[PATCH/RFC (version B)] gitweb: Allow UTF-8 encoded CGI query parameters and path_info

[Jakub Narebski <jnareb@gmail.com>]

Gitweb tries hard to properly process UTF-8 data, by marking output
from git commands and contents of files as UTF-8 with to_utf8()
subroutine.  This ensures that gitweb would print correctly UTF-8
e.g. in 'log' and 'commit' views.

Unfortunately it misses another source of potentially Unicode input,
namely query parameters.  The result is that one cannot search for a
string containing characters outside US-ASCII.  For example searching
for "Michał Kiedrowicz" (containing letter 'ł' - LATIN SMALL LETTER L
WITH STROKE, with Unicode codepoint U+0142, represented with 0xc5 0x82
bytes in UTF-8 and percent-encoded as %C5%81) result in the following
incorrect data in search field

	Michał Kiedrowicz

This is caused by CGI by default treating '0xc5 0x82' bytes as two
characters in Perl legacy encoding latin-1 (iso-8859-1), because 's'
query parameter is not processed explicitly as UTF-8 encoded string.

The solution used here follows "Using Unicode in a Perl CGI script"
article on http://www.lemoda.net/cgi/perl-unicode/index.html:

	use CGI;
	use Encode 'decode_utf8;
	my $value = params('input');
	$value = decode_utf8($value);

This is done when filling %input_params hash; this required to move
from explicit $cgi->param(<label>) to $input_params{<name>} in a few
places.

Alternate solution would be to simply use the '-utf8' pragma (via
"use CGI '-utf8';"), but according to CGI.pm documentation it may
cause problems with POST requests containing binary files... and
it doesn't work with old CGI.pm version 3.10 from Perl v5.8.6.

Noticed-by: Michał Kiedrowicz <michal.kiedrowicz@gmail.com>
Signed-off-by: Jakub Narębski <jnareb@gmail.com>
---
 gitweb/gitweb.perl |   12 ++++++------
 1 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/gitweb/gitweb.perl b/gitweb/gitweb.perl
index 9cf7e71..55b2c24 100755
--- a/gitweb/gitweb.perl
+++ b/gitweb/gitweb.perl
@@ -52,7 +52,7 @@ sub evaluate_uri {
 	# as base URL.
 	# Therefore, if we needed to strip PATH_INFO, then we know that we have
 	# to build the base URL ourselves:
-	our $path_info = $ENV{"PATH_INFO"};
+	our $path_info = decode_utf8($ENV{"PATH_INFO"});
 	if ($path_info) {
 		if ($my_url =~ s,\Q$path_info\E$,, &&
 		    $my_uri =~ s,\Q$path_info\E$,, &&
@@ -816,9 +816,9 @@ sub evaluate_query_params {
 
 	while (my ($name, $symbol) = each %cgi_param_mapping) {
 		if ($symbol eq 'opt') {
-			$input_params{$name} = [ $cgi->param($symbol) ];
+			$input_params{$name} = [ map { decode_utf8($_) } $cgi->param($symbol) ];
 		} else {
-			$input_params{$name} = $cgi->param($symbol);
+			$input_params{$name} = decode_utf8($cgi->param($symbol));
 		}
 	}
 }
@@ -2767,7 +2767,7 @@ sub git_populate_project_tagcloud {
 	}
 
 	my $cloud;
-	my $matched = $cgi->param('by_tag');
+	my $matched = $input_params{'ctag'};
 	if (eval { require HTML::TagCloud; 1; }) {
 		$cloud = HTML::TagCloud->new;
 		foreach my $ctag (sort keys %ctags_lc) {
@@ -5282,7 +5282,7 @@ sub git_project_list_body {
 
 	my $check_forks = gitweb_check_feature('forks');
 	my $show_ctags  = gitweb_check_feature('ctags');
-	my $tagfilter = $show_ctags ? $cgi->param('by_tag') : undef;
+	my $tagfilter = $show_ctags ? $input_params{'ctag'} : undef;
 	$check_forks = undef
 		if ($tagfilter || $searchtext);
 
@@ -6197,7 +6197,7 @@ sub git_tag {
 
 sub git_blame_common {
 	my $format = shift || 'porcelain';
-	if ($format eq 'porcelain' && $cgi->param('js')) {
+	if ($format eq 'porcelain' && $input_params{'javascript'}) {
 		$format = 'incremental';
 		$action = 'blame_incremental'; # for page title etc
 	}
-- 
1.7.6