/*
* Copyright (C) 2011 Apple 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
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, 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 COMPUTER, 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.
*/
#ifndef PODFreeListArena_h
#define PODFreeListArena_h
#include "platform/PODArena.h"
namespace WebCore {
template <class T>
class PODFreeListArena : public RefCounted<PODFreeListArena<T> > {
public:
static PassRefPtr<PODFreeListArena> create()
{
return adoptRef(new PODFreeListArena);
}
// Creates a new PODFreeListArena configured with the given Allocator.
static PassRefPtr<PODFreeListArena> create(PassRefPtr<PODArena::Allocator> allocator)
{
return adoptRef(new PODFreeListArena(allocator));
}
// Allocates an object from the arena.
T* allocateObject()
{
void* ptr = allocateFromFreeList();
if (ptr) {
// Use placement operator new to allocate a T at this location.
new(ptr) T();
return static_cast<T*>(ptr);
}
// PODArena::allocateObject calls T's constructor.
return static_cast<T*>(m_arena->allocateObject<T>());
}
template<class Argument1Type> T* allocateObject(const Argument1Type& argument1)
{
void* ptr = allocateFromFreeList();
if (ptr) {
// Use placement operator new to allocate a T at this location.
new(ptr) T(argument1);
return static_cast<T*>(ptr);
}
// PODArena::allocateObject calls T's constructor.
return static_cast<T*>(m_arena->allocateObject<T>(argument1));
}
void freeObject(T* ptr)
{
FixedSizeMemoryChunk* oldFreeList = m_freeList;
m_freeList = reinterpret_cast<FixedSizeMemoryChunk*>(ptr);
m_freeList->next = oldFreeList;
}
private:
PODFreeListArena()
: m_arena(PODArena::create()), m_freeList(0) { }
explicit PODFreeListArena(PassRefPtr<PODArena::Allocator> allocator)
: m_arena(PODArena::create(allocator)), m_freeList(0) { }
~PODFreeListArena() { }
void* allocateFromFreeList()
{
if (m_freeList) {
void* memory = m_freeList;
m_freeList = m_freeList->next;
return memory;
}
return 0;
}
int getFreeListSizeForTesting() const
{
int total = 0;
for (FixedSizeMemoryChunk* cur = m_freeList; cur; cur = cur->next) {
total++;
}
return total;
}
RefPtr<PODArena> m_arena;
// This free list contains pointers within every chunk that's been allocated so
// far. None of the individual chunks can be freed until the arena is
// destroyed.
struct FixedSizeMemoryChunk {
FixedSizeMemoryChunk* next;
};
FixedSizeMemoryChunk* m_freeList;
COMPILE_ASSERT(sizeof(T) >= sizeof(FixedSizeMemoryChunk), PODFreeListArena_type_should_be_larger);
friend class WTF::RefCounted<PODFreeListArena>;
friend class PODFreeListArenaTest;
};
} // namespace WebCore
#endif