Cheaper thread-safe atomic initialization of static references.

Source/core/fetch/FetchUtils.cpp

 // Copyright 2014 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 "config.h"
 #include "core/fetch/FetchUtils.h"
 
 #include "platform/network/HTTPHeaderMap.h"
 #include "platform/network/HTTPParsers.h"
 #include "wtf/HashSet.h"
 #include "wtf/Threading.h"
 #include "wtf/text/AtomicString.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
 
 namespace {
 
 class ForbiddenHeaderNames {
     WTF_MAKE_NONCOPYABLE(ForbiddenHeaderNames); WTF_MAKE_FAST_ALLOCATED;
 public:
     bool has(const String& name) const
     {
         return m_fixedNames.contains(name)
             || name.startsWith(m_proxyHeaderPrefix, false)
             || name.startsWith(m_secHeaderPrefix, false);
     }
 
-    static const ForbiddenHeaderNames* get();
+    static const ForbiddenHeaderNames& get();
 
 private:
     ForbiddenHeaderNames();
 
     String m_proxyHeaderPrefix;
     String m_secHeaderPrefix;
     HashSet<String, CaseFoldingHash> m_fixedNames;
 };
 
 ForbiddenHeaderNames::ForbiddenHeaderNames()
@@ skipping 16 matching lines @@
     m_fixedNames.add("origin");
     m_fixedNames.add("referer");
     m_fixedNames.add("te");
     m_fixedNames.add("trailer");
     m_fixedNames.add("transfer-encoding");
     m_fixedNames.add("upgrade");
     m_fixedNames.add("user-agent");
     m_fixedNames.add("via");
 }
 
-const ForbiddenHeaderNames* ForbiddenHeaderNames::get()
+const ForbiddenHeaderNames& ForbiddenHeaderNames::get()
 {
-    AtomicallyInitializedStatic(const ForbiddenHeaderNames*, instance = new ForbiddenHeaderNames);
+    AtomicallyInitializedStaticReference(const ForbiddenHeaderNames, instance, new ForbiddenHeaderNames);
     return instance;
 }
 
 } // namespace
 
 bool FetchUtils::isSimpleMethod(const String& method)
 {
     // http://fetch.spec.whatwg.org/#simple-method
     // "A simple method is a method that is `GET`, `HEAD`, or `POST`."
     return method == "GET" || method == "HEAD" || method == "POST";
@@ skipping 53 matching lines @@
     // http://fetch.spec.whatwg.org/#forbidden-header-name
     // "A forbidden header name is a header names that is one of:
     //   `Accept-Charset`, `Accept-Encoding`, `Access-Control-Request-Headers`,
     //   `Access-Control-Request-Method`, `Connection`,
     //   `Content-Length, Cookie`, `Cookie2`, `Date`, `DNT`, `Expect`, `Host`,
     //   `Keep-Alive`, `Origin`, `Referer`, `TE`, `Trailer`,
     //   `Transfer-Encoding`, `Upgrade`, `User-Agent`, `Via`
     // or starts with `Proxy-` or `Sec-` (including when it is just `Proxy-` or
     // `Sec-`)."
 
-    return ForbiddenHeaderNames::get()->has(name);
+    return ForbiddenHeaderNames::get().has(name);
 }
 
 bool FetchUtils::isForbiddenResponseHeaderName(const String& name)
 {
     // http://fetch.spec.whatwg.org/#forbidden-response-header-name
     // "A forbidden response header name is a header name that is one of:
     // `Set-Cookie`, `Set-Cookie2`"
 
     return equalIgnoringCase(name, "set-cookie") || equalIgnoringCase(name, "set-cookie2");
 }
@@ skipping 30 matching lines @@
         if (equalIgnoringCase(method, known)) {
             // Don't bother allocating a new string if it's already all
             // uppercase.
             return method == known ? method : known;
         }
     }
     return method;
 }
 
 } // namespace blink