Have Chrome Frame "support" IE conditional comment tags (of the downlevel-hid...

chrome_frame/html_utils.cc

 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 #include "chrome_frame/html_utils.h"
 
 #include <atlbase.h>
 #include <urlmon.h>
 
 #include "base/string_util.h"
@@ skipping 197 matching lines @@
   bool in_quote;
   bool in_escape;
   wchar_t quote_char;
   ScanState() : in_quote(false), in_escape(false) {}
 };
 
 bool HTMLScanner::IsQuote(wchar_t c) {
   return quotes_.find(c) != std::wstring::npos;
 }
 
-bool HTMLScanner::IsHTMLCommentClose(StringRange* html_string, StrPos pos) {
+bool HTMLScanner::IsHTMLCommentClose(const StringRange* html_string,
+                                     StrPos pos) {
   if (pos < html_string->end_ && pos > html_string->start_ + 2 &&
       *pos == L'>') {
     return *(pos-1) == L'-' && *(pos-2) == L'-';
   }
   return false;
 }
 
+bool HTMLScanner::IsIEConditionalCommentClose(const StringRange* html_string,
+                                              StrPos pos) {
+  if (pos < html_string->end_ && pos > html_string->start_ + 2 &&
+      *pos == L'>') {
+    return *(pos-1) == L']';
+  }
+  return false;
+}
+
+
 bool HTMLScanner::NextTag(StringRange* html_string, StringRange* tag) {
   DCHECK(NULL != html_string);
   DCHECK(NULL != tag);
 
   tag->start_ = html_string->start_;
   while (tag->start_ < html_string->end_ && *tag->start_ != L'<') {
     tag->start_++;
   }
 
   // we went past the end of the string.
   if (tag->start_ >= html_string->end_) {
     return false;
   }
 
   tag->end_ = tag->start_ + 1;
 
   // Get the tag name to see if we are in an HTML comment. If we are, then
   // don't consider quotes. This should work for example:
   // <!-- foo ' --> <meta foo='bar'>
   std::wstring tag_name;
   StringRange start_range(tag->start_, html_string->end_);
   start_range.GetTagName(&tag_name);
-  if (StartsWith(tag_name, L"!--", true)) {
-    // We're inside a comment tag, keep going until we get out of it.
+  if (StartsWith(tag_name, L"!--[if", true)) {
+    // This looks like the beginning of an IE conditional comment, scan until
+    // we hit the end which always looks like ']>'. For now we disregard the
+    // contents of the condition, and always assume true.
+    // TODO(robertshield): Optionally support the grammar defined by
+    // http://msdn.microsoft.com/en-us/library/ms537512(VS.85).aspx#syntax.
     while (tag->end_ < html_string->end_ &&
+           !IsIEConditionalCommentClose(html_string, tag->end_)) {
+      tag->end_++;
+    }
+  } else if (StartsWith(tag_name, L"!--", true)) {
+    // We're inside a comment tag which ends in '-->'. Keep going until we
+    // reach the end.
+    while (tag->end_ < html_string->end_ &&
+           !IsHTMLCommentClose(html_string, tag->end_)) {
+      tag->end_++;
+    }
+  } else if (StartsWith(tag_name, L"![endif", true)) {
+    // We're inside the closing tag of an IE conditional comment which ends in
+    // either '-->' of ']>'. Keep going until we reach the end.
+    while (tag->end_ < html_string->end_ &&
+           !IsIEConditionalCommentClose(html_string, tag->end_) &&
            !IsHTMLCommentClose(html_string, tag->end_)) {
       tag->end_++;
     }
   } else {
     // Properly handle quoted strings within non-comment tags by maintaining
     // some state while scanning. Specifically, we have to maintain state on
     // whether we are inside a string, what the string terminating character
     // will be and whether we are inside an escape sequence.
     ScanState state;
     while (tag->end_ < html_string->end_) {
@@ skipping 130 matching lines @@
                                         const std::string& headers) {
   net::HttpUtil::HeadersIterator it(headers.begin(), headers.end(), "\r\n");
   while (it.GetNext()) {
     if (!lstrcmpiA(it.name().c_str(), header.c_str()))
       return std::string(it.values_begin(), it.values_end());
   }
   return std::string();
 }
 
 }  // namespace http_utils