/*******************************************************************************
* Copyright (c) 2010, 2014 Ericsson, École Polytechnique de Montréal, and others
*
* All rights reserved. This program and the accompanying materials are
* made available under the terms of the Eclipse Public License v1.0 which
* accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Alexandre Montplaisir - Initial API and implementation
* Florian Wininger - Add Extension and Leaf Node
*******************************************************************************/
package fr.inria.linuxtools.internal.statesystem.core.backend.historytree;
import java.io.IOException;
import java.io.PrintWriter;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.channels.FileChannel;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.locks.ReentrantReadWriteLock;
import fr.inria.linuxtools.statesystem.core.exceptions.TimeRangeException;
import fr.inria.linuxtools.statesystem.core.interval.ITmfStateInterval;
import fr.inria.linuxtools.statesystem.core.statevalue.TmfStateValue;
/**
* The base class for all the types of nodes that go in the History Tree.
*
* @author Alexandre Montplaisir
*/
public abstract class HTNode {
// ------------------------------------------------------------------------
// Class fields
// ------------------------------------------------------------------------
/**
* The type of node
*/
public static enum NodeType {
/**
* Core node, which is a "front" node, at any level of the tree except
* the bottom-most one. It has children, and may have extensions.
*/
CORE,
/**
* Leaf node, which is a node at the last bottom level of the tree. It
* cannot have any children or extensions.
*/
LEAF;
/**
* Determine a node type by reading a serialized byte.
*
* @param rep
* The byte representation of the node type
* @return The corresponding NodeType
* @throws IOException
* If the NodeType is unrecognized
*/
public static NodeType fromByte(byte rep) throws IOException {
switch (rep) {
case 1:
return CORE;
case 2:
return LEAF;
default:
throw new IOException();
}
}
/**
* Get the byte representation of this node type. It can then be read
* with {@link #fromByte}.
*
* @return The byte matching this node type
*/
public byte toByte() {
switch (this) {
case CORE:
return 1;
case LEAF:
return 2;
default:
throw new IllegalStateException();
}
}
}
// ------------------------------------------------------------------------
// Attributes
// ------------------------------------------------------------------------
/* Configuration of the History Tree to which belongs this node */
private final HTConfig config;
/* Time range of this node */
private final long nodeStart;
private long nodeEnd;
/* Sequence number = position in the node section of the file */
private final int sequenceNumber;
private int parentSequenceNumber; /* = -1 if this node is the root node */
/* Where the Strings section begins (from the start of the node */
private int stringSectionOffset;
/* Sum of bytes of all intervals in the node */
private int sizeOfIntervalSection;
/* True if this node was read from disk (meaning its end time is now fixed) */
private volatile boolean isOnDisk;
/* Vector containing all the intervals contained in this node */
private final List<HTInterval> intervals;
/* Lock used to protect the accesses to intervals, nodeEnd and such */
private final ReentrantReadWriteLock rwl = new ReentrantReadWriteLock(false);
/**
* Constructor
*
* @param config
* Configuration of the History Tree
* @param seqNumber
* The (unique) sequence number assigned to this particular node
* @param parentSeqNumber
* The sequence number of this node's parent node
* @param start
* The earliest timestamp stored in this node
*/
protected HTNode(HTConfig config, int seqNumber, int parentSeqNumber, long start) {
this.config = config;
this.nodeStart = start;
this.sequenceNumber = seqNumber;
this.parentSequenceNumber = parentSeqNumber;
this.stringSectionOffset = config.getBlockSize();
this.sizeOfIntervalSection = 0;
this.isOnDisk = false;
this.intervals = new ArrayList<>();
}
/**
* Reader factory method. Build a Node object (of the right type) by reading
* a block in the file.
*
* @param config
* Configuration of the History Tree
* @param fc
* FileChannel to the history file, ALREADY SEEKED at the start
* of the node.
* @return The node object
* @throws IOException
* If there was an error reading from the file channel
*/
public static final HTNode readNode(HTConfig config, FileChannel fc)
throws IOException {
HTNode newNode = null;
int res, i;
ByteBuffer buffer = ByteBuffer.allocate(config.getBlockSize());
buffer.order(ByteOrder.LITTLE_ENDIAN);
buffer.clear();
res = fc.read(buffer);
assert (res == config.getBlockSize());
buffer.flip();
/* Read the common header part */
byte typeByte = buffer.get();
NodeType type = NodeType.fromByte(typeByte);
long start = buffer.getLong();
long end = buffer.getLong();
int seqNb = buffer.getInt();
int parentSeqNb = buffer.getInt();
int intervalCount = buffer.getInt();
int stringSectionOffset = buffer.getInt();
buffer.get(); // TODO Used to be "isDone", to be removed from the header
/* Now the rest of the header depends on the node type */
switch (type) {
case CORE:
/* Core nodes */
newNode = new CoreNode(config, seqNb, parentSeqNb, start);
newNode.readSpecificHeader(buffer);
break;
case LEAF:
/* Leaf nodes */
newNode = new LeafNode(config, seqNb, parentSeqNb, start);
newNode.readSpecificHeader(buffer);
break;
default:
/* Unrecognized node type */
throw new IOException();
}
/*
* At this point, we should be done reading the header and 'buffer'
* should only have the intervals left
*/
for (i = 0; i < intervalCount; i++) {
newNode.intervals.add(HTInterval.readFrom(buffer));
}
/* Assign the node's other information we have read previously */
newNode.nodeEnd = end;
newNode.stringSectionOffset = stringSectionOffset;
newNode.isOnDisk = true;
return newNode;
}
/**
* Write this node to the given file channel.
*
* @param fc
* The file channel to write to (should be sought to be correct
* position)
* @throws IOException
* If there was an error writing
*/
public final void writeSelf(FileChannel fc) throws IOException {
/*
* Yes, we are taking the *read* lock here, because we are reading the
* information in the node to write it to disk.
*/
rwl.readLock().lock();
try {
final int blockSize = config.getBlockSize();
int curStringsEntryEndPos = blockSize;
ByteBuffer buffer = ByteBuffer.allocate(blockSize);
buffer.order(ByteOrder.LITTLE_ENDIAN);
buffer.clear();
/* Write the common header part */
buffer.put(this.getNodeType().toByte());
buffer.putLong(nodeStart);
buffer.putLong(nodeEnd);
buffer.putInt(sequenceNumber);
buffer.putInt(parentSequenceNumber);
buffer.putInt(intervals.size());
buffer.putInt(stringSectionOffset);
buffer.put((byte) 1); // TODO Used to be "isDone", to be removed from header
/* Now call the inner method to write the specific header part */
this.writeSpecificHeader(buffer);
/* Back to us, we write the intervals */
for (HTInterval interval : intervals) {
int size = interval.writeInterval(buffer, curStringsEntryEndPos);
curStringsEntryEndPos -= size;
}
/*
* Write padding between the end of the Data section and the start
* of the Strings section (needed to fill the node in case there is
* no Strings section)
*/
while (buffer.position() < stringSectionOffset) {
buffer.put((byte) 0);
}
/*
* If the offsets were right, the size of the Strings section should
* be == to the expected size
*/
assert (curStringsEntryEndPos == stringSectionOffset);
/* Finally, write everything in the Buffer to disk */
// if we don't do this, flip() will lose what's after.
buffer.position(blockSize);
buffer.flip();
int res = fc.write(buffer);
assert (res == blockSize);
} finally {
rwl.readLock().unlock();
}
isOnDisk = true;
}
// ------------------------------------------------------------------------
// Accessors
// ------------------------------------------------------------------------
/**
* Retrieve the history tree configuration used for this node.
*
* @return The history tree config
*/
protected HTConfig getConfig() {
return config;
}
/**
* Get the start time of this node.
*
* @return The start time of this node
*/
public long getNodeStart() {
return nodeStart;
}
/**
* Get the end time of this node.
*
* @return The end time of this node
*/
public long getNodeEnd() {
if (this.isOnDisk) {
return nodeEnd;
}
return 0;
}
/**
* Get the sequence number of this node.
*
* @return The sequence number of this node
*/
public int getSequenceNumber() {
return sequenceNumber;
}
/**
* Get the sequence number of this node's parent.
*
* @return The parent sequence number
*/
public int getParentSequenceNumber() {
return parentSequenceNumber;
}
/**
* Change this node's parent. Used when we create a new root node for
* example.
*
* @param newParent
* The sequence number of the node that is the new parent
*/
public void setParentSequenceNumber(int newParent) {
parentSequenceNumber = newParent;
}
/**
* Return if this node is "done" (full and written to disk).
*
* @return If this node is done or not
*/
public boolean isOnDisk() {
return isOnDisk;
}
/**
* Add an interval to this node
*
* @param newInterval
* Interval to add to this node
*/
public void addInterval(HTInterval newInterval) {
rwl.writeLock().lock();
try {
/* Just in case, should be checked before even calling this function */
assert (newInterval.getIntervalSize() <= this.getNodeFreeSpace());
intervals.add(newInterval);
sizeOfIntervalSection += newInterval.getIntervalSize();
/* Update the in-node offset "pointer" */
stringSectionOffset -= (newInterval.getStringsEntrySize());
} finally {
rwl.writeLock().unlock();
}
}
/**
* We've received word from the containerTree that newest nodes now exist to
* our right. (Puts isDone = true and sets the endtime)
*
* @param endtime
* The nodeEnd time that the node will have
*/
public void closeThisNode(long endtime) {
rwl.writeLock().lock();
try {
assert (endtime >= this.nodeStart);
if (!intervals.isEmpty()) {
/*
* Sort the intervals by ascending order of their end time. This
* speeds up lookups a bit
*/
Collections.sort(intervals);
/*
* Make sure there are no intervals in this node with their
* EndTime > the one requested. Only need to check the last one
* since they are now sorted
*/
assert (endtime >= intervals.get(intervals.size() - 1).getEndTime());
}
this.nodeEnd = endtime;
} finally {
rwl.writeLock().unlock();
}
}
/**
* The method to fill up the stateInfo (passed on from the Current State
* Tree when it does a query on the SHT). We'll replace the data in that
* vector with whatever relevant we can find from this node
*
* @param stateInfo
* The same stateInfo that comes from SHT's doQuery()
* @param t
* The timestamp for which the query is for. Only return
* intervals that intersect t.
* @throws TimeRangeException
* If 't' is invalid
*/
public void writeInfoFromNode(List<ITmfStateInterval> stateInfo, long t)
throws TimeRangeException {
/* This is from a state system query, we are "reading" this node */
rwl.readLock().lock();
try {
for (int i = getStartIndexFor(t); i < intervals.size(); i++) {
/*
* Now we only have to compare the Start times, since we now the
* End times necessarily fit.
*
* Second condition is to ignore new attributes that might have
* been created after stateInfo was instantiated (they would be
* null anyway).
*/
ITmfStateInterval interval = intervals.get(i);
if (interval.getStartTime() <= t &&
interval.getAttribute() < stateInfo.size()) {
stateInfo.set(interval.getAttribute(), interval);
}
}
} finally {
rwl.readLock().unlock();
}
}
/**
* Get a single Interval from the information in this node If the
* key/timestamp pair cannot be found, we return null.
*
* @param key
* The attribute quark to look for
* @param t
* The timestamp
* @return The Interval containing the information we want, or null if it
* wasn't found
* @throws TimeRangeException
* If 't' is invalid
*/
public HTInterval getRelevantInterval(int key, long t) throws TimeRangeException {
rwl.readLock().lock();
try {
for (int i = getStartIndexFor(t); i < intervals.size(); i++) {
HTInterval curInterval = intervals.get(i);
if (curInterval.getAttribute() == key
&& curInterval.getStartTime() <= t
&& curInterval.getEndTime() >= t) {
return curInterval;
}
}
/* We didn't find the relevant information in this node */
return null;
} finally {
rwl.readLock().unlock();
}
}
private int getStartIndexFor(long t) throws TimeRangeException {
/* Should only be called by methods with the readLock taken */
if (intervals.isEmpty()) {
return 0;
}
/*
* Since the intervals are sorted by end time, we can skip all the ones
* at the beginning whose end times are smaller than 't'. Java does
* provides a .binarySearch method, but its API is quite weird...
*/
HTInterval dummy = new HTInterval(0, t, 0, TmfStateValue.nullValue());
int index = Collections.binarySearch(intervals, dummy);
if (index < 0) {
/*
* .binarySearch returns a negative number if the exact value was
* not found. Here we just want to know where to start searching, we
* don't care if the value is exact or not.
*/
index = -index - 1;
}
/* Sometimes binarySearch yields weird stuff... */
if (index < 0) {
index = 0;
}
if (index >= intervals.size()) {
index = intervals.size() - 1;
}
/*
* Another API quirkiness, the returned index is the one of the *last*
* element of a series of equal endtimes, which happens sometimes. We
* want the *first* element of such a series, to read through them
* again.
*/
while (index > 0
&& intervals.get(index - 1).compareTo(intervals.get(index)) == 0) {
index--;
}
return index;
}
/**
* <pre>
* 1 - byte (type)
* 16 - 2x long (start time, end time)
* 16 - 4x int (seq number, parent seq number, intervalcount,
* strings section pos.)
* 1 - byte (done or not)
* </pre>
*/
private static final int COMMON_HEADER_SIZE = 34;
/**
* Return the total header size of this node (will depend on the node type).
*
* @return The total header size
*/
public final int getTotalHeaderSize() {
return COMMON_HEADER_SIZE + getSpecificHeaderSize();
}
/**
* @return The offset, within the node, where the Data section ends
*/
private int getDataSectionEndOffset() {
return this.getTotalHeaderSize() + sizeOfIntervalSection;
}
/**
* Returns the free space in the node, which is simply put, the
* stringSectionOffset - dataSectionOffset
*
* @return The amount of free space in the node (in bytes)
*/
public int getNodeFreeSpace() {
rwl.readLock().lock();
int ret = stringSectionOffset - this.getDataSectionEndOffset();
rwl.readLock().unlock();
return ret;
}
/**
* Returns the current space utilization of this node, as a percentage.
* (used space / total usable space, which excludes the header)
*
* @return The percentage (value between 0 and 100) of space utilization in
* in this node.
*/
public long getNodeUsagePercent() {
rwl.readLock().lock();
try {
final int blockSize = config.getBlockSize();
float freePercent = (float) this.getNodeFreeSpace()
/ (float) (blockSize - this.getTotalHeaderSize())
* 100F;
return (long) (100L - freePercent);
} finally {
rwl.readLock().unlock();
}
}
/**
* @name Debugging functions
*/
@SuppressWarnings("nls")
@Override
public String toString() {
/* Only used for debugging, shouldn't be externalized */
StringBuffer buf = new StringBuffer("Node #" + sequenceNumber + ", ");
buf.append(this.toStringSpecific());
buf.append(intervals.size() + " intervals (" + this.getNodeUsagePercent()
+ "% used), ");
buf.append("[" + this.nodeStart + " - ");
if (this.isOnDisk) {
buf = buf.append("" + this.nodeEnd + "]");
} else {
buf = buf.append("...]");
}
return buf.toString();
}
/**
* Debugging function that prints out the contents of this node
*
* @param writer
* PrintWriter in which we will print the debug output
*/
@SuppressWarnings("nls")
public void debugPrintIntervals(PrintWriter writer) {
/* Only used for debugging, shouldn't be externalized */
writer.println("Node #" + sequenceNumber + ":");
/* Array of children */
if (this.getNodeType() == NodeType.CORE) { /* Only Core Nodes can have children */
CoreNode thisNode = (CoreNode) this;
writer.print(" " + thisNode.getNbChildren() + " children");
if (thisNode.getNbChildren() >= 1) {
writer.print(": [ " + thisNode.getChild(0));
for (int i = 1; i < thisNode.getNbChildren(); i++) {
writer.print(", " + thisNode.getChild(i));
}
writer.print(']');
}
writer.print('\n');
}
/* List of intervals in the node */
writer.println(" Intervals contained:");
for (int i = 0; i < intervals.size(); i++) {
writer.println(intervals.get(i).toString());
}
writer.println('\n');
}
// ------------------------------------------------------------------------
// Abstract methods
// ------------------------------------------------------------------------
/**
* Get the byte value representing the node type.
*
* @return The node type
*/
public abstract NodeType getNodeType();
/**
* Return the specific header size of this node. This means the size
* occupied by the type-specific section of the header (not counting the
* common part).
*
* @return The specific header size
*/
protected abstract int getSpecificHeaderSize();
/**
* Read the type-specific part of the node header from a byte buffer.
*
* @param buffer
* The byte buffer to read from. It should be already positioned
* correctly.
*/
protected abstract void readSpecificHeader(ByteBuffer buffer);
/**
* Write the type-specific part of the header in a byte buffer.
*
* @param buffer
* The buffer to write to. It should already be at the correct
* position.
*/
protected abstract void writeSpecificHeader(ByteBuffer buffer);
/**
* Node-type-specific toString method. Used for debugging.
*
* @return A string representing the node
*/
protected abstract String toStringSpecific();
}