webkitgtk-2.16.5HEADwebkitgtk-2.16.5master

1 files changed, 59 insertions, 0 deletions

diff --git a/Source/WTF/wtf/text/SymbolImpl.cpp b/Source/WTF/wtf/text/SymbolImpl.cpp
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+++ b/Source/WTF/wtf/text/SymbolImpl.cpp
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+/*
+ * Copyright (C) 2016 Yusuke Suzuki <utatane.tea@gmail.com>.
+ *
+ * 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
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
+ * THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+#include "SymbolImpl.h"
+
+namespace WTF {
+
+// In addition to the normal hash value, store specialized hash value for
+// symbolized StringImpl*. And don't use the normal hash value for symbolized
+// StringImpl* when they are treated as Identifiers. Unique nature of these
+// symbolized StringImpl* keys means that we don't need them to match any other
+// string (in fact, that's exactly the oposite of what we want!), and the
+// normal hash would lead to lots of conflicts.
+unsigned SymbolImpl::nextHashForSymbol()
+{
+    static unsigned s_nextHashForSymbol = 0;
+    s_nextHashForSymbol += 1 << s_flagCount;
+    s_nextHashForSymbol |= 1 << 31;
+    return s_nextHashForSymbol;
+}
+
+Ref<SymbolImpl> SymbolImpl::create(StringImpl& rep)
+{
+    auto* ownerRep = (rep.bufferOwnership() == BufferSubstring) ? rep.substringBuffer() : &rep;
+    ASSERT(ownerRep->bufferOwnership() != BufferSubstring);
+    if (rep.is8Bit())
+        return adoptRef(*new SymbolImpl(rep.m_data8, rep.length(), *ownerRep));
+    return adoptRef(*new SymbolImpl(rep.m_data16, rep.length(), *ownerRep));
+}
+
+Ref<SymbolImpl> SymbolImpl::createNullSymbol()
+{
+    return adoptRef(*new SymbolImpl);
+}
+
+} // namespace WTF