MIME type predicates and case-insensitive matching.

Source/core/dom/DOMImplementation.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Samuel Weinig (sam@webkit.org)
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 215 matching lines @@
 
 PassRefPtr<CSSStyleSheet> DOMImplementation::createCSSStyleSheet(const String&, const String& media)
 {
     // FIXME: Title should be set.
     // FIXME: Media could have wrong syntax, in which case we should generate an exception.
     RefPtr<CSSStyleSheet> sheet = CSSStyleSheet::create(StyleSheetContents::create());
     sheet->setMediaQueries(MediaQuerySet::create(media));
     return sheet;
 }
 
+static bool equalToUpperCaseASCIIIgnoringCase(char asciiUpper, UChar u)
+{
+    return static_cast<UChar>(asciiUpper) == (u & static_cast<UChar>(~0x20));

[jochen (gone - plz use gerrit), 2014/01/03 11:31:09]

nit. use toASCIIUpper() 

+}
+
 bool DOMImplementation::isXMLMIMEType(const String& mimeType)
 {
-    if (mimeType == "text/xml" || mimeType == "application/xml" || mimeType == "text/xsl")
+    if (equalIgnoringCase(mimeType, "text/xml")
+        || equalIgnoringCase(mimeType, "application/xml")
+        || equalIgnoringCase(mimeType, "text/xsl"))
         return true;
 
-    // Per RFCs 3023 and 2045 a mime type is of the form:
+    // Per RFCs 3023 and 2045, an XML MIME type is of the form:
     // ^[0-9a-zA-Z_\\-+~!$\\^{}|.%'`#&*]+/[0-9a-zA-Z_\\-+~!$\\^{}|.%'`#&*]+\+xml$
 
     int length = mimeType.length();
     if (length < 7)
         return false;
 
-    if (mimeType[0] == '/' ||
-        mimeType[length - 5] == '/' ||
-        mimeType[length - 4] != '+' ||
-        mimeType[length - 3] != 'x' ||
-        mimeType[length - 2] != 'm' ||
-        mimeType[length - 1] != 'l')
+    if (mimeType[0] == '/'
+        || mimeType[length - 5] == '/'
+        || mimeType[length - 4] != '+'
+        || !equalToUpperCaseASCIIIgnoringCase('X', mimeType[length - 3])

[jochen (gone - plz use gerrit), 2014/01/03 11:31:09]

why not !mimeType.endsWith("+xml", true)

[sof, 2014/01/03 13:51:02]

Nice; switched to this simpler form instead (removing the added helper in the
process.)

+        || !equalToUpperCaseASCIIIgnoringCase('M', mimeType[length - 2])
+        || !equalToUpperCaseASCIIIgnoringCase('L', mimeType[length - 1]))
         return false;
 
     bool hasSlash = false;
     for (int i = 0; i < length - 4; ++i) {
         UChar ch = mimeType[i];
         if (ch >= '0' && ch <= '9')
             continue;
         if (ch >= 'a' && ch <= 'z')
             continue;
         if (ch >= 'A' && ch <= 'Z')
@@ skipping 116 matching lines @@
         return TextDocument::create(init);
     if (type == "image/svg+xml")
         return SVGDocument::create(init);
     if (isXMLMIMEType(type))
         return Document::create(init);
 
     return HTMLDocument::create(init);
 }
 
 }