internal void RollbackCommit(Directory dir)
{
if (pendingSegnOutput != null)
{
try
{
pendingSegnOutput.Close();
}
catch (System.Exception)
{
// Suppress so we keep throwing the original exception
// in our caller
}
// Must carefully compute fileName from "generation"
// since lastGeneration isn't incremented:
try
{
System.String segmentFileName = IndexFileNames.FileNameFromGeneration(IndexFileNames.SEGMENTS, "", generation);
dir.DeleteFile(segmentFileName);
}
catch (System.Exception)
{
// Suppress so we keep throwing the original exception
// in our caller
}
pendingSegnOutput = null;
}
}
internal void FinishCommit(Directory dir)
{
if (pendingSegnOutput == null)
{
throw new System.SystemException("prepareCommit was not called");
}
bool success = false;
try
{
pendingSegnOutput.FinishCommit();
pendingSegnOutput.Close();
pendingSegnOutput = null;
success = true;
}
finally
{
if (!success)
{
RollbackCommit(dir);
}
}
// NOTE: if we crash here, we have left a segments_N
// file in the directory in a possibly corrupt state (if
// some bytes made it to stable storage and others
// didn't). But, the segments_N file includes checksum
// at the end, which should catch this case. So when a
// reader tries to read it, it will throw a
// CorruptIndexException, which should cause the retry
// logic in SegmentInfos to kick in and load the last
// good (previous) segments_N-1 file.
System.String fileName = IndexFileNames.FileNameFromGeneration(IndexFileNames.SEGMENTS, "", generation);
success = false;
try
{
dir.Sync(fileName);
success = true;
}
finally
{
if (!success)
{
try
{
dir.DeleteFile(fileName);
}
catch (System.Exception)
{
// Suppress so we keep throwing the original exception
}
}
}
lastGeneration = generation;
try
{
IndexOutput genOutput = dir.CreateOutput(IndexFileNames.SEGMENTS_GEN);
try
{
genOutput.WriteInt(FORMAT_LOCKLESS);
genOutput.WriteLong(generation);
genOutput.WriteLong(generation);
}
finally
{
genOutput.Close();
}
}
catch (System.Exception)
{
// It's OK if we fail to write this file since it's
// used only as one of the retry fallbacks.
}
}
private void Write(Directory directory)
{
System.String segmentFileName = GetNextSegmentFileName();
// Always advance the generation on write:
if (generation == -1)
{
generation = 1;
}
else
{
generation++;
}
var segnOutput = new ChecksumIndexOutput(directory.CreateOutput(segmentFileName));
bool success = false;
try
{
segnOutput.WriteInt(CURRENT_FORMAT); // write FORMAT
segnOutput.WriteLong(++version); // every write changes
// the index
segnOutput.WriteInt(counter); // write counter
segnOutput.WriteInt(Count); // write infos
for (int i = 0; i < Count; i++)
{
Info(i).Write(segnOutput);
}
segnOutput.WriteStringStringMap(userData);
segnOutput.PrepareCommit();
success = true;
pendingSegnOutput = segnOutput;
}
finally
{
if (!success)
{
// We hit an exception above; try to close the file
// but suppress any exception:
try
{
segnOutput.Close();
}
catch (System.Exception)
{
// Suppress so we keep throwing the original exception
}
try
{
// Try not to leave a truncated segments_N file in
// the index:
directory.DeleteFile(segmentFileName);
}
catch (System.Exception)
{
// Suppress so we keep throwing the original exception
}
}
}
}