public AmbientContextSuppressor() {
_savedScope = DbContextScope.GetAmbientScope();
// We're hiding the ambient scope but not removing its instance
// altogether. This is to be tolerant to some programming errors.
//
// Suppose we removed the ambient scope instance here. If someone
// was to start a parallel task without suppressing
// the ambient context and then tried to suppress the ambient
// context within the parallel task while the original flow
// of execution was still ongoing (a strange thing to do, I know,
// but I'm sure this is going to happen), we would end up
// removing the ambient context instance of the original flow
// of execution from within the parallel flow of execution!
//
// As a result, any code in the original flow of execution
// that would attempt to access the ambient scope would end up
// with a null value since we removed the instance.
//
// It would be a fairly nasty bug to track down. So don't let
// that happen. Hiding the ambient scope (i.e. clearing the CallContext
// in our execution flow but leaving the ambient scope instance untouched)
// is safe.
DbContextScope.HideAmbientScope();
}
public AmbientContextSuppressor()
{
_savedScope = DbContextScope.GetAmbientScope();
// We're hiding the ambient scope but not removing its instance
// altogether. This is to be tolerant to some programming errors.
//
// Suppose we removed the ambient scope instance here. If someone
// was to start a parallel task without suppressing
// the ambient context and then tried to suppress the ambient
// context within the parallel task while the original flow
// of execution was still ongoing (a strange thing to do, I know,
// but I'm sure this is going to happen), we would end up
// removing the ambient context instance of the original flow
// of execution from within the parallel flow of execution!
//
// As a result, any code in the original flow of execution
// that would attempt to access the ambient scope would end up
// with a null value since we removed the instance.
//
// It would be a fairly nasty bug to track down. So don't let
// that happen. Hiding the ambient scope (i.e. clearing the CallContext
// in our execution flow but leaving the ambient scope instance untouched)
// is safe.
DbContextScope.HideAmbientScope();
}
private static DbContextScope GetConfirmScope()
{
var scope = DbContextScope.GetAmbientScope();
if (scope == null)
{
throw new InvalidOperationException("No open DB Scope detected, did you forget to open one?");
}
return(scope);
}
public void Dispose() {
if (_disposed)
return;
if (_savedScope != null) {
DbContextScope.SetAmbientScope(_savedScope);
_savedScope = null;
}
_disposed = true;
}
public DbContextScope(ILocalCache cache, Func <ApiContext> apiContextCreator, ISettingsStorage settingsStorage)
{
_parentScope = GetAmbientScope();
if (_parentScope == null)
{
_contexts = new DbContexts(cache, apiContextCreator, settingsStorage);
}
else
{
_contexts = _parentScope._contexts;
_nested = true;
}
SetAmbientScope(this);
}
public void Dispose()
{
if (_disposed)
{
return;
}
if (_savedScope != null)
{
DbContextScope.SetAmbientScope(_savedScope);
_savedScope = null;
}
_disposed = true;
}
/// <summary>
/// Makes the provided 'dbContextScope' available as the the ambient scope via the CallContext.
/// </summary>
internal static void SetAmbientScope(DbContextScope newAmbientScope)
{
if (newAmbientScope == null)
{
throw new ArgumentNullException(nameof(newAmbientScope));
}
var current = GetIdentifier();
var id = newAmbientScope._instanceIdentifier;
if (current == id)
{
return;
}
// Store the new scope's instance identifier in the CallContext, making it the ambient scope
SetId(id);
// Keep track of this instance (or do nothing if we're already tracking it)
dbContextScopeInstances.GetValue(id, key => newAmbientScope);
}
/// <summary>
/// Makes the provided 'dbContextScope' available as the the ambient scope via the CallContext.
/// </summary>
internal static void SetAmbientScope(DbContextScope newAmbientScope) {
if (newAmbientScope == null)
throw new ArgumentNullException(nameof(newAmbientScope));
var current = GetIdentifier();
var id = newAmbientScope._instanceIdentifier;
if (current == id)
return;
// Store the new scope's instance identifier in the CallContext, making it the ambient scope
SetId(id);
// Keep track of this instance (or do nothing if we're already tracking it)
dbContextScopeInstances.GetValue(id, key => newAmbientScope);
}
public DbContextScope(ILocalCache cache, Func<ApiContext> apiContextCreator, ISettingsStorage settingsStorage) {
_parentScope = GetAmbientScope();
if (_parentScope == null)
_contexts = new DbContexts(cache, apiContextCreator, settingsStorage);
else {
_contexts = _parentScope._contexts;
_nested = true;
}
SetAmbientScope(this);
}