Experimental CompressibleString UMA

third_party/WebKit/Source/bindings/core/v8/V8StringResource.cpp

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 30 matching lines @@
     static const String& fromStringResource(WebCoreStringResourceBase* resource)
     {
         return resource->webcoreString();
     }
     template <typename V8StringTrait>
     static String fromV8String(v8::Local<v8::String>, int);
 };
 
 template<>
 struct StringTraits<AtomicString> {
-    static const AtomicString& fromStringResource(WebCoreStringResourceBase* resource)
+    static AtomicString fromStringResource(WebCoreStringResourceBase* resource)
     {
         return resource->atomicString();
     }
     template <typename V8StringTrait>
     static AtomicString fromV8String(v8::Local<v8::String>, int);
 };
 
 struct V8StringTwoBytesTrait {
     typedef UChar CharType;
     ALWAYS_INLINE static void write(v8::Local<v8::String> v8String, CharType* buffer, int length)
@@ skipping 38 matching lines @@
 
 template<typename StringType>
 StringType v8StringToWebCoreString(v8::Local<v8::String> v8String, ExternalMode external)
 {
     {
         // This portion of this function is very hot in certain Dromeao benchmarks.
         v8::String::Encoding encoding;
         v8::String::ExternalStringResourceBase* resource = v8String->GetExternalStringResourceBase(&encoding);
         if (LIKELY(!!resource)) {
             WebCoreStringResourceBase* base;
-            if (encoding == v8::String::ONE_BYTE_ENCODING)
-                base = static_cast<WebCoreStringResource8*>(resource);
-            else
-                base = static_cast<WebCoreStringResource16*>(resource);
+            if (UNLIKELY(resource->IsCompressible())) {
+                if (encoding == v8::String::ONE_BYTE_ENCODING)
+                    base = static_cast<WebCoreCompressibleStringResource8*>(resource);
+                else
+                    base = static_cast<WebCoreCompressibleStringResource16*>(resource);
+            } else {
+                if (encoding == v8::String::ONE_BYTE_ENCODING)
+                    base = static_cast<WebCoreStringResource8*>(resource);
+                else
+                    base = static_cast<WebCoreStringResource16*>(resource);
+            }
             return StringTraits<StringType>::fromStringResource(base);
         }
     }
 
     int length = v8String->Length();
     if (UNLIKELY(!length))
         return StringType("");
 
     bool oneByte = v8String->ContainsOnlyOneByte();
     StringType result(oneByte ? StringTraits<StringType>::template fromV8String<V8StringOneByteTrait>(v8String, length) : StringTraits<StringType>::template fromV8String<V8StringTwoBytesTrait>(v8String, length));
@@ skipping 44 matching lines @@
 
 String int32ToWebCoreString(int value)
 {
     // If we are on the main thread (this should always true for non-workers), call the faster one.
     if (isMainThread())
         return int32ToWebCoreStringFast(value);
     return String::number(value);
 }
 
 } // namespace blink