 OK');

 
        # Optimization: skip generating the body if client asks only
        # for Last-Modified date.
 
        # Optimization: skip generating the body if client asks only
        # for Last-Modified date.