org.apache.flink.runtime.io.disk.FileBasedBufferIterator Maven / Gradle / Ivy
/*
* 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.flink.runtime.io.disk;
import org.apache.flink.annotation.Internal;
import org.apache.flink.core.fs.RefCountedFile;
import org.apache.flink.runtime.io.network.buffer.Buffer;
import org.apache.flink.runtime.io.network.buffer.FreeingBufferRecycler;
import org.apache.flink.runtime.io.network.buffer.NetworkBuffer;
import org.apache.flink.util.CloseableIterator;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import static org.apache.flink.core.memory.MemorySegmentFactory.wrap;
import static org.apache.flink.runtime.io.network.buffer.Buffer.DataType.DATA_BUFFER;
import static org.apache.flink.util.IOUtils.closeAll;
import static org.apache.flink.util.Preconditions.checkArgument;
import static org.apache.flink.util.Preconditions.checkNotNull;
import static org.apache.flink.util.Preconditions.checkState;
/** {@link CloseableIterator} of {@link Buffer buffers} over file content. */
@Internal
public class FileBasedBufferIterator implements CloseableIterator {
private final RefCountedFile file;
private final FileInputStream stream;
private final int bufferSize;
private int offset;
private int bytesToRead;
public FileBasedBufferIterator(RefCountedFile file, int bytesToRead, int bufferSize)
throws FileNotFoundException {
checkNotNull(file);
checkArgument(bytesToRead >= 0);
checkArgument(bufferSize > 0);
this.stream = new FileInputStream(file.getFile());
this.file = file;
this.bufferSize = bufferSize;
this.bytesToRead = bytesToRead;
file.retain();
}
@Override
public boolean hasNext() {
return bytesToRead > 0;
}
@Override
public Buffer next() {
byte[] buffer = new byte[bufferSize];
int bytesRead = read(buffer);
checkState(
bytesRead >= 0,
"unexpected end of file, file = " + file.getFile() + ", offset=" + offset);
offset += bytesRead;
bytesToRead -= bytesRead;
return new NetworkBuffer(
wrap(buffer), FreeingBufferRecycler.INSTANCE, DATA_BUFFER, bytesRead);
}
private int read(byte[] buffer) {
int limit = Math.min(buffer.length, bytesToRead);
try {
return stream.read(buffer, 0, limit);
} catch (IOException e) {
throw new RuntimeException(e);
}
}
@Override
public void close() throws Exception {
closeAll(stream, file::release);
}
}