/// <summary>
/// Increment shared instance id and return a process buffer with new Wpid
/// </summary>
/// <returns></returns>
public ProcessConfigRecord CreateNew()
{
using (var txn = Environment.BeginTransaction())
{
while (true)
{
// ReSharper disable once ImpureMethodCallOnReadonlyValueField
var newInsatnceId = unchecked ((uint)SharedRecord._processBuffer.InterlockedIncrementInt32(ProcessConfigRecord.SharedInstanceIdCounterOffset));
try
{
// We try to increment instance id instead of reuse existing
// At some point after running for very very long time it might overflow
// and start from zero again - this is fine.
if (_processDb.TryGet(txn, ref newInsatnceId, out BufferRef bufferRef))
{
continue;
}
bufferRef = Allocate(txn, 0, out var fromFreeList, null);
_processDb.Put(txn, newInsatnceId, bufferRef, TransactionPutOptions.NoOverwrite);
txn.Commit();
if (!fromFreeList)
{
Environment.Sync(true);
}
var result = _buckets[bufferRef];
if (fromFreeList)
{
// in Delete we clear the buffer after commit, there is small chance a process died after commit but before cleaning
result.Clear(0, result.Length);
}
else
{
Debug.Assert(result.IsFilledWithValue(0), "a new ProcessConfig buffer must be clean.");
}
result.WriteInt64(ProcessConfigRecord.WpidOffset, Wpid.Create(newInsatnceId));
var record = new ProcessConfigRecord(result);
return(record);
}
catch (Exception ex)
{
txn.Abort();
Trace.TraceError(ex.ToString());
throw;
}
}
}
}
public ProcessConfigStorage(string directoryPath)
: base(directoryPath, StartupConfig.ProcessConfigEnvFlags, default, ProcessConfigRecord.BufferSize,
1024L * 1024 * 1024) // 1GB is way too much but it takes no resources above actually used
{
// BRA dbs and _env are set in base class
// InstanceId -> BufferRef
_processDb = Environment.OpenDatabase("_processConfig",
new DatabaseConfig(DbFlags.Create | DbFlags.IntegerKey));
_buckets = new SharedMemoryBuckets(directoryPath, ProcessConfigRecord.BufferSize, 0);
using (var txn = Environment.BeginTransaction())
{
try
{
uint sharedInstanceId = 0;
if (_processDb.TryGet(txn, ref sharedInstanceId, out BufferRef sharedBufferRef))
{
txn.Abort();
}
else
{
sharedBufferRef = Allocate(txn, 0, out var fromFreeList, null);
_processDb.Put(txn, sharedInstanceId, sharedBufferRef, TransactionPutOptions.NoOverwrite);
txn.Commit();
if (!fromFreeList)
{
Environment.Sync(true);
}
}
SharedRecord = new ProcessConfigRecord(_buckets[sharedBufferRef]);
}
catch (Exception ex)
{
txn.Abort();
Trace.TraceError(ex.ToString());
throw;
}
}
}
public bool Delete(ProcessConfigRecord processConfigRecord)
{
if (!processConfigRecord.IsValid)
{
return(false);
}
using (var txn = Environment.BeginTransaction())
{
var wpid = processConfigRecord.Wpid;
// Debug.Assert(!IsWpidAlive(processConfigRecord));
uint insatnceId = wpid.InstanceId;
try
{
// We try to increment instance id instead of reuse existing
// At some point after running for very very long time it might overflow
// and start from zero again - this is fine.
if (!_processDb.TryGet(txn, ref insatnceId, out BufferRef bufferRef))
{
// was already deleted
// TODO (?) throw? review
txn.Abort();
return(false);
}
Free(txn, bufferRef);
_processDb.Delete(txn, insatnceId);
txn.Commit();
var db = _buckets[bufferRef];
db.Clear(0, db.Length);
return(true);
}
catch (Exception ex)
{
txn.Abort();
Trace.TraceError(ex.ToString());
throw;
}
}
}
