| 1 | /******************************************************************************* |
| 2 | * Copyright (c) 2010, 2014 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 | *******************************************************************************/ |
| 13 | |
| 14 | package org.eclipse.tracecompass.internal.statesystem.core.backend.historytree; |
| 15 | |
| 16 | import java.nio.ByteBuffer; |
| 17 | import java.util.concurrent.locks.ReentrantReadWriteLock; |
| 18 | |
| 19 | /** |
| 20 | * A Core node is a first-level node of a History Tree which is not a leaf node. |
| 21 | * |
| 22 | * It extends HTNode by adding support for child nodes, and also extensions. |
| 23 | * |
| 24 | * @author Alexandre Montplaisir |
| 25 | */ |
| 26 | public final class CoreNode extends HTNode { |
| 27 | |
| 28 | /** Number of bytes in a int */ |
| 29 | private static final int SIZE_INT = 4; |
| 30 | |
| 31 | /** Number of bytes in a long */ |
| 32 | private static final int SIZE_LONG = 8; |
| 33 | |
| 34 | /** Nb. of children this node has */ |
| 35 | private int nbChildren; |
| 36 | |
| 37 | /** Seq. numbers of the children nodes (size = MAX_NB_CHILDREN) */ |
| 38 | private int[] children; |
| 39 | |
| 40 | /** Start times of each of the children (size = MAX_NB_CHILDREN) */ |
| 41 | private long[] childStart; |
| 42 | |
| 43 | /** Seq number of this node's extension. -1 if none */ |
| 44 | private volatile int extension = -1; |
| 45 | |
| 46 | /** |
| 47 | * Lock used to gate the accesses to the children arrays. Meant to be a |
| 48 | * different lock from the one in {@link HTNode}. |
| 49 | */ |
| 50 | private final ReentrantReadWriteLock rwl = new ReentrantReadWriteLock(false); |
| 51 | |
| 52 | /** |
| 53 | * Initial constructor. Use this to initialize a new EMPTY node. |
| 54 | * |
| 55 | * @param config |
| 56 | * Configuration of the History Tree |
| 57 | * @param seqNumber |
| 58 | * The (unique) sequence number assigned to this particular node |
| 59 | * @param parentSeqNumber |
| 60 | * The sequence number of this node's parent node |
| 61 | * @param start |
| 62 | * The earliest timestamp stored in this node |
| 63 | */ |
| 64 | public CoreNode(HTConfig config, int seqNumber, int parentSeqNumber, |
| 65 | long start) { |
| 66 | super(config, seqNumber, parentSeqNumber, start); |
| 67 | this.nbChildren = 0; |
| 68 | int size = config.getMaxChildren(); |
| 69 | |
| 70 | /* |
| 71 | * We instantiate the two following arrays at full size right away, |
| 72 | * since we want to reserve that space in the node's header. |
| 73 | * "this.nbChildren" will tell us how many relevant entries there are in |
| 74 | * those tables. |
| 75 | */ |
| 76 | this.children = new int[size]; |
| 77 | this.childStart = new long[size]; |
| 78 | } |
| 79 | |
| 80 | @Override |
| 81 | protected void readSpecificHeader(ByteBuffer buffer) { |
| 82 | int size = getConfig().getMaxChildren(); |
| 83 | |
| 84 | extension = buffer.getInt(); |
| 85 | nbChildren = buffer.getInt(); |
| 86 | |
| 87 | children = new int[size]; |
| 88 | for (int i = 0; i < nbChildren; i++) { |
| 89 | children[i] = buffer.getInt(); |
| 90 | } |
| 91 | for (int i = nbChildren; i < size; i++) { |
| 92 | buffer.getInt(); |
| 93 | } |
| 94 | |
| 95 | this.childStart = new long[size]; |
| 96 | for (int i = 0; i < nbChildren; i++) { |
| 97 | childStart[i] = buffer.getLong(); |
| 98 | } |
| 99 | for (int i = nbChildren; i < size; i++) { |
| 100 | buffer.getLong(); |
| 101 | } |
| 102 | } |
| 103 | |
| 104 | @Override |
| 105 | protected void writeSpecificHeader(ByteBuffer buffer) { |
| 106 | int size = getConfig().getMaxChildren(); |
| 107 | |
| 108 | buffer.putInt(extension); |
| 109 | buffer.putInt(nbChildren); |
| 110 | |
| 111 | /* Write the "children's seq number" array */ |
| 112 | for (int i = 0; i < nbChildren; i++) { |
| 113 | buffer.putInt(children[i]); |
| 114 | } |
| 115 | for (int i = nbChildren; i < size; i++) { |
| 116 | buffer.putInt(0); |
| 117 | } |
| 118 | |
| 119 | /* Write the "children's start times" array */ |
| 120 | for (int i = 0; i < nbChildren; i++) { |
| 121 | buffer.putLong(childStart[i]); |
| 122 | } |
| 123 | for (int i = nbChildren; i < size; i++) { |
| 124 | buffer.putLong(0); |
| 125 | } |
| 126 | } |
| 127 | |
| 128 | /** |
| 129 | * Return the number of child nodes this node has. |
| 130 | * |
| 131 | * @return The number of child nodes |
| 132 | */ |
| 133 | public int getNbChildren() { |
| 134 | rwl.readLock().lock(); |
| 135 | int ret = nbChildren; |
| 136 | rwl.readLock().unlock(); |
| 137 | return ret; |
| 138 | } |
| 139 | |
| 140 | /** |
| 141 | * Get the child node corresponding to the specified index |
| 142 | * |
| 143 | * @param index The index of the child to lookup |
| 144 | * @return The child node |
| 145 | */ |
| 146 | public int getChild(int index) { |
| 147 | rwl.readLock().lock(); |
| 148 | try { |
| 149 | return children[index]; |
| 150 | } finally { |
| 151 | rwl.readLock().unlock(); |
| 152 | } |
| 153 | } |
| 154 | |
| 155 | /** |
| 156 | * Get the latest (right-most) child node of this node. |
| 157 | * |
| 158 | * @return The latest child node |
| 159 | */ |
| 160 | public int getLatestChild() { |
| 161 | rwl.readLock().lock(); |
| 162 | try { |
| 163 | return children[nbChildren - 1]; |
| 164 | } finally { |
| 165 | rwl.readLock().unlock(); |
| 166 | } |
| 167 | } |
| 168 | |
| 169 | /** |
| 170 | * Get the start time of the specified child node. |
| 171 | * |
| 172 | * @param index |
| 173 | * The index of the child node |
| 174 | * @return The start time of the that child node. |
| 175 | */ |
| 176 | public long getChildStart(int index) { |
| 177 | rwl.readLock().lock(); |
| 178 | try { |
| 179 | return childStart[index]; |
| 180 | } finally { |
| 181 | rwl.readLock().unlock(); |
| 182 | } |
| 183 | } |
| 184 | |
| 185 | /** |
| 186 | * Get the start time of the latest (right-most) child node. |
| 187 | * |
| 188 | * @return The start time of the latest child |
| 189 | */ |
| 190 | public long getLatestChildStart() { |
| 191 | rwl.readLock().lock(); |
| 192 | try { |
| 193 | return childStart[nbChildren - 1]; |
| 194 | } finally { |
| 195 | rwl.readLock().unlock(); |
| 196 | } |
| 197 | } |
| 198 | |
| 199 | /** |
| 200 | * Get the sequence number of the extension to this node (if there is one). |
| 201 | * |
| 202 | * @return The sequence number of the extended node. '-1' is returned if |
| 203 | * there is no extension node. |
| 204 | */ |
| 205 | public int getExtensionSequenceNumber() { |
| 206 | return extension; |
| 207 | } |
| 208 | |
| 209 | /** |
| 210 | * Tell this node that it has a new child (Congrats!) |
| 211 | * |
| 212 | * @param childNode |
| 213 | * The SHTNode object of the new child |
| 214 | */ |
| 215 | public void linkNewChild(HTNode childNode) { |
| 216 | rwl.writeLock().lock(); |
| 217 | try { |
| 218 | assert (nbChildren < getConfig().getMaxChildren()); |
| 219 | |
| 220 | children[nbChildren] = childNode.getSequenceNumber(); |
| 221 | childStart[nbChildren] = childNode.getNodeStart(); |
| 222 | nbChildren++; |
| 223 | |
| 224 | } finally { |
| 225 | rwl.writeLock().unlock(); |
| 226 | } |
| 227 | } |
| 228 | |
| 229 | @Override |
| 230 | public NodeType getNodeType() { |
| 231 | return NodeType.CORE; |
| 232 | } |
| 233 | |
| 234 | @Override |
| 235 | protected int getSpecificHeaderSize() { |
| 236 | int maxChildren = getConfig().getMaxChildren(); |
| 237 | int specificSize = |
| 238 | SIZE_INT /* 1x int (extension node) */ |
| 239 | + SIZE_INT /* 1x int (nbChildren) */ |
| 240 | |
| 241 | /* MAX_NB * int ('children' table) */ |
| 242 | + SIZE_INT * maxChildren |
| 243 | |
| 244 | /* MAX_NB * Timevalue ('childStart' table) */ |
| 245 | + SIZE_LONG * maxChildren; |
| 246 | |
| 247 | return specificSize; |
| 248 | } |
| 249 | |
| 250 | @Override |
| 251 | public String toStringSpecific() { |
| 252 | /* Only used for debugging, shouldn't be externalized */ |
| 253 | return "Core Node, " + nbChildren + " children, "; //$NON-NLS-1$ //$NON-NLS-2$ |
| 254 | } |
| 255 | |
| 256 | } |