Source/WTF/wtf/MetaAllocatorHandle.h

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 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
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 *
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 *     notice, this list of conditions and the following disclaimer. 
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 *     notice, this list of conditions and the following disclaimer in the
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#pragma once

#include <wtf/Assertions.h>
#include <wtf/MetaAllocatorPtr.h>
#include <wtf/RedBlackTree.h>
#include <wtf/ThreadSafeRefCounted.h>

namespace WTF {

class MetaAllocator;
class PrintStream;

DECLARE_ALLOCATOR_WITH_HEAP_IDENTIFIER(MetaAllocatorHandle);
class MetaAllocatorHandle : public ThreadSafeRefCounted<MetaAllocatorHandle>, public RedBlackTree<MetaAllocatorHandle, void*>::Node {
    WTF_MAKE_FAST_ALLOCATED_WITH_HEAP_IDENTIFIER(MetaAllocatorHandle);

public:
    using MemoryPtr = MetaAllocatorPtr<HandleMemoryPtrTag>;

    WTF_EXPORT_PRIVATE ~MetaAllocatorHandle();

    MemoryPtr start() const
    {
        return m_start;
    }

    MemoryPtr end() const
    {
        return m_end;
    }

    uintptr_t startAsInteger() const
    {
        return m_start.untaggedPtr<uintptr_t>();
    }

    uintptr_t endAsInteger() const
    {
        return m_end.untaggedPtr<uintptr_t>();
    }

    size_t sizeInBytes() const
    {
        return m_end.untaggedPtr<size_t>() - m_start.untaggedPtr<size_t>();
    }
    
    bool containsIntegerAddress(uintptr_t address) const
    {
        return address >= startAsInteger() && address < endAsInteger();
    }
    
    bool contains(void* address) const
    {
        return containsIntegerAddress(reinterpret_cast<uintptr_t>(address));
    }
        
    WTF_EXPORT_PRIVATE void shrink(size_t newSizeInBytes);
    
    MetaAllocator& allocator()
    {
        return m_allocator;
    }

    void* key()
    {
        return m_start.untaggedPtr();
    }

    WTF_EXPORT_PRIVATE void dump(PrintStream& out) const;
    
private:
    MetaAllocatorHandle(MetaAllocator&, MemoryPtr start, size_t sizeInBytes);

    MetaAllocator& m_allocator;
    MemoryPtr m_start;
    MemoryPtr m_end;

    friend class MetaAllocator;
};

}