ChenSammi commented on code in PR #6372: URL: https://github.com/apache/ozone/pull/6372#discussion_r1524296271
########## hadoop-ozone/ozonefs-common/src/main/java/org/apache/hadoop/fs/ByteBufferPositionedReadable.java: ########## @@ -0,0 +1,92 @@ +/** + * 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; + +import java.io.EOFException; +import java.io.IOException; +import java.nio.ByteBuffer; + +import org.apache.hadoop.classification.InterfaceAudience; +import org.apache.hadoop.classification.InterfaceStability; + +/** + * FIXME: Hack: This is copied from Hadoop 3.3.6. Remove this interface once + * we drop Hadoop 3.1, 3.2 support. + * Implementers of this interface provide a positioned read API that writes to a + * {@link ByteBuffer} rather than a {@code byte[]}. + * + * @see PositionedReadable + * @see ByteBufferReadable + */ [email protected] [email protected] +public interface ByteBufferPositionedReadable { + /** + * Reads up to {@code buf.remaining()} bytes into buf from a given position + * in the file and returns the number of bytes read. Callers should use + * {@code buf.limit(...)} to control the size of the desired read and + * {@code buf.position(...)} to control the offset into the buffer the data + * should be written to. + * <p> + * After a successful call, {@code buf.position()} will be advanced by the + * number of bytes read and {@code buf.limit()} will be unchanged. + * <p> + * In the case of an exception, the state of the buffer (the contents of the + * buffer, the {@code buf.position()}, the {@code buf.limit()}, etc.) is + * undefined, and callers should be prepared to recover from this + * eventuality. + * <p> + * Callers should use {@link StreamCapabilities#hasCapability(String)} with + * {@link StreamCapabilities#PREADBYTEBUFFER} to check if the underlying + * stream supports this interface, otherwise they might get a + * {@link UnsupportedOperationException}. + * <p> + * Implementations should treat 0-length requests as legitimate, and must not + * signal an error upon their receipt. + * <p> + * This does not change the current offset of a file, and is thread-safe. + * + * @param position position within file + * @param buf the ByteBuffer to receive the results of the read operation. + * @return the number of bytes read, possibly zero, or -1 if reached + * end-of-stream + * @throws IOException if there is some error performing the read + */ + int read(long position, ByteBuffer buf) throws IOException; + + /** + * Reads {@code buf.remaining()} bytes into buf from a given position in + * the file or until the end of the data was reached before the read + * operation completed. Callers should use {@code buf.limit(...)} to + * control the size of the desired read and {@code buf.position(...)} to + * control the offset into the buffer the data should be written to. + * <p> + * This operation provides similar semantics to + * {@link #read(long, ByteBuffer)}, the difference is that this method is + * guaranteed to read data until the {@link ByteBuffer} is full, or until + * the end of the data stream is reached. + * + * @param position position within file + * @param buf the ByteBuffer to receive the results of the read operation. + * @throws IOException if there is some error performing the read + * @throws EOFException the end of the data was reached before + * the read operation completed + * @see #read(long, ByteBuffer) + */ + void readFully(long position, ByteBuffer buf) throws IOException; +} Review Comment: We will use the ByteBufferPositionedReadable interface defined in hadoop-common directly. This file can be removed. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
