gitweb: Handle non UTF-8 text better

gitweb assumes that everything is in UTF-8. If a text contains invalid
UTF-8 character sequences, the text must be in a different encoding.

This commit introduces $fallback_encoding which would be used as input
encoding if gitweb encounters text with is not valid UTF-8.

Add basic test for this in t/t9500-gitweb-standalone-no-errors.sh

Signed-off-by: Martin Koegler <mkoegler@auto.tuwien.ac.at>
Signed-off-by: Jakub Narebski <jnareb@gmail.com>
Tested-by: Alexandre Julliard <julliard@winehq.org>
Tested-by: Ismail Dönmez <ismail@pardus.org.tr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

gitweb/gitweb.perl

@@ -94,6 +94,13 @@ BEGIN
 # (relative to the current git repository)
 our $mimetypes_file = undef;
 
+# assume this charset if line contains non-UTF-8 characters;
+# it should be valid encoding (see Encoding::Supported(3pm) for list),
+# for which encoding all byte sequences are valid, for example
+# 'iso-8859-1' aka 'latin1' (it is decoded without checking, so it
+# could be even 'utf-8' for the old behavior)
+our $fallback_encoding = 'latin1';
+
 # You define site-wide feature defaults here; override them with
 # $GITWEB_CONFIG as necessary.
 our %feature = (
@@ -602,6 +609,20 @@ sub validate_refname {
 	return $input;
 }
 
+# decode sequences of octets in utf8 into Perl's internal form,
+# which is utf-8 with utf8 flag set if needed.  gitweb writes out
+# in utf-8 thanks to "binmode STDOUT, ':utf8'" at beginning
+sub to_utf8 {
+	my $str = shift;
+	my $res;
+	eval { $res = decode_utf8($str, Encode::FB_CROAK); };
+	if (defined $res) {
+		return $res;
+	} else {
+		return decode($fallback_encoding, $str, Encode::FB_DEFAULT);
+	}
+}
+
 # quote unsafe chars, but keep the slash, even when it's not
 # correct, but quoted slashes look too horrible in bookmarks
 sub esc_param {
@@ -626,7 +647,7 @@ ($;%)
 	my $str = shift;
 	my %opts = @_;
 
-	$str = decode_utf8($str);
+	$str = to_utf8($str);
 	$str = $cgi->escapeHTML($str);
 	if ($opts{'-nbsp'}) {
 		$str =~ s/ / /g;
@@ -640,7 +661,7 @@ sub esc_path {
 	my $str = shift;
 	my %opts = @_;
 
-	$str = decode_utf8($str);
+	$str = to_utf8($str);
 	$str = $cgi->escapeHTML($str);
 	if ($opts{'-nbsp'}) {
 		$str =~ s/ / /g;
@@ -925,7 +946,7 @@ sub format_subject_html {
 
 	if (length($short) < length($long)) {
 		return $cgi->a({-href => $href, -class => "list subject",
-		                -title => decode_utf8($long)},
+		                -title => to_utf8($long)},
 		       esc_html($short) . $extra);
 	} else {
 		return $cgi->a({-href => $href, -class => "list subject"},
@@ -1239,7 +1260,7 @@ sub git_get_projects_list {
 			if (check_export_ok("$projectroot/$path")) {
 				my $pr = {
 					path => $path,
-					owner => decode_utf8($owner),
+					owner => to_utf8($owner),
 				};
 				push @list, $pr;
 				(my $forks_path = $path) =~ s/\.git$//;
@@ -1269,7 +1290,7 @@ sub git_get_project_owner {
 			$pr = unescape($pr);
 			$ow = unescape($ow);
 			if ($pr eq $project) {
-				$owner = decode_utf8($ow);
+				$owner = to_utf8($ow);
 				last;
 			}
 		}
@@ -1759,7 +1780,7 @@ sub get_file_owner {
 	}
 	my $owner = $gcos;
 	$owner =~ s/[,;].*$//;
-	return decode_utf8($owner);
+	return to_utf8($owner);
 }
 
 ## ......................................................................
@@ -1842,7 +1863,7 @@ sub git_header_html {
 
 	my $title = "$site_name";
 	if (defined $project) {
-		$title .= " - " . decode_utf8($project);
+		$title .= " - " . to_utf8($project);
 		if (defined $action) {
 			$title .= "/$action";
 			if (defined $file_name) {
@@ -2116,7 +2137,7 @@ sub git_print_page_path {
 
 	print "<div class=\"page_path\">";
 	print $cgi->a({-href => href(action=>"tree", hash_base=>$hb),
-	              -title => 'tree root'}, decode_utf8("[$project]"));
+	              -title => 'tree root'}, to_utf8("[$project]"));
 	print " / ";
 	if (defined $name) {
 		my @dirname = split '/', $name;
@@ -2936,7 +2957,7 @@ sub git_project_list_body {
 		($pr->{'age'}, $pr->{'age_string'}) = @aa;
 		if (!defined $pr->{'descr'}) {
 			my $descr = git_get_project_description($pr->{'path'}) || "";
-			$pr->{'descr_long'} = decode_utf8($descr);
+			$pr->{'descr_long'} = to_utf8($descr);
 			$pr->{'descr'} = chop_str($descr, 25, 5);
 		}
 		if (!defined $pr->{'owner'}) {
@@ -3981,7 +4002,7 @@ sub git_snapshot {
 	my $git = git_cmd_str();
 	my $name = $project;
 	$name =~ s/\047/\047\\\047\047/g;
-	my $filename = decode_utf8(basename($project));
+	my $filename = to_utf8(basename($project));
 	my $cmd;
 	if ($suffix eq 'zip') {
 		$filename .= "-$hash.$suffix";

t/t9500-gitweb-standalone-no-errors.sh

@@ -487,4 +487,32 @@ test_expect_success \
 	'gitweb_run "p=.git;a=atom"'
 test_debug 'cat gitweb.log'
 
+# ----------------------------------------------------------------------
+# encoding/decoding
+
+test_expect_success \
+	'encode(commit): utf8' \
+	'. ../t3901-utf8.txt &&
+	 echo "UTF-8" >> file &&
+	 git add file &&
+	 git commit -F ../t3900/1-UTF-8.txt &&
+	 gitweb_run "p=.git;a=commit"'
+test_debug 'cat gitweb.log'
+
+test_expect_success \
+	'encode(commit): iso-8859-1' \
+	'. ../t3901-8859-1.txt &&
+	 echo "ISO-8859-1" >> file &&
+	 git add file &&
+	 git config i18n.commitencoding ISO-8859-1 &&
+	 git commit -F ../t3900/ISO-8859-1.txt &&
+	 git config --unset i18n.commitencoding &&
+	 gitweb_run "p=.git;a=commit"'
+test_debug 'cat gitweb.log'
+
+test_expect_success \
+	'encode(log): utf-8 and iso-8859-1' \
+	'gitweb_run "p=.git;a=log"'
+test_debug 'cat gitweb.log'
+
 test_done