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package com.oracle.svm.core.image;

import java.nio.ByteBuffer;


This class is responsible for computing and storing the layout of the native image heap. A native image heap consist of multiple ImageHeapPartitions. Every object in the native image heap is assigned to a position within a ImageHeapPartition. 
/**
 * This class is responsible for computing and storing the layout of the native image heap. A native
 * image heap consist of multiple {@link ImageHeapPartition}s. Every object in the native image heap
 * is assigned to a position within a {@link ImageHeapPartition}.
 */
public interface ImageHeapLayouter {
    
Returns all native image heap partitions.

/**
     * Returns all native image heap partitions.
     */
    ImageHeapPartition[] getPartitions();

    
Assign an object to the most suitable partition.

/**
     * Assign an object to the most suitable partition.
     */
    void assignObjectToPartition(ImageHeapObject info, boolean immutable, boolean references, boolean relocatable);

    
This method places all heap partitions as one contiguous memory block in one section. After
calling that method, all native image heap objects are assigned their final address. This
address must not change anymore.

/**
     * This method places all heap partitions as one contiguous memory block in one section. After
     * calling that method, all native image heap objects are assigned their final address. This
     * address must not change anymore.
     */
    ImageHeapLayoutInfo layout(ImageHeap imageHeap, int pageSize);

    
Based on the layout decided during an earlier call to layout, fill the image heap in the supplied buffer with additional data structures, if any. At this time, the buffer already contains the laid out objects, which are not meant to be modified in this step. 
Params:
  • imageHeapOffsetInBuffer – The offset of the first byte of the laid out image heap in the
           buffer. If a layouter subclass can be instructed to start laying out the image
           heap at a specific non-zero offset, and the image heap is intended to start at the
           same offset in the given buffer, the same offset must be specified to this method.
/**
     * Based on the layout decided during an earlier call to {@link #layout}, fill the image heap in
     * the supplied buffer with additional data structures, if any. At this time, the buffer already
     * contains the laid out objects, which are not meant to be modified in this step.
     *
     * @param imageHeapOffsetInBuffer The offset of the first byte of the laid out image heap in the
     *            buffer. If a layouter subclass can be instructed to start laying out the image
     *            heap at a specific non-zero offset, and the image heap is intended to start at the
     *            same offset in the given buffer, the same offset must be specified to this method.
     */
    void writeMetadata(ByteBuffer imageHeapBytes, long imageHeapOffsetInBuffer);
}