From bc311cda51a2b3c4b9b8fea5a257bca6c5b70c28 Mon Sep 17 00:00:00 2001
From: "Kyle J. McKay" <mackyle@gmail.com>
Date: Mon, 13 Apr 2015 19:46:46 -0700
Subject: [PATCH] gitweb: improve blob_plain charset

When gitweb returns blob_plain data it doesn't really
do a very good job returning the correct charset value.

Update the logic so that when returning a text/...
type the charset will be set correctly in most
cases based on the first portion of the content.

Signed-off-by: Kyle J. McKay <mackyle@gmail.com>
---
 gitweb/gitweb.perl | 77 +++++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 53 insertions(+), 24 deletions(-)

diff --git a/gitweb/gitweb.perl b/gitweb/gitweb.perl
index faac5e5a12..e6e8678904 100755
--- a/gitweb/gitweb.perl
+++ b/gitweb/gitweb.perl
@@ -165,7 +165,7 @@ our $strict_export = "++GITWEB_STRICT_EXPORT++";
 our @git_base_url_list = grep { $_ ne '' } ("++GITWEB_BASE_URL++");
 
 # default blob_plain mimetype and default charset for text/plain blob
-our $default_blob_plain_mimetype = 'text/plain';
+our $default_blob_plain_mimetype = 'application/octet-stream';
 our $default_text_plain_charset  = undef;
 
 # file to use for guessing MIME types before trying /etc/mime.types
@@ -3908,39 +3908,65 @@ sub mimetype_guess {
 sub blob_mimetype {
 	my $fd = shift;
 	my $filename = shift;
+	my $mime;
+
+	$mime = mimetype_guess($filename) if defined $filename;
 
-	if ($filename) {
-		my $mime = mimetype_guess($filename);
-		$mime and return $mime;
+	if (!$mime && $filename) {
+		if ($filename =~ m/\.html?$/i) {
+			$mime = 'text/html';
+		} elsif ($filename =~ m/\.xht(?:ml)?$/i) {
+			$mime = 'text/html';
+		} elsif ($filename =~ m/\.te?xt?$/i) {
+			$mime = 'text/plain';
+		} elsif ($filename =~ m/\.(?:markdown|md)$/i) {
+			$mime = 'text/plain';
+		} elsif ($filename =~ m/\.png$/i) {
+			$mime = 'image/png';
+		} elsif ($filename =~ m/\.gif$/i) {
+			$mime = 'image/gif';
+		} elsif ($filename =~ m/\.jpe?g$/i) {
+			$mime = 'image/jpeg';
+		} elsif ($filename =~ m/\.svgz?$/i) {
+			$mime = 'image/svg+xml';
+		}
 	}
 
 	# just in case
-	return $default_blob_plain_mimetype unless $fd;
-
-	if (-T $fd) {
-		return 'text/plain';
-	} elsif (! $filename) {
-		return 'application/octet-stream';
-	} elsif ($filename =~ m/\.png$/i) {
-		return 'image/png';
-	} elsif ($filename =~ m/\.gif$/i) {
-		return 'image/gif';
-	} elsif ($filename =~ m/\.jpe?g$/i) {
-		return 'image/jpeg';
-	} else {
-		return 'application/octet-stream';
-	}
+	return $default_blob_plain_mimetype unless $fd || $mime;
+
+	$mime = -T $fd ? 'text/plain' : 'application/octet-stream' unless $mime;
+
+	return $mime;
+}
+
+sub is_ascii {
+	use bytes;
+	my $data = shift;
+	return scalar($data =~ /^[\x00-\x7f]*$/);
+}
+
+sub is_valid_utf8 {
+	my $data = shift;
+	return utf8::decode($data);
 }
 
 sub blob_contenttype {
 	my ($fd, $file_name, $type) = @_;
+	my $leader;
 
 	$type ||= blob_mimetype($fd, $file_name);
-	if ($type eq 'text/plain' && defined $default_text_plain_charset) {
-		$type .= "; charset=$default_text_plain_charset";
+	return $type unless $type =~ m!^text/.+!;
+	if ($fd && read($fd, $leader, 16384)) {
+		return ("$type; charset=US-ASCII", $leader) if is_ascii($leader);
+		return ("$type; charset=UTF-8", $leader) if is_valid_utf8($leader);
+		return ("$type; charset=ISO-8859-1", $leader)
+			if defined $default_text_plain_charset &&
+			   $default_text_plain_charset =~ /utf-?8/i;
 	}
-
-	return $type;
+	return ("$type; charset=$default_text_plain_charset", $leader)
+		if defined $default_text_plain_charset;
+	return ($type, $leader);
 }
 
 # guess file syntax for syntax highlighting; return undef if no highlighting
@@ -7023,7 +7049,8 @@ sub git_blob_plain {
 	binmode($fd);
 
 	# content-type (can include charset)
-	$type = blob_contenttype($fd, $file_name, $type);
+	my $leader;
+	($type, $leader) = blob_contenttype($fd, $file_name, $type);
 
 	# "save as" filename, even when no $file_name is given
 	my $save_as = "$hash";
@@ -7058,6 +7085,7 @@ sub git_blob_plain {
 			($sandbox ? 'attachment' : 'inline')
 			. '; filename="' . $save_as . '"');
 	binmode STDOUT, ':raw';
+	print $leader if defined $leader;
 	my $buf;
 	while (read($fd, $buf, 32768)) {
 		print $buf;
@@ -7085,6 +7113,7 @@ sub git_blob {
 	my $have_blame = gitweb_check_feature('blame');
 	defined(my $fd = git_cmd_pipe "cat-file", "blob", $hash)
 		or die_error(500, "Couldn't cat $file_name, $hash");
+	binmode($fd);
 	my $mimetype = blob_mimetype($fd, $file_name);
 	# use 'blob_plain' (aka 'raw') view for files that cannot be displayed
 	if ($mimetype !~ m!^(?:text/|image/(?:gif|png|jpeg)$)! && -B $fd) {
-- 
2.11.4.GIT