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Swirlds is a software platform designed to build fully-distributed applications that harness the power of the cloud without servers. Now you can develop applications with fairness in decision making, speed, trust and reliability, at a fraction of the cost of traditional server-based platforms.
/*
* Copyright (C) 2021-2024 Hedera Hashgraph, LLC
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.swirlds.merkledb.files.hashmap;
import static com.hedera.pbj.runtime.ProtoParserTools.TAG_FIELD_OFFSET;
import static com.swirlds.logging.legacy.LogMarker.MERKLE_DB;
import static com.swirlds.merkledb.files.hashmap.HalfDiskHashMap.INVALID_VALUE;
import com.hedera.pbj.runtime.FieldDefinition;
import com.hedera.pbj.runtime.FieldType;
import com.hedera.pbj.runtime.ProtoConstants;
import com.hedera.pbj.runtime.ProtoWriterTools;
import com.hedera.pbj.runtime.io.ReadableSequentialData;
import com.hedera.pbj.runtime.io.WritableSequentialData;
import com.hedera.pbj.runtime.io.buffer.BufferedData;
import com.hedera.pbj.runtime.io.buffer.Bytes;
import java.io.Closeable;
import java.io.IOException;
import java.util.concurrent.atomic.AtomicInteger;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
/**
* Class for accessing the data in a bucket. Each bucket has an index and contains a number
* of bucket entries. Entries contain key hash codes (as a single bucket may contain keys
* with different hash codes), values, and full serialized key bytes.
*
* This class is not fully thread safe. Buckets may be updated in one thread and then
* accessed from different threads, this use case is supported. However, buckets aren't
* designed to be updated concurrently from multiple threads.
*
*
Protobuf schema:
*
*
* message Bucket {
*
* // Bucket index
* uint32 index = 1;
*
* // Items
* repeated BucketEntry entries = 11;
* }
*
* message BucketEntry {
*
* // Key hash code
* int32 hashCode = 1;
*
* // Entry value, e.g. path
* int64 value = 2;
*
* // Serialized key
* bytes keyBytes = 3;
* }
*
*/
public sealed class Bucket implements Closeable permits ParsedBucket {
private static final Logger logger = LogManager.getLogger(Bucket.class);
/** Keep track of the bucket with most keys we have ever created for logging */
private static final AtomicInteger LARGEST_BUCKET_CREATED = new AtomicInteger(0);
protected static final FieldDefinition FIELD_BUCKET_INDEX =
new FieldDefinition("index", FieldType.FIXED32, false, false, false, 1);
protected static final FieldDefinition FIELD_BUCKET_ENTRIES =
new FieldDefinition("entries", FieldType.MESSAGE, true, true, false, 11);
protected static final FieldDefinition FIELD_BUCKETENTRY_HASHCODE =
new FieldDefinition("hashCode", FieldType.FIXED32, false, false, false, 1);
protected static final FieldDefinition FIELD_BUCKETENTRY_VALUE =
new FieldDefinition("value", FieldType.FIXED64, false, false, false, 2);
protected static final FieldDefinition FIELD_BUCKETENTRY_KEYBYTES =
new FieldDefinition("keyBytes", FieldType.BYTES, false, false, false, 3);
/** Size of FIELD_BUCKET_INDEX, in bytes. */
private static final int METADATA_SIZE =
ProtoWriterTools.sizeOfTag(FIELD_BUCKET_INDEX, ProtoConstants.WIRE_TYPE_FIXED_32_BIT) + Integer.BYTES;
/**
* Bucket pool this bucket is managed by, optional. If not null, the bucket is
* released back to the pool on close.
*/
protected final ReusableBucketPool bucketPool;
private BufferedData bucketData;
private volatile long bucketIndexFieldOffset = 0;
private int entryCount = 0;
/**
* Create a new bucket with the default size.
*/
protected Bucket() {
this(null);
}
/**
* Create a new bucket with the default size.
*/
protected Bucket(final ReusableBucketPool bucketPool) {
this.bucketPool = bucketPool;
this.bucketData = BufferedData.allocate(METADATA_SIZE);
clear();
}
private void setSize(final int size, final boolean keepContent) {
if (bucketData.capacity() < size) {
final BufferedData newData = BufferedData.allocate(size);
if (keepContent) {
bucketData.resetPosition();
newData.writeBytes(bucketData);
}
bucketData = newData;
}
bucketData.resetPosition();
bucketData.limit(size);
}
/**
* {@inheritDoc}
*/
@Override
public void close() throws IOException {
if (bucketPool != null) {
bucketPool.releaseBucket(this);
}
}
/**
* Reset for next use.
*/
public void clear() {
setSize(METADATA_SIZE, false);
bucketIndexFieldOffset = 0;
setBucketIndex(0);
entryCount = 0;
}
/** Get the index for this bucket */
public int getBucketIndex() {
final long bucketIndexValueOffset = bucketIndexFieldOffset
+ ProtoWriterTools.sizeOfTag(FIELD_BUCKET_INDEX, ProtoConstants.WIRE_TYPE_FIXED_32_BIT);
return bucketData.getInt(bucketIndexValueOffset);
}
/** Set the index for this bucket */
public void setBucketIndex(int index) {
bucketData.position(bucketIndexFieldOffset);
ProtoWriterTools.writeTag(bucketData, FIELD_BUCKET_INDEX);
bucketData.writeInt(index);
}
public boolean isEmpty() {
return bucketData.length() == METADATA_SIZE;
}
/** Get the number of entries stored in this bucket */
public int getBucketEntryCount() {
return entryCount;
}
protected void checkLargestBucket(final int count) {
if (!logger.isDebugEnabled(MERKLE_DB.getMarker())) {
return;
}
if (count > LARGEST_BUCKET_CREATED.get()) {
LARGEST_BUCKET_CREATED.set(count);
logger.debug(MERKLE_DB.getMarker(), "New largest bucket, now = {} entries", count);
}
}
/** Get the size of this bucket in bytes, including header */
public int sizeInBytes() {
return Math.toIntExact(bucketData.length());
}
/**
* Find a value for given key
*
* @param keyHashCode the int hash for the key
* @param key the key object
* @param notFoundValue the long to return if the key is not found
* @return the stored value for given key or notFoundValue if nothing is stored for the key
* @throws IOException If there was a problem reading the value from file
*/
public long findValue(final int keyHashCode, final Bytes key, final long notFoundValue) throws IOException {
final FindResult result = findEntry(keyHashCode, key);
if (result.found()) {
// yay! we found it
return result.entryValue();
} else {
return notFoundValue;
}
}
/**
* Put a key/value entry into this bucket.
*
* @param key the entry key
* @param value the entry value, this can also be special
* HalfDiskHashMap.INVALID_VALUE to mean delete
*/
public final void putValue(final Bytes key, final int keyHashCode, final long value) {
putValue(key, keyHashCode, INVALID_VALUE, value);
}
/**
* Optionally check the current value, and if it matches the given value, then put a
* key/value entry into this bucket. If the existing value check is requested, but there
* is no existing value for the key, the value is not added.
*
* @param key the entry key
* @param keyHashCode the key hash code
* @param oldValue the value to check the existing value against, if {@code checkOldValue} is true. If
* {@code checkOldValue} is false, this old value is ignored
* @param value the entry value, this can also be special
* HalfDiskHashMap.INVALID_VALUE to mean delete
*/
public void putValue(final Bytes key, final int keyHashCode, final long oldValue, final long value) {
final boolean needCheckOldValue = oldValue != INVALID_VALUE;
final FindResult result = findEntry(keyHashCode, key);
if (value == INVALID_VALUE) {
if (result.found()) {
if (needCheckOldValue && (oldValue != result.entryValue)) {
return;
}
final long nextEntryOffset = result.entryOffset() + result.entrySize();
final long remainderSize = bucketData.length() - nextEntryOffset;
if (remainderSize > 0) {
final BufferedData remainder = bucketData.slice(nextEntryOffset, remainderSize);
bucketData.position(result.entryOffset());
bucketData.writeBytes(remainder);
}
if (bucketIndexFieldOffset > result.entryOffset()) {
// It should not happen with default implementation, but if buckets are serialized
// using 3rd-party tools, field order may be arbitrary, and "bucket index" field
// may be after the deleted entry
bucketIndexFieldOffset -= result.entrySize();
}
bucketData.position(0); // limit() doesn't work if the new limit is less than the current pos
bucketData.limit(result.entryOffset() + remainderSize);
entryCount--;
} else {
// entry not found, nothing to delete
}
return;
}
if (result.found()) {
// yay! we found it, so update value
if (needCheckOldValue && (oldValue != result.entryValue)) {
return;
}
bucketData.position(result.entryValueOffset());
bucketData.writeLong(value);
} else {
if (needCheckOldValue) {
return;
}
// add a new entry
writeNewEntry(keyHashCode, value, key);
checkLargestBucket(++entryCount);
}
}
private void writeNewEntry(final int hashCode, final long value, final Bytes key) {
final long entryOffset = bucketData.limit();
final int keySize = Math.toIntExact(key.length());
final int entrySize =
ProtoWriterTools.sizeOfTag(FIELD_BUCKETENTRY_HASHCODE, ProtoConstants.WIRE_TYPE_FIXED_32_BIT)
+ Integer.BYTES
+ ProtoWriterTools.sizeOfTag(FIELD_BUCKETENTRY_VALUE, ProtoConstants.WIRE_TYPE_FIXED_64_BIT)
+ Long.BYTES
+ ProtoWriterTools.sizeOfDelimited(FIELD_BUCKETENTRY_KEYBYTES, keySize);
final int totalSize = ProtoWriterTools.sizeOfDelimited(FIELD_BUCKET_ENTRIES, entrySize);
setSize(Math.toIntExact(entryOffset + totalSize), true);
bucketData.position(entryOffset);
ProtoWriterTools.writeDelimited(bucketData, FIELD_BUCKET_ENTRIES, entrySize, out -> {
ProtoWriterTools.writeTag(out, FIELD_BUCKETENTRY_HASHCODE);
out.writeInt(hashCode);
ProtoWriterTools.writeTag(out, FIELD_BUCKETENTRY_VALUE);
out.writeLong(value);
ProtoWriterTools.writeDelimited(out, FIELD_BUCKETENTRY_KEYBYTES, keySize, t -> t.writeBytes(key));
});
}
public void readFrom(final ReadableSequentialData in) {
final int size = Math.toIntExact(in.remaining());
setSize(size, false);
in.readBytes(bucketData);
bucketData.flip();
entryCount = 0;
while (bucketData.hasRemaining()) {
final long fieldOffset = bucketData.position();
final int tag = bucketData.readVarInt(false);
final int fieldNum = tag >> TAG_FIELD_OFFSET;
if (fieldNum == FIELD_BUCKET_INDEX.number()) {
bucketIndexFieldOffset = fieldOffset;
bucketData.skip(Integer.BYTES);
} else if (fieldNum == FIELD_BUCKET_ENTRIES.number()) {
final int entryBytesSize = bucketData.readVarInt(false);
bucketData.skip(entryBytesSize);
entryCount++;
} else {
logger.error(
MERKLE_DB.getMarker(),
"Cannot read bucket: in={} off={} bd.pos={} bd.lim={} bd.data={}",
in,
fieldOffset,
bucketData.position(),
bucketData.limit(),
bucketData);
throw new IllegalArgumentException("Unknown bucket field: " + fieldNum);
}
}
checkLargestBucket(entryCount);
}
public void writeTo(final WritableSequentialData out) {
bucketData.resetPosition();
out.writeBytes(bucketData);
}
// =================================================================================================================
// Private API
private FindResult findEntry(final int keyHashCode, final Bytes key) {
bucketData.resetPosition();
while (bucketData.hasRemaining()) {
final long fieldOffset = bucketData.position();
final int tag = bucketData.readVarInt(false);
final int fieldNum = tag >> TAG_FIELD_OFFSET;
if (fieldNum == FIELD_BUCKET_INDEX.number()) {
bucketData.skip(Integer.BYTES);
} else if (fieldNum == FIELD_BUCKET_ENTRIES.number()) {
final int entrySize = bucketData.readVarInt(false);
final long nextEntryOffset = bucketData.position() + entrySize;
final long oldLimit = bucketData.limit();
bucketData.limit(nextEntryOffset);
try {
int entryHashCode = -1;
long entryValueOffset = -1;
long entryValue = 0;
long entryKeyBytesOffset = -1;
int entryKeyBytesSize = -1;
while (bucketData.hasRemaining()) {
final int entryTag = bucketData.readVarInt(false);
final int entryFieldNum = entryTag >> TAG_FIELD_OFFSET;
if (entryFieldNum == FIELD_BUCKETENTRY_HASHCODE.number()) {
entryHashCode = bucketData.readInt();
if (entryHashCode != keyHashCode) {
break;
}
} else if (entryFieldNum == FIELD_BUCKETENTRY_VALUE.number()) {
entryValueOffset = bucketData.position();
entryValue = bucketData.readLong();
} else if (entryFieldNum == FIELD_BUCKETENTRY_KEYBYTES.number()) {
entryKeyBytesSize = bucketData.readVarInt(false);
entryKeyBytesOffset = bucketData.position();
bucketData.skip(entryKeyBytesSize);
} else {
throw new IllegalArgumentException("Unknown bucket entry field: " + entryFieldNum);
}
}
if (entryHashCode == keyHashCode) {
if ((entryValueOffset == -1) || (entryKeyBytesOffset == -1)) {
logger.warn(MERKLE_DB.getMarker(), "Broken bucket entry");
} else {
if (keyEquals(entryKeyBytesOffset, entryKeyBytesSize, key)) {
return new FindResult(
true,
fieldOffset,
Math.toIntExact(nextEntryOffset - fieldOffset),
entryValueOffset,
entryValue);
}
}
}
} finally {
bucketData.limit(oldLimit);
bucketData.position(nextEntryOffset);
}
} else {
throw new IllegalArgumentException("Unknown bucket field: " + fieldNum);
}
}
return FindResult.NOT_FOUND;
}
private boolean keyEquals(final long pos, final int size, final Bytes key) {
for (int i = 0; i < size; i++) {
if (bucketData.getByte(pos + i) != key.getByte(i)) {
return false;
}
}
return true;
}
/** toString for debugging */
@Override
public String toString() {
final int entryCount = getBucketEntryCount();
final int size = sizeInBytes();
return "Bucket{bucketIndex=" + getBucketIndex() + ", entryCount=" + entryCount + ", size=" + size + "}";
}
/**
* Simple record for entry lookup results. If an entry is found, "found" is set to true,
* "entryOffset" is the entry offset in bytes in the bucket buffer, entrySize is the size of entry in
* bytes, and "entryValue" is the entry value. If no entity is found, "found" is false, "entryOffset"
* and "entrySize" are -1, and "entryValue" is undefined.
*/
private record FindResult(boolean found, long entryOffset, int entrySize, long entryValueOffset, long entryValue) {
static FindResult NOT_FOUND = new FindResult(false, -1, -1, -1, -1);
}
}