llvm::Optional<Syntax> SyntaxParsingCache::lookUpFrom(const Syntax &Node,
size_t NodeStart,
size_t Position,
SyntaxKind Kind) {
if (nodeCanBeReused(Node, NodeStart, Position, Kind)) {
return Node;
}
// Compute the child's position on the fly
size_t ChildStart = NodeStart;
for (size_t I = 0, E = Node.getNumChildren(); I < E; ++I) {
llvm::Optional<Syntax> Child = Node.getChild(I);
if (!Child.hasValue() || Child->isMissing()) {
continue;
}
auto ChildEnd = ChildStart + Child->getTextLength();
if (ChildStart <= Position && Position < ChildEnd) {
return lookUpFrom(Child.getValue(), ChildStart, Position, Kind);
}
// The next child starts where the previous child ended
ChildStart = ChildEnd;
}
return llvm::None;
}
