overlay[local]

module;

/**

* A local predicate that always holds for the overlay variant and never holds for the base variant.

* This is used to define local predicates that behave differently for the base and overlay variant.

*/

private predicate isOverlay() { databaseMetadata("isOverlay", "true") }

private string getXmlFile(@xmllocatable locatable) {

exists(@location_default location, @file file | xmllocations(locatable, location) |

locations_default(location, file, _, _, _, _) and

files(file, result)

)

}

private string getXmlFileInBase(@xmllocatable locatable) {

not isOverlay() and

result = getXmlFile(locatable)

}

/**

* Holds if the given `file` was extracted as part of the overlay and was extracted by the HTML/XML

* extractor.

*/

private predicate overlayXmlExtracted(string file) {

isOverlay() and

exists(@xmllocatable locatable |

not files(locatable, _) and not xmlNs(locatable, _, _, _) and file = getXmlFile(locatable)

)

}

/**

* Holds if the given XML `locatable` should be discarded, because it is part of the overlay base

* and is in a file that was also extracted as part of the overlay database.

*/

overlay[discard_entity]

private predicate discardXmlLocatable(@xmllocatable locatable) {

exists(string file | file = getXmlFileInBase(locatable) |

overlayChangedFiles(file)

or

// The HTML/XML extractor is currently not incremental and may extract more files than those

// included in overlayChangedFiles.

overlayXmlExtracted(file)

)

}