Experimental CompressibleString UMA

third_party/WebKit/Source/core/fetch/ScriptResource.cpp

 /*
     Copyright (C) 1998 Lars Knoll (knoll@mpi-hd.mpg.de)
     Copyright (C) 2001 Dirk Mueller (mueller@kde.org)
     Copyright (C) 2002 Waldo Bastian (bastian@kde.org)
     Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
     Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
 
     This library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Library General Public
     License as published by the Free Software Foundation; either
@@ skipping 63 matching lines @@
     ResourceClientWalker<ScriptResourceClient> walker(m_clients);
     while (ScriptResourceClient* client = walker.next())
         client->notifyAppendData(this);
 }
 
 void ScriptResource::onMemoryDump(WebMemoryDumpLevelOfDetail levelOfDetail, WebProcessMemoryDump* memoryDump) const
 {
     Resource::onMemoryDump(levelOfDetail, memoryDump);
     const String name = getMemoryDumpName() + "/decoded_script";
     auto dump = memoryDump->createMemoryAllocatorDump(name);
-    dump->addScalar("size", "bytes", m_script.string().sizeInBytes());
+    dump->addScalar("size", "bytes", m_script.currentSizeInBytes());
     memoryDump->addSuballocation(dump->guid(), String(WTF::Partitions::kAllocatedObjectPoolName));
 }
 
 AtomicString ScriptResource::mimeType() const
 {
     return extractMIMETypeFromMediaType(m_response.httpHeaderField(HTTPNames::Content_Type)).lower();
 }
 
-const String& ScriptResource::script()
+const CompressibleString& ScriptResource::script()
 {
     ASSERT(!isPurgeable());
     ASSERT(isLoaded());
 
-    if (!m_script && m_data) {
+    if (m_script.isNull() && m_data) {
         String script = decodedText();
         m_data.clear();
         // We lie a it here and claim that script counts as encoded data (even though it's really decoded data).
         // That's because the MemoryCache thinks that it can clear out decoded data by calling destroyDecodedData(),
         // but we can't destroy script in destroyDecodedData because that's our only copy of the data!
         setEncodedSize(script.sizeInBytes());
-        m_script = AtomicString(script);
+        m_script = CompressibleString(script.impl());
     }
 
-    return m_script.string();
+    return m_script;
 }
 
 void ScriptResource::destroyDecodedDataForFailedRevalidation()
 {
-    m_script = AtomicString();
+    m_script = CompressibleString(StringImpl::empty());

[haraken, 2016/01/15 12:46:21]

Can't we call CompressibleString()? Why do you need StringImpl::empty()?

[hajimehoshi, 2016/01/18 09:42:26]

Done.

 }
 
 bool ScriptResource::mimeTypeAllowedByNosniff() const
 {
     return parseContentTypeOptionsHeader(m_response.httpHeaderField(HTTPNames::X_Content_Type_Options)) != ContentTypeOptionsNosniff || MIMETypeRegistry::isSupportedJavaScriptMIMEType(mimeType());
 }
 
 bool ScriptResource::mustRefetchDueToIntegrityMetadata(const FetchRequest& request) const
 {
     if (request.integrityMetadata().isEmpty())
         return false;
 
     return !IntegrityMetadata::setsEqual(m_integrityMetadata, request.integrityMetadata());
 }
 
 } // namespace blink