public void Apply(HashSet <Fact> facts, HashSet <Fact> newFacts, HashSet <ulong> restrictedSymbols)
{
HashSet <ulong> variablesSet = new HashSet <ulong>();
foreach (Predicate pred in this.Body)
{
variablesSet.AddAll(pred.Ids.Where(id => id is ID.Variable).Select(id => ((ID.Variable)id).Value));
}
MatchedVariables variables = new MatchedVariables(variablesSet);
if (!this.Body.Any())
{
Option <Dictionary <ulong, ID> > h_opt = variables.CheckExpressions(this.Expressions);
if (h_opt.IsDefined)
{
Dictionary <ulong, ID> h = h_opt.Get();
Predicate predicate = this.Head.Clone();
for (int i = 0; i < predicate.Ids.Count; i++)
{
ID id = predicate.Ids[i];
if (id is ID.Variable)
{
ID value = h[((ID.Variable)id).Value];
predicate.Ids[i] = value;
}
}
newFacts.Add(new Fact(predicate));
}
}
var combined = new Combinator(variables, this.Body, this.Expressions, facts).Combine();
foreach (Dictionary <ulong, ID> h in combined)
{
Predicate predicate = this.Head.Clone();
bool unbound_variable = false;
for (int i = 0; i < predicate.Ids.Count; i++)
{
ID id = predicate.Ids[i];
if (id is ID.Variable)
{
bool isInDictionnary = h.TryGetValue(((ID.Variable)id).Value, out ID value);
predicate.Ids[i] = value;
// variables that appear in the head should appear in the body and constraints as well
if (value == null)
{
unbound_variable = true;
}
}
}
// if the generated fact has #authority or #ambient as first element and we're n ot in a privileged rule
// do not generate it
bool isRestrictedSymbol = false;
ID first = predicate.Ids.FirstOrDefault();
if (first != null && first is ID.Symbol)
{
if (restrictedSymbols.Contains(((ID.Symbol)first).Value))
{
isRestrictedSymbol = true;
}
}
if (!unbound_variable && !isRestrictedSymbol)
{
newFacts.Add(new Fact(predicate));
}
}
}
