SecTransformActionBlock

Declaration

typealias SecTransformActionBlock = () -> Unmanaged<CFTypeRef>?

Return Value

A dictionary of the custom items to be exported if this block is used to override the kSecTransformActionExternalizeExtraData action or NULL for any other action. Alternatively, the block returns a CFError object if an error occurs.

Discussion

A block of this type is used to override the default behavior of a custom transform. This block is associated with the SecTransformOverrideTransformAction block.

The behaviors that can be overridden are:

• kSecTransformActionCanExecute - Determine if the transform has all of the data needed to run.

• kSecTransformActionStartingExecution - Called just before running ProcessData.

• kSecTransformActionFinalize - Called just before deleting the custom transform.

• kSecTransformActionExternalizeExtraData - Called to allow for writing out custom data to be exported.

For example:

SecTransformImplementationRef ref;
CFErrorRef error = NULL;
 
error = SecTransformSetTransformAction(ref, kSecTransformActionStartingExecution, ^{
    // Initialize any data needed before running
    CFErrorRef result = DoMyInitialization();
    return result;});
 
SecTransformTransformActionBlock actionBlock =
^{
    // Clean up any existing data before running
    CFErrorRef result = DoMyFinalization();
    return result;};
 
error = SecTransformSetTransformAction(ref, kSecTransformActionFinalize,actionBlock);