gitweb: Teach "a=blob" action to be more lenient about blob/file mime type

Since 930cf7dd7c 'blob' action knows the
file type; if the file type is not "text/*" or one of common network
image formats/mimetypes (gif, png, jpeg) then the action "blob"
defaulted to "blob_plain".  This caused the problem if mimetypes file
was not well suited for web, for example returning "application/x-sh"
for "*.sh" shell scripts, instead of "text/plain" (or other "text/*").

Now "blob" action defaults to "blob_plain" ('raw' view) only if file
is of type which is neither "text/*" nor "image/{gif,png,jpeg}"
AND it is binary file.  Otherwise it assumes that it can be displayed
either in <img> tag ("image/*" mimetype), or can be displayed line by
line (otherwise).

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

gitweb/gitweb.perl

@@ -4290,7 +4290,7 @@ sub git_blob {
 	open my $fd, "-|", git_cmd(), "cat-file", "blob", $hash
 		or die_error(undef, "Couldn't cat $file_name, $hash");
 	my $mimetype = blob_mimetype($fd, $file_name);
-	if ($mimetype !~ m!^(?:text/|image/(?:gif|png|jpeg)$)!) {
+	if ($mimetype !~ m!^(?:text/|image/(?:gif|png|jpeg)$)! && -B $fd) {
 		close $fd;
 		return git_blob_plain($mimetype);
 	}
@@ -4331,16 +4331,7 @@ sub git_blob {
 	}
 	git_print_page_path($file_name, "blob", $hash_base);
 	print "<div class=\"page_body\">\n";
-	if ($mimetype =~ m!^text/!) {
-		my $nr;
-		while (my $line = <$fd>) {
-			chomp $line;
-			$nr++;
-			$line = untabify($line);
-			printf "<div class=\"pre\"><a id=\"l%i\" href=\"#l%i\" class=\"linenr\">%4i</a> %s</div>\n",
-			       $nr, $nr, $nr, esc_html($line, -nbsp=>1);
-		}
-	} elsif ($mimetype =~ m!^image/!) {
+	if ($mimetype =~ m!^image/!) {
 		print qq!<img type="$mimetype"!;
 		if ($file_name) {
 			print qq! alt="$file_name" title="$file_name"!;
@@ -4349,6 +4340,15 @@ sub git_blob {
 		      href(action=>"blob_plain", hash=>$hash,
 		           hash_base=>$hash_base, file_name=>$file_name) .
 		      qq!" />\n!;
+	} else {
+		my $nr;
+		while (my $line = <$fd>) {
+			chomp $line;
+			$nr++;
+			$line = untabify($line);
+			printf "<div class=\"pre\"><a id=\"l%i\" href=\"#l%i\" class=\"linenr\">%4i</a> %s</div>\n",
+			       $nr, $nr, $nr, esc_html($line, -nbsp=>1);
+		}
 	}
 	close $fd
 		or print "Reading blob failed.\n";