gitweb: Fix handling of whitespace in generated links

When creating path_info part of link, don't encode space as '+', because
while $cgi->param('foo') translates '+' in query param to ' ', neither
$ENV{'PATH_INFO'} nor $cgi->path_info() do.

This fixes the issue with pathnames with embedded whitespace and
$feature{'pathinfo'} / path_info links.  It is done by using newly
introduced esc_path_info() instead of esc_url() in href() subroutine.

Also while links are more clear not escaping space (' ') characters in
generated links, the trailing space must be URI-encoded, otherwise would
get discarded.

Issue noticed thanks to John 'Warthog9' Hawley.

Signed-off-by: Jakub Narebski <jnareb@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

gitweb/gitweb.perl

@@ -1186,7 +1186,7 @@ sub href {
 		$href =~ s,/$,,;
 
 		# Then add the project name, if present
-		$href .= "/".esc_url($params{'project'});
+		$href .= "/".esc_path_info($params{'project'});
 		delete $params{'project'};
 
 		# since we destructively absorb parameters, we keep this
@@ -1196,7 +1196,8 @@ sub href {
 		# Summary just uses the project path URL, any other action is
 		# added to the URL
 		if (defined $params{'action'}) {
-			$href .= "/".esc_url($params{'action'}) unless $params{'action'} eq 'summary';
+			$href .= "/".esc_path_info($params{'action'})
+				unless $params{'action'} eq 'summary';
 			delete $params{'action'};
 		}
 
@@ -1206,13 +1207,13 @@ sub href {
 			|| $params{'hash_parent'} || $params{'hash'});
 		if (defined $params{'hash_base'}) {
 			if (defined $params{'hash_parent_base'}) {
-				$href .= esc_url($params{'hash_parent_base'});
+				$href .= esc_path_info($params{'hash_parent_base'});
 				# skip the file_parent if it's the same as the file_name
 				if (defined $params{'file_parent'}) {
 					if (defined $params{'file_name'} && $params{'file_parent'} eq $params{'file_name'}) {
 						delete $params{'file_parent'};
 					} elsif ($params{'file_parent'} !~ /\.\./) {
-						$href .= ":/".esc_url($params{'file_parent'});
+						$href .= ":/".esc_path_info($params{'file_parent'});
 						delete $params{'file_parent'};
 					}
 				}
@@ -1220,19 +1221,19 @@ sub href {
 				delete $params{'hash_parent'};
 				delete $params{'hash_parent_base'};
 			} elsif (defined $params{'hash_parent'}) {
-				$href .= esc_url($params{'hash_parent'}). "..";
+				$href .= esc_path_info($params{'hash_parent'}). "..";
 				delete $params{'hash_parent'};
 			}
 
-			$href .= esc_url($params{'hash_base'});
+			$href .= esc_path_info($params{'hash_base'});
 			if (defined $params{'file_name'} && $params{'file_name'} !~ /\.\./) {
-				$href .= ":/".esc_url($params{'file_name'});
+				$href .= ":/".esc_path_info($params{'file_name'});
 				delete $params{'file_name'};
 			}
 			delete $params{'hash'};
 			delete $params{'hash_base'};
 		} elsif (defined $params{'hash'}) {
-			$href .= esc_url($params{'hash'});
+			$href .= esc_path_info($params{'hash'});
 			delete $params{'hash'};
 		}
 
@@ -1265,6 +1266,9 @@ sub href {
 	}
 	$href .= "?" . join(';', @result) if scalar @result;
 
+	# final transformation: trailing spaces must be escaped (URI-encoded)
+	$href =~ s/(\s+)$/CGI::escape($1)/e;
+
 	return $href;
 }
 
@@ -1347,6 +1351,17 @@ sub esc_param {
 	return $str;
 }
 
+# the quoting rules for path_info fragment are slightly different
+sub esc_path_info {
+	my $str = shift;
+	return undef unless defined $str;
+
+	# path_info doesn't treat '+' as space (specially), but '?' must be escaped
+	$str =~ s/([^A-Za-z0-9\-_.~();\/;:@&= +]+)/CGI::escape($1)/eg;
+
+	return $str;
+}
+
 # quote unsafe chars in whole URL, so some characters cannot be quoted
 sub esc_url {
 	my $str = shift;