Getting path to current document. Automation plugin

How to get path for current document? (C++ plugin)

I've used listener and getter - but I cannot see that information there.

I understand that there should be something in reverse of:

FullPathToAlias("... filename.psd", aliasValue);

error = sPSActionDescriptor->PutAlias(someDesc, keyFileReference, aliasValue);

but how to get someDesc if there are lots of document opened