Introduce StringImpl::createPreallocatedStatic

third_party/WebKit/Source/wtf/text/StringImpl.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) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Andrew Wellington (proton@wiretapped.net)
  *
  * 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 323 matching lines @@
 
 void StringImpl::freezeStaticStrings()
 {
     ASSERT(isMainThread());
 
 #if ENABLE(ASSERT)
     s_allowCreationOfStaticStrings = false;
 #endif
 }
 
+
 unsigned StringImpl::m_highestStaticStringLength = 0;
 
-StringImpl* StringImpl::createStatic(const char* string, unsigned length, unsigned hash)
+StringImpl* StringImpl::createPreallocatedStatic(void* buffer, unsigned length, unsigned hash)
 {
     ASSERT(s_allowCreationOfStaticStrings);
-    ASSERT(string);
+    ASSERT(buffer);
     ASSERT(length);
 
+    StringImpl* impl = static_cast<StringImpl*>(buffer);
+
     StaticStringsTable::const_iterator it = staticStrings().find(hash);
     if (it != staticStrings().end()) {
-        ASSERT(!memcmp(string, it->value + 1, length * sizeof(LChar)));
+        ASSERT(!memcmp(reinterpret_cast<LChar*>(impl + 1), it->value + 1, length * sizeof(LChar)));
         return it->value;
     }
 
-    // Allocate a single buffer large enough to contain the StringImpl
-    // struct as well as the data which it contains. This removes one
-    // heap allocation from this call.
-    RELEASE_ASSERT(length <= ((std::numeric_limits<unsigned>::max() - sizeof(StringImpl)) / sizeof(LChar)));
-    size_t size = sizeof(StringImpl) + length * sizeof(LChar);
-
-    WTF_ANNOTATE_SCOPED_MEMORY_LEAK;
-    StringImpl* impl = static_cast<StringImpl*>(Partitions::bufferMalloc(size));
-
-    LChar* data = reinterpret_cast<LChar*>(impl + 1);
     impl = new (impl) StringImpl(length, hash, StaticString);
-    memcpy(data, string, length * sizeof(LChar));
 #if ENABLE(ASSERT)
     impl->assertHashIsCorrect();
 #endif
 
     ASSERT(isMainThread());
     m_highestStaticStringLength = std::max(m_highestStaticStringLength, length);
     staticStrings().add(hash, impl);
     WTF_ANNOTATE_BENIGN_RACE(impl,
-        "Benign race on the reference counter of a static string created by StringImpl::createStatic");
+        "Benign race on the reference counter of a static string created by StringImpl::createPreallocatedStatic");
 
     return impl;
 }
 
 void StringImpl::reserveStaticStringsCapacityForSize(unsigned size)
 {
     ASSERT(s_allowCreationOfStaticStrings);
     staticStrings().reserveCapacityForSize(size);
 }
 
@@ skipping 1720 matching lines @@
         } else if (localeIdMatchesLang(localeIdentifier, "lt")) {
             // TODO(rob.buis) implement upper-casing rules for lt
             // like in StringImpl::upper(locale).
         }
     }
 
     return toUpper(c);
 }
 
 } // namespace WTF