How to use

concat

method

in

io.pravega.segmentstore.storage.rolling.RollingStorage

  AssertExtensions.assertThrows(
      "Unexpected error reported from concat.",
      () -> s.concat(targetHandle, initialTargetLength, sourceSegmentName),
      ex -> ex instanceof IntentionalException);
s.concat(targetHandle, initialTargetLength, sourceSegmentName);
checkConcatResult(s, targetHandle, sourceSegmentName, 1 + sourceHandle.chunks().size(), initialTargetLength + (int) sourceHandle.length());
checkWrittenData(writeStream.toByteArray(), s.openRead(SEGMENT_NAME), s);

/**
 * Tests the ability to concat using the header file for those cases when native concat cannot be used because the
 * source Segment has multiple SegmentChunks.
 */
@Test
public void testConcatHeaderMultiFile() throws Exception {
  final int initialTargetLength = (int) DEFAULT_ROLLING_POLICY.getMaxLength() / 2;
  final String sourceSegmentName = "SourceSegment";
  @Cleanup
  val baseStorage = new InMemoryStorage();
  @Cleanup
  val s = new RollingStorage(baseStorage, DEFAULT_ROLLING_POLICY);
  s.initialize(1);
  // Create a Target Segment and a Source Segment and write some data to them.
  s.create(SEGMENT_NAME);
  val targetHandle = (RollingSegmentHandle) s.openWrite(SEGMENT_NAME);
  val writeStream = new ByteArrayOutputStream();
  populate(s, targetHandle, 1, initialTargetLength, initialTargetLength, writeStream);
  s.create(sourceSegmentName);
  val sourceHandle = (RollingSegmentHandle) s.openWrite(sourceSegmentName);
  populate(s, sourceHandle, APPENDS_PER_SEGMENT, initialTargetLength, initialTargetLength, writeStream);
  s.seal(sourceHandle);
  // Concat and verify the handle has been updated accordingly.
  s.concat(targetHandle, initialTargetLength, sourceSegmentName);
  checkConcatResult(s, targetHandle, sourceSegmentName, 1 + sourceHandle.chunks().size(), initialTargetLength + (int) sourceHandle.length());
  checkWrittenData(writeStream.toByteArray(), s.openRead(SEGMENT_NAME), s);
}

AssertExtensions.assertThrows(
    "concat() allowed using a truncated segment as a source.",
    () -> s.concat(targetSegmentHandle, 0, SEGMENT_NAME),
    ex -> ex instanceof IllegalStateException);

/**
 * Tests the ability to use native concat for those cases when it's appropriate.
 */
@Test
public void testConcatNatively() throws Exception {
  final int initialTargetLength = (int) DEFAULT_ROLLING_POLICY.getMaxLength() / 2;
  final int initialSourceLength = (int) DEFAULT_ROLLING_POLICY.getMaxLength() - initialTargetLength;
  final String sourceSegmentName = "SourceSegment";
  @Cleanup
  val baseStorage = new InMemoryStorage();
  @Cleanup
  val s = new RollingStorage(baseStorage, DEFAULT_ROLLING_POLICY);
  s.initialize(1);
  // Create a target Segment and write a little data to it.
  s.create(SEGMENT_NAME);
  val targetHandle = (RollingSegmentHandle) s.openWrite(SEGMENT_NAME);
  val writeStream = new ByteArrayOutputStream();
  populate(s, targetHandle, 1, initialTargetLength, initialTargetLength, writeStream);
  // Create a source Segment and write a little data to it, making sure it is small enough to fit into the target
  // when we need to concat.
  s.create(sourceSegmentName);
  val sourceHandle = (RollingSegmentHandle) s.openWrite(sourceSegmentName);
  populate(s, sourceHandle, 1, initialSourceLength, initialSourceLength, writeStream);
  s.seal(sourceHandle);
  // Concat and verify the handle has been updated accordingly.
  s.concat(targetHandle, initialTargetLength, sourceSegmentName);
  checkConcatResult(s, targetHandle, sourceSegmentName, 1, initialTargetLength + initialSourceLength);
  checkWrittenData(writeStream.toByteArray(), s.openRead(SEGMENT_NAME), s);
}

/**
 * Tests the ability to concat using the header file for those cases when native concat cannot be used because the
 * source Segment has a single SegmentChunk, but it's too large to fit into the Target's active SegmentChunk.
 */
@Test
public void testConcatHeaderSingleFile() throws Exception {
  final int initialTargetLength = (int) DEFAULT_ROLLING_POLICY.getMaxLength() / 2;
  final int bigSourceLength = (int) DEFAULT_ROLLING_POLICY.getMaxLength() - initialTargetLength + 1;
  final String sourceSegmentName = "SourceSegment";
  @Cleanup
  val baseStorage = new InMemoryStorage();
  @Cleanup
  val s = new RollingStorage(baseStorage, DEFAULT_ROLLING_POLICY);
  s.initialize(1);
  // Create a Target Segment and a Source Segment and write some data to them.
  s.create(SEGMENT_NAME);
  val targetHandle = (RollingSegmentHandle) s.openWrite(SEGMENT_NAME);
  val writeStream = new ByteArrayOutputStream();
  populate(s, targetHandle, 1, initialTargetLength, initialTargetLength, writeStream);
  s.create(sourceSegmentName);
  val sourceHandle = (RollingSegmentHandle) s.openWrite(sourceSegmentName);
  populate(s, sourceHandle, 1, bigSourceLength, bigSourceLength, writeStream);
  s.seal(sourceHandle);
  // Concat and verify the handle has been updated accordingly.
  s.concat(targetHandle, initialTargetLength, sourceSegmentName);
  checkConcatResult(s, targetHandle, sourceSegmentName, 2, initialTargetLength + bigSourceLength);
  checkWrittenData(writeStream.toByteArray(), s.openRead(SEGMENT_NAME), s);
}

AssertExtensions.assertThrows(
    "Unexpected exception when doing native concat.",
    () -> s.concat(targetHandle, initialTargetLength, sourceSegmentName),
    ex -> ex instanceof IntentionalException);

baseStorage.create(nonHeaderName);
val nonHeaderHandle = s.openWrite(nonHeaderName);
s.concat(nonHeaderHandle, 0, segmentName);
Assert.assertFalse("NonHeader source still exists after concat to NonHeader Segment.", s.exists(segmentName));
checkWrittenData(writtenData, s.openRead(nonHeaderName), s);
s.seal(nonHeaderHandle);
val withHeaderHandle = s.openWrite(withHeaderName);
s.concat(withHeaderHandle, 0, nonHeaderName);
Assert.assertFalse("NonHeader source still exists after concat to Header Segment.", s.exists(nonHeaderName));
val h1 = (RollingSegmentHandle) s.openRead(withHeaderName);
s.concat(s.openWrite(nonHeaderName), 0, withHeaderName);
Assert.assertFalse("NonHeader source still exists after concat to Header Segment.", s.exists(withHeaderName));
val h2 = (RollingSegmentHandle) s.openRead(nonHeaderName);