Github user markap14 commented on a diff in the pull request:
https://github.com/apache/nifi/pull/1202#discussion_r88708219
--- Diff:
nifi-nar-bundles/nifi-provenance-repository-bundle/nifi-persistent-provenance-repository/src/main/java/org/apache/nifi/provenance/serialization/CompressableRecordReader.java
---
@@ -0,0 +1,277 @@
+/*
+ * 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.nifi.provenance.serialization;
+
+import java.io.DataInputStream;
+import java.io.EOFException;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.charset.StandardCharsets;
+import java.util.zip.GZIPInputStream;
+
+import org.apache.nifi.provenance.ProvenanceEventRecord;
+import org.apache.nifi.provenance.StandardProvenanceEventRecord;
+import org.apache.nifi.provenance.StandardRecordReader;
+import org.apache.nifi.provenance.toc.TocReader;
+import org.apache.nifi.stream.io.BufferedInputStream;
+import org.apache.nifi.stream.io.ByteCountingInputStream;
+import org.apache.nifi.stream.io.LimitingInputStream;
+import org.apache.nifi.stream.io.StreamUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public abstract class CompressableRecordReader implements RecordReader {
+ private static final Logger logger =
LoggerFactory.getLogger(StandardRecordReader.class);
+
+ private final ByteCountingInputStream rawInputStream;
+ private final String filename;
+ private final int serializationVersion;
+ private final boolean compressed;
+ private final TocReader tocReader;
+ private final int headerLength;
+ private final int maxAttributeChars;
+
+ private DataInputStream dis;
+ private ByteCountingInputStream byteCountingIn;
+
+ public CompressableRecordReader(final InputStream in, final String
filename, final int maxAttributeChars) throws IOException {
+ this(in, filename, null, maxAttributeChars);
+ }
+
+ public CompressableRecordReader(final InputStream in, final String
filename, final TocReader tocReader, final int maxAttributeChars) throws
IOException {
+ logger.trace("Creating RecordReader for {}", filename);
+
+ rawInputStream = new ByteCountingInputStream(in);
+ this.maxAttributeChars = maxAttributeChars;
+
+ final InputStream limitedStream;
+ if (tocReader == null) {
+ limitedStream = rawInputStream;
+ } else {
+ final long offset1 = tocReader.getBlockOffset(1);
+ if (offset1 < 0) {
+ limitedStream = rawInputStream;
+ } else {
+ limitedStream = new LimitingInputStream(rawInputStream,
offset1 - rawInputStream.getBytesConsumed());
+ }
+ }
+
+ final InputStream readableStream;
+ if (filename.endsWith(".gz")) {
+ readableStream = new BufferedInputStream(new
GZIPInputStream(limitedStream));
+ compressed = true;
+ } else {
+ readableStream = new BufferedInputStream(limitedStream);
+ compressed = false;
+ }
+
+ byteCountingIn = new ByteCountingInputStream(readableStream);
+ dis = new DataInputStream(byteCountingIn);
+
+ final String repoClassName = dis.readUTF();
+ final int serializationVersion = dis.readInt();
+ headerLength =
repoClassName.getBytes(StandardCharsets.UTF_8).length + 2 + 4; // 2 bytes for
string length, 4 for integer.
+
+ this.serializationVersion = serializationVersion;
+ this.filename = filename;
+ this.tocReader = tocReader;
+
+ readHeader(dis, serializationVersion);
+ }
+
+ @Override
+ public void skipToBlock(final int blockIndex) throws IOException {
+ if (tocReader == null) {
+ throw new IllegalStateException("Cannot skip to block " +
blockIndex + " for Provenance Log " + filename + " because no Table-of-Contents
file was found for this Log");
+ }
+
+ if (blockIndex < 0) {
+ throw new IllegalArgumentException("Cannot skip to block " +
blockIndex + " because the value is negative");
+ }
+
+ if (blockIndex == getBlockIndex()) {
+ return;
+ }
+
+ final long offset = tocReader.getBlockOffset(blockIndex);
+ if (offset < 0) {
+ throw new IOException("Unable to find block " + blockIndex + "
in Provenance Log " + filename);
+ }
+
+ final long curOffset = rawInputStream.getBytesConsumed();
+
+ final long bytesToSkip = offset - curOffset;
+ if (bytesToSkip >= 0) {
+ try {
+ StreamUtils.skip(rawInputStream, bytesToSkip);
+ logger.debug("Skipped stream from offset {} to {} ({}
bytes skipped)", curOffset, offset, bytesToSkip);
+ } catch (final IOException e) {
+ throw new IOException("Failed to skip to offset " + offset
+ " for block " + blockIndex + " of Provenance Log " + filename, e);
+ }
+
+ resetStreamForNextBlock();
+ }
+ }
+
+ private void resetStreamForNextBlock() throws IOException {
+ final InputStream limitedStream;
+ if (tocReader == null) {
+ limitedStream = rawInputStream;
+ } else {
+ final long offset = tocReader.getBlockOffset(1 +
getBlockIndex());
+ if (offset < 0) {
+ limitedStream = rawInputStream;
+ } else {
+ limitedStream = new LimitingInputStream(rawInputStream,
offset - rawInputStream.getBytesConsumed());
+ }
+ }
+
+ final InputStream readableStream;
+ if (compressed) {
+ readableStream = new BufferedInputStream(new
GZIPInputStream(limitedStream));
+ } else {
+ readableStream = new BufferedInputStream(limitedStream);
+ }
+
+ byteCountingIn = new ByteCountingInputStream(readableStream,
rawInputStream.getBytesConsumed());
+ dis = new DataInputStream(byteCountingIn);
+ }
+
+
+ @Override
+ public TocReader getTocReader() {
+ return tocReader;
+ }
+
+ @Override
+ public boolean isBlockIndexAvailable() {
+ return tocReader != null;
+ }
+
+ @Override
+ public int getBlockIndex() {
+ if (tocReader == null) {
+ throw new IllegalStateException("Cannot determine Block Index
because no Table-of-Contents could be found for Provenance Log " + filename);
+ }
+
+ return tocReader.getBlockIndex(rawInputStream.getBytesConsumed());
+ }
+
+ @Override
+ public long getBytesConsumed() {
+ return byteCountingIn.getBytesConsumed();
+ }
+
+ private boolean isData() throws IOException {
+ byteCountingIn.mark(1);
+ int nextByte = byteCountingIn.read();
+ byteCountingIn.reset();
+
+ if (nextByte < 0) {
+ try {
+ resetStreamForNextBlock();
+ } catch (final EOFException eof) {
+ return false;
+ }
+
+ byteCountingIn.mark(1);
+ nextByte = byteCountingIn.read();
+ byteCountingIn.reset();
+ }
+
+ return nextByte >= 0;
+ }
+
+ @Override
+ public long getMaxEventId() throws IOException {
+ if (tocReader != null) {
+ final long lastBlockOffset = tocReader.getLastBlockOffset();
+ skipToBlock(tocReader.getBlockIndex(lastBlockOffset));
+ }
+
+ ProvenanceEventRecord record;
+ ProvenanceEventRecord lastRecord = null;
+ try {
+ while ((record = nextRecord()) != null) {
+ lastRecord = record;
+ }
+ } catch (final EOFException eof) {
+ // This can happen if we stop NIFi while the record is being
written.
+ // This is OK, we just ignore this record. The session will
not have been
+ // committed, so we can just process the FlowFile again.
+ }
+
+ return lastRecord == null ? -1L : lastRecord.getEventId();
+ }
+
+ @Override
+ public void close() throws IOException {
+ logger.trace("Closing Record Reader for {}", filename);
+
+ dis.close();
+ rawInputStream.close();
+
+ if (tocReader != null) {
+ tocReader.close();
+ }
+ }
--- End diff --
This is a good call. Pushed another commit to address.
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