ClickHouse/src/Analyzer/WindowFunctionsUtils.cpp

#include <Analyzer/WindowFunctionsUtils.h>

#include <Analyzer/IQueryTreeNode.h>
#include <Analyzer/InDepthQueryTreeVisitor.h>
#include <Analyzer/FunctionNode.h>

namespace DB
{

namespace ErrorCodes
{
    extern const int ILLEGAL_AGGREGATION;
}

namespace
{

class CollectWindowFunctionNodeVisitor : public ConstInDepthQueryTreeVisitor<CollectWindowFunctionNodeVisitor>
{
public:
    explicit CollectWindowFunctionNodeVisitor(QueryTreeNodes * window_function_nodes_)
        : window_function_nodes(window_function_nodes_)
    {}

    explicit CollectWindowFunctionNodeVisitor(String assert_no_window_functions_place_message_)
        : assert_no_window_functions_place_message(std::move(assert_no_window_functions_place_message_))
    {}

    void visitImpl(const QueryTreeNodePtr & node)
    {
        auto * function_node = node->as<FunctionNode>();
        if (!function_node || !function_node->isWindowFunction())
            return;

        if (!assert_no_window_functions_place_message.empty())
            throw Exception(ErrorCodes::ILLEGAL_AGGREGATION,
                "Window function {} is found {} in query",
                function_node->getName(),
                assert_no_window_functions_place_message);

        if (window_function_nodes)
            window_function_nodes->push_back(node);
    }

    static bool needChildVisit(const QueryTreeNodePtr &, const QueryTreeNodePtr & child_node)
    {
        return !(child_node->getNodeType() == QueryTreeNodeType::QUERY || child_node->getNodeType() == QueryTreeNodeType::UNION);
    }

private:
    QueryTreeNodes * window_function_nodes = nullptr;
    String assert_no_window_functions_place_message;
};

}

QueryTreeNodes collectWindowFunctionNodes(const QueryTreeNodePtr & node)
{
    QueryTreeNodes window_function_nodes;
    CollectWindowFunctionNodeVisitor visitor(&window_function_nodes);
    visitor.visit(node);

    return window_function_nodes;
}

void collectWindowFunctionNodes(const QueryTreeNodePtr & node, QueryTreeNodes & result)
{
    CollectWindowFunctionNodeVisitor visitor(&result);
    visitor.visit(node);
}

void assertNoWindowFunctionNodes(const QueryTreeNodePtr & node, const String & assert_no_window_functions_place_message)
{
    CollectWindowFunctionNodeVisitor visitor(assert_no_window_functions_place_message);
    visitor.visit(node);
}

}