Github user paul-rogers commented on a diff in the pull request:
https://github.com/apache/drill/pull/611#discussion_r86404983
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/util/filereader/BufferedDirectBufInputStream.java
---
@@ -0,0 +1,460 @@
+/**
+ * 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
+ * <p/>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p/>
+ * 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.drill.exec.util.filereader;
+
+import com.google.common.base.Preconditions;
+import io.netty.buffer.DrillBuf;
+import org.apache.drill.common.config.DrillConfig;
+import org.apache.drill.exec.memory.BufferAllocator;
+import org.apache.drill.exec.memory.RootAllocatorFactory;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.ByteBufferReadable;
+import org.apache.hadoop.fs.FSDataInputStream;
+import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
+import org.apache.parquet.hadoop.Footer;
+import org.apache.parquet.hadoop.ParquetFileReader;
+import org.apache.parquet.hadoop.metadata.BlockMetaData;
+import org.apache.parquet.hadoop.metadata.ColumnChunkMetaData;
+import org.apache.parquet.hadoop.util.CompatibilityUtil;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.ByteBuffer;
+import java.util.List;
+
+/**
+ * <code>BufferedDirectBufInputStream</code> reads from the
+ * underlying <code>InputStream</code> in blocks of data, into an
+ * internal buffer. The internal buffer is a direct memory backed
+ * buffer. The implementation is similar to the
<code>BufferedInputStream</code>
+ * class except that the internal buffer is a Drillbuf and
+ * not a byte array. The mark and reset methods of the underlying
+ * <code>InputStream</code>are not supported.
+ */
+public class BufferedDirectBufInputStream extends DirectBufInputStream
implements Closeable {
+
+ private static final org.slf4j.Logger logger =
+
org.slf4j.LoggerFactory.getLogger(BufferedDirectBufInputStream.class);
+
+ private static int defaultBufferSize = 8192 * 1024; // 8 MiB
+ private static int defaultTempBufferSize = 8192; // 8 KiB
+
+ /**
+ * The internal buffer to keep data read from the underlying inputStream.
+ * <code>internalBuffer[0]</code> through <code>internalBuffer[count-1]
</code>
+ * contains data read from the underlying input stream.
+ */
+ protected volatile DrillBuf internalBuffer; // the internal buffer
+
+ /**
+ * The number of valid bytes in <code>internalBuffer</code>.
+ * <code> count </code> is always in the range
<code>[0,internalBuffer.capacity]</code>
+ * <code>internalBuffer[count-1]</code> is the last valid byte in the
buffer.
+ */
+ protected int count;
+
+ /**
+ * The current read position in the buffer; the index of the next
+ * character to be read from the <code>internalBuffer</code> array.
+ * <p>
+ * This value is always in the range <code>[0,count]</code>.
+ * If <code>curPosInBuffer</code> is equal to <code>count></code> then
we have read
+ * all the buffered data and the next read (or skip) will require more
data to be read
+ * from the underlying input stream.
+ */
+ protected int curPosInBuffer;
+
+ protected long curPosInStream; // current offset in the input stream
+
+ private final int bufSize;
+
+ private volatile DrillBuf tempBuffer; // a temp Buffer for use by
read(byte[] buf, int off, int len)
+
+
+ private DrillBuf getBuf() throws IOException {
+ checkInputStreamState();
+ if (internalBuffer == null) {
+ throw new IOException("Input stream is closed.");
+ }
+ return this.internalBuffer;
+ }
+
+ /**
+ * Creates a <code>BufferedDirectBufInputStream</code>
+ * with the default (8 MiB) buffer size.
+ */
+ public BufferedDirectBufInputStream(InputStream in, BufferAllocator
allocator, String id,
+ long startOffset, long totalByteSize, boolean enableHints) {
+ this(in, allocator, id, startOffset, totalByteSize, defaultBufferSize,
enableHints);
+ }
+
+ /**
+ * Creates a <code>BufferedDirectBufInputStream</code>
+ * with the specified buffer size.
+ */
+ public BufferedDirectBufInputStream(InputStream in, BufferAllocator
allocator, String id,
+ long startOffset, long totalByteSize, int bufSize, boolean
enableHints) {
+ super(in, allocator, id, startOffset, totalByteSize, enableHints);
+ Preconditions.checkArgument(bufSize >= 0);
+ // We make the buffer size the smaller of the buffer Size parameter or
the total Byte Size
+ // rounded to next highest pwoer of two
+ int bSize = bufSize < (int) totalByteSize ? bufSize : (int)
totalByteSize;
+ // round up to next power of 2
+ bSize--;
+ bSize |= bSize >>> 1;
+ bSize |= bSize >>> 2;
+ bSize |= bSize >>> 4;
+ bSize |= bSize >>> 8;
+ bSize |= bSize >>> 16;
+ bSize++;
+ this.bufSize = bSize;
+
+ }
+
+ @Override
+ public void init() throws UnsupportedOperationException, IOException {
+ super.init();
+ this.internalBuffer = this.allocator.buffer(this.bufSize);
+ this.tempBuffer = this.allocator.buffer(defaultTempBufferSize);
+ int bytesRead = getNextBlock();
+ if (bytesRead <= 0) {
+ throw new IOException("End of stream reached while initializing
buffered reader.");
+ }
+ }
+
+ /**
+ * Read one more block from the underlying stream.
+ * Assumes we have reached the end of buffered data
+ * Assumes it is being called from a synchronized block.
+ * returns number of bytes read or -1 if EOF
+ */
+ private int getNextBlock() throws IOException {
+ Preconditions.checkState(this.curPosInBuffer >= this.count,
+ "Internal error: Buffered stream has not been consumed and trying
to read more from underlying stream");
+ checkInputStreamState();
+ DrillBuf buffer = getBuf();
+ buffer.clear();
+ this.count = this.curPosInBuffer = 0;
+
+ // We *cannot* rely on the totalByteSize being correct because
+ // metadata for Parquet files is incorrect. So we read as
+ // much as we can up to the size of the buffer
+ //int bytesToRead = buffer.capacity() <= (totalByteSize + startOffset
- curPosInStream ) ?
+ // buffer.Capacity() :
+ // (int) (totalByteSize + startOffset - curPosInStream );
+ int bytesToRead = buffer.capacity();
+
+ ByteBuffer directBuffer = buffer.nioBuffer(curPosInBuffer,
bytesToRead);
+ // The DFS can return *more* bytes than requested if the capacity of
the buffer is greater.
+ // i.e 'n' can be greater than bytes requested which is pretty stupid
and violates
+ // the API contract; but we still have to deal with it. So we make
sure the size of the
+ // buffer is exactly the same as the number of bytes requested
+ int bytesRead = -1;
+ int nBytes = 0;
+ if (bytesToRead > 0) {
+ try {
+ nBytes = CompatibilityUtil.getBuf(getInputStream(), directBuffer,
bytesToRead);
+ } catch (Exception e) {
+ logger.error("Error reading from stream {}. Error was : {}",
this.streamId, e.getMessage());
+ }
+ if (nBytes > 0) {
+ buffer.writerIndex(nBytes);
+ this.count = nBytes + this.curPosInBuffer;
+ this.curPosInStream = getInputStream().getPos();
+ bytesRead = nBytes;
+ logger.trace(
+ "Stream: {}, StartOffset: {}, TotalByteSize: {}, BufferSize:
{}, BytesRead: {}, Count: {}, " +
+ "CurPosInStream: {}, CurPosInBuffer: {}",
+ this.streamId, this.startOffset, this.totalByteSize,
this.bufSize, bytesRead, this.count,
+ this.curPosInStream, this.curPosInBuffer);
+ }
+ }
+ return this.count - this.curPosInBuffer;
+ }
+
+ // Reads from the internal Buffer into the output buffer
+ // May read less than the requested size if the remaining data in the
buffer
+ // is less than the requested amount
+ private int readInternal(DrillBuf buf, int off, int len) throws
IOException {
+ // check how many bytes are available in the buffer.
+ int bytesAvailable = this.count - this.curPosInBuffer;
+ if (bytesAvailable <= 0) {
+ // read more
+ int bytesRead = getNextBlock();
+ if (bytesRead <= 0) { // End of stream
+ return -1;
+ }
+ }
+ bytesAvailable = this.count - this.curPosInBuffer;
+ //copy into output buffer
+ int copyBytes = bytesAvailable < len ? bytesAvailable : len;
+ getBuf().getBytes(curPosInBuffer, buf, off, copyBytes);
+ buf.writerIndex(off + copyBytes);
+ this.curPosInBuffer += copyBytes;
+
+ return copyBytes;
+ }
+
+ // Reads from the internal Buffer into the output buffer
+ // May read less than the requested size if the remaining data in the
buffer
+ // is less than the requested amount
+ // Does not make a copy but returns a slice of the internal buffer.
+ // Returns null if end of stream is reached
+ private DrillBuf readInternal(int off, int len) throws IOException {
+ // check how many bytes are available in the buffer.
+ int bytesAvailable = this.count - this.curPosInBuffer;
+ if (bytesAvailable <= 0) {
+ // read more
+ int bytesRead = getNextBlock();
+ if (bytesRead <= 0) { // End of stream
+ return null;
+ }
+ }
+ bytesAvailable = this.count - this.curPosInBuffer;
+ // return a slice as the output
+ int bytesToRead = bytesAvailable < len ? bytesAvailable : len;
+ DrillBuf newBuf = this.getBuf().slice(off, bytesToRead);
+ newBuf.retain();
+ return newBuf;
+ }
+
+ /**
+ * Implements the <code>read</code> method of <code>InputStream</code>.
+ * returns one more byte or -1 if end of stream is reached.
+ */
+ public synchronized int read() throws IOException {
+ if (this.count - this.curPosInBuffer <= 0) {
+ int bytesRead = getNextBlock();
+ // reached end of stream
+ if (bytesRead <= 0) {
+ return -1;
+ }
+ }
+ this.curPosInBuffer++;
+ return getBuf().nioBuffer().get() & 0xff;
+ }
+
+ /**
+ Has the same contract as {@link java.io.InputStream#read(byte[], int,
int)}
+ Except with DrillBuf
+ */
+ public synchronized int read(DrillBuf buf, int off, int len) throws
IOException {
+ checkInputStreamState();
+ Preconditions.checkArgument((off >= 0) && (len >= 0) &&
(buf.capacity()) >= (off + len));
+ int bytesRead = 0;
+ do {
+ int readStart = off + bytesRead;
+ int lenToRead = len - bytesRead;
+ int nRead = readInternal(buf, readStart, lenToRead);
+ if (nRead <= 0) {// if End of stream
+ if (bytesRead == 0) { // no bytes read at all
+ return -1;
+ } else {
+ return bytesRead;
+ }
+ } else {
+ bytesRead += nRead;
+ // If the last read caused us to reach the end of stream
+ // we are done
+ InputStream input = in;
+ if (input != null && input.available() <= 0) {
+ return bytesRead;
+ }
+ }
+ } while (bytesRead < len);
+ return bytesRead;
+ }
+
+
+ @Override public int read(byte[] b) throws IOException {
+ return b.length == 1 ? read() : read(b, (int) 0, b.length);
+ }
+
+
+ @Override public int read(byte[] buf, int off, int len) throws
IOException {
+ checkInputStreamState();
+ Preconditions.checkArgument((off >= 0) && (len >= 0) && (buf.length)
>= (off + len));
+ int bytesRead = 0;
+ if (len == 0) {
+ return 0;
+ }
+ DrillBuf byteBuf;
+ if(len <= defaultTempBufferSize){
+ byteBuf = tempBuffer;
+ } else {
+ byteBuf = this.allocator.buffer(len);
+ }
+ do {
+ int readStart = off + bytesRead;
+ int lenToRead = len - bytesRead;
+ int nRead = readInternal(byteBuf, readStart, lenToRead);
+ if (nRead <= 0) {// if End of stream
+ if (bytesRead == 0) { // no bytes read at all
+ return -1;
+ } else {
+ return bytesRead;
+ }
+ } else {
+ byteBuf.nioBuffer().get(buf, off + bytesRead, len - bytesRead);
+ byteBuf.clear();
+ bytesRead += nRead;
+ }
+ } while (bytesRead < len);
+
+ if(len > defaultTempBufferSize){
+ byteBuf.release();
+ }
+
+ return bytesRead;
+ }
+
+
+ /**
+ Has the same contract as {@link java.io.InputStream#skip(long)}
+ * Skips upto the next n bytes.
+ * Skip may return with less than n bytes skipped
+ */
+ @Override
+ public synchronized long skip(long n) throws IOException {
+ checkInputStreamState();
+ long bytesAvailable = this.count - this.curPosInBuffer;
+ long bytesSkipped = 0;
+ if (n <= 0) {
+ return 0;
+ }
+ if (bytesAvailable <= 0) {
+ checkInputStreamState();
+ bytesAvailable = getNextBlock();
+ if (bytesAvailable <= 0) { // End of stream
+ return 0;
+ }
+ }
+ bytesSkipped = bytesAvailable < n ? bytesAvailable : n;
+ this.curPosInBuffer += bytesSkipped;
+
+ return bytesSkipped;
+ }
+
+
+ @Override
+ public synchronized int available() throws IOException {
+ checkInputStreamState();
+ int bytesAvailable = this.count - this.curPosInBuffer;
+ int underlyingAvailable = getInputStream().available();
+ int available = bytesAvailable + underlyingAvailable;
+ if (available < 0) { // overflow
+ return Integer.MAX_VALUE;
+ }
+ return available;
+ }
+
+ @Override
+ public synchronized void mark(int readlimit) {
+ throw new UnsupportedOperationException("Mark/reset is not
supported.");
+ }
+
+ @Override
+ public synchronized void reset() throws IOException {
+ throw new UnsupportedOperationException("Mark/reset is not
supported.");
+ }
+
+ @Override
+ public boolean markSupported() {
+ return false;
+ }
+
+ /*
+ Returns the current position from the beginning of the underlying
input stream
+ */
+ public long getPos() throws IOException {
+ return curPosInBuffer+startOffset;
+ }
+
+ public boolean hasRemainder() throws IOException {
+ return available() > 0;
+ }
+
+ public void close() throws IOException {
+ DrillBuf buffer;
+ InputStream inp;
+ if ((inp = in) != null) {
+ in = null;
+ inp.close();
+ }
+ if ((buffer = this.internalBuffer) != null) {
+ synchronized (this) {
+ this.internalBuffer = null;
+ buffer.release();
+ }
+ }
+ if ((buffer = this.tempBuffer) != null) {
+ synchronized (this) {
+ this.tempBuffer = null;
+ buffer.release();
+ }
+ }
--- End diff --
Should the above be done within on synchronized block? What are we
synchronizing against? Multiple calls to close?
Can both internal buffer and tempBuffer be non-null? Should we release both
and set all buffers to nil? Can the nullity of buffer tell us that this stream
is closed?
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