heaphelper.java

来自「纯java操作系统jnode,安装简单和操作简单的个人使用的Java操作系统」· Java 代码 · 共 117 行

/*
 * $Id: HeapHelper.java,v 1.8 2004/02/24 08:05:25 epr Exp $
 */
package org.jnode.vm.memmgr;

import org.jnode.assembler.ObjectResolver;
import org.jnode.vm.Address;
import org.jnode.vm.Monitor;
import org.jnode.vm.VmArchitecture;
import org.jnode.vm.VmThread;
import org.jnode.vm.classmgr.VmClassType;
import org.jnode.vm.classmgr.VmMethod;

/**
 * @author Ewout Prangsma ([e-mail])
 */
public abstract class HeapHelper extends ObjectResolver {

	public abstract Object getTib(Object object);

	public abstract VmClassType getVmClass(Object object);

	public abstract byte getByte(Object src, int offset);

	public abstract int getInt(Object src, int offset);

	public abstract Object getObject(Object src, int offset);

	/**
	 * Gets the color of the given object.
	 * @param src
	 * @return
	 * @see org.jnode.vm.classmgr.ObjectFlags#GC_BLACK
	 * @see org.jnode.vm.classmgr.ObjectFlags#GC_GREY
	 * @see org.jnode.vm.classmgr.ObjectFlags#GC_WHITE
     * @see org.jnode.vm.classmgr.ObjectFlags#GC_YELLOW
	 */
	public abstract int getObjectColor(Object src);

	/**
	 * Gets the flags of the given object.
	 * @param src
	 * @return
	 */
	public abstract int getObjectFlags(Object src);

	/**
	 * Has the given object been finalized.
	 * @param src
	 * @return
	 */
	public abstract boolean isFinalized(Object src);
	
	/**
	 * Mark the given object as finalized.
	 * @param src
	 */
	public abstract void setFinalized(Object src);
	
	public abstract void setByte(Object dst, int offset, byte value);

	public abstract void setInt(Object dst, int offset, int value);

	public abstract void setObject(Object dst, int offset, Object value);

	public abstract void unsafeSetObjectFlags(Object dst, int flags);

	/**
	 * Change the color of the given object from oldColor to newColor.
	 * @param dst
	 * @param oldColor
	 * @param newColor
	 * @return True if the color was changed, false if the current color of the object was not equal to oldColor.
	 */
	public abstract boolean atomicChangeObjectColor(Object dst, int oldColor, int newColor);

	public abstract void copy(Address src, Address dst, int size);

	public abstract void clear(Address dst, int size);

	public abstract long addressToLong(Address a);

	public abstract Object getStack(VmThread thread);

	public abstract Address allocateBlock(int size);

	public abstract Address getBootHeapStart();

	public abstract Address getBootHeapEnd();

	public abstract void invokeFinalizer(VmMethod finalizer, Object object);
	
	public abstract void die(String msg);
	
	/**
	 * Gets the inflated monitor of an object (if any).
	 * 
	 * @param object
	 * @param arch
	 * @return The inflated monitor of the given object, or null if the given object has no
	 *         inflated monitor.
	 */
	public abstract Monitor getInflatedMonitor(Object object, VmArchitecture arch);
	
	/**
	 * Stop and block all threads (on all processors) on a GC safe point.
	 * Only the calling thread (the GC thread) will continue.
	 */
	public abstract void stopThreadsAtSafePoint(); 
	
	/**
	 * Unblock all threads (on all processors).
	 * This method is called after a call a call to {@link #stopThreadsAtSafePoint()}.
	 */
	public abstract void restartThreads(); 
}