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package org.graalvm.visualvm.lib.jfluid.server;

import org.graalvm.visualvm.lib.jfluid.server.system.Classes;
import org.graalvm.visualvm.lib.jfluid.server.system.Stacks;
import java.util.HashMap;
import java.util.Map;


/**
 * This class contains methods and data structures that are common for both modes of memory profiling - object
 * allocation and object liveness.
 *
 * @author Tomas Hurka
 * @author Misha Dmitriev
 */
public class ProfilerRuntimeMemory extends ProfilerRuntime {
    //~ Static fields/initializers -----------------------------------------------------------------------------------------------

    protected static final int MAX_STACK_FRAMES = 100; // Maximum number of stack frames that we can sample
    protected static final int NO_OF_PROFILER_FRAMES = 3; // Number of our own frames on stack when we take a stack sample
    protected static int[] allocatedInstancesCount;
    protected static int allocatedInstArrayLength;
    protected static short[] allocatedInstThreshold;
    protected static char[] objectSize;
    protected static short samplingInterval;
    protected static int stackSamplingDepth;
    static final Object classIdMapLock = new Object();
    private static int currentStackDepth;
    private static int[] stackFrameIds;
    private static Map classIdMap;
    private static volatile boolean resultsAvailable;
    private static final boolean DEBUG = false;

    // -------------------------------------- Miscellaneous support routines ------------------------------------------
    private static long randSeed;
    private static int bits;
    private static short samplingIntervalBase;

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

    public static void setAllocatedInstancesCountArray(int[] aic) {
        allocatedInstancesCount = aic;

        if (aic == null) {
            allocatedInstThreshold = null;
            objectSize = null;
            stackFrameIds = null;
            Stacks.clearNativeStackFrameBuffer();

            return;
        } else if (allocatedInstArrayLength < aic.length) {
            short[] oldThresh = (allocatedInstThreshold != null) ? allocatedInstThreshold : null;
            allocatedInstThreshold = new short[aic.length];

            if (oldThresh != null) {
                System.arraycopy(oldThresh, 0, allocatedInstThreshold, 0, allocatedInstArrayLength);
            }

            char[] oldObjectSize = (objectSize != null) ? objectSize : null;
            objectSize = new char[aic.length];

            if (oldObjectSize != null) {
                System.arraycopy(oldObjectSize, 0, objectSize, 0, allocatedInstArrayLength);
            }

            allocatedInstArrayLength = aic.length;
        }
    }

    /** Negative parameter means the depth is not limited. val == 0 means we should not take stack samples */
    public static void setStackSamplingDepth(int val) {
        if (val < 0) {
            val = MAX_STACK_FRAMES;
        } else if (val > 0) {
            val += NO_OF_PROFILER_FRAMES; // Top frames are always our own methods

            if (val > MAX_STACK_FRAMES) {
                val = MAX_STACK_FRAMES;
            }
        } else {
            currentStackDepth = 0;
        }

        stackSamplingDepth = val;
    }

    public static void setSamplingInterval(short val) {
        samplingInterval = val;
        initRandomGenerator();
    }

    /** Memory profiling-specific reset collectors functionality. */
    public static void resetProfilerCollectors(int instrType) {
        if (allocatedInstancesCount != null) {
            for (int i = 0; i < allocatedInstancesCount.length; i++) {
                allocatedInstancesCount[i] = 0;
                allocatedInstThreshold[i] = 0;
            }
        }

        if (instrType == INSTR_OBJECT_LIVENESS) {
            ProfilerRuntimeObjLiveness.resetProfilerCollectors();
        }

        classIdMap = new HashMap();
        resultsAvailable = false;
    }

    public static void traceVMObjectAlloc(Object instance, Class clazz) {
        if ((classIdMap == null) || ThreadInfo.profilingSuspended() || ThreadInfo.isProfilerServerThread(Thread.currentThread())) {
            // Avoid counting objects allocated by our own agent threads, or by this method's callees
            return;
        }

        ThreadInfo ti = ThreadInfo.getThreadInfo();
        int classId;
        boolean isObjectLiveness;

        if (ti.inProfilingRuntimeMethod > 0) {
            return;
        }

        if (!ti.isInitialized()) {
            ti.initialize();
            if (lockContentionMonitoringEnabled) writeThreadCreationEvent(ti);
        }

        ti.inProfilingRuntimeMethod++;
        classId = getClassId(clazz);
        if (classId == -1) {
            // System.err.println("*** JFluid warning: Invalid classId for class:"+classNameId);
            ti.inProfilingRuntimeMethod--;

            return;
        }

        isObjectLiveness = ProfilerInterface.getCurrentInstrType() == INSTR_OBJECT_LIVENESS;
        ti.inProfilingRuntimeMethod--;

        if (isObjectLiveness) {
            ProfilerRuntimeObjLiveness.traceObjAlloc(instance, (char)classId);
        } else {
            ProfilerRuntimeObjAlloc.traceObjAlloc(instance, (char)classId);
        }
    }

    static int getClassId(Class clazz) {
        String className = clazz.getName();
        int definingClassLoaderId = ClassLoaderManager.registerLoader(clazz);
        String classNameId = new StringBuffer(className).append('#').append(definingClassLoaderId).toString();
        Integer classIdInt;
        
        synchronized (classIdMapLock) {
            classIdInt = (Integer) classIdMap.get(classNameId);
        }

        if (classIdInt == null) {
            int newClassId = externalActionsHandler.handleFirstTimeVMObjectAlloc(className, definingClassLoaderId);

            classIdInt = new Integer(newClassId);
            synchronized (classIdMapLock) {
                classIdMap.put(classNameId, classIdInt);
            }
            if (newClassId == -1) {
                if (DEBUG) System.out.println("ProfilerRuntimeMemory.DEBUG: Invalid classId for class:"+classNameId);
//                if (classNameId.startsWith("org.graalvm.visualvm.lib.jfluid")) Thread.dumpStack();
//                if (classNameId.startsWith("[")) Thread.dumpStack();
            }
        }
        return classIdInt.intValue();
    }
    
    static boolean isInternalClass(Class clazz) {
        return clazz == ThreadInfo.class || clazz == ThreadInfo[].class;
    }
    
    // ------------------------------------------ Stack trace obtaining -----------------------------------------------

    /** This is used in Object Allocation profiling mode */
    protected static synchronized void getAndSendCurrentStackTrace(int classId, long objSize) {
        if (eventBuffer == null) {
            return; // Chances are that instrumentation has been removed while we were executing instrumentation code
        }

        synchronized (eventBuffer) { // Note that we have to use synchronization here due to the static stackFrameIds[] array

            if (stackSamplingDepth != 0) {
                currentStackDepth = Stacks.getCurrentStackFrameIds(Thread.currentThread(), stackSamplingDepth, stackFrameIds);
            }

            writeObjAllocStackTraceEvent(classId, objSize);
        }
    }

    /** This is used in Object Liveness profiling mode */
    protected static synchronized void getAndSendCurrentStackTrace(int classId, char epoch, int objCount, long objSize) {
        if (eventBuffer == null) {
            return; // Chances are that instrumentation has been removed while we were executing instrumentation code
        }

        synchronized (eventBuffer) { // Note that we have to use synchronization here due to the static stackFrameIds[] array

            if (stackSamplingDepth != 0) {
                currentStackDepth = Stacks.getCurrentStackFrameIds(Thread.currentThread(), stackSamplingDepth, stackFrameIds);
            }

            writeObjLivenessStackTraceEvent(classId, epoch, objCount, objSize);
        }
    }

    protected static long getCachedObjectSize(int classInt, Object object) {
        long objSize = objectSize[classInt];

        if (objSize <= 1) { // An array (variable size, value 1) or cached size unset (value 0)

            if (object == null) { // Should not happen, this is a debugging/critical error statement
                System.err.println("*** JFluid critical error: received null object for classId = " + classInt
                                   + " in getCachedObjectSize"); // NOI18N
                Thread.dumpStack();
                System.err.println("*** End JFluid critical error message ---------------------------"); // NOI18N
            }

            if (objSize == 0) { // Size not determined yet
                objSize = Classes.getObjectSize(object);

                if (object.getClass().isArray() || (objSize > 0xFFFF)) {
                    objectSize[classInt] = 1; // Size will be determined separately every time
                } else {
                    objectSize[classInt] = (char) objSize; // Size will be used for all objects of this class
                }
            } else {
                objSize = Classes.getObjectSize(object);
            }
        }

        return objSize;
    }

    protected static void clearDataStructures() {
        ProfilerRuntime.clearDataStructures();
        allocatedInstancesCount = null;
        stackFrameIds = null;
        Stacks.clearNativeStackFrameBuffer();
    }

    protected static void createNewDataStructures() {
        ProfilerRuntime.createNewDataStructures();
        stackFrameIds = new int[MAX_STACK_FRAMES];
        Stacks.createNativeStackFrameBuffer(MAX_STACK_FRAMES);
        classIdMap = new HashMap();
        resultsAvailable = false;
    }

    protected static void enableProfiling(boolean v) {
        // Doesn't call createNewDataStructures() or clearDataStructures() since this is an "abstract" class
    }

    protected static void initRandomGenerator() {
        randSeed = System.currentTimeMillis();

        if (samplingInterval == 1) {
            return;
        } else if ((samplingInterval == 2) || (samplingInterval == 3)) {
            bits = 1;
            samplingIntervalBase = (short) (samplingInterval - 1);

            return;
        } else {
            bits = 1;

            int val = 1; // That should be the nearest power of two smaller than samplingInterval

            while (true) {
                int newVal = val << 1;

                if (newVal < samplingInterval) {
                    bits++;
                    val = newVal;
                } else {
                    break;
                }
            }

            // Set samplingIntervalBase to (samplingInterval - val/2), and make bits correspond to val/2
            samplingIntervalBase = (short) (samplingInterval - (val >> 1));
            bits -= 1;
        }
    }

    protected static short nextRandomizedInterval() {
        if (samplingInterval == 1) {
            return 1;
        }

        // This is copied from 'int java.util.Random.next(int bits)'
        randSeed = ((randSeed * 0x5DEECE66DL) + 0xBL) & ((1L << 48) - 1);

        return (short) (samplingIntervalBase + ((int) (randSeed >>> (48 - bits))));
    }

    // ---------------------------------------- Writing profiler events -----------------------------------------

    /** Note that there is no synchronized(eventBuffer) in this method, since synchronization is already required by its callers */
    protected static void writeObjAllocStackTraceEvent(int classId, long objSize) {
        if (eventBuffer == null) {
            return; // Instrumentation removal happened when we were in instrumentation 
        }

        if (currentStackDepth != 0) {
            currentStackDepth -= NO_OF_PROFILER_FRAMES; // Top frames are our own methods
        }

        if (!resultsAvailable) {
            resultsAvailable = true;
            ProfilerServer.notifyClientOnResultsAvailability();
        }

        int curPos = globalEvBufPos;

        if ((curPos + 16 + (currentStackDepth * 4)) > globalEvBufPosThreshold) { // Dump the buffer
            externalActionsHandler.handleEventBufferDump(eventBuffer, 0, curPos);
            curPos = 0;
        }

        eventBuffer[curPos++] = OBJ_ALLOC_STACK_TRACE;
        eventBuffer[curPos++] = (byte) ((classId >> 8) & 0xFF);
        eventBuffer[curPos++] = (byte) ((classId) & 0xFF);

        eventBuffer[curPos++] = (byte) ((objSize >> 32) & 0xFF);
        eventBuffer[curPos++] = (byte) ((objSize >> 24) & 0xFF);
        eventBuffer[curPos++] = (byte) ((objSize >> 16) & 0xFF);
        eventBuffer[curPos++] = (byte) ((objSize >> 8) & 0xFF);
        eventBuffer[curPos++] = (byte) (objSize & 0xFF);

        curPos = writeStack(curPos);
        globalEvBufPos = curPos;
    }

    protected static void writeObjGCEvent(long objectId) {
        if (eventBuffer == null) {
            return; // Instrumentation removal happened when we were in instrumentation 
        }

        synchronized (eventBuffer) {
            int curPos = globalEvBufPos;

            if (curPos > globalEvBufPosThreshold) { // Dump the buffer
                externalActionsHandler.handleEventBufferDump(eventBuffer, 0, curPos);
                curPos = 0;
            }

            eventBuffer[curPos++] = OBJ_GC_HAPPENED;
            eventBuffer[curPos++] = (byte) ((objectId >> 56) & 0xFF);
            eventBuffer[curPos++] = (byte) ((objectId >> 48) & 0xFF);
            eventBuffer[curPos++] = (byte) ((objectId >> 40) & 0xFF);
            eventBuffer[curPos++] = (byte) ((objectId >> 32) & 0xFF);
            eventBuffer[curPos++] = (byte) ((objectId >> 24) & 0xFF);
            eventBuffer[curPos++] = (byte) ((objectId >> 16) & 0xFF);
            eventBuffer[curPos++] = (byte) ((objectId >> 8) & 0xFF);
            eventBuffer[curPos++] = (byte) (objectId & 0xFF);
            globalEvBufPos = curPos;
        }
    }

    /** Note that there is no synchronized(eventBuffer) in this method, since synchronization is already required by its callers */
    protected static void writeObjLivenessStackTraceEvent(int classId, char epoch, int objCount, long objSize) {
        if (eventBuffer == null) {
            return; // Instrumentation removal happened when we were in instrumentation 
        }

        if (currentStackDepth != 0) {
            currentStackDepth -= NO_OF_PROFILER_FRAMES; // Top 4 frames are our own methods
        }

        if (!resultsAvailable) {
            resultsAvailable = true;
            ProfilerServer.notifyClientOnResultsAvailability();
        }

        int curPos = globalEvBufPos;

        if ((curPos + 24 + (currentStackDepth * 4)) > globalEvBufPosThreshold) { // Dump the buffer
            externalActionsHandler.handleEventBufferDump(eventBuffer, 0, curPos);
            curPos = 0;
        }

        eventBuffer[curPos++] = OBJ_LIVENESS_STACK_TRACE;
        eventBuffer[curPos++] = (byte) ((classId >> 8) & 0xFF);
        eventBuffer[curPos++] = (byte) ((classId) & 0xFF);
        eventBuffer[curPos++] = (byte) ((epoch >> 8) & 0xFF);
        eventBuffer[curPos++] = (byte) ((epoch) & 0xFF);
        eventBuffer[curPos++] = (byte) ((objCount >> 24) & 0xFF);
        eventBuffer[curPos++] = (byte) ((objCount >> 16) & 0xFF);
        eventBuffer[curPos++] = (byte) ((objCount >> 8) & 0xFF);
        eventBuffer[curPos++] = (byte) ((objCount) & 0xFF);

        eventBuffer[curPos++] = (byte) ((objSize >> 32) & 0xFF);
        eventBuffer[curPos++] = (byte) ((objSize >> 24) & 0xFF);
        eventBuffer[curPos++] = (byte) ((objSize >> 16) & 0xFF);
        eventBuffer[curPos++] = (byte) ((objSize >> 8) & 0xFF);
        eventBuffer[curPos++] = (byte) (objSize & 0xFF);

        curPos = writeStack(curPos);
        globalEvBufPos = curPos;
    }

    private static int writeStack(int curPos) {
        eventBuffer[curPos++] = (byte) ((currentStackDepth >> 16) & 0xFF);
        eventBuffer[curPos++] = (byte) ((currentStackDepth >> 8) & 0xFF);
        eventBuffer[curPos++] = (byte) ((currentStackDepth) & 0xFF);

        /// A variant when we send non-reversed call graph
        //int base = depth + NO_OF_PROFILER_FRAMES - 1;
        //for (int i = 0; i < depth; i++) {
        //  eventBuffer[curPos++] = (char) ((stackFrameIds[base-i] >> 16) & 0xFFFF);
        //  eventBuffer[curPos++] = (char) ((stackFrameIds[base-i]) & 0xFFFF);
        //}
        int frameIdx = NO_OF_PROFILER_FRAMES;

        for (int i = 0; i < currentStackDepth; i++) {
            eventBuffer[curPos++] = (byte) ((stackFrameIds[frameIdx] >> 24) & 0xFF);
            eventBuffer[curPos++] = (byte) ((stackFrameIds[frameIdx] >> 16) & 0xFF);
            eventBuffer[curPos++] = (byte) ((stackFrameIds[frameIdx] >> 8) & 0xFF);
            eventBuffer[curPos++] = (byte) ((stackFrameIds[frameIdx]) & 0xFF);
            frameIdx++;
        }

        return curPos;
    }
}
