From 846ddce24e5bbde2ee54d00fe661594b0af4e7ee Mon Sep 17 00:00:00 2001
From: Alex Schroeder <alex@gnu.org>
Date: Fri, 17 Jul 2015 15:21:16 +0200
Subject: [PATCH] $PrintedHeader renamed to $HeaderIsPrinted

I also added some comments explaining why we need it. When calling
ReportError, we don't know whether HTTP headers have already been
printed. If not, we need to print them or the error message will be an
invalid HTTP response. If we did, we must not reprint them or the HTML
page will contain HTTP headers as part of its response body.
$HeaderIsPrinted makes sure the HTTP headers are printed just once.
---
 wiki.pl | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/wiki.pl b/wiki.pl
index 34681cea..316fc13a 100755
--- a/wiki.pl
+++ b/wiki.pl
@@ -51,7 +51,7 @@ our ($ScriptName, $FullUrl, $ModuleDir, $PageDir, $TempDir, $LockDir, $KeepDir,
 # Internal variables:
 our ($q, $bol, $OpenPageName, %Page, %Translate, %IndexHash, @IndexList,
      @HtmlStack, @HtmlAttrStack, @Blocks, @Flags,
-     %Includes, $FootnoteNumber, $CollectingJournal, $PrintedHeader,
+     %Includes, $FootnoteNumber, $CollectingJournal, $HeaderIsPrinted,
      %Locks, $Fragment, $Today, $ModulesDescription, %RssInterwikiTranslate,
      $Message, $Now, %RecentVisitors, %MyInc, $WikiDescription, %InterSite, %OldCookie);
 
@@ -264,7 +264,7 @@ sub InitVariables {  # Init global session variables for mod_perl!
   $WikiDescription = $q->p($q->a({-href=>'http://www.oddmuse.org/'}, 'Oddmuse'),
 			   $Counter++ > 0 ? Ts('%s calls', $Counter) : '');
   $WikiDescription .= $ModulesDescription if $ModulesDescription;
-  $PrintedHeader = 0; # Error messages don't print headers unless necessary
+  $HeaderIsPrinted = 0; # print HTTP headers only once
   $ScriptName //= $q->url(); # URL used in links
   $FullUrl ||= $ScriptName; # URL used in forms
   %Locks = ();
@@ -2263,15 +2263,18 @@ sub GetHeaderTitle {
 }
 
 sub GetHttpHeader {
-  return if $PrintedHeader;
-  $PrintedHeader = 1;
+  return if $HeaderIsPrinted; # When calling ReportError, we don't know whether HTTP headers have
+  $HeaderIsPrinted = 1;       # already been printed. We want them printed just once.
   my ($type, $ts, $status, $encoding) = @_;
   $q->charset($type =~ m!^(text/|application/xml)! ? 'utf-8' : ''); # text/plain, text/html, application/xml: UTF-8
   my %headers = (-cache_control=>($UseCache < 0 ? 'no-cache' : 'max-age=10'));
-  # Set $ts when serving raw content that cannot be modified by cookie parameters; or 'nocache'; or undef. If you
-  # provide a $ts, the last-modiefied header generated will by used by HTTP/1.0 clients. If you provide no $ts, the etag
-  # header generated will be used by HTTP/1.1 clients. In this situation, cookie parameters can influence the look of
-  # the page and we cannot rely on $LastUpdate. HTTP/1.0 clients will ignore etags. See RFC 2616 section 13.3.4.
+  # Set $ts when serving raw content that cannot be modified by cookie
+  # parameters; or 'nocache'; or undef. If you provide a $ts, the last-modified
+  # header generated will by used by HTTP/1.0 clients. If you provide no $ts,
+  # the etag header generated will be used by HTTP/1.1 clients. In this
+  # situation, cookie parameters can influence the look of the page and we
+  # cannot rely on $LastUpdate. HTTP/1.0 clients will ignore etags. See RFC 2616
+  # section 13.3.4.
   if (GetParam('cache', $UseCache) >= 2 and $ts ne 'nocache') {
     $headers{'-last-modified'} = TimeToRFC822($ts) if $ts;
     $headers{-etag} = PageEtag();