* java/org/gnu/emacs/EmacsSafThread.java (EmacsSafThread, getCache) (pruneCache1, pruneCache, cacheChild, cacheDirectoryFromCursor) (documentIdFromName1, openDocumentDirectory1): Implement the cache referred to by the commentary. * java/org/gnu/emacs/EmacsService.java (deleteDocument): Invalidate the cache upon document removal. * src/androidvfs.c (android_saf_exception_check) (android_document_id_from_name): Correctly preserve or set errno in error cases.