/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-

 * vim: set ts=8 sts=4 et sw=4 tw=99:

 * This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef vm_ArrayObject_h

#define vm_ArrayObject_h

#include "vm/NativeObject.h"

namespace js {

class AutoSetNewObjectMetadata;

class ArrayObject : public NativeObject

{

  public:

    // Array(x) eagerly allocates dense elements if x <= this value. Without

    // the subtraction the max would roll over to the next power-of-two (4096)

    // due to the way that growElements() and goodAllocated() work.

    static const uint32_t EagerAllocationMaxLength = 2048 - ObjectElements::VALUES_PER_HEADER;

    static const Class class_;

    bool lengthIsWritable() const {

        return !getElementsHeader()->hasNonwritableArrayLength();

    }

    uint32_t length() const {

        return getElementsHeader()->length;

    }

    void setNonWritableLength(JSContext* cx) {

        shrinkCapacityToInitializedLength(cx);

        getElementsHeader()->setNonwritableArrayLength();

    }

    inline void setLength(JSContext* cx, uint32_t length);

    // Variant of setLength for use on arrays where the length cannot overflow int32_t.

    void setLengthInt32(uint32_t length) {

        MOZ_ASSERT(lengthIsWritable());

        MOZ_ASSERT_IF(length != getElementsHeader()->length, !denseElementsAreFrozen());

        MOZ_ASSERT(length <= INT32_MAX);

        getElementsHeader()->length = length;

    }

    // Make an array object with the specified initial state.

    static inline ArrayObject*

    createArray(JSContext* cx,

                gc::AllocKind kind,

                gc::InitialHeap heap,

                HandleShape shape,

                HandleObjectGroup group,

                uint32_t length,

                AutoSetNewObjectMetadata& metadata);

    // Make a copy-on-write array object which shares the elements of an

    // existing object.

    static inline ArrayObject*

    createCopyOnWriteArray(JSContext* cx,

                           gc::InitialHeap heap,

                           HandleArrayObject sharedElementsOwner);

  private:

    // Helper for the above methods.

    static inline ArrayObject*

    createArrayInternal(JSContext* cx,

                        gc::AllocKind kind,

                        gc::InitialHeap heap,

                        HandleShape shape,

                        HandleObjectGroup group,

                        AutoSetNewObjectMetadata&);

    static inline ArrayObject*

    finishCreateArray(ArrayObject* obj, HandleShape shape, AutoSetNewObjectMetadata& metadata);

};

} // namespace js

#endif // vm_ArrayObject_h