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Common functionality for HBase
/*
* 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.hbase.io.util;
import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import org.apache.hadoop.fs.ByteBufferReadable;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.hbase.nio.ByteBuff;
import org.apache.hadoop.io.IOUtils;
import org.apache.yetus.audience.InterfaceAudience;
@InterfaceAudience.Private
public final class BlockIOUtils {
// Disallow instantiation
private BlockIOUtils() {
}
public static boolean isByteBufferReadable(FSDataInputStream is) {
InputStream cur = is.getWrappedStream();
for (;;) {
if ((cur instanceof FSDataInputStream)) {
cur = ((FSDataInputStream) cur).getWrappedStream();
} else {
break;
}
}
return cur instanceof ByteBufferReadable;
}
/**
* Read length bytes into ByteBuffers directly.
* @param buf the destination {@link ByteBuff}
* @param dis the HDFS input stream which implement the ByteBufferReadable interface.
* @param length bytes to read.
* @throws IOException exception to throw if any error happen
*/
public static void readFully(ByteBuff buf, FSDataInputStream dis, int length) throws IOException {
if (!isByteBufferReadable(dis)) {
// If InputStream does not support the ByteBuffer read, just read to heap and copy bytes to
// the destination ByteBuff.
byte[] heapBuf = new byte[length];
IOUtils.readFully(dis, heapBuf, 0, length);
copyToByteBuff(heapBuf, 0, length, buf);
return;
}
ByteBuffer[] buffers = buf.nioByteBuffers();
int remain = length;
int idx = 0;
ByteBuffer cur = buffers[idx];
while (remain > 0) {
while (!cur.hasRemaining()) {
if (++idx >= buffers.length) {
throw new IOException(
"Not enough ByteBuffers to read the reminding " + remain + " " + "bytes");
}
cur = buffers[idx];
}
cur.limit(cur.position() + Math.min(remain, cur.remaining()));
int bytesRead = dis.read(cur);
if (bytesRead < 0) {
throw new IOException(
"Premature EOF from inputStream, but still need " + remain + " " + "bytes");
}
remain -= bytesRead;
}
}
/**
* Copying bytes from InputStream to {@link ByteBuff} by using an temporary heap byte[] (default
* size is 1024 now).
* @param in the InputStream to read
* @param out the destination {@link ByteBuff}
* @param length to read
* @throws IOException if any io error encountered.
*/
public static void readFullyWithHeapBuffer(InputStream in, ByteBuff out, int length)
throws IOException {
byte[] buffer = new byte[1024];
if (length < 0) {
throw new IllegalArgumentException("Length must not be negative: " + length);
}
int remain = length, count;
while (remain > 0) {
count = in.read(buffer, 0, Math.min(remain, buffer.length));
if (count < 0) {
throw new IOException(
"Premature EOF from inputStream, but still need " + remain + " bytes");
}
out.put(buffer, 0, count);
remain -= count;
}
}
/**
* Read from an input stream at least necessaryLen and if possible,
* extraLen also if available. Analogous to
* {@link IOUtils#readFully(InputStream, byte[], int, int)}, but specifies a number of "extra"
* bytes to also optionally read.
* @param in the input stream to read from
* @param buf the buffer to read into
* @param bufOffset the destination offset in the buffer
* @param necessaryLen the number of bytes that are absolutely necessary to read
* @param extraLen the number of extra bytes that would be nice to read
* @return true if succeeded reading the extra bytes
* @throws IOException if failed to read the necessary bytes
*/
private static boolean readWithExtraOnHeap(InputStream in, byte[] buf, int bufOffset,
int necessaryLen, int extraLen) throws IOException {
int bytesRemaining = necessaryLen + extraLen;
while (bytesRemaining > 0) {
int ret = in.read(buf, bufOffset, bytesRemaining);
if (ret < 0) {
if (bytesRemaining <= extraLen) {
// We could not read the "extra data", but that is OK.
break;
}
throw new IOException("Premature EOF from inputStream (read " + "returned " + ret
+ ", was trying to read " + necessaryLen + " necessary bytes and " + extraLen
+ " extra bytes, " + "successfully read " + (necessaryLen + extraLen - bytesRemaining));
}
bufOffset += ret;
bytesRemaining -= ret;
}
return bytesRemaining <= 0;
}
/**
* Read bytes into ByteBuffers directly, those buffers either contains the extraLen bytes or only
* contains necessaryLen bytes, which depends on how much bytes do the last time we read.
* @param buf the destination {@link ByteBuff}.
* @param dis input stream to read.
* @param necessaryLen bytes which we must read
* @param extraLen bytes which we may read
* @return if the returned flag is true, then we've finished to read the extraLen into our
* ByteBuffers, otherwise we've not read the extraLen bytes yet.
* @throws IOException if failed to read the necessary bytes.
*/
public static boolean readWithExtra(ByteBuff buf, FSDataInputStream dis, int necessaryLen,
int extraLen) throws IOException {
if (!isByteBufferReadable(dis)) {
// If InputStream does not support the ByteBuffer read, just read to heap and copy bytes to
// the destination ByteBuff.
byte[] heapBuf = new byte[necessaryLen + extraLen];
boolean ret = readWithExtraOnHeap(dis, heapBuf, 0, necessaryLen, extraLen);
copyToByteBuff(heapBuf, 0, heapBuf.length, buf);
return ret;
}
ByteBuffer[] buffers = buf.nioByteBuffers();
int bytesRead = 0;
int remain = necessaryLen + extraLen;
int idx = 0;
ByteBuffer cur = buffers[idx];
while (bytesRead < necessaryLen) {
while (!cur.hasRemaining()) {
if (++idx >= buffers.length) {
throw new IOException("Not enough ByteBuffers to read the reminding " + remain + "bytes");
}
cur = buffers[idx];
}
cur.limit(cur.position() + Math.min(remain, cur.remaining()));
int ret = dis.read(cur);
if (ret < 0) {
throw new IOException("Premature EOF from inputStream (read returned " + ret
+ ", was trying to read " + necessaryLen + " necessary bytes and " + extraLen
+ " extra bytes, successfully read " + bytesRead);
}
bytesRead += ret;
remain -= ret;
}
return (extraLen > 0) && (bytesRead == necessaryLen + extraLen);
}
/**
* Read from an input stream at least necessaryLen and if possible,
* extraLen also if available. Analogous to
* {@link IOUtils#readFully(InputStream, byte[], int, int)}, but uses positional read and
* specifies a number of "extra" bytes that would be desirable but not absolutely necessary to
* read.
* @param buff ByteBuff to read into.
* @param dis the input stream to read from
* @param position the position within the stream from which to start reading
* @param necessaryLen the number of bytes that are absolutely necessary to read
* @param extraLen the number of extra bytes that would be nice to read
* @return true if and only if extraLen is > 0 and reading those extra bytes was successful
* @throws IOException if failed to read the necessary bytes
*/
public static boolean preadWithExtra(ByteBuff buff, FSDataInputStream dis, long position,
int necessaryLen, int extraLen) throws IOException {
return preadWithExtra(buff, dis, position, necessaryLen, extraLen, false);
}
/**
* Read from an input stream at least necessaryLen and if possible,
* extraLen also if available. Analogous to
* {@link IOUtils#readFully(InputStream, byte[], int, int)}, but uses positional read and
* specifies a number of "extra" bytes that would be desirable but not absolutely necessary to
* read.
* @param buff ByteBuff to read into.
* @param dis the input stream to read from
* @param position the position within the stream from which to start reading
* @param necessaryLen the number of bytes that are absolutely necessary to read
* @param extraLen the number of extra bytes that would be nice to read
* @param readAllBytes whether we must read the necessaryLen and extraLen
* @return true if and only if extraLen is > 0 and reading those extra bytes was successful
* @throws IOException if failed to read the necessary bytes
*/
public static boolean preadWithExtra(ByteBuff buff, FSDataInputStream dis, long position,
int necessaryLen, int extraLen, boolean readAllBytes) throws IOException {
int remain = necessaryLen + extraLen;
byte[] buf = new byte[remain];
int bytesRead = 0;
int lengthMustRead = readAllBytes ? remain : necessaryLen;
while (bytesRead < lengthMustRead) {
int ret = dis.read(position + bytesRead, buf, bytesRead, remain);
if (ret < 0) {
throw new IOException("Premature EOF from inputStream (positional read returned " + ret
+ ", was trying to read " + necessaryLen + " necessary bytes and " + extraLen
+ " extra bytes, successfully read " + bytesRead);
}
bytesRead += ret;
remain -= ret;
}
// Copy the bytes from on-heap bytes[] to ByteBuffer[] now, and after resolving HDFS-3246, we
// will read the bytes to ByteBuffer[] directly without allocating any on-heap byte[].
// TODO I keep the bytes copy here, because I want to abstract the ByteBuffer[]
// preadWithExtra method for the upper layer, only need to refactor this method if the
// ByteBuffer pread is OK.
copyToByteBuff(buf, 0, bytesRead, buff);
return (extraLen > 0) && (bytesRead == necessaryLen + extraLen);
}
private static int copyToByteBuff(byte[] buf, int offset, int len, ByteBuff out)
throws IOException {
if (offset < 0 || len < 0 || offset + len > buf.length) {
throw new IOException("Invalid offset=" + offset + " and len=" + len + ", cap=" + buf.length);
}
ByteBuffer[] buffers = out.nioByteBuffers();
int idx = 0, remain = len, copyLen;
ByteBuffer cur = buffers[idx];
while (remain > 0) {
while (!cur.hasRemaining()) {
if (++idx >= buffers.length) {
throw new IOException("Not enough ByteBuffers to read the reminding " + remain + "bytes");
}
cur = buffers[idx];
}
copyLen = Math.min(cur.remaining(), remain);
cur.put(buf, offset, copyLen);
remain -= copyLen;
offset += copyLen;
}
return len;
}
}