[PATCH] Pull gitweb If-Modified-Since handling out into its own function and use for snapshots.

["W. Trevor King" <wking@xxxxxxxxxx>]

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 modified_since.  This makes the code easy
to reuse for other actions where it is appropriate, and I've added the
code to do that in git_snapshot.

Signed-off-by: W Trevor King <wking@xxxxxxxxxx>

---
 gitweb/gitweb.perl |   54 ++++++++++++++++++++++++++++++++++++---------------
 1 files changed, 38 insertions(+), 16 deletions(-)

diff --git a/gitweb/gitweb.perl b/gitweb/gitweb.perl
index a8b5fad..96a13e7 100755
--- a/gitweb/gitweb.perl
+++ b/gitweb/gitweb.perl
@@ -7003,6 +7003,31 @@ sub snapshot_name {
 	return wantarray ? ($name, $name) : $name;
 }
 
+sub modified_since {
+	my ($content_type, $latest_epoch, $timezone) = @_;
+	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, $timezone);
+			print $cgi->header(
+				-type => $content_type,
+				-charset => 'utf-8',
+				-last_modified => $latest_date{'rfc2822'},
+				-status => '304 Not Modified');
+			return 0;
+		}
+	}
+	return 1;
+}
+
 sub git_snapshot {
 	my $format = $input_params{'snapshot_format'};
 	if (!@snapshot_fmts) {
@@ -7029,6 +7054,14 @@ sub git_snapshot {
 
 	my ($name, $prefix) = snapshot_name($project, $hash);
 	my $filename = "$name$known_snapshot_formats{$format}{'suffix'}";
+
+	my %co = parse_commit($hash) or die_error(404, "Unknown commit object");
+	if (! modified_since($known_snapshot_formats{$format}{'type'},
+	                     $co{'committer_epoch'},
+	                     $co{'committer_tz'})) {
+		return;
+	}
+
 	my $cmd = quote_command(
 		git_cmd(), 'archive',
 		"--format=$known_snapshot_formats{$format}{'format'}",
@@ -7038,9 +7071,11 @@ sub git_snapshot {
 	}
 
 	$filename =~ s/(["\\])/\\$1/g;
+	my %latest_date = parse_date($co{'committer_epoch'}, $co{'committer_tz'});
 	print $cgi->header(
 		-type => $known_snapshot_formats{$format}{'type'},
 		-content_disposition => 'inline; filename="' . $filename . '"',
+		-last_modified => $latest_date{'rfc2822'},
 		-status => '200 OK');
 
 	open my $fd, "-|", $cmd
@@ -7821,22 +7856,9 @@ sub git_feed {
 		%latest_commit = %{$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 => $latest_date{'rfc2822'},
-					-status => '304 Not Modified');
-				return;
-			}
+		if (! modified_since($content_type, $latest_epoch,
+		                     $latest_commit{'comitter_tz'})) {
+			return;
 		}
 		print $cgi->header(
 			-type => $content_type,
-- 
1.7.3.4

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