private void StartProduction(
RequestExecutionContext context, RequestExecutionBuffer buffer, out IDriverDataEnumerator sourceEnumerator)
{
ReadRequest(context);
context.AttachContainerDescriptor(m_containerDescriptor);
if (!context.CacheInfo.HaveParsingResults)
{
lock (context.CacheInfo)
{
context.CacheInfo.CheckIsError();
if (!context.CacheInfo.HaveParsingResults)
{
try
{
ParseRequest(context.Request, context.RequestBulk, context.CacheInfo.ParsedRequest, context.CancellationTokenSource.Token);
CompileClauses(context.ContainerDescriptor, context.CacheInfo);
Thread.MemoryBarrier();
context.CacheInfo.HaveParsingResults = true;
}
catch (Exception e)
{
// make sure that partially complete results do not become visible
context.CacheInfo.IsError(e);
throw;
}
}
}
}
context.CacheInfo.WriteParsingResults(context.ParsedRequest);
if (context.ParsedRequest.SpecialCommand.IsSpecialCommand)
{
sourceEnumerator = null;
ExecuteSpecialCommandStatement(context, buffer);
return;
}
// structure of output buffer depends on which fields client is asking for
// therefore, we re-create and re-attach a driver output buffer for every request
context.AttachDriverOutputBufferAndInputParameters(
QueryParser.CreateDriverRowDataBuffer(context.ParsedRequest.BaseDataset.BaseFields),
context.ParsedRequest);
// this enumerator will yield our own driverOutputBuffer for every source record
// e.g. the very same context.DriverOutputBuffer is going to be yielded N times from this enumerator
if (context.ParsedRequest.StatementType == StatementType.Insert)
{
if (context.ParsedRequest.IsBulk)
{
sourceEnumerator = CreateInputDataEnumerator(context);
//m_storageDriver.AllocateCapacityForDocumentType(context.ParsedRequest.TargetEntity.DocumentType, context.RequestBulk.InputItemsCount);
}
else
{
sourceEnumerator = CreatePseudoEnumeratorForInsertValues(context);
}
}
else
{
if (context.ParsedRequest.IsBulk)
{
// for SELECT and DELETE, we only use PK values from the input enumerator
// for UPDATE, we use both PK values and other field values from input enumerator
context.AttachInputDataEnumerator(CreateInputDataEnumerator(context));
}
// driver returns set of rows related to given set of PK values
// for a bulk request, sourceEnumerator will yield exactly one item for each item in input enumerator
sourceEnumerator = m_storageDriver.GetData(context);
}
switch (context.ParsedRequest.StatementType)
{
case StatementType.Select:
{
context.AttachResponseHeaders(CreateResponseSchemeForSelect(context));
context.PrepareBuffersForSelect();
context.ResponseHeaders.RecordsAffected = 0;
}
break;
case StatementType.Update:
{
context.AttachResponseHeaders(new DataResponse(0, "Update successful"));
context.PrepareBuffersForUpdate();
ExecuteInsertUpdateStatement(context, buffer, sourceEnumerator, DriverChangeType.Update);
context.ResponseHeaders.RecordsAffected = context.RecordsAffected;
}
break;
case StatementType.Delete:
{
context.AttachResponseHeaders(new DataResponse(0, "Delete successful"));
context.PrepareBuffersForDelete();
ExecuteDeleteStatement(context, buffer, sourceEnumerator);
context.ResponseHeaders.RecordsAffected = context.RecordsAffected;
}
break;
case StatementType.Insert:
{
context.AttachResponseHeaders(new DataResponse(0, "Insert successful"));
context.PrepareChangeBufferForInsert();
ExecuteInsertUpdateStatement(context, buffer, sourceEnumerator, DriverChangeType.Insert);
context.ResponseHeaders.RecordsAffected = context.RecordsAffected;
}
break;
default:
throw new Exception("Invalid statement type: " + context.ParsedRequest.StatementType);
}
}