YanivKunda commented on code in PR #7732: URL: https://github.com/apache/hadoop/pull/7732#discussion_r2143605258
########## hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/impl/TrackingByteBufferPool.java: ########## @@ -0,0 +1,327 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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 org.apache.hadoop.fs.impl; + +import java.nio.ByteBuffer; +import java.util.HashMap; +import java.util.Map; +import java.util.Objects; +import java.util.concurrent.atomic.AtomicInteger; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import org.apache.hadoop.io.ByteBufferPool; + +/** + * A wrapper {@link ByteBufferPool} implementation that tracks whether all allocated buffers + * are released. + * <p> + * It throws the related exception at {@link #close()} if any buffer remains un-released. + * It also clears the buffers at release so if they continued being used it'll generate errors. + * <p> + * To be used for testing only. + * <p> + * The stacktraces of the allocation are not stored by default because + * it can significantly decreases the unit test performance. + * Configuring this class to log at DEBUG will trigger their collection. + * @see ByteBufferAllocationStacktraceException + * <p> + * Adapted from Parquet class {@code org.apache.parquet.bytes.TrackingByteBufferAllocator}. + */ +public final class TrackingByteBufferPool implements ByteBufferPool, AutoCloseable { + + private static final Logger LOG = LoggerFactory.getLogger(TrackingByteBufferPool.class); + + /** + * Wrap an existing allocator with this tracking allocator. + * @param allocator allocator to wrap. + * @return a new allocator. + */ + public static TrackingByteBufferPool wrap(ByteBufferPool allocator) { + return new TrackingByteBufferPool(allocator); + } + + /** + * Key for the tracker map. + * This uses the identity hash code of the buffer as the hash code + * for the map. + */ + private static class Key { + + private final int hashCode; + + private final ByteBuffer buffer; + + Key(ByteBuffer buffer) { + hashCode = System.identityHashCode(buffer); + this.buffer = buffer; + } + + @Override + public boolean equals(Object o) { + if (this == o) { + return true; + } + if (o == null || getClass() != o.getClass()) { + return false; + } + Key key = (Key) o; + return this.buffer == key.buffer; + } + + @Override + public int hashCode() { + return hashCode; + } + + @Override + public String toString() { + return buffer.toString(); + } + } + + public static class LeakDetectorHeapByteBufferPoolException + extends RuntimeException { + + private LeakDetectorHeapByteBufferPoolException(String msg) { + super(msg); + } + + private LeakDetectorHeapByteBufferPoolException(String msg, Throwable cause) { + super(msg, cause); + } + + private LeakDetectorHeapByteBufferPoolException( + String message, + Throwable cause, + boolean enableSuppression, + boolean writableStackTrace) { + super(message, cause, enableSuppression, writableStackTrace); + } + } + + /** + * Strack trace of allocation as saved in the tracking map. + */ + public static final class ByteBufferAllocationStacktraceException + extends LeakDetectorHeapByteBufferPoolException { + + /** + * Single stack trace instance to use when DEBUG is not enabled. + */ + private static final ByteBufferAllocationStacktraceException WITHOUT_STACKTRACE = + new ByteBufferAllocationStacktraceException(false); + + /** + * Create a stack trace for the map, either using the shared static one + * or a dynamically created one. + * @return a stack + */ + private static ByteBufferAllocationStacktraceException create() { + return LOG.isDebugEnabled() + ? new ByteBufferAllocationStacktraceException() + : WITHOUT_STACKTRACE; + } + + private ByteBufferAllocationStacktraceException() { + super("Allocation stacktrace of the first ByteBuffer:"); + } + + /** + * Private constructor to for the singleton {@link #WITHOUT_STACKTRACE}, + * telling develoers how to see a trace per buffer. + */ + private ByteBufferAllocationStacktraceException(boolean unused) { + super("Log org.apache.hadoop.fs.impl.TrackingByteBufferPool at DEBUG for stack traces", + null, + false, + false); + } + } + + /** + * Exception raised in {@link TrackingByteBufferPool#putBuffer(ByteBuffer)} if the + * buffer to release was not in the hash map. + */ + public static final class ReleasingUnallocatedByteBufferException + extends LeakDetectorHeapByteBufferPoolException { + + private ReleasingUnallocatedByteBufferException(final ByteBuffer b) { + super(String.format("Releasing a ByteBuffer instance that is not allocated" + + " by this buffer pool or already been released: %s size %d", b, b.capacity())); + } + } + + /** + * Exception raised in {@link TrackingByteBufferPool#close()} if there + * was an unreleased buffer. + */ + public static final class LeakedByteBufferException + extends LeakDetectorHeapByteBufferPoolException { + + private final int count; + + private LeakedByteBufferException(int count, ByteBufferAllocationStacktraceException e) { + super(count + " ByteBuffer object(s) is/are remained unreleased" + + " after closing this buffer pool.", e); + this.count = count; + } + + /** + * Get the number of unreleased buffers. + * @return number of unreleased buffers + */ + public int getCount() { + return count; + } + } + + /** + * Tracker of allocations. + * <p> + * The key maps by the object id of the buffer, and refers to either a common stack trace + * or one dynamically created for each allocation. + */ + private final Map<Key, ByteBufferAllocationStacktraceException> allocated = Review Comment: I think this can be replaced with `java.util.IdentityHashMap`, which will make the `Key` class redundant: ```suggestion private final Map<ByteBuffer, ByteBufferAllocationStacktraceException> allocated = new IdentityHashMap(); ``` -- This is an automated message from the Apache Git Service. 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