public virtual void TestDoubleBuffer()
{
EditsDoubleBuffer buf = new EditsDoubleBuffer(1024);
NUnit.Framework.Assert.IsTrue(buf.IsFlushed());
byte[] data = new byte[100];
buf.WriteRaw(data, 0, data.Length);
NUnit.Framework.Assert.AreEqual("Should count new data correctly", data.Length, buf
.CountBufferedBytes());
NUnit.Framework.Assert.IsTrue("Writing to current buffer should not affect flush state"
, buf.IsFlushed());
// Swap the buffers
buf.SetReadyToFlush();
NUnit.Framework.Assert.AreEqual("Swapping buffers should still count buffered bytes"
, data.Length, buf.CountBufferedBytes());
NUnit.Framework.Assert.IsFalse(buf.IsFlushed());
// Flush to a stream
DataOutputBuffer outBuf = new DataOutputBuffer();
buf.FlushTo(outBuf);
NUnit.Framework.Assert.AreEqual(data.Length, outBuf.GetLength());
NUnit.Framework.Assert.IsTrue(buf.IsFlushed());
NUnit.Framework.Assert.AreEqual(0, buf.CountBufferedBytes());
// Write some more
buf.WriteRaw(data, 0, data.Length);
NUnit.Framework.Assert.AreEqual("Should count new data correctly", data.Length, buf
.CountBufferedBytes());
buf.SetReadyToFlush();
buf.FlushTo(outBuf);
NUnit.Framework.Assert.AreEqual(data.Length * 2, outBuf.GetLength());
NUnit.Framework.Assert.AreEqual(0, buf.CountBufferedBytes());
outBuf.Close();
}
/// <summary>Flush ready buffer to persistent store.</summary>
/// <remarks>
/// Flush ready buffer to persistent store. currentBuffer is not flushed as it
/// accumulates new log records while readyBuffer will be flushed and synced.
/// </remarks>
/// <exception cref="System.IO.IOException"/>
protected internal override void FlushAndSync(bool durable)
{
if (fp == null)
{
throw new IOException("Trying to use aborted output stream");
}
if (doubleBuf.IsFlushed())
{
Log.Info("Nothing to flush");
return;
}
Preallocate();
// preallocate file if necessary
doubleBuf.FlushTo(fp);
if (durable && !shouldSkipFsyncForTests && !shouldSyncWritesAndSkipFsync)
{
fc.Force(false);
}
}
/// <exception cref="System.IO.IOException"/>
protected internal override void FlushAndSync(bool durable)
{
// EditLogOutputStream
System.Diagnostics.Debug.Assert(@out.GetLength() == 0, "Output buffer is not empty"
);
if (doubleBuf.IsFlushed())
{
Log.Info("Nothing to flush");
return;
}
int numReadyTxns = doubleBuf.CountReadyTxns();
long firstTxToFlush = doubleBuf.GetFirstReadyTxId();
doubleBuf.FlushTo(@out);
if (@out.GetLength() > 0)
{
System.Diagnostics.Debug.Assert(numReadyTxns > 0);
byte[] data = Arrays.CopyOf(@out.GetData(), @out.GetLength());
@out.Reset();
System.Diagnostics.Debug.Assert(@out.GetLength() == 0, "Output buffer is not empty"
);
backupNode.Journal(journalInfo, 0, firstTxToFlush, numReadyTxns, data);
}
}