statesystem/org.eclipse.tracecompass.statesystem.core/src/org/eclipse/tracecompass/internal/statesystem/core/backend/historytree/HTNode.java

   1 /*******************************************************************************
   2  * Copyright (c) 2010, 2016 Ericsson, École Polytechnique de Montréal, and others
   3  *
   4  * All rights reserved. This program and the accompanying materials are
   5  * made available under the terms of the Eclipse Public License v1.0 which
   6  * accompanies this distribution, and is available at
   7  * http://www.eclipse.org/legal/epl-v10.html
   8  *
   9  * Contributors:
  10  *   Alexandre Montplaisir - Initial API and implementation
  11  *   Florian Wininger - Add Extension and Leaf Node
  12  *   Patrick Tasse - Keep interval list sorted on insert
  13  *******************************************************************************/
  14
  15 package org.eclipse.tracecompass.internal.statesystem.core.backend.historytree;
  16
  17 import java.io.IOException;
  18 import java.io.PrintWriter;
  19 import java.nio.ByteBuffer;
  20 import java.nio.ByteOrder;
  21 import java.nio.channels.FileChannel;
  22 import java.util.ArrayList;
  23 import java.util.Collections;
  24 import java.util.List;
  25 import java.util.concurrent.locks.ReentrantReadWriteLock;
  26
  27 import org.eclipse.jdt.annotation.NonNull;
  28 import org.eclipse.tracecompass.statesystem.core.exceptions.TimeRangeException;
  29 import org.eclipse.tracecompass.statesystem.core.interval.ITmfStateInterval;
  30 import org.eclipse.tracecompass.statesystem.core.statevalue.TmfStateValue;
  31
  32 import com.google.common.collect.Iterables;
  33
  34 /**
  35  * The base class for all the types of nodes that go in the History Tree.
  36  *
  37  * @author Alexandre Montplaisir
  38  */
  39 public abstract class HTNode {
  40
  41     // ------------------------------------------------------------------------
  42     // Class fields
  43     // ------------------------------------------------------------------------
  44
  45     /**
  46      * The type of node
  47      */
  48     public static enum NodeType {
  49         /**
  50          * Core node, which is a "front" node, at any level of the tree except
  51          * the bottom-most one. It has children, and may have extensions.
  52          */
  53         CORE,
  54         /**
  55          * Leaf node, which is a node at the last bottom level of the tree. It
  56          * cannot have any children or extensions.
  57          */
  58         LEAF;
  59
  60         /**
  61          * Determine a node type by reading a serialized byte.
  62          *
  63          * @param rep
  64          *            The byte representation of the node type
  65          * @return The corresponding NodeType
  66          * @throws IOException
  67          *             If the NodeType is unrecognized
  68          */
  69         public static NodeType fromByte(byte rep) throws IOException {
  70             switch (rep) {
  71             case 1:
  72                 return CORE;
  73             case 2:
  74                 return LEAF;
  75             default:
  76                 throw new IOException();
  77             }
  78         }
  79
  80         /**
  81          * Get the byte representation of this node type. It can then be read
  82          * with {@link #fromByte}.
  83          *
  84          * @return The byte matching this node type
  85          */
  86         public byte toByte() {
  87             switch (this) {
  88             case CORE:
  89                 return 1;
  90             case LEAF:
  91                 return 2;
  92             default:
  93                 throw new IllegalStateException();
  94             }
  95         }
  96     }
  97
  98     /**
  99      * <pre>
 100      *  1 - byte (type)
 101      * 16 - 2x long (start time, end time)
 102      * 16 - 4x int (seq number, parent seq number, intervalcount,
 103      *              strings section pos.)
 104      *  1 - byte (done or not)
 105      * </pre>
 106      */
 107     private static final int COMMON_HEADER_SIZE = Byte.BYTES
 108             + 2 * Long.BYTES
 109             + 4 * Integer.BYTES
 110             + Byte.BYTES;
 111
 112     // ------------------------------------------------------------------------
 113     // Attributes
 114     // ------------------------------------------------------------------------
 115
 116     /* Configuration of the History Tree to which belongs this node */
 117     private final HTConfig fConfig;
 118
 119     /* Time range of this node */
 120     private final long fNodeStart;
 121     private long fNodeEnd;
 122
 123     /* Sequence number = position in the node section of the file */
 124     private final int fSequenceNumber;
 125     private int fParentSequenceNumber; /* = -1 if this node is the root node */
 126
 127     /* Sum of bytes of all intervals in the node */
 128     private int fSizeOfIntervalSection;
 129
 130     /* True if this node was read from disk (meaning its end time is now fixed) */
 131     private volatile boolean fIsOnDisk;
 132
 133     /* Vector containing all the intervals contained in this node */
 134     private final List<HTInterval> fIntervals;
 135
 136     /* Lock used to protect the accesses to intervals, nodeEnd and such */
 137     private final ReentrantReadWriteLock fRwl = new ReentrantReadWriteLock(false);
 138
 139     /**
 140      * Constructor
 141      *
 142      * @param config
 143      *            Configuration of the History Tree
 144      * @param seqNumber
 145      *            The (unique) sequence number assigned to this particular node
 146      * @param parentSeqNumber
 147      *            The sequence number of this node's parent node
 148      * @param start
 149      *            The earliest timestamp stored in this node
 150      */
 151     protected HTNode(HTConfig config, int seqNumber, int parentSeqNumber, long start) {
 152         fConfig = config;
 153         fNodeStart = start;
 154         fSequenceNumber = seqNumber;
 155         fParentSequenceNumber = parentSeqNumber;
 156
 157         fSizeOfIntervalSection = 0;
 158         fIsOnDisk = false;
 159         fIntervals = new ArrayList<>();
 160     }
 161
 162     /**
 163      * Reader factory method. Build a Node object (of the right type) by reading
 164      * a block in the file.
 165      *
 166      * @param config
 167      *            Configuration of the History Tree
 168      * @param fc
 169      *            FileChannel to the history file, ALREADY SEEKED at the start
 170      *            of the node.
 171      * @param nodeFactory
 172      *            The factory to create the nodes for this tree
 173      * @return The node object
 174      * @throws IOException
 175      *             If there was an error reading from the file channel
 176      */
 177     public static final @NonNull HTNode readNode(HTConfig config, FileChannel fc, IHistoryTree.IHTNodeFactory nodeFactory)
 178             throws IOException {
 179         HTNode newNode = null;
 180         int res, i;
 181
 182         ByteBuffer buffer = ByteBuffer.allocate(config.getBlockSize());
 183         buffer.order(ByteOrder.LITTLE_ENDIAN);
 184         buffer.clear();
 185         res = fc.read(buffer);
 186         assert (res == config.getBlockSize());
 187         buffer.flip();
 188
 189         /* Read the common header part */
 190         byte typeByte = buffer.get();
 191         NodeType type = NodeType.fromByte(typeByte);
 192         long start = buffer.getLong();
 193         long end = buffer.getLong();
 194         int seqNb = buffer.getInt();
 195         int parentSeqNb = buffer.getInt();
 196         int intervalCount = buffer.getInt();
 197         buffer.get(); // TODO Used to be "isDone", to be removed from the header
 198
 199         /* Now the rest of the header depends on the node type */
 200         switch (type) {
 201         case CORE:
 202             /* Core nodes */
 203             newNode = nodeFactory.createCoreNode(config, seqNb, parentSeqNb, start);
 204             newNode.readSpecificHeader(buffer);
 205             break;
 206
 207         case LEAF:
 208             /* Leaf nodes */
 209             newNode = nodeFactory.createLeafNode(config, seqNb, parentSeqNb, start);
 210             newNode.readSpecificHeader(buffer);
 211             break;
 212
 213         default:
 214             /* Unrecognized node type */
 215             throw new IOException();
 216         }
 217
 218         /*
 219          * At this point, we should be done reading the header and 'buffer'
 220          * should only have the intervals left
 221          */
 222         for (i = 0; i < intervalCount; i++) {
 223             HTInterval interval = HTInterval.readFrom(buffer);
 224             newNode.fIntervals.add(interval);
 225             newNode.fSizeOfIntervalSection += interval.getSizeOnDisk();
 226         }
 227
 228         /* Assign the node's other information we have read previously */
 229         newNode.fNodeEnd = end;
 230         newNode.fIsOnDisk = true;
 231
 232         return newNode;
 233     }
 234
 235     /**
 236      * Write this node to the given file channel.
 237      *
 238      * @param fc
 239      *            The file channel to write to (should be sought to be correct
 240      *            position)
 241      * @throws IOException
 242      *             If there was an error writing
 243      */
 244     public final void writeSelf(FileChannel fc) throws IOException {
 245         /*
 246          * Yes, we are taking the *read* lock here, because we are reading the
 247          * information in the node to write it to disk.
 248          */
 249         fRwl.readLock().lock();
 250         try {
 251             final int blockSize = fConfig.getBlockSize();
 252
 253             ByteBuffer buffer = ByteBuffer.allocate(blockSize);
 254             buffer.order(ByteOrder.LITTLE_ENDIAN);
 255             buffer.clear();
 256
 257             /* Write the common header part */
 258             buffer.put(getNodeType().toByte());
 259             buffer.putLong(fNodeStart);
 260             buffer.putLong(fNodeEnd);
 261             buffer.putInt(fSequenceNumber);
 262             buffer.putInt(fParentSequenceNumber);
 263             buffer.putInt(fIntervals.size());
 264             buffer.put((byte) 1); // TODO Used to be "isDone", to be removed from header
 265
 266             /* Now call the inner method to write the specific header part */
 267             writeSpecificHeader(buffer);
 268
 269             /* Back to us, we write the intervals */
 270             fIntervals.forEach(i -> i.writeInterval(buffer));
 271
 272             /*
 273              * Fill the rest with zeros
 274              */
 275             while (buffer.position() < blockSize) {
 276                 buffer.put((byte) 0);
 277             }
 278
 279             /* Finally, write everything in the Buffer to disk */
 280             buffer.flip();
 281             int res = fc.write(buffer);
 282             if (res != blockSize) {
 283                 throw new IllegalStateException("Wrong size of block written: Actual: " + res + ", Expected: " + blockSize); //$NON-NLS-1$ //$NON-NLS-2$
 284             }
 285
 286         } finally {
 287             fRwl.readLock().unlock();
 288         }
 289         fIsOnDisk = true;
 290     }
 291
 292     // ------------------------------------------------------------------------
 293     // Accessors
 294     // ------------------------------------------------------------------------
 295
 296     /**
 297      * Retrieve the history tree configuration used for this node.
 298      *
 299      * @return The history tree config
 300      */
 301     protected HTConfig getConfig() {
 302         return fConfig;
 303     }
 304
 305     /**
 306      * Get the start time of this node.
 307      *
 308      * @return The start time of this node
 309      */
 310     public long getNodeStart() {
 311         return fNodeStart;
 312     }
 313
 314     /**
 315      * Get the end time of this node.
 316      *
 317      * @return The end time of this node
 318      */
 319     public long getNodeEnd() {
 320         if (fIsOnDisk) {
 321             return fNodeEnd;
 322         }
 323         return 0;
 324     }
 325
 326     /**
 327      * Get the sequence number of this node.
 328      *
 329      * @return The sequence number of this node
 330      */
 331     public int getSequenceNumber() {
 332         return fSequenceNumber;
 333     }
 334
 335     /**
 336      * Get the sequence number of this node's parent.
 337      *
 338      * @return The parent sequence number
 339      */
 340     public int getParentSequenceNumber() {
 341         return fParentSequenceNumber;
 342     }
 343
 344     /**
 345      * Change this node's parent. Used when we create a new root node for
 346      * example.
 347      *
 348      * @param newParent
 349      *            The sequence number of the node that is the new parent
 350      */
 351     public void setParentSequenceNumber(int newParent) {
 352         fParentSequenceNumber = newParent;
 353     }
 354
 355     /**
 356      * Return if this node is "done" (full and written to disk).
 357      *
 358      * @return If this node is done or not
 359      */
 360     public boolean isOnDisk() {
 361         return fIsOnDisk;
 362     }
 363
 364     /**
 365      * Add an interval to this node
 366      *
 367      * @param newInterval
 368      *            Interval to add to this node
 369      */
 370     public void addInterval(HTInterval newInterval) {
 371         fRwl.writeLock().lock();
 372         try {
 373             /* Just in case, should be checked before even calling this function */
 374             assert (newInterval.getSizeOnDisk() <= getNodeFreeSpace());
 375
 376             /* Find the insert position to keep the list sorted */
 377             int index = fIntervals.size();
 378             while (index > 0 && newInterval.compareTo(fIntervals.get(index - 1)) < 0) {
 379                 index--;
 380             }
 381
 382             fIntervals.add(index, newInterval);
 383             fSizeOfIntervalSection += newInterval.getSizeOnDisk();
 384
 385         } finally {
 386             fRwl.writeLock().unlock();
 387         }
 388     }
 389
 390     /**
 391      * We've received word from the containerTree that newest nodes now exist to
 392      * our right. (Puts isDone = true and sets the endtime)
 393      *
 394      * @param endtime
 395      *            The nodeEnd time that the node will have
 396      */
 397     public void closeThisNode(long endtime) {
 398         fRwl.writeLock().lock();
 399         try {
 400             /**
 401              * FIXME: was assert (endtime >= fNodeStart); but that exception
 402              * is reached with an empty node that has start time endtime + 1
 403              */
 404 //            if (endtime < fNodeStart) {
 405 //                throw new IllegalArgumentException("Endtime " + endtime + " cannot be lower than start time " + fNodeStart);
 406 //            }
 407
 408             if (!fIntervals.isEmpty()) {
 409                 /*
 410                  * Make sure there are no intervals in this node with their
 411                  * EndTime > the one requested. Only need to check the last one
 412                  * since they are sorted
 413                  */
 414                 if (endtime < Iterables.getLast(fIntervals).getEndTime()) {
 415                     throw new IllegalArgumentException("Closing end time should be greater than or equal to the end time of the intervals of this node"); //$NON-NLS-1$
 416                 }
 417             }
 418
 419             fNodeEnd = endtime;
 420         } finally {
 421             fRwl.writeLock().unlock();
 422         }
 423     }
 424
 425     /**
 426      * The method to fill up the stateInfo (passed on from the Current State
 427      * Tree when it does a query on the SHT). We'll replace the data in that
 428      * vector with whatever relevant we can find from this node
 429      *
 430      * @param stateInfo
 431      *            The same stateInfo that comes from SHT's doQuery()
 432      * @param t
 433      *            The timestamp for which the query is for. Only return
 434      *            intervals that intersect t.
 435      * @throws TimeRangeException
 436      *             If 't' is invalid
 437      */
 438     public void writeInfoFromNode(List<ITmfStateInterval> stateInfo, long t)
 439             throws TimeRangeException {
 440         /* This is from a state system query, we are "reading" this node */
 441         fRwl.readLock().lock();
 442         try {
 443             for (int i = getStartIndexFor(t); i < fIntervals.size(); i++) {
 444                 /*
 445                  * Now we only have to compare the Start times, since we now the
 446                  * End times necessarily fit.
 447                  *
 448                  * Second condition is to ignore new attributes that might have
 449                  * been created after stateInfo was instantiated (they would be
 450                  * null anyway).
 451                  */
 452                 ITmfStateInterval interval = fIntervals.get(i);
 453                 if (t >= interval.getStartTime() &&
 454                         interval.getAttribute() < stateInfo.size()) {
 455                     stateInfo.set(interval.getAttribute(), interval);
 456                 }
 457             }
 458         } finally {
 459             fRwl.readLock().unlock();
 460         }
 461     }
 462
 463     /**
 464      * Get a single Interval from the information in this node If the
 465      * key/timestamp pair cannot be found, we return null.
 466      *
 467      * @param key
 468      *            The attribute quark to look for
 469      * @param t
 470      *            The timestamp
 471      * @return The Interval containing the information we want, or null if it
 472      *         wasn't found
 473      * @throws TimeRangeException
 474      *             If 't' is invalid
 475      */
 476     public HTInterval getRelevantInterval(int key, long t) throws TimeRangeException {
 477         fRwl.readLock().lock();
 478         try {
 479             for (int i = getStartIndexFor(t); i < fIntervals.size(); i++) {
 480                 HTInterval curInterval = fIntervals.get(i);
 481                 if (curInterval.getAttribute() == key
 482                         && curInterval.getStartTime() <= t
 483                         && curInterval.getEndTime() >= t) {
 484                     return curInterval;
 485                 }
 486             }
 487
 488             /* We didn't find the relevant information in this node */
 489             return null;
 490
 491         } finally {
 492             fRwl.readLock().unlock();
 493         }
 494     }
 495
 496     private int getStartIndexFor(long t) throws TimeRangeException {
 497         /* Should only be called by methods with the readLock taken */
 498
 499         if (fIntervals.isEmpty()) {
 500             return 0;
 501         }
 502         /*
 503          * Since the intervals are sorted by end time, we can skip all the ones
 504          * at the beginning whose end times are smaller than 't'. Java does
 505          * provides a .binarySearch method, but its API is quite weird...
 506          */
 507         HTInterval dummy = new HTInterval(0, t, 0, TmfStateValue.nullValue());
 508         int index = Collections.binarySearch(fIntervals, dummy);
 509
 510         if (index < 0) {
 511             /*
 512              * .binarySearch returns a negative number if the exact value was
 513              * not found. Here we just want to know where to start searching, we
 514              * don't care if the value is exact or not.
 515              */
 516             index = -index - 1;
 517
 518         } else {
 519             /*
 520              * Another API quirkiness, the returned index is the one of the *last*
 521              * element of a series of equal endtimes, which happens sometimes. We
 522              * want the *first* element of such a series, to read through them
 523              * again.
 524              */
 525             while (index > 0
 526                     && fIntervals.get(index - 1).compareTo(fIntervals.get(index)) == 0) {
 527                 index--;
 528             }
 529         }
 530
 531         return index;
 532     }
 533
 534     /**
 535      * Return the total header size of this node (will depend on the node type).
 536      *
 537      * @return The total header size
 538      */
 539     public final int getTotalHeaderSize() {
 540         return COMMON_HEADER_SIZE + getSpecificHeaderSize();
 541     }
 542
 543     /**
 544      * @return The offset, within the node, where the Data section ends
 545      */
 546     private int getDataSectionEndOffset() {
 547         return getTotalHeaderSize() + fSizeOfIntervalSection;
 548     }
 549
 550     /**
 551      * Returns the free space in the node, which is simply put, the
 552      * stringSectionOffset - dataSectionOffset
 553      *
 554      * @return The amount of free space in the node (in bytes)
 555      */
 556     public int getNodeFreeSpace() {
 557         fRwl.readLock().lock();
 558         int ret = fConfig.getBlockSize() - getDataSectionEndOffset();
 559         fRwl.readLock().unlock();
 560
 561         return ret;
 562     }
 563
 564     /**
 565      * Returns the current space utilization of this node, as a percentage.
 566      * (used space / total usable space, which excludes the header)
 567      *
 568      * @return The percentage (value between 0 and 100) of space utilization in
 569      *         in this node.
 570      */
 571     public long getNodeUsagePercent() {
 572         fRwl.readLock().lock();
 573         try {
 574             final int blockSize = fConfig.getBlockSize();
 575             float freePercent = (float) getNodeFreeSpace()
 576                     / (float) (blockSize - getTotalHeaderSize())
 577                     * 100F;
 578             return (long) (100L - freePercent);
 579
 580         } finally {
 581             fRwl.readLock().unlock();
 582         }
 583     }
 584
 585     /**
 586      * @name Debugging functions
 587      */
 588
 589     @SuppressWarnings("nls")
 590     @Override
 591     public String toString() {
 592         /* Only used for debugging, shouldn't be externalized */
 593         return String.format("Node #%d, %s, %s, %d intervals (%d%% used), [%d - %s]",
 594                 fSequenceNumber,
 595                 (fParentSequenceNumber == -1) ? "Root" : "Parent #" + fParentSequenceNumber,
 596                 toStringSpecific(),
 597                 fIntervals.size(),
 598                 getNodeUsagePercent(),
 599                 fNodeStart,
 600                 (fIsOnDisk || fNodeEnd != 0) ? fNodeEnd : "...");
 601     }
 602
 603     /**
 604      * Debugging function that prints out the contents of this node
 605      *
 606      * @param writer
 607      *            PrintWriter in which we will print the debug output
 608      */
 609     @SuppressWarnings("nls")
 610     public void debugPrintIntervals(PrintWriter writer) {
 611         /* Only used for debugging, shouldn't be externalized */
 612         writer.println("Intervals for node #" + fSequenceNumber + ":");
 613
 614         /* Array of children */
 615         if (getNodeType() != NodeType.LEAF) { /* Only Core Nodes can have children */
 616             ParentNode thisNode = (ParentNode) this;
 617             writer.print("  " + thisNode.getNbChildren() + " children");
 618             if (thisNode.getNbChildren() >= 1) {
 619                 writer.print(": [ " + thisNode.getChild(0));
 620                 for (int i = 1; i < thisNode.getNbChildren(); i++) {
 621                     writer.print(", " + thisNode.getChild(i));
 622                 }
 623                 writer.print(']');
 624             }
 625             writer.print('\n');
 626         }
 627
 628         /* List of intervals in the node */
 629         writer.println("  Intervals contained:");
 630         for (int i = 0; i < fIntervals.size(); i++) {
 631             writer.println(fIntervals.get(i).toString());
 632         }
 633         writer.println('\n');
 634     }
 635
 636     // ------------------------------------------------------------------------
 637     // Abstract methods
 638     // ------------------------------------------------------------------------
 639
 640     /**
 641      * Get the byte value representing the node type.
 642      *
 643      * @return The node type
 644      */
 645     public abstract NodeType getNodeType();
 646
 647     /**
 648      * Return the specific header size of this node. This means the size
 649      * occupied by the type-specific section of the header (not counting the
 650      * common part).
 651      *
 652      * @return The specific header size
 653      */
 654     protected abstract int getSpecificHeaderSize();
 655
 656     /**
 657      * Read the type-specific part of the node header from a byte buffer.
 658      *
 659      * @param buffer
 660      *            The byte buffer to read from. It should be already positioned
 661      *            correctly.
 662      */
 663     protected abstract void readSpecificHeader(ByteBuffer buffer);
 664
 665     /**
 666      * Write the type-specific part of the header in a byte buffer.
 667      *
 668      * @param buffer
 669      *            The buffer to write to. It should already be at the correct
 670      *            position.
 671      */
 672     protected abstract void writeSpecificHeader(ByteBuffer buffer);
 673
 674     /**
 675      * Node-type-specific toString method. Used for debugging.
 676      *
 677      * @return A string representing the node
 678      */
 679     protected abstract String toStringSpecific();
 680 }