internal void Undo(Thread currentThread)
{
//
// Don't use an uninitialized switcher, or one that's already been used.
//
if (thread == null)
return; // Don't do anything
Contract.Assert(currentThread == this.thread);
//
// Restore the HostExecutionContext before restoring the ExecutionContext.
//
#if FEATURE_CAS_POLICY
if (hecsw != null)
HostExecutionContextSwitcher.Undo(hecsw);
#endif // FEATURE_CAS_POLICY
//
// restore the saved Execution Context. Note that this will also restore the
// SynchronizationContext, Logical/IllogicalCallContext, etc.
//
#if !FEATURE_PAL && FEATURE_IMPERSONATION
ExecutionContext.Reader innerEC = currentThread.GetExecutionContextReader();
#endif
currentThread.SetExecutionContext(outerEC, outerECBelongsToScope);
#if !MONO && DEBUG
try
{
currentThread.ForbidExecutionContextMutation = true;
#endif
//
// Tell the SecurityContext to do the side-effects of restoration.
//
#if FEATURE_IMPERSONATION || FEATURE_COMPRESSEDSTACK
if (scsw.currSC != null)
{
// Any critical failure inside scsw will cause FailFast
scsw.Undo();
}
#endif // #if FEATURE_IMPERSONATION || FEATURE_COMPRESSEDSTACK
#if !FEATURE_PAL && FEATURE_IMPERSONATION
if (wiIsValid)
SecurityContext.RestoreCurrentWI(outerEC, innerEC, wi, cachedAlwaysFlowImpersonationPolicy);
#endif
thread = null; // this will prevent the switcher object being used again
#if !MONO && DEBUG
}
finally
{
currentThread.ForbidExecutionContextMutation = false;
}
#endif
}
static internal void EstablishCopyOnWriteScope(Thread currentThread, bool knownNullWindowsIdentity, ref ExecutionContextSwitcher ecsw)
{
Contract.Assert(currentThread == Thread.CurrentThread);
ecsw.outerEC = currentThread.GetExecutionContextReader();
ecsw.outerECBelongsToScope = currentThread.ExecutionContextBelongsToCurrentScope;
#if !FEATURE_PAL && FEATURE_IMPERSONATION
ecsw.cachedAlwaysFlowImpersonationPolicy = SecurityContext.AlwaysFlowImpersonationPolicy;
if (knownNullWindowsIdentity)
Contract.Assert(SecurityContext.GetCurrentWI(ecsw.outerEC, ecsw.cachedAlwaysFlowImpersonationPolicy) == null);
else
ecsw.wi = SecurityContext.GetCurrentWI(ecsw.outerEC, ecsw.cachedAlwaysFlowImpersonationPolicy);
ecsw.wiIsValid = true;
#endif
currentThread.ExecutionContextBelongsToCurrentScope = false;
ecsw.thread = currentThread;
}
