builder_i.hpp

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#pragma once
 
#include "../query/builder_i.hpp"
 
namespace flecs {

template<typename Base, typename ... Components>
struct observer_builder_i : query_builder_i<Base, Components ...> {
    using BaseClass = query_builder_i<Base, Components ...>;
    observer_builder_i()
        : BaseClass(nullptr)
        , desc_(nullptr)
        , event_count_(0) { }

    observer_builder_i(ecs_observer_desc_t *desc)
        : BaseClass(&desc->query)
        , desc_(desc)
        , event_count_(0) { }

    Base& event(entity_t evt) {
        desc_->events[event_count_ ++] = evt;
        return *this;
    }

    template <typename E>
    Base& event() {
        desc_->events[event_count_ ++] = _::type<E>().id(world_v());
        return *this;
    }

    Base& yield_existing(bool value = true) {
        desc_->yield_existing = value;
        return *this;
    }

    Base& observer_flags(ecs_flags32_t flags) {
        desc_->flags_ |= flags;
        return *this;
    }

    Base& ctx(void *ptr) {
        desc_->ctx = ptr;
        return *this;
    }

    Base& run(ecs_iter_action_t action) {
        desc_->run = action;
        return *this;
    }
 
protected:
    virtual flecs::world_t* world_v() override = 0;
 
private:
    operator Base&() {
        return *static_cast<Base*>(this);
    }
 
    ecs_observer_desc_t *desc_;
    int32_t event_count_;
};
 
}