public void Recover()
{
string currentManifest;
using (var currentFile = storageContext.FileSystem.OpenForReading(storageContext.FileSystem.GetCurrentFileName()))
using (var reader = new StreamReader(currentFile))
{
currentManifest = reader.ReadToEnd();
}
if (string.IsNullOrEmpty(currentManifest))
{
throw new FormatException("CURRENT file should not be empty.");
}
log.Info("Current manifect is: {0}", currentManifest);
using (var manifestFile = storageContext.FileSystem.OpenForReading(currentManifest))
{
var logReader = new LogReader(manifestFile, true, 0, storageContext.Options.BufferPool);
var builder = new Builder(storageContext, this, current);
ulong? nextFileFromManifest = null;
ulong? lastSequenceFromManifest = null;
ulong? logNumberFromManifest = null;
ulong? prevLogNumberFromManifest = null;
Stream recordStream;
while (logReader.TryReadRecord(out recordStream))
{
VersionEdit edit;
using (recordStream)
{
edit = VersionEdit.DecodeFrom(recordStream);
}
if (log.IsDebugEnabled)
log.Debug("Read version edit with the following information:\r\n{0}", edit.DebugInfo);
if (edit.Comparator != storageContext.Options.Comparator.Name)
{
throw new InvalidOperationException(
string.Format("Decoded version edit comparator '{0}' does not match '{1}' that is currently in use.",
edit.Comparator, storageContext.Options.Comparator.Name));
}
builder.Apply(edit);
if (edit.NextFileNumber.HasValue)
{
nextFileFromManifest = edit.NextFileNumber;
}
if (edit.PrevLogNumber.HasValue)
{
prevLogNumberFromManifest = edit.PrevLogNumber;
}
if (edit.LogNumber.HasValue)
{
logNumberFromManifest = edit.LogNumber;
}
if (edit.LastSequence.HasValue)
{
lastSequenceFromManifest = edit.LastSequence;
}
}
if (nextFileFromManifest == null)
{
throw new ManifestFileException("No NextFileNumber entry");
}
if (logNumberFromManifest == null)
{
throw new ManifestFileException("No LogNumber entry");
}
if (lastSequenceFromManifest == null)
{
throw new ManifestFileException("No LastSequenceNumber entry");
}
if (prevLogNumberFromManifest == null)
{
prevLogNumberFromManifest = 0;
}
MarkFileNumberUsed(prevLogNumberFromManifest.Value);
MarkFileNumberUsed(logNumberFromManifest.Value);
var version = new Version(storageContext, this);
builder.SaveTo(version);
Version.Finalize(version);
AppendVersion(version);
ManifestFileNumber = nextFileFromManifest.Value;
NextFileNumber = nextFileFromManifest.Value + 1;
LastSequence = lastSequenceFromManifest.Value;
LogNumber = logNumberFromManifest.Value;
PrevLogNumber = prevLogNumberFromManifest.Value;
}
}
public async Task LogAndApplyAsync(VersionEdit edit, AsyncLock.LockScope locker)
{
string newManifestFile = null;
try
{
Version version;
using (await locker.LockAsync())
{
if (!edit.LogNumber.HasValue) edit.SetLogNumber(VersionSet.LogNumber);
else if (edit.LogNumber < VersionSet.LogNumber || edit.LogNumber >= VersionSet.NextFileNumber)
throw new InvalidOperationException("LogNumber");
if (!edit.PrevLogNumber.HasValue) edit.SetPrevLogNumber(VersionSet.PrevLogNumber);
edit.SetNextFile(VersionSet.NextFileNumber);
edit.SetLastSequence(VersionSet.LastSequence);
version = new Version(this, VersionSet);
var builder = new Builder(this, VersionSet, VersionSet.Current);
builder.Apply(edit);
builder.SaveTo(version);
Version.Finalize(version);
// Initialize new descriptor log file if necessary by creating
// a temporary file that contains a snapshot of the current version.
if (DescriptorLogWriter == null)
{
// No reason to unlock *mu here since we only hit this path in the
// first call to LogAndApply (when opening the database).
newManifestFile = FileSystem.DescriptorFileName(VersionSet.ManifestFileNumber);
edit.SetNextFile(VersionSet.NextFileNumber);
var descriptorFile = FileSystem.NewWritable(newManifestFile);
DescriptorLogWriter = new LogWriter(FileSystem, descriptorFile, Options.BufferPool);
Snapshooter.WriteSnapshot(DescriptorLogWriter, VersionSet);
}
}
// Write new record to MANIFEST log
edit.EncodeTo(DescriptorLogWriter);
// If we just created a new descriptor file, install it by writing a
// new CURRENT file that points to it.
if (!string.IsNullOrEmpty(newManifestFile))
{
SetCurrentFile(VersionSet.ManifestFileNumber);
// No need to double-check MANIFEST in case of error since it
// will be discarded below.
}
using (await locker.LockAsync())
{
// Install the new version
VersionSet.AppendVersion(version);
VersionSet.SetLogNumber(edit.LogNumber.Value);
VersionSet.SetPrevLogNumber(edit.PrevLogNumber.Value);
}
}
catch (Exception)
{
if (!string.IsNullOrEmpty(newManifestFile))
{
if (DescriptorLogWriter != null)
{
DescriptorLogWriter.Dispose();
DescriptorLogWriter = null;
}
FileSystem.DeleteFile(newManifestFile);
}
throw;
}
}
