/// <summary>
/// Acquires the lock on the specified temporary table.
/// </summary>
/// <param name="context">The <see cref="EnumerationContext"/>.</param>
/// <param name="descriptor">The descriptor of temporary table.</param>
/// <returns>
/// A <see cref="IDisposable"/> implementor that should be used to free acquired lock.
/// </returns>
public IDisposable Acquire(EnumerationContext context, TemporaryTableDescriptor descriptor)
{
var name = descriptor.Name;
var session = context.Session;
var registry = GetRegistry(session);
bool isLocked;
if (!registry.States.TryGetValue(name, out isLocked))
{
backEnd.InitializeTable(context, descriptor);
}
else if (isLocked)
{
return(null);
}
registry.States[name] = true;
backEnd.AcquireTable(context, descriptor);
return(new Disposable(disposing => {
backEnd.ReleaseTable(context, descriptor);
registry.States[name] = false;
}));
}
protected void ExecuteNonQuery(EnumerationContext context, string statement)
{
var executor = context.Session.Services.Demand <ISqlExecutor>();
executor.ExecuteNonQuery(statement);
}
/// <summary> /// Releases the lock on a temporary table. /// </summary> public abstract void ReleaseTable(EnumerationContext context, TemporaryTableDescriptor descriptor);
/// <summary> /// Initializes the table. This is called once per session on a first acquire request. /// </summary> public abstract void InitializeTable(EnumerationContext context, TemporaryTableDescriptor descriptor);
public override void ReleaseTable(EnumerationContext context, TemporaryTableDescriptor descriptor)
{
}
public override void InitializeTable(EnumerationContext context, TemporaryTableDescriptor descriptor)
{
ExecuteNonQuery(context, descriptor.CreateStatement);
}
public override void ReleaseTable(EnumerationContext context, TemporaryTableDescriptor descriptor)
{
ExecuteNonQuery(context, descriptor.DropStatement);
}
public override void InitializeTable(EnumerationContext context, TemporaryTableDescriptor descriptor)
{
}
