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/*
* Copyright (C) 2017 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. ``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
* 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.
*/
#pragma once
#include "HashMapHelper.h"
#include "WeakMapImpl.h"
WTF_ALLOW_UNSAFE_BUFFER_USAGE_BEGIN
namespace JSC {
ALWAYS_INLINE uint32_t jsWeakMapHash(JSCell* key)
{
return wangsInt64Hash(JSValue::encode(key));
}
ALWAYS_INLINE uint32_t nextCapacityAfterBatchRemoval(uint32_t capacity, uint32_t keyCount)
{
while (shouldShrink(capacity, keyCount))
capacity = nextCapacity(capacity, keyCount);
return capacity;
}
static ALWAYS_INLINE bool canBeHeldWeakly(JSValue value)
{
// https://tc39.es/proposal-symbols-as-weakmap-keys/#sec-canbeheldweakly-abstract-operation
if (value.isObject())
return true;
if (!value.isSymbol())
return false;
return !asSymbol(value)->uid().isRegistered();
}
template <typename WeakMapBucket>
ALWAYS_INLINE void WeakMapImpl<WeakMapBucket>::add(VM& vm, JSCell* key, JSValue value)
{
AssertNoGC assertNoGC;
add(vm, key, value, jsWeakMapHash(key));
}
template <typename WeakMapBucket>
ALWAYS_INLINE void WeakMapImpl<WeakMapBucket>::add(VM& vm, JSCell* key, JSValue value, uint32_t hash)
{
AssertNoGC assertNoGC;
ASSERT_WITH_MESSAGE(jsWeakMapHash(key) == hash, "We expect hash value is what we expect.");
addInternal(vm, key, value, hash);
if (shouldRehashAfterAdd())
rehash();
}
template <typename WeakMapBucket>
ALWAYS_INLINE void WeakMapImpl<WeakMapBucket>::addBucket(VM& vm, JSCell* key, JSValue value, uint32_t hash, size_t index)
{
UNUSED_PARAM(hash);
ASSERT(jsWeakMapHash(key) == hash);
ASSERT(!findBucket(key, hash));
WeakMapBucket* newEntry = buffer() + index;
ASSERT(newEntry);
ASSERT(newEntry->isEmpty());
newEntry->setKey(vm, this, key);
newEntry->setValue(vm, this, value);
++m_keyCount;
if (shouldRehashAfterAdd())
rehash();
}
// Note that this function can be executed in parallel as long as the mutator stops.
template<typename WeakMapBucket>
void WeakMapImpl<WeakMapBucket>::finalizeUnconditionally(VM& vm, CollectionScope)
{
auto* buffer = this->buffer();
for (uint32_t index = 0; index < m_capacity; ++index) {
auto* bucket = buffer + index;
if (bucket->isEmpty() || bucket->isDeleted())
continue;
if (vm.heap.isMarked(bucket->key()))
continue;
bucket->makeDeleted();
++m_deleteCount;
RELEASE_ASSERT(m_keyCount > 0);
--m_keyCount;
}
if (shouldShrink())
rehash(RehashMode::RemoveBatching);
}
template<typename WeakMapBucket>
void WeakMapImpl<WeakMapBucket>::rehash(RehashMode mode)
{
// Since shrinking is done just after GC runs (finalizeUnconditionally), WeakMapImpl::rehash()
// function must not touch any GC related features. This is why we do not allocate WeakMapBuffer
// in auxiliary buffer.
uint32_t oldCapacity = m_capacity;
MallocPtr<WeakMapBufferType> oldBuffer = WTFMove(m_buffer);
uint32_t capacity = m_capacity;
if (mode == RehashMode::RemoveBatching) {
ASSERT(shouldShrink());
capacity = nextCapacityAfterBatchRemoval(capacity, m_keyCount);
} else
capacity = nextCapacity(capacity, m_keyCount);
makeAndSetNewBuffer(capacity);
auto* buffer = this->buffer();
const uint32_t mask = m_capacity - 1;
for (uint32_t oldIndex = 0; oldIndex < oldCapacity; ++oldIndex) {
auto* entry = oldBuffer->buffer() + oldIndex;
if (entry->isEmpty() || entry->isDeleted())
continue;
uint32_t index = jsWeakMapHash(entry->key()) & mask;
WeakMapBucket* bucket = buffer + index;
while (!bucket->isEmpty()) {
index = (index + 1) & mask;
bucket = buffer + index;
}
bucket->copyFrom(*entry);
}
m_deleteCount = 0;
checkConsistency();
}
template<typename WeakMapBucket>
ALWAYS_INLINE uint32_t WeakMapImpl<WeakMapBucket>::shouldRehashAfterAdd() const
{
return JSC::shouldRehash(m_capacity, m_keyCount, m_deleteCount);
}
} // namespace JSC
WTF_ALLOW_UNSAFE_BUFFER_USAGE_END
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