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// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
/**
* @class document::select::Node
* @ingroup select
*
* @brief Base class for all nodes in the document selection tree.
*
* @author Håkon Humberset
*/
#pragma once
#include "resultlist.h"
#include "context.h"
#include "parser_limits.h"
namespace document::select {
class Visitor;
class Node : public Printable
{
protected:
vespalib::string _name;
uint32_t _max_depth;
bool _parentheses; // Set to true if parentheses was used around this part
// Set such that we can recreate original query in print.
public:
using UP = std::unique_ptr<Node>;
using SP = std::shared_ptr<Node>;
Node(vespalib::stringref name, uint32_t max_depth)
: _name(name), _max_depth(max_depth), _parentheses(false)
{
throw_parse_error_if_max_depth_exceeded();
}
explicit Node(vespalib::stringref name)
: _name(name), _max_depth(1), _parentheses(false)
{}
~Node() override = default;
// Depth is explicitly tracked to limit recursion to a sane maximum when building and
// processing ASTs, as the Bison framework does not have anything useful for us there.
// The AST is built from the leaves up towards the root, so we can cheaply track depth
// of subtrees in O(1) time per node by computing a node's own depth based on immediate
// children at node construction time.
[[nodiscard]] uint32_t max_depth() const noexcept { return _max_depth; }
void setParentheses() { _parentheses = true; }
void clearParentheses() { _parentheses = false; }
bool hadParentheses() const { return _parentheses; }
virtual ResultList contains(const Context&) const = 0;
virtual ResultList trace(const Context&, std::ostream& trace) const = 0;
virtual bool isLeafNode() const { return true; }
virtual void visit(Visitor&) const = 0;
virtual Node::UP clone() const = 0;
protected:
void throw_parse_error_if_max_depth_exceeded() const {
if (_max_depth > ParserLimits::MaxRecursionDepth) {
throw_max_depth_exceeded_exception();
}
}
Node::UP wrapParens(Node* node) const {
Node::UP ret(node);
if (_parentheses) {
ret->setParentheses();
}
return ret;
}
};
}
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