find_action.h

#pragma once
 
#include <cgv/base/action.h>
 
namespace cgv {
        namespace base {
 
template <class X>
class find_action : public action
{
        X* x;
protected:
        std::vector<X*>& result;
public:
        find_action(std::vector<X*>& _result) : action(true,true), result(_result) {}
        void select(base_ptr p) {
                x = p->get_interface<X>();
        }
        bool begin()
        {
                if (x) {
                        result.push_back(x);
                        return true;
                }
                else
                        return false;
        }
        bool implements_action() const {
                return x != 0;
        }
};
 
template <class X>
void find_interface(base_ptr start, std::vector<X*>& result) {
        find_action<X> fa(result);
        traverser(fa).traverse(start);
}
 
template <class X, typename T>
bool ensure_by_find(X* start, T*& pointer, unsigned i = 0)
{
        if (pointer)
                return true;
 
        std::vector<T*> instances;
        cgv::base::find_interface<T>(base_ptr(start), instances);
        if (instances.empty())
                return false;
        pointer = instances[i < instances.size() ? i : instances.size() - 1];
        return true;
}
 
        }
}