dcapwell commented on code in PR #2299: URL: https://github.com/apache/cassandra/pull/2299#discussion_r1186516814
########## test/unit/org/apache/cassandra/io/filesystem/ListenableFileSystem.java: ########## @@ -0,0 +1,541 @@ +/* + * 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.cassandra.io.filesystem; + +import java.io.EOFException; +import java.io.File; +import java.io.IOException; +import java.io.InputStream; +import java.io.OutputStream; +import java.io.UncheckedIOException; +import java.net.URI; +import java.nio.ByteBuffer; +import java.nio.MappedByteBuffer; +import java.nio.channels.AsynchronousFileChannel; +import java.nio.channels.Channels; +import java.nio.channels.FileChannel; +import java.nio.channels.ReadableByteChannel; +import java.nio.channels.SeekableByteChannel; +import java.nio.channels.WritableByteChannel; +import java.nio.file.FileSystem; +import java.nio.file.FileSystems; +import java.nio.file.OpenOption; +import java.nio.file.Path; +import java.nio.file.StandardOpenOption; +import java.nio.file.attribute.FileAttribute; +import java.nio.file.spi.FileSystemProvider; +import java.util.Arrays; +import java.util.HashSet; +import java.util.List; +import java.util.Map; +import java.util.Set; +import java.util.concurrent.CopyOnWriteArrayList; +import java.util.concurrent.ExecutorService; +import java.util.concurrent.atomic.AtomicReference; + +import org.apache.cassandra.utils.ByteBufferUtil; +import org.apache.cassandra.utils.memory.MemoryUtil; + +public class ListenableFileSystem extends ForwardingFileSystem +{ + public interface Listener + { + } + + public interface OnOpen extends Listener + { + default void preOpen(Path path, Set<? extends OpenOption> options, FileAttribute<?>[] attrs) throws IOException + { + } + + void postOpen(Path path, Set<? extends OpenOption> options, FileAttribute<?>[] attrs, FileChannel channel) throws IOException; + } + + public interface OnRead extends Listener + { + default void preRead(Path path, FileChannel channel, long position, ByteBuffer dst) throws IOException + { + } + + void postRead(Path path, FileChannel channel, long position, ByteBuffer dst, int read) throws IOException; + } + + public interface OnTransferTo extends Listener + { + default void preTransferTo(Path path, FileChannel channel, long position, long count, WritableByteChannel target) throws IOException + { + } + + void postTransferTo(Path path, FileChannel channel, long position, long count, WritableByteChannel target, long transfered) throws IOException; + } + + public interface OnTransferFrom extends Listener + { + default void preTransferFrom(Path path, FileChannel channel, ReadableByteChannel src, long position, long count) throws IOException + { + } + + void postTransferFrom(Path path, FileChannel channel, ReadableByteChannel src, long position, long count, long transfered) throws IOException; + } + + public interface OnWrite extends Listener + { + void preWrite(Path path, FileChannel channel, long position, ByteBuffer src) throws IOException; + + void postWrite(Path path, FileChannel channel, long position, ByteBuffer src, int wrote) throws IOException; + } + + public interface OnChannelMeta extends Listener + { + default void prePosition(Path path, FileChannel channel, long position, long newPosition) throws IOException + { + } + + default void postPosition(Path path, FileChannel channel, long position, long newPosition) throws IOException + { + } + + default void preTruncate(Path path, FileChannel channel, long size, long targetSize) throws IOException + { + } + + default void postTruncate(Path path, FileChannel channel, long size, long targetSize, long newSize) throws IOException + { + } + + default void preForce(Path path, FileChannel channel, boolean metaData) throws IOException + { + } + + default void postForce(Path path, FileChannel channel, boolean metaData) throws IOException + { + } + } + + public interface Unsubscribable extends AutoCloseable + { + @Override + void close(); + } + + private final List<OnOpen> onOpen = new CopyOnWriteArrayList<>(); + private final List<OnTransferTo> onTransferTo = new CopyOnWriteArrayList<>(); + private final List<OnRead> onRead = new CopyOnWriteArrayList<>(); + private final List<OnWrite> onWrite = new CopyOnWriteArrayList<>(); + private final List<OnTransferFrom> onTransferFrom = new CopyOnWriteArrayList<>(); + private final List<OnChannelMeta> onChannelMeta = new CopyOnWriteArrayList<>(); + private final List<List<? extends Listener>> lists = Arrays.asList(onOpen, onRead, onTransferTo, onWrite, onTransferFrom, onChannelMeta); + private final ListenableFileSystemProvider provider; + + public ListenableFileSystem(FileSystem delegate) + { + super(delegate); + this.provider = new ListenableFileSystemProvider(super.provider()); + } + + public Unsubscribable listen(Listener listener) + { + if (listener instanceof OnOpen) + onOpen.add((OnOpen) listener); + if (listener instanceof OnRead) + onRead.add((OnRead) listener); + if (listener instanceof OnTransferTo) + onTransferTo.add((OnTransferTo) listener); + if (listener instanceof OnWrite) + onWrite.add((OnWrite) listener); + if (listener instanceof OnTransferFrom) + onTransferFrom.add((OnTransferFrom) listener); + if (listener instanceof OnChannelMeta) + onChannelMeta.add((OnChannelMeta) listener); + return () -> remove(listener); + } + + public void remove(Listener listener) + { + lists.forEach(l -> l.remove(listener)); + } + + public void clearListeners() + { + lists.forEach(List::clear); + } + + private interface ListenerAction<T> + { + void accept(T value) throws IOException; + } + + private <T> void notifyListeners(List<T> listeners, ListenerAction<T> fn) throws IOException + { + for (T listener : listeners) + fn.accept(listener); + } + + @Override + protected Path wrap(Path p) + { + return p instanceof ListenablePath ? p : new ListenablePath(p); + } + + @Override + protected Path unwrap(Path p) + { + return p instanceof ListenablePath ? ((ListenablePath) p).delegate : p; + } + + @Override + public ListenableFileSystemProvider provider() + { + return provider; + } + + + private class ListenableFileSystemProvider extends ForwardingFileSystemProvider + { + ListenableFileSystemProvider(FileSystemProvider delegate) + { + super(delegate); + } + + @Override + protected Path wrap(Path a) + { + return ListenableFileSystem.this.wrap(a); + } + + @Override + protected Path unwrap(Path p) + { + return ListenableFileSystem.this.unwrap(p); + } + + @Override + public OutputStream newOutputStream(Path path, OpenOption... options) throws IOException + { + int len = options.length; + Set<OpenOption> opts = new HashSet<>(len + 3); + if (len == 0) + { + opts.add(StandardOpenOption.CREATE); + opts.add(StandardOpenOption.TRUNCATE_EXISTING); + } + else + { + for (OpenOption opt : options) + { + if (opt == StandardOpenOption.READ) + throw new IllegalArgumentException("READ not allowed"); + opts.add(opt); + } + } + opts.add(StandardOpenOption.WRITE); + return Channels.newOutputStream(newFileChannel(path, opts)); + } + + @Override + public InputStream newInputStream(Path path, OpenOption... options) throws IOException + { + if (options.length > 0) Review Comment: was copy/paste from java... prob to avoid iterators? -- This is an automated message from the Apache Git Service. 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