blob: 98d22c91e04277cda675ce57da44975c3de54d99 [file] [log] [blame]
/*
* Copyright (C) 2015 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.
*/
#ifndef WTF_SymbolRegistry_h
#define WTF_SymbolRegistry_h
#include <wtf/HashSet.h>
#include <wtf/text/StringHash.h>
#include <wtf/text/SymbolImpl.h>
#include <wtf/text/WTFString.h>
namespace WTF {
// Since StringImpl* used for Symbol uid doesn't have a hash value reflecting the string content,
// to compare with an external string in string contents, introduce SymbolRegistryKey.
// SymbolRegistryKey holds a hash value reflecting the string content additionally.
class SymbolRegistryKey {
public:
SymbolRegistryKey() = default;
explicit SymbolRegistryKey(StringImpl* uid);
SymbolRegistryKey(WTF::HashTableDeletedValueType);
unsigned hash() const { return m_hash; }
StringImpl* impl() const { return m_impl; }
bool isHashTableDeletedValue() const { return m_impl == hashTableDeletedValue(); }
private:
static StringImpl* hashTableDeletedValue() { return reinterpret_cast<StringImpl*>(-1); }
StringImpl* m_impl { nullptr };
unsigned m_hash { 0 };
};
template<typename T> struct DefaultHash;
template<> struct DefaultHash<SymbolRegistryKey> {
struct Hash : StringHash {
static unsigned hash(const SymbolRegistryKey& key)
{
return key.hash();
}
static bool equal(const SymbolRegistryKey& a, const SymbolRegistryKey& b)
{
return StringHash::equal(a.impl(), b.impl());
}
};
};
template<> struct HashTraits<SymbolRegistryKey> : SimpleClassHashTraits<SymbolRegistryKey> {
static const bool hasIsEmptyValueFunction = true;
static bool isEmptyValue(const SymbolRegistryKey& key)
{
return key.impl() == nullptr;
}
};
class SymbolRegistry {
WTF_MAKE_NONCOPYABLE(SymbolRegistry);
public:
SymbolRegistry() = default;
WTF_EXPORT_PRIVATE ~SymbolRegistry();
WTF_EXPORT_PRIVATE Ref<RegisteredSymbolImpl> symbolForKey(const String&);
void remove(RegisteredSymbolImpl&);
private:
HashSet<SymbolRegistryKey> m_table;
};
inline SymbolRegistryKey::SymbolRegistryKey(StringImpl* uid)
: m_impl(uid)
{
if (uid->isSymbol()) {
if (uid->is8Bit())
m_hash = StringHasher::computeHashAndMaskTop8Bits(uid->characters8(), uid->length());
else
m_hash = StringHasher::computeHashAndMaskTop8Bits(uid->characters16(), uid->length());
} else
m_hash = uid->hash();
}
inline SymbolRegistryKey::SymbolRegistryKey(WTF::HashTableDeletedValueType)
: m_impl(hashTableDeletedValue())
{
}
}
#endif