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#ifndef QV4GC_H
#define QV4GC_H

#include "qv4global_p.h"
#include "qv4context_p.h"
#include "qv4value_p.h"

#include <QScopedPointer>

//#define DETAILED_MM_STATS

QT_BEGIN_NAMESPACE

namespace QV4 {

struct ExecutionEngine;
struct ExecutionContext;
struct Managed;
struct GCDeletable;

class Q_QML_EXPORT MemoryManager
{
    MemoryManager(const MemoryManager &);
    MemoryManager &operator=(const MemoryManager&);

public:
    struct Data;

    class GCBlocker
    {
    public:
        GCBlocker(MemoryManager *mm)
            : mm(mm)
            , wasBlocked(mm->isGCBlocked())
        {
            mm->setGCBlocked(true);
        }

        ~GCBlocker()
        {
            mm->setGCBlocked(wasBlocked);
        }

    private:
        MemoryManager *mm;
        bool wasBlocked;
    };

public:
    MemoryManager();
    ~MemoryManager();

    // TODO: this is only for 64bit (and x86 with SSE/AVX), so exend it for other architectures to be slightly more efficient (meaning, align on 8-byte boundaries).
    // Note: all occurances of "16" in alloc/dealloc are also due to the alignment.
    static inline std::size_t align(std::size_t size)
    { return (size + 15) & ~0xf; }

    inline Managed *allocManaged(std::size_t size)
    {
        size = align(size);
        Managed *o = alloc(size);
        return o;
    }

    ExecutionContext *allocContext(uint size);

    bool isGCBlocked() const;
    void setGCBlocked(bool blockGC);
    void runGC();

    void setEnableGC(bool enableGC);
    void setExecutionEngine(ExecutionEngine *engine);

    void dumpStats() const;

protected:
    /// expects size to be aligned
    // TODO: try to inline
    Managed *alloc(std::size_t size);

    ExecutionEngine *engine() const;

#ifdef DETAILED_MM_STATS
    void willAllocate(std::size_t size);
#endif // DETAILED_MM_STATS

private:
    void collectFromStack() const;
    void collectFromJSStack() const;
    void mark();
    void sweep(bool lastSweep = false);
    void sweep(char *chunkStart, std::size_t chunkSize, size_t size, GCDeletable **deletable);

protected:
    QScopedPointer<Data> m_d;
    ExecutionContext *m_contextList;
public:
    PersistentValuePrivate *m_persistentValues;
    PersistentValuePrivate *m_weakValues;
};

inline ExecutionContext *MemoryManager::allocContext(uint size)
{
    ExecutionContext *newContext = (ExecutionContext *)malloc(size);
    newContext->next = m_contextList;
    m_contextList = newContext;
    return newContext;
}


}

QT_END_NAMESPACE

#endif // QV4GC_H
