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/*
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 *
 * Oracle and Java are registered trademarks of Oracle and/or its affiliates.
 * Other names may be trademarks of their respective owners.
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 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common
 * Development and Distribution License("CDDL") (collectively, the
 * "License"). You may not use this file except in compliance with the
 * License. You can obtain a copy of the License at
 * http://www.netbeans.org/cddl-gplv2.html
 * or nbbuild/licenses/CDDL-GPL-2-CP. See the License for the
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 * The Original Software is NetBeans. The Initial Developer of the Original
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package org.netbeans.lib.profiler.heap;

import java.io.IOException;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;


/**
 *
 * @author Tomas Hurka
 */
class NearestGCRoot {
    //~ Static fields/initializers -----------------------------------------------------------------------------------------------

    private static final int BUFFER_SIZE = (64 * 1024) / 8;
    private static final String[] REF_CLASSES = {
        "java.lang.ref.WeakReference",    // NOI18N
        "java.lang.ref.SoftReference",    // NOI18N
        "java.lang.ref.FinalReference",   // NOI18N
        "java.lang.ref.PhantomReference"  // NOI18N
    };
    private static final String JAVA_LANG_REF_REFERENCE = "java.lang.ref.Reference";   // NOI18N
    private static final String REFERENT_FILED_NAME = "referent"; // NOI18N

    //~ Instance fields ----------------------------------------------------------------------------------------------------------

    private Field referentFiled;
    private HprofHeap heap;
    private LongBuffer readBuffer;
    private LongBuffer writeBuffer;
    private LongBuffer leaves;
    private LongBuffer multipleParents;
    private Set referenceClasses;
    private boolean gcRootsComputed;
    private long allInstances;
    private long processedInstances;
//private long leavesCount;
//private long firstLevel;
//private long multiParentsCount;

    //~ Constructors -------------------------------------------------------------------------------------------------------------

    NearestGCRoot(HprofHeap h) {
        heap = h;
    }

    //~ Methods ------------------------------------------------------------------------------------------------------------------

    Instance getNearestGCRootPointer(Instance instance) {
        if (heap.getGCRoot(instance) != null) {
            return instance;
        }
        computeGCRoots();
        long nextGCPathId = heap.idToOffsetMap.get(instance.getInstanceId()).getNearestGCRootPointer();
        return heap.getInstanceByID(nextGCPathId);
    }

    private boolean isSpecialReference(FieldValue value, Instance instance) {
        Field f = value.getField();

        return f.equals(referentFiled) && referenceClasses.contains(instance.getJavaClass());
    }

    private synchronized void computeGCRoots() {
        if (gcRootsComputed) {
            return;
        }
        referenceClasses = new HashSet();
        for (int i=0; i processedClasses = new HashSet(heap.getAllClasses().size()*4/3);

        try {
            createBuffers();
            fillZeroLevel();

            do {
                switchBuffers();
                computeOneLevel(processedClasses);
            } while (hasMoreLevels());
        } catch (IOException ex) {
            ex.printStackTrace();
        }

        deleteBuffers();
        heap.idToOffsetMap.flush();
        HeapProgress.progressFinish();
        gcRootsComputed = true;
    }

    private void computeOneLevel(Set processedClasses) throws IOException {
        int idSize = heap.dumpBuffer.getIDSize();
        for (;;) {
            long instanceId = readLong();
            Instance instance;
            List fieldValues;
            Iterator valuesIt;
            boolean hasValues = false;

            if (instanceId == 0L) { // end of level
                break;
            }
            HeapProgress.progress(processedInstances++,allInstances);
            instance = heap.getInstanceByID(instanceId);
            if (instance instanceof ObjectArrayInstance) {
                ObjectArrayDump array = (ObjectArrayDump) instance;
                int size = array.getLength();
                long offset = array.getOffset();

                for (int i=0;i fieldRef = reference.getFields().iterator();

        while (fieldRef.hasNext()) {
            Field f = (Field) fieldRef.next();

            if (f.getName().equals(REFERENT_FILED_NAME)) {

                return f;
            }
        }

        throw new IllegalArgumentException("reference field not found in " + reference.getName()); // NOI18N
    }

    private void createBuffers() {
        readBuffer = new LongBuffer(BUFFER_SIZE);
        writeBuffer = new LongBuffer(BUFFER_SIZE);
        leaves = new LongBuffer(BUFFER_SIZE);
        multipleParents = new LongBuffer(BUFFER_SIZE);
    }

    private void deleteBuffers() {
        readBuffer.delete();
        writeBuffer.delete();
    }

    private void fillZeroLevel() throws IOException {
        Iterator gcIt = heap.getGCRoots().iterator();

        while (gcIt.hasNext()) {
            HprofGCRoot root = (HprofGCRoot) gcIt.next();

            writeLong(root.getInstanceId());
        }
    }

    private boolean hasMoreLevels() {
        return writeBuffer.hasData();
    }

    private long readLong() throws IOException {
        return readBuffer.readLong();
    }

    private void switchBuffers() throws IOException {
        LongBuffer b = readBuffer;
        readBuffer = writeBuffer;
        writeBuffer = b;
        readBuffer.startReading();
        writeBuffer.reset();
    }

    private boolean writeClassConnection(final Set processedClasses, final long instanceId, final JavaClass jcls) throws IOException {
        if (!processedClasses.contains(jcls)) {
            long jclsId = jcls.getJavaClassId();

            processedClasses.add(jcls);
            if (writeConnection(instanceId, jclsId, true)) {
                return true;
            }
        }
        return false;
    }

    private boolean writeConnection(long instanceId, long refInstanceId)
                          throws IOException {
        return writeConnection(instanceId, refInstanceId, false);
    }

    private boolean writeConnection(long instanceId, long refInstanceId, boolean addRefInstanceId)
                          throws IOException {
        if (refInstanceId != 0) {
            LongMap.Entry entry = heap.idToOffsetMap.get(refInstanceId);

            if (entry != null && entry.getNearestGCRootPointer() == 0L && heap.getGCRoot(refInstanceId) == null) {
                writeLong(refInstanceId);
                if (addRefInstanceId) {
                    if (!checkReferences(refInstanceId, instanceId)) {
                        entry.addReference(instanceId);
                    }
                }
                entry.setNearestGCRootPointer(instanceId);
                if (!entry.hasOnlyOneReference()) {
                    multipleParents.writeLong(refInstanceId);
//multiParentsCount++;
                }
                return true;
            }
            return !addRefInstanceId && entry != null;
        }
        return false;
    }

    private boolean checkReferences(final long refInstanceId, final long instanceId) {
        Instance instance = heap.getInstanceByID(instanceId);
        Iterator fieldIt = instance.getFieldValues().iterator();

        while (fieldIt.hasNext()) {
            Object field = fieldIt.next();

            if (field instanceof HprofInstanceObjectValue) {
                HprofInstanceObjectValue objectValue = (HprofInstanceObjectValue) field;

                if (objectValue.getInstanceId() == refInstanceId) {
                    return true;
                }
            }
        }
        return false;
    }

    private void writeLong(long instanceId) throws IOException {
        writeBuffer.writeLong(instanceId);
    }

    private void writeLeaf(long instanceId, long size) throws IOException {
        LongMap.Entry entry = heap.idToOffsetMap.get(instanceId);

        entry.setTreeObj();
        entry.setRetainedSize(size);
//leavesCount++;
        if (entry.hasOnlyOneReference()) {
            long gcRootPointer = entry.getNearestGCRootPointer();
            if (gcRootPointer != 0) {
                LongMap.Entry gcRootPointerEntry = heap.idToOffsetMap.get(gcRootPointer);

                if (gcRootPointerEntry.getRetainedSize() == 0) {
                    gcRootPointerEntry.setRetainedSize(-1);
                    leaves.writeLong(gcRootPointer);
//firstLevel++;
                }
            }
        }
    }

    LongBuffer getLeaves() {
        computeGCRoots();
//System.out.println("Multi par.  "+multiParentsCount);
//System.out.println("Leaves      "+leavesCount);
//System.out.println("Tree obj.   "+heap.idToOffsetMap.treeObj);
//System.out.println("First level "+firstLevel);
        return leaves;
    }

    LongBuffer getMultipleParents() {
        computeGCRoots();
        return multipleParents;
    }
}




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