package org.eclipse.tracecompass.internal.statesystem.core.backend.historytree;
+import static org.eclipse.tracecompass.common.core.NonNullUtils.checkNotNull;
+
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.logging.Logger;
import org.eclipse.jdt.annotation.NonNull;
-import org.eclipse.jdt.annotation.NonNullByDefault;
import org.eclipse.tracecompass.common.core.log.TraceCompassLog;
+import java.util.Objects;
+import java.util.concurrent.ExecutionException;
+
+import org.eclipse.jdt.annotation.Nullable;
import org.eclipse.tracecompass.internal.statesystem.core.Activator;
+import com.google.common.cache.CacheBuilder;
+import com.google.common.cache.CacheLoader;
+import com.google.common.cache.LoadingCache;
+
/**
* This class abstracts inputs/outputs of the HistoryTree nodes.
*
*/
class HT_IO {
- @NonNullByDefault
- private static final class CacheElement {
- private final HTNode value;
- private final HT_IO key;
+ private static final Logger LOGGER = TraceCompassLog.getLogger(HT_IO.class);
+
+ // ------------------------------------------------------------------------
+ // Global cache of nodes
+ // ------------------------------------------------------------------------
+
+ private static final class CacheKey {
- public CacheElement(HT_IO ss, HTNode node) {
- key = ss;
- value = node;
+ public final HT_IO fStateHistory;
+ public final int fSeqNumber;
+
+ public CacheKey(HT_IO stateHistory, int seqNumber) {
+ fStateHistory = stateHistory;
+ fSeqNumber = seqNumber;
}
- public HT_IO getKey() {
- return key;
+ @Override
+ public int hashCode() {
+ return Objects.hash(fStateHistory, fSeqNumber);
}
- public HTNode getValue() {
- return value;
+ @Override
+ public boolean equals(@Nullable Object obj) {
+ if (this == obj) {
+ return true;
+ }
+ if (obj == null) {
+ return false;
+ }
+ if (getClass() != obj.getClass()) {
+ return false;
+ }
+ CacheKey other = (CacheKey) obj;
+ return (fStateHistory.equals(other.fStateHistory) &&
+ fSeqNumber == other.fSeqNumber);
}
}
+ private static final int CACHE_SIZE = 256;
+
+ private static final LoadingCache<CacheKey, HTNode> NODE_CACHE =
+ checkNotNull(CacheBuilder.newBuilder()
+ .maximumSize(CACHE_SIZE)
+ .build(new CacheLoader<CacheKey, HTNode>() {
+ @Override
+ public HTNode load(CacheKey key) throws IOException {
+ HT_IO io = key.fStateHistory;
+ int seqNb = key.fSeqNumber;
+
+ LOGGER.finest(() -> "[HtIo:CacheMiss] seqNum=" + seqNb); //$NON-NLS-1$
+
+ io.seekFCToNodePos(io.fFileChannelIn, seqNb);
+ return HTNode.readNode(io.fConfig, io.fFileChannelIn);
+ }
+ }));
+
+
+ // ------------------------------------------------------------------------
+ // Instance fields
+ // ------------------------------------------------------------------------
+
/* Configuration of the History Tree */
private final HTConfig fConfig;
private final FileChannel fFileChannelIn;
private final FileChannel fFileChannelOut;
- // TODO test/benchmark optimal cache size
- /**
- * Cache size, must be a power of 2
- */
- private static final int CACHE_SIZE = 256;
- private static final int CACHE_MASK = CACHE_SIZE - 1;
- private static final CacheElement NODE_CACHE[] = new CacheElement[CACHE_SIZE];
+ // ------------------------------------------------------------------------
+ // Methods
+ // ------------------------------------------------------------------------
+
- private static final Logger LOGGER = TraceCompassLog.getLogger(HT_IO.class);
/**
* Standard constructor
* just catch this exception.
*/
public synchronized @NonNull HTNode readNode(int seqNumber) throws ClosedChannelException {
- /* Do a cache lookup */
- int offset = (seqNumber + hashCode()) & CACHE_MASK;
- CacheElement cachedNode = NODE_CACHE[offset];
-
- if (cachedNode != null && cachedNode.getKey() == this && cachedNode.getValue().getSequenceNumber() == seqNumber) {
- LOGGER.finest(() -> "[HtIo:CacheHit] seqNum=" + seqNumber); //$NON-NLS-1$
- return cachedNode.getValue();
- }
-
- /* Lookup on disk */
+ /* Do a cache lookup. If it's not present it will be loaded from disk */
+ LOGGER.finest(() -> "[HtIo:CacheLookup] seqNum=" + seqNumber); //$NON-NLS-1$
+ CacheKey key = new CacheKey(this, seqNumber);
try {
- seekFCToNodePos(fFileChannelIn, seqNumber);
- HTNode readNode = HTNode.readNode(fConfig, fFileChannelIn);
- LOGGER.finest(() -> "[HtIo:CacheMiss] seqNum=" + seqNumber); //$NON-NLS-1$
-
- /* Put the node in the cache. */
- NODE_CACHE[offset] = new CacheElement(this, readNode);
- return readNode;
+ return checkNotNull(NODE_CACHE.get(key));
- } catch (ClosedChannelException e) {
- throw e;
- } catch (IOException e) {
+ } catch (ExecutionException e) {
+ /* Get the inner exception that was generated */
+ Throwable cause = e.getCause();
+ if (cause instanceof ClosedChannelException) {
+ throw (ClosedChannelException) cause;
+ }
/*
- * Other types of IOExceptions shouldn't happen at this point though
+ * Other types of IOExceptions shouldn't happen at this point though.
*/
Activator.getDefault().logError(e.getMessage(), e);
throw new IllegalStateException();
public synchronized void writeNode(HTNode node) {
try {
- /* Insert the node into the cache. */
int seqNumber = node.getSequenceNumber();
- int offset = (seqNumber + hashCode()) & CACHE_MASK;
- NODE_CACHE[offset] = new CacheElement(this, node);
+
+ /* "Write-back" the node into the cache */
+ CacheKey key = new CacheKey(this, seqNumber);
+ NODE_CACHE.put(key, node);
/* Position ourselves at the start of the node and write it */
seekFCToNodePos(fFileChannelOut, seqNumber);
projects / deliverable / tracecompass.git / commitdiff
